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Engine Controls/fuel - 2.0l - DTC p0340 Through DTC p2635 and Symptom Troubleshooting & Diagnosis Buick Regal V

Testing & Diagnostics ~39720 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Intake Camshaft Position Sensor 5 V ReferenceP0340, P0641P0340P0641P0341
Intake Camshaft Position Sensor Low ReferenceP0340
Intake Camshaft Position Sensor SignalP0340P0340P0340
Exhaust Camshaft Position Sensor 5 V ReferenceP0641P0365P0641P0366
Exhaust Camshaft Position Sensor Low ReferenceP0365
Exhaust Camshaft Position Sensor SignalP0365P0365P0365

Circuit/System Description

The 4 X camshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit, and an output signal circuit. The camshaft position sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the camshaft position sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with 4 varying width output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the camshaft position sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses camshaft position sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and for limp-home operation.

Conditions for Running the DTC

  1. The mass air flow (MAF) is greater than 3 grams per second.
  2. The engine is cranking or running.
  3. DTCs P0101, P0102, P0103, P0340 and P0365 run continuously when the above condition is met.

Conditions for Setting the DTC

P0340

The ECM does not receive 4 camshaft pulses within 3 s.

P0365

The ECM does not receive 4 camshaft pulses within 3 s.

Action Taken When the DTC Sets

DTC P0340, and P0365 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTC P0340, and P0365 are Type B DTCs.

Reference Information

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Engine idling, observe the scan tool Camshaft Position Active Counter parameter. The parameter should be incrementing.
  2. Engine idling, observe the DTC information with a scan tool. DTC P0340 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

  1. Engine idling, move the related harnesses/connectors of the B23 camshaft position sensor while monitoring the scan tool Camshaft Position Variance parameter. The Camshaft Position Variance parameter should not change when moving the harness/connectors. If the above condition exists, repair the harness/connectors, as necessary.
  2. Ignition OFF, inspect the B23 camshaft position sensor for correct installation. If the B23 camshaft position sensor is loose, inspect the sensor and the O-ring for damage and replace, as necessary.
  3. Ignition OFF, disconnect the harness connector at the B23 camshaft position sensor.
  4. Ignition OFF, all vehicle systems OFF, it may take 2 minutes for all systems to power down, test for less than 5 ohms between the appropriate low reference circuit terminal B and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, test for 4.8-5.2 V between the appropriate 5 V reference circuit terminal A and ground. If less than the specified range, test the 5 V reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Ignition ON, test for 4.8-5.2 V between the appropriate signal circuit terminal C and ground. If less than the specified range, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the affected signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  7. Ignition OFF, connect a 3 A fused jumper wire to the B23 camshaft position signal circuit terminal C.
  8. Ignition ON, momentarily touch the other end of the fused jumper wire to the battery negative post. The Camshaft Position Active Counter parameter on the scan tool should increment. If the Camshaft Position Active Counter increments, replace the B23 camshaft position sensor. If the Camshaft Position Active Counter does not increment, replace the K20 ECM.

Component Testing

Note. You must perform the Circuit/System Testing before proceeding with Component Testing.

  1. Inspect the camshaft position sensor for correct installation. Remove the B23 camshaft position sensor from the engine and inspect the sensor and the O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, repair or replace the B23 camshaft position sensor.
  2. Connect the sensor connector to the B23 camshaft position sensor.
  3. Ignition ON, and engine OFF. Observe the Camshaft Position Active Counter parameter on the scan tool. While passing a steel object by the tip of the sensor repeatedly. The Camshaft Position Active Counter parameter should increment. If the parameter does not increment, replace the B23 camshaft position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Camshaft Position Sensor Replacement - Exhaust»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Camshaft Position Sensor Replacement - Intake»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  3. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Intake Camshaft Position Sensor 5 V ReferenceP0641P0340P0641P0341
Intake Camshaft Position Sensor Low ReferenceP0340
Intake Camshaft Position Sensor SignalP0340P0340P0340
Exhaust Camshaft Position Sensor 5 V ReferenceP0641P0365P0641P0366
Exhaust Camshaft Position Sensor Low ReferenceP0365
Exhaust Camshaft Position Sensor SignalP0365P0365P0365

The 4 X camshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit, and an output signal circuit. The camshaft position sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the camshaft position sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with 4 varying width output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the camshaft position sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses camshaft position sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and for limp-home operation.

P0341 - Near Engine Start, Camshaft Position Fast Event Based Test

  1. The engine is cranking.
  2. The medium resolution is less than or equal to 10 counts.

P0341 - After Engine Start, Camshaft Position Slow Event Based Test

  1. The engine is running.
  2. DTCs P0335, P0336, and P0340 are not set.
  3. DTC P0341 runs continuously when the above conditions are met.

P0366 - Near Engine Start, Camshaft Position Fast Event Based Test

  1. The engine is cranking.
  2. The medium resolution is less than or equal to 10 counts.

P0366 - After Engine Start, Camshaft Position Slow Event Based Test

  1. The engine is running.
  2. DTCs P0335, P0336, and P0365 are not set.
  3. DTC P0366 runs continuously when the above conditions are met.

P0341 - Near Engine Start, Camshaft Position Fast Event Based Test

The ECM detects the incorrect number of camshaft position sensor pulses in 2 revolutions of the crankshaft, which is usually within 1 s.

P0341 - After Engine Start, Camshaft Position Slow Event Based Test

The ECM detects the incorrect number of camshaft position sensor pulses in 2, 000 revolutions of the crankshaft, which is usually within 4 min.

P0366 - Near Engine Start, Camshaft Position Fast Event Based Test

The ECM detects the incorrect number of camshaft position sensor pulses in 2 revolutions of the crankshaft, which is usually within 1 s.

P0366 - After Engine Start, Camshaft Position Slow Event Based Test

The ECM detects the incorrect number of camshaft position sensor pulses in 2, 000 revolutions of the crankshaft, which is usually within 4 min.

DTCs P0341 and P0366 are Type B DTCs.

DTCs P0341 and P0366 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, inspect the engine wiring harnesses carrying the camshaft position sensor circuits for the following conditions: Close routing of aftermarket electrical equipment Close to solenoids, motors, and relays Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference.
  2. Engine idling, observe the scan tool Camshaft Position Active Counter parameters. Both parameters should be incrementing.
  3. Engine idling, observe the DTC information with a scan tool. DTC P0340 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, inspect the B23 camshaft position sensor for correct installation. If the sensor is loose, inspect the sensor and the O-ring for damage, replace as necessary.
  2. Inspect the engine for the following conditions: The engine oil for debris The camshaft reluctor wheel for damage The timing chain, tensioner, and sprockets for wear or damage If debris is found in the engine oil, inspect the internal engine components to determine the cause. Repair or replace any worn or damaged components. Refer to «Camshaft Timing Chain and Sprocket Cleaning and Inspection (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__camshaft-timing-chain-and-sprocket-cleaning) , and «Camshaft Cleaning and Inspection (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__camshaft-cleaning-and-inspection-ldk-lhu) .

Note. You must perform the Circuit/System Testing before proceeding with Component Testing.

  1. Inspect the B23 camshaft position sensor for correct installation. Remove the B23 camshaft position sensor from the engine and inspect the sensor and the O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, repair or replace the B23 camshaft position sensor.
  2. Connect the connector to the B23 camshaft position sensor. Turn ON the ignition, with the engine OFF.
  3. Ignition ON, and engine OFF. Observe the Camshaft Position Active Counter parameter on the scan tool. Pass a steel object by the tip of the sensor repeatedly. The Camshaft Position Active Counter parameter should increment. If the parameter does not increment, replace the B23 camshaft position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Camshaft Position Sensor Replacement - Exhaust»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Camshaft Position Sensor Replacement - Intake»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  3. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to Voltage
Ignition Coil 1 Control CircuitP2300P0351P0351P2301
Ignition Coil 2 Control CircuitP2303P0352P0352P2304
Ignition Coil 3 Control CircuitP2306P0353P0353P2307
Ignition Coil 4 Control CircuitP2309P0354P0354P2310

The ignition system uses individual ignition coil/module assemblies for each cylinder. The engine control module (ECM) controls the individual coils by transmitting timing pulses on the ignition control (IC) circuit of each ignition coil/module to enable a spark event. When the engine is running the ECM monitors each IC circuit for improper voltage levels.

Conditions for Running the DTCs

  1. The engine speed is less than 6, 000 RPM.
  2. The ignition 1 voltage signal is between 9-18 V.
  3. DTCs P0351, P0352, P0353, P0354 run continuously when the above conditions are met.

Conditions for Setting the DTCs

The ECM detects an open in the circuit or the ignition coil/module for greater than 4 seconds continuously or 50 seconds cumulative.

DTCs P0351, P0352, P0353, P0354 are Type B DTCs.

DTCs P0351, P0352, P0353, P0354 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine running, observe the following scan tool control circuit status parameters for the appropriate cylinder T8 ignition coil: Ignition Coil 1-4 Control Circuit Low Voltage Test Status Ignition Coil 1-4 Control Circuit Open Test Status Ignition Coil 1-4 Control Circuit High Voltage Test Status Each parameter should display Not Run or OK.
  2. Engine idling, observe the DTC information with a scan tool. DTC P0351, P0352, P0353, or P0354 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the appropriate T8 ignition coil.
  2. Ignition OFF, all vehicle systems OFF, it may take up to 2 minutes for all the systems to power down, test for less than 5 ohms between the ground circuit terminal A and ground. If greater than the specified range, repair the ground circuit for an open/high resistance.
  3. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground. If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
  5. Engine running, observe the Ignition Coil 1-4 Control Circuit Low Voltage Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Malfunction test for open or short to ground.
  6. Engine running, observe the Ignition Coil 1-4 Control Circuit Open Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Malfunction test for open circuit.
  7. Engine running, observe the Ignition Coil 1-4 Control Circuit High Voltage Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Malfunction test for short to voltage.
  8. If all circuits test normal, test or replace the T8 ignition coil.
  1. «Ignition Coil Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Repair Verification

If the customer concern was a flashing MIL, then perform the following procedure

  1. Install any components that have been removed or replaced during diagnosis.
  2. Perform any adjustments, programming or setup procedures that are required when a component is removed or replaced.
  3. Clear the DTCs.
  4. Turn OFF the ignition for 60 seconds.
  5. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and perform the appropriate diagnostic procedure.
  6. To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair Verification for DTC P0420. Refer to «DTC P0420»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Note. A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 h may correct the condition.

A 3-way catalytic converter controls emissions by converting hydrocarbons and CO into CO2, and NOx into nitrogen. The 3-way catalytic converter also stores oxygen. When the listed driving conditions are met, the Catalyst System Efficiency test will run. The ECM monitors this oxygen storage capacity by comparing the pre and post-catalyst oxygen sensor signals while adding and subtracting fuel during specific driving conditions. The ECM compares the pre and post-catalyst oxygen sensor signals to determine if the oxygen storage capacity of the catalyst is degraded.

  1. DTC P0016, P0017, P0030, P0036, P0053, P0054, P0068, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P0140, P0141, P0171, P0172, P0191, P0192, P0193, P0222, P0223, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0340, P0341, P0365, P0366, P0443, P0506, P0507, P0606, P0697, P06A3, P16F3, P2101, P2122, P2123, P2127, P2128, P2135, P2138, P2227, P2228, P2229, P2230, P2270, P2271, P228C, P228D, P2A00 is not set.
  2. The engine speed is greater than 1125 RPM for 20 s since end of last idle period.
  3. The vehicle is in Drive on an automatic transmission vehicle.
  4. The vehicle speed is less than 1.2 MPH.
  5. The battery voltage is greater than 11 V.
  6. Closed Loop fueling is enabled.
  7. The Intake Air Temperature (IAT) is greater than -20°C (-4°F).
  8. The calculated exhaust mass gas flow is between 2-12 g/s, and stable.
  9. The calculated catalyst temperature is between 400-700°C (852-1, 382°F), and stable.
  10. The Barometric Pressure (BARO) is greater than 70 kPa (10.2 psi).
  11. The Engine Coolant Temperature (ECT) is between 40-140°C (104-284°F).
  12. The diagnostic attempts one test during each period when the above conditions have been met and may attempt up to 8 tests during each drive cycle.

The ECM has detected that the catalyst efficiency has degraded below a calibrated threshold.

DTC P0420 is a Type A DTC.

DTC P0420 is a Type A DTC.

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Heated Oxygen Sensor Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__heated-oxygen-sensor-wiring-repairs)

DTC Types Reference

Scan Tool Reference

Control Module References for scan tool information

Note. A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 h may correct the condition.

  1. If any other DTCs are set, perform those diagnostics first.
  2. Inspect for the following conditions, which may cause a catalytic converter to degrade: An engine misfire High engine oil or high coolant consumption Retarded spark timing A weak or poor spark A lean fuel mixture A rich fuel mixture A damaged oxygen sensor or wiring harness The catalyst test may abort if the vehicle falls outside the conditions for running the DTC. A catalyst may be temporarily degraded if a fuel with high sulfur content has been used. Drive the vehicle at highway speeds for 10 minutes and retest the converter.
  3. Operate the vehicle within the Conditions for Running the DTC. If the DTC fails this key cycle, continue with this procedure.
  4. Inspect the catalytic converter for the following conditions: Dents A severe discoloration caused by excessive temperatures Road damage An internal rattle caused by damaged catalyst substrate Restrictions If a condition is found, replace the catalytic converter.
  5. Inspect the exhaust system for the following conditions: Leaks Physical damage Loose or missing hardware Properly torqued B52B HO2S Restrictions If a condition is found, repair the exhaust system.
  6. Inspect the post catalyst B52B HO2S for the following conditions: A grounded wiring harness Damage If a condition is found, replace the post catalyst B52B HO2S. If no physical condition is detected, replace the catalytic converter.

Note. A new converter with less than 161 kilometers (100 miles) on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 h may correct the condition.

  1. «Restricted Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system)
  2. «Exhaust Leakage»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system__exhaust-leakage)
  3. «Catalytic Converter Replacement (L4)»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system) , «Catalytic Converter Replacement (LDK or LHU)»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system)
  4. «Heated Oxygen Sensor Replacement - Sensor 2»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  1. Clear the DTCs.
  2. Operate the vehicle within the Conditions for Running and Setting for at least 10 minutes
  3. Stop the vehicle.
  4. Engine OFF, allow the ECM to power down.
  5. Operate the vehicle within the Conditions for Running and Setting for at least 10 minutes. DTC P0420 should run and pass.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine off natural vacuum (EONV) test is the small leak detection diagnostic for the evaporative emission system. This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met. Heat from the exhaust system is transferred into the fuel tank while the vehicle is operating. When the vehicle is turned OFF and the EVAP system is sealed a change in the fuel tank vapor temperature occurs which results in a corresponding pressure change in the fuel tank vapor space. This change is monitored by the ECM using the fuel tank pressure sensor input. With a leak in the system, the amount of pressure change will be less than that of a sealed system.

  1. DTCs P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0222, P0223, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0461, P0462, P0463, P0464, P0496, P0502, P0503, P0608, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
  2. The ignition 1 voltage is between 10-16 V.
  3. The barometric pressure (BARO) is greater than 74 kPa.
  4. No fuel filling during the EONV test period.
  5. The fuel level is between 15-85 percent.
  6. The start-up engine coolant temperature (ECT) and the start-up intake air temperature (IAT) are between 0-40°C (32-104°F).
  7. The barometric pressure (BARO) is more than 74 kPa.
  8. The engine run time before engine shut-off was greater than 10 min.
  9. The drive distance before engine shut-off was more than 5 kilometers (3.1 miles).
  10. The ignition is OFF.
  11. The ambient air temperature at the end of the drive cycle is between 0-32°C (32-93°F).
  12. DTC P0442 runs once per drive cycle during the hot soak period after the ignition is turned OFF and may require up to 45 min to complete. The controller will not make more than 2 test attempts per day. The time since the last completed EONV test must be at least 17 hours.
  1. The ECM detects a leak in the EVAP system that is greater than a calibrated amount.
  2. The ECM must complete several EONV tests before the diagnostic can turn the MIL ON or OFF.

DTC P0442 is a Type A DTC.

Conditions for Clearing the DTC

DTC P0442 is a Type A DTC.

Diagnostic Aids

  1. The evaporative emission system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. When injecting smoke at the service port tool temporarily leave the EVAP vent solenoid valve open until smoke is observed then close the system and continue testing.
  2. To help locate intermittent leaks using the EN 41413-A EEST, move all evaporative emission components while observing smoke with the EN 41413-SPT White Light.
  3. Individual components can be isolated and tested using adapters in the EN 41413-300 Kit.
  4. A condition may exist where a leak in the evaporative emission system only exists under a vacuum condition. This type of leak may be detected by using the scan tool Purge/Seal function to create a vacuum in the evaporative emission system and then observe the fuel tank pressure parameter for vacuum decay.

DTC Type Reference

Description and Operation

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 48096 EVAP Service Port Access Tool
  2. EN 41413 A Evaporative Emissions System Tester (EEST)
  3. EN 41413 300 EVAP Cap and Plug Kit
  4. EN 41413 SPT High Intensity White Light

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) .

Note. Refer to the EN 41413-A EEST operation manual for detailed instructions in Evaporative Emission Control System Description . Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Ensure that the underbody temperature of the vehicle and the tester are similar.

  1. Disconnect the purge tube at the quick connector on the evaporative emission canister side of the Q12 evaporative emission canister purge solenoid valve and install the CH 48096 Port Tool.
  2. Connect the EN 41413-A EEST to the CH 48096 Port Tool.
  3. Using a scan tool close the evaporative emission canister vent solenoid valve to seal the evaporative emission system.
  4. Use the flow meter on the EN 41413-A EEST, calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the evaporative emission system. If a leak is detected, use the EN 41413-A EEST to apply smoke to the evaporative emission system at the purge tube until the leak is located using the EN 41413-SPT White Light.
  1. Seal the EVAP system and use the flow meter on the EN 41413-A EEST, calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
  2. Clear DTCs.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Ignition 1 Voltage - Purge SupplyP0443P0443P0443
Battery Positive - Vent SupplyP0449P0449P0449
Evaporative Emission Purge Solenoid Valve ControlP0443P0443P0443P0443
Evaporative Emission Vent Solenoid Valve ControlP0449P0449P0449P0449

An ignition voltage is supplied directly to the evaporative emission (EVAP) purge solenoid valve. The engine control module (ECM) grounds the (EVAP) purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The (EVAP) purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.

Battery voltage is supplied to the (EVAP) vent solenoid valve. The ECM grounds the (EVAP) vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the (EVAP) vent solenoid valve as Venting and Not Venting.

  1. The ignition is ON.
  2. The system voltage is greater than 11 V.
  3. DTCs P0443 and P0449 run continuously when the above conditions are met.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 s.

DTCs P0443 and P0449 are Type B DTCs.

DTCs P0443 and P0449 are Type B DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Troubleshooting with a Test Lamp»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__troubleshooting-with-a-test-lamp)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

P0443

  1. Ignition ON, engine OFF, you should hear a clicking sound when the (EVAP) purge solenoid valve is commanded to 50 % with a scan tool. The clicking sound should stop when the (EVAP) purge solenoid valve is commanded to 0 %. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
  2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

P0449

  1. Ignition ON, engine OFF, command the (EVAP) vent solenoid to Venting and Not Venting with a scan tool. Listen for a click when the valve operates.
  2. Verify that both the Venting and the Not Venting states are commanded with a scan tool while observing their parameter status. EVAP Vent Solenoid Circuit Short To Ground Test Status EVAP Vent Solenoid Circuit Open Test Status EVAP Vent Solenoid Circuit Short To Voltage Test Status Their parameter status should display OK or Not Run
  3. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the, Q 12 evaporative emission purge solenoid valve for P0443 Q 13 evaporative emission vent solenoid valve for P0449
  2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal and ground. If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the, EVAP purge solenoid valve for P0443 EVAP vent solenoid valve for P0449
  3. Connect a test lamp between the voltage supply circuit terminal and the control circuit terminal.
  4. With a scan tool command the, EVAP purge solenoid valve to 50 % EVAP vent solenoid valve to Venting and Not Venting The test lamp should respond to the command. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. If all circuits test normal, replace the appropriate solenoid valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Evaporative Emission Canister Vent Solenoid Valve Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  3. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Typical Scan Tool Data

Fuel Tank Pressure Sensor Signal VoltageFuel Tank Pressure
1.5 VAtmospheric Pressure/BARO
Less than 1.5 VPositive Pressure
More than 1.5 VNegative Pressure/Vacuum

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path that would cause excess amounts of vacuum to be developed in the EVAP system. With the purge valve open and the canister vent valve open, if the EVAP system vacuum goes above a calibrated threshold, the test will fail.

  1. DTCs P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0442, P0443, P0449, P0451, P0452, P0453, P0454, P0464, P0496, P0608, P0609, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
  2. The ignition voltage is between 11-18 V.
  3. The barometric pressure (BARO) is more than 65 kPa.
  4. The fuel level is between 11-88 %.
  5. DTC P0446 runs once per cold start when the above conditions are met.
  1. The fuel tank vacuum is greater than -12 in. H2O vacuum for 5 s. OR
  2. The fuel tank pressure is less than -2.5 in. H2O or more than +5 in. for 60 s after a cold start.

DTC P0446 is a Type B DTC.

DTC P0446 is a Type B DTC.

  1. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system may also cause a poor fuel fill condition.
  2. An EVAP canister filter that is restricted can cause this DTC to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  3. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON and fuel cap removed, verify that the Fuel Tank Pressure Sensor parameter is between 1.3-1.7 volts. If not within the specified range, go to the fuel tank pressure sensor section in Circuit/System Testing.
  2. Install the fuel cap.
  3. With the engine running, the EVAP canister vent solenoid valve open, use a scan tool to command the EVAP canister purge solenoid valve to 100 percent. The fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O). If the fuel tank vacuum is greater than the specified range, go to the restriction section in Circuit/System Testing.
  4. Using the scan tool, decrease the canister purge duty cycle from 100 percent to 0 percent. The vacuum should decrease to near zero. If the fuel tank vacuum does not return to zero or appears to decrease too slowly go to the restriction section in Circuit/System Testing.
  5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Note. Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

Restriction

  1. With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O). If the fuel tank vacuum is greater than the specified value, isolate the restriction by disconnecting one component at a time while the EVAP canister purge solenoid valve is commanded to 100 percent and the vent valve is open.
  2. Using the scan tool, decrease the canister purge duty cycle from 100 percent to 0 percent. The vacuum should decrease to near zero. If the fuel tank vacuum does not return to zero, or appears to decrease too slowly, inspect the components in the EVAP vent system for a restriction.

Fuel Tank Pressure Sensor

  1. Ignition OFF, disconnect the harness connector at the fuel tank pressure sensor.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the fuel tank pressure sensor.
  1. «Evaporative Emission Canister Vent Solenoid Valve Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Evaporative Emission Canister Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  3. «Fuel Tank Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  4. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references)

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

With the engine running, the EVAP canister vent solenoid valve open and the EVAP canister purge solenoid valve commanded to 100 %, the fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O).

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Fuel Tank Pressure Sensor 5 V ReferenceP0452, P0532, P0641P0451P0446, P0452P0453, P0641
Fuel Tank Pressure Sensor SignalP0452P0451P0452P0453P0451, P0454
Fuel Tank Pressure Sensor Low ReferenceP0446, P0451P0446P0451
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, Engine OFF Parameter Normal Range: 1.3-1.7 V
Fuel Tank Pressure Sensor 5 V Reference0 V0 V4.2-5 V
Fuel Tank Pressure Sensor Signal0 V0 V5 V
Fuel Tank Pressure Sensor Low Reference4.5 V

Fuel Tank Pressure Sensor Voltage

The fuel tank pressure sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The engine control module (ECM) supplies a 5 V reference and a low reference circuit to the fuel tank pressure sensor. The fuel tank pressure sensor signal voltage varies depending on EVAP system pressure or vacuum. The controller also uses this fuel tank pressure signal to determine atmospheric pressure for use in the engine-off small leak test, DTC P0442. Before using this signal as an atmospheric reference it must first be re-zeroed.

P0451

  1. DTC P0451 runs only when the engine-off natural vacuum small leak test, P0442, executes.
  2. The number of times this test runs can range from 0-2 per engine-off period. The length of the test can be up to 10 minutes.

P0452 and P0453

DTC P0452 and P0453 run continuously when the ignition is ON.

P0454

  1. DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes.
  2. This test can run once per engine-off period. The length of the test can be up to 10 minutes.
  3. A refueling event is not detected.

P0451

This DTC will set if the controller is unable to re-zero the fuel tank pressure sensor voltage within a calibrated range during the engine-off small leak test, P0442.

P0452

The fuel tank pressure sensor voltage is less than 0.1 V for more than 5 seconds.

P0453

The fuel tank pressure sensor voltage is more than 4.9 V for more than 5 seconds.

P0454

If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt fuel tank pressure signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of 0.45 inch H2O in the span of 1 second.

  1. DTCs P0451 and P0454 are Type A DTCs.
  2. DTCs P0452 and P0453 are Type B DTCs.
  1. DTCs P0451 and P0454 are Type A DTCs.
  2. DTCs P0452 and P0453 are Type B DTCs.

P0451 and P0454

  1. A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
  2. Ensure that the reference port on the fuel tank pressure sensor is unobstructed.
  3. An fuel tank pressure sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 EEST while taking a snapshot.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 41413-200 Evaporative Emission System Tester (EEST)

  1. Remove the fuel cap.
  2. Ignition ON, engine OFF.
  3. Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
  4. The fuel tank pressure Sensor parameter should be 1.3-1.7 V.
  1. Ignition OFF, disconnect the harness connector at the B150 fuel tank pressure sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool B150 fuel tank pressure sensor parameter is less than 0.2 V. If greater than the specified range, test the signal circuit terminal for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal and the 5 V reference circuit terminal. Verify the scan tool fuel tank pressure sensor parameter is greater than 4.7 V. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, test or replace the B150 fuel tank pressure sensor.
  1. «Fuel Tank Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. For DTC P0452 or P0453, always perform the «Diagnostic Repair Verification»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-repair-verification) after completing the diagnostic procedure
  3. For DTC P0451 or P0454, clear DTCs with a scan tool
  4. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ECM tests the Evaporative Emission (EVAP) System for a large leak or restrictions to the purge path in the EVAP system. When the enabling criteria has been met the ECM commands the evaporative emission canister vent solenoid valve ON and the evaporative emission canister purge solenoid valve ON, allowing vacuum into the evaporative emission system. The ECM monitors the fuel tank pressure sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time.

  1. Before the ECM can report DTC P0455 failed, DTC P0496 must run and pass.
  2. DTCs P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0442, P0443, P0449, P0451, P0452, P0453, P0454, P0464, P0496, P0608, P0609, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
  3. The ignition voltage is between 11-18 V.
  4. The barometric pressure (BARO) is more than 74 kPa.
  5. The fuel level is between 10-90 percent.
  6. The engine coolant temperature (ECT) at start-up is less than 35°C (95°F).
  7. The intake air temperature (IAT) is between 4-30°C (39-86°F).
  8. DTC P0455 runs once per cold start when the above conditions are met.

The evaporative emission system is not able to achieve or maintain a calibrated level of vacuum within a set amount of time.

DTC P0455 is a Type B DTC.

DTC P0455 is a Type B DTC.

  1. Inspect for a loose, missing, damaged, or incorrect fuel fill cap.
  2. Inspect for a damaged fuel filler neck seal surface.
  3. A blockage or restriction in the evaporative emission purge solenoid valve, purge pipe, evaporative emission canister, or vapor pipe, can cause this DTC to set.
  4. The evaporative emission system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. Close the system once smoke is observed.
  5. To help locate intermittent leaks using the J 41413-200 EEST, move all evaporative emission components while observing smoke with the J 41413-SPT White Light.
  6. Individual components can be isolated and tested using adapters in the J 41413-300A Kit.
  7. A condition may exist where a leak in the evaporative emission system only exists under a vacuum condition. This type of leak may be detected by using the scan tool Purge/Seal function to create a vacuum in the evaporative emission system and then observe the fuel tank pressure parameter for vacuum decay.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 48096 Evaporative Emissions Service Access Port Tool
  2. J 41415-30 Fuel Tank Adapter
  3. J 41413-200 Evaporative Emissions System Tester (EEST)
  4. J 41413-300A Evaporative Emissions Cap and Plug Kit
  5. J 41413-311 Evaporative Emissions Plug
  6. J 41413-SPT High Intensity White Light
  7. J 41413-VLV Evaporative Emissions Service Port Vent Tool
  8. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-special-tools-and-equipment__special-tools-diagnostic-tools) .

Note. Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Refer to the J 41413-200 EEST operation manual for detailed instructions in Evaporative Emission System Diagnosis .

  1. Disconnect the purge tube at the quick connector on the evaporative emission canister side of the Q12 evaporative emission canister purge solenoid valve. Install the CH 48096 Port Tool between the disconnected purge tube and the purge solenoid valve. Connect the J 41413-200 EEST to the service access port tool.
  2. Use a scan tool to seal the evaporative emission system.
  3. Use the flow meter on the J 41413-200 EEST, calibrated to 0.51 millimeter (0.020 inch) to determine that there is no leak in the evaporative emission system. If a leak is detected, use the J 41413-200 EEST to apply smoke to the evaporative emission system at the purge tube until the leak is located using the J 41413-SPT White Light.
  4. To test for a restriction, connect the J 41413-200 EEST nitrogen/smoke hose to the to the J 41413-311 Evaporative Emission Plug brass cone adapter. Disconnect the hose at the fuel cap end of the J 41415-30 Adapter. Connect the J 41413-311 Evaporative Emission Plug to the disconnected hose on the J 41415-30 Adapter. Install the J 41415-30 Adapter filler neck end only to the vehicle.
  5. Allow the engine to idle.
  6. Use the Purge/Seal function to seal the system with a scan tool.
  7. Command the EVAP Purge Solenoid Valve to 30 percent.
  8. The vacuum/pressure gauge on the J 41413-200 EEST and the fuel tank pressure parameter on the scan tool should both show vacuum. If the vacuum/pressure gauge shows vacuum, but the fuel tank pressure parameter does not show vacuum, replace the fuel tank pressure sensor. If neither the fuel tank pressure parameter nor the vacuum/pressure gauge shows vacuum, repair the restriction in the purge path.
  9. Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 V, and the values are similar between the scan tool and the vacuum/pressure gauge on the J 41413-200 EEST. If the values are not similar, or the voltage did not reach 3.2 V, replace the B150 fuel tank pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The engine control module (ECM) seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the EVAP canister vent solenoid valve ON. The ECM monitors the fuel tank pressure sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

Control Module CommandEVAP Canister Purge Solenoid ValveEVAP Canister Vent Solenoid Valve
ONOpenClosed
OFFClosedOpen
  1. DTCs P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0464, P0608, P0609, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138 are not set.
  2. The ignition voltage is between 11-18 volts.
  3. The barometric pressure (BARO) is more than 74 kPa.
  4. The fuel level is between 15-85 percent.
  5. The engine coolant temperature (ECT) at start-up is less than 35°C (95°F).
  6. The intake air temperature (IAT) is between 4-30°C (39-86°F).
  7. DTC P0496 runs once per cold start when the above conditions are met.

The ECM detects more than 10 inch H2O vacuum for 5 seconds during a non-purge condition.

DTC P0496 is a Type B DTC.

DTC P0496 is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  3. «Troubleshooting with a Test Lamp»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__troubleshooting-with-a-test-lamp)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, engine OFF, seal the EVAP system using the Purge/Seal function with a scan tool.
  2. Start the engine.
  3. Observe the fuel tank pressure sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts after 90 seconds. If the Fuel Tank Pressure Sensor parameter is greater than the specified range, go to Circuit/System Testing.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition ON, engine OFF.
  2. Seal the EVAP system using the Purge/Seal function with a scan tool.
  3. Start the engine.
  4. Observe the fuel tank pressure sensor with a scan tool. The Fuel Tank Pressure Sensor parameter should be less than 1.7 volts after 90 seconds. If the Fuel Tank Pressure Sensor parameter is greater than the specified range, replace the Q12 EVAP canister purge solenoid valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The throttle actuator control (TAC) motor is a DC motor that is part of the throttle body assembly. The TAC motor drives the throttle valve. The engine control module (ECM) controls the TAC motor based on throttle position sensor input. The idle speed is controlled by the ECM based on various inputs. The ECM commands the TAC motor to open or close the throttle valve in order to maintain the desired idle speed.

  1. DTCs P0068, P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0201-P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268. P0270, P0271, P0300-P0304, P0351-P0354, P0461-P0464, P0496, P0627, P0628, P0629, P0722, P1248, P1249, P124A, P124B, P1516, P2066-P2068, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157 are not set.
  2. The barometric pressure (BARO) is greater than 70 kPa.
  3. The engine coolant temperature (ECT) is greater than 60°C (140°F).
  4. The engine run time is greater than 60 s.
  5. The ignition voltage is between 11-32 V.
  6. The transmission is not changing gears.
  7. The torque converter clutch (TCC) is not changing states.
  8. The intake air temperature (IAT) is warmer than -20°C (-4°F).
  9. The vehicle speed is less than 3 km/h (2 mph).
  10. The commanded engine speed is steady within 25 RPM.
  11. The engine is idling for greater than 5 s.
  12. The DTCs run when the above conditions are met.

P0506

The actual engine speed is 94 RPM less than the desired idle speed for 10 s.

P0507

The actual engine speed is 188 RPM greater than the desired idle speed for 10 s.

DTCs P0506 and P0507 are Type B DTCs.

DTCs P0506 and P0507 are Type B DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON.
  2. Verify there are no other DTCs set. If any other DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If no other DTCs are set
  3. Verify the scan tool Throttle Body Idle Airflow Compensation parameter is less than 90 %. 90 % or greater Refer to «Throttle Body Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__throttle-body-cleaning) . If less than 90 %
  4. Engine Idling at the normal operating temperature.
  5. Verify the actual Engine Speed is not 100 RPM less than the Desired Idle Speed. If 100 RPM less than the Desired Idle Speed Refer to Circuit/System Testing If 100 RPM greater than the Desired Idle Speed
  6. Verify the actual Engine Speed is not 200 RPM greater than the Desired Idle Speed. If 200 RPM greater than the Desired Idle Speed Refer to Circuit/System Testing If 200 RPM less than the Desired Idle Speed
  7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  8. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing If the DTC does not set
  9. All OK

Verify the conditions listed below do not exist

P0506

  1. Restricted exhaust
  2. Mechanical conditions that limits engine speed
  3. Parasitic load on the engine-For example, a transmission condition, a belt driven accessory condition. If a condition is found, repair as necessary.

P0507

  1. Vacuum leaks
  2. A throttle valve that does not close correctly
  3. Verify the correct operation of the crankcase ventilation system. Inspect for the conditions listed below: The routing of the positive crankcase ventilation (PCV) system Vacuum leaks in the PCV system-Refer to «Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc) . If a condition is found, repair as necessary.

Perform the Diagnostic Repair Verification after completing the repair.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

During a cold start, the engine control module (ECM) commands dual-pulse mode during Open Loop operation to improve cold start emissions. In dual-pulse mode, the injectors are energized twice during each injection event. As with misfire diagnosis, in dual-pulse mode the ECM monitors the crankshaft position sensor and the camshaft position sensors to calculate crankshaft rotation speed. In normal operation, optimum fuel delivery during dual-pulse mode produces a steady crankshaft rotation speed. If the variations exceed a calibrated value, the code will be set.

  1. DTCs P0010, P0011, P0013, P0014, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0101-P0103, P0106-P0108, P0112, P0113, P0116-P0118, P0122, P0123, P0128, P0171, P0172, P0192, P0193, P0201- P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301-P0304, P0335, P0336, P0351-P0354, P0506, P0507, P0627-P0629, P0722, P0723, P1248, P1249, P124A, P124B, P2122, P2123, P2127, P2128, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157 are not set.
  2. The catalyst temperature is less than 500°C (932°F).
  3. The engine coolant temperature is warmer than -10°C (14°F).
  4. The barometric pressure is greater than 60 kPa.
  5. The engine speed is between 250-1900 RPM.
  6. The engine is running and a cold start has been detected.
  7. DTC P050D runs once per cold start.

This DTC will set if the ECM detects variations in crankshaft rotation speed caused by the lack of adequate fuel delivery during dual-pulse mode.

  1. DTC P050D is a Type B DTC.
  2. The ECM disables dual pulse mode and energizes the fuel injector as it would for a warm engine.

DTC P050D is a Type B DTC.

  1. This DTC may be set with a misfire DTC, however the existence of this DTC is a higher priority and indicates the condition to diagnose is related to fuel and/or injectors, not the ignition/spark system.
  2. A restricted fuel injector may cause this DTC to set.
  3. High resistance in the circuits of the injectors could set this DTC without setting an injector DTC. Test the injector circuits of the affected cylinders for a high resistance if you suspect a condition.
  4. A drop in system voltage during cold start may set this DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Circuit/System Testing requires cold start. Do not start vehicle prior to connecting scan tool and preparing to evaluate the condition during engine crank.

  1. Start the engine and observe the Cylinder 1-4 Current Misfire Counters during first 500 engine cycles. The Cylinder 1-4 Current Misfire Counters should not be incrementing. If the misfire counters are incrementing on one or more cylinders, verify that the following conditions do not exist: Fuel pressure that is too low or too high-Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Contaminated fuel-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  2. If all conditions test normal, replace fuel injectors as indicated by high misfire counts.

Note. Repair Verification requires cold start.

  1. Ignition ON, engine OFF, clear the DTCs with a scan tool.
  2. Start the engine.
  3. Verify the DTC does not reset.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed, or is programmed incorrectly.

P0601, P0602, P0630, P16F3

These DTCs run continuously when the ignition is ON.

P0603, P062F

These DTCs run at power up.

P0604

DTC P0604 runs continuously when the ignition is ON. First memory scan may take up to 30 s.

P0606, P062B

  1. The ignition is ON.
  2. System voltage is greater than 11 V.
  3. These DTCs run continuously when the above conditions are met.

P2610

DTC P2610 runs on ECM power down.

The ECM detects an internal failure or incomplete or incorrect programming.

  1. DTCs P0601, P0602, P0603, P0604, P0606, P062B, P062F, P0630 and P16F3 are Type A DTCs.
  2. DTC P2610 is a Type B DTC.
  1. DTCs P0601, P0602, P0603, P0604, P0606, P062B, P062F, P0630 and P16F3 are Type A DTCs.
  2. DTC P2610 is a Type B DTC.

Low voltage or a momentary loss of power or ground to the ECM may cause a DTC to set. Verify for the following

  1. The battery cables are clean and tight, and the battery is fully charged-Refer to «Battery Inspection/Test»(/buick/regal/v-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-non-hybrid) .
  2. The ECM ground circuits do not have an open or high resistance
  3. The ECM power circuits do not have an open, short to ground, or high resistance

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0641, P0651, P0697, or P06A3 does not set. If a DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) for further diagnosis.
  2. Observe the DTC information with a scan tool. DTC P0601, P0602, P0603, P0604, P0606, P062B, P062F, P0630, P16F3, or P2610 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition ON, clear the DTC information with a scan tool.
  2. Observe the scan tool DTC information. Verify that DTC P0602 or P0630 does not set. If DTC P0602 or P0630 failed this ignition, reprogram the K20 ECM. Refer to «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) . If the DTC resets, replace the K20 ECM.
  3. Observe the DTC information with a scan tool. Verify that DTC P0601, P0603, P0604, P0606, P062B, P062F, P16F3, or P2610 does not set. If a DTC failed this ignition, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The internal fault detection is handled inside the fuel pump control module. No external circuits are involved.

The fuel pump control module runs the program to detect an internal fault when power up is commanded. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

The fuel pump control module has detected an internal malfunction.

DTC P0601, P0602, P0603, P0604, P0606 and P062F are type A DTCs.

DTC P0601, P0602, P0603, P0604, P0606 and P062F are type A DTCs.

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Note. This DTC may be stored as a history DTC without affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module.

Verify that DTC P0602 is not set.

  1. If the DTC is set, program the K27 fuel pump control module.

Verify that DTCs P0601, P0603, P0604, P0606, and P062F are not set.

  1. If any of the DTCs are set, program the K27 fuel pump control module. If a DTC resets, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for fuel pump control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Fuel Pump EnableP0628, P069EP0627, P069EP0629, P069E

The engine control module (ECM) provides ignition voltage to the fuel pump flow control module whenever the engine is cranking or running. The control module enables the fuel pump flow control module as long as the engine is cranking or running, and ignition system reference pulses are received. While this enable voltage is being received, the fuel pump flow control module supplies a varying voltage to the in-tank fuel pump module in order to maintain the desired fuel line pressure.

  1. The engine speed is greater than 0 RPM.
  2. The ignition voltage is greater than 11 V.
  3. The DTCs run continuously when the conditions above are met.
  1. The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match.
  2. The above condition is met for a minimum of 2.5 s.

DTCs P0627, P0628, and P0629 are Type B DTCs.

DTCs P0627, P0628, and P0629 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Attempt to start the engine. Observe the DTC information with a scan tool. DTC P0627, P0628, or P0629 should not set.
  2. Ignition ON, command the fuel pump ON and OFF with a scan tool while observing the following control circuit status parameters: Fuel Pump Enable Circuit Low Voltage Test Status Fuel Pump Enable Circuit Open Test Status Fuel Pump Enable Circuit High Voltage Test Status Each parameter should toggle between OK and Not Run or Not Run and OK.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the K27 fuel pump control module harness connector.
  2. Ignition OFF, and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for 0 V on the enable circuit terminal 13 of the fuel pump control module. If greater than the specified value, test for a short to voltage on the enable circuit. If the circuit/connections test normal, replace the K20 ECM.
  3. Ignition ON, command the Fuel Pump Enable ON with a scan tool. Test for B+ on the enable circuit terminal 13 of the fuel pump control module. If less than the specified range, test for a short to ground or an open/high resistance on the enable circuit. If the circuit/connections test normal, replace the K20 ECM.
  4. Ignition ON, test for 2-3 V on the enable circuit terminal 13 of the fuel pump control module. If not within the specified range, replace the K20 ECM.
  5. If all circuits/connections test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM or fuel pump control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) has 4 internal 5 V reference circuits. Each internal reference circuit provides external 5 V reference circuits for more than one sensor. A short to ground or short to voltage on one external 5 V reference circuit can affect all the components connected to the same internal 5 V reference circuit.

These DTCs run continuously when the ignition voltage is greater than 6.4 V.

The 5 V reference circuit voltage is greater or less than a predetermined threshold.

DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.

DTCs P0641, P0651, P0697, and P06A3 are Type A DTCs.

DTC P0641

The 5 V reference 1 circuit provides 5 V to the following sensors

  1. Fuel tank pressure (FTP) sensor
  2. Fuel rail pressure (FRP) sensor
  3. A/C refrigerant pressure sensor
  4. Exhaust camshaft position sensor
  5. Intake camshaft position sensor
  6. Throttle inlet absolute pressure sensor

DTC P0651

The 5 V reference 2 circuit provides 5 V to the following sensors

  1. Brake pedal position sensor
  2. Clutch pedal position sensor, if equipped
  3. Crankshaft position sensor
  4. Mass air flow/intake air temperature sensor
  5. Vehicle speed sensor

DTC P0697

The 5 V reference 3 circuit provides 5 V to the following sensors

  1. Manifold absolute pressure (MAP) sensor
  2. Accelerator pedal position sensor 2

DTC P06A3

The 5 V reference 4 circuit provides 5 V to the following sensors

  1. Throttle position sensor
  2. Accelerator pedal position sensor 1

It may be possible to locate the fault by disconnecting one component at a time from the affected 5 V reference circuit while viewing the 5 V Reference Circuit parameter on the scan tool. The scan tool parameter will change from Malfunction to OK when the source of the fault is disconnected. If all 5 V reference components have been disconnected and a fault is still indicated, the fault may exist in the wiring harness.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. DTC P0641, P0651, P0697, or P06A3 should not set.
  2. Observe the circuit status parameters listed below: 5 V Reference 1 Circuit Status 5 V Reference 2 Circuit Status 5 V Reference 3 Circuit Status 5 V Reference 4 Circuit Status Each parameter should display OK.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids.
  2. Ignition ON, test for 4.8-5.2 V between one of the affected 5 V reference circuits and ground. If less than the specified range, test for a short to ground on the 5 V reference circuit for each of the affected components. If all circuits test normal, replace the K20 ECM. If greater than the specified range, test for a short to voltage on the 5 V reference circuit for each of the affected components. If all circuits test normal, replace the K20 ECM.
  3. Connect each component associated with the affected 5 V reference circuit one at a time while monitoring the appropriate scan tool 5 V Reference 1, 2, 3, or 4 Voltage parameter. Verify the voltage remains between 4.8-5.2 V. If not within the specified range when a component is connected, test the signal circuit of that component for a short to voltage. If the circuit tests normal, replace the component.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accelerator Pedal Position Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
  3. «Camshaft Position Sensor Replacement - Intake»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  4. «Camshaft Position Sensor Replacement - Exhaust»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  5. «Crankshaft Position Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  6. «Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  7. «Fuel Tank Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  8. «Input and Output Speed Sensor Installation»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-repair-instructions-off-vehicle)
  9. «Manifold Absolute Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  10. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  11. «Throttle Body Assembly Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  12. «Throttle Inlet Absolute Pressure Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  13. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0641P0641, P06A6P0641P06A6
SignalP018CP018B, P018CP018DP018B
Low ReferenceP0641, P06A6P06A6

The fuel pressure sensor is located on the fuel line. The fuel pressure sensor monitors the fuel pressure in the fuel line. The fuel pump control module monitors the voltage signal from the fuel pressure sensor.

The ignition is ON.

The fuel pump control module detects that the fuel pressure 5 V reference is above or below a predetermined voltage threshold.

DTCs P0641 and P06A6 are Type A DTCs.

DTCs P0641 and P06A6 are Type A DTCs.

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect harness connector of the B47 fuel pressure sensor.
  2. Ignition OFF, test for less than 1.0 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module.
  4. If all circuits test normal, replace the B47 fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel Pressure Sensor Replacement - Fuel Feed Pipe»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition VoltageP0650P0650
MIL ControlP0650*P0650P0650
* The MIL remains ON

The malfunction indicator lamp (MIL) illuminates to inform the driver that an emission system fault has occurred and the engine control system requires service. Ignition voltage is supplied directly to the MIL and, when the emission system fault occurs, the engine control module (ECM) turns the MIL ON by grounding the MIL control circuit. Under normal operating conditions, the MIL should be ON only when the ignition is ON and the engine is OFF.

  1. The engine speed is greater than 80 RPM.
  2. The ignition voltage is between 11-32 V.
  3. DTC P0650 runs continuously when the above conditions are met.

The ECM detects that the commanded state of the MIL driver and the actual state of the control circuit do not match for greater than 5 seconds.

DTC P0650 is a Type B DTC.

DTC P0650 is a Type B DTC.

If the condition is intermittent, move the related harnesses and connectors with the ignition ON and the engine OFF, and with the engine operating while monitoring the scan tool MIL control circuit status parameters. The MIL control circuit status parameters will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

  1. «Engine Controls Schematics»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-wiring-schematic-diagrams)
  2. «Instrument Cluster Schematics»(/buick/regal/v-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
  2. Command the MIL ON and OFF while observing the following control circuit status parameters: The MIL Control Circuit Low Voltage Test Status The MIL Control Circuit Open Test Status The MIL Control Circuit High Voltage Test Status Each parameter should display OK or Not Run.
  3. Engine running, command the MIL ON and OFF while observing the following control circuit status parameters: The MIL Control Circuit Low Voltage Test Status The MIL Control Circuit Open Test Status The MIL Control Circuit High Voltage Test Status Each parameter should display OK or Not Run.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the X1 harness connector at the K20 ECM.
  2. Ignition ON, the MIL should not illuminate. If the MIL is illuminated, test the MIL control circuit terminal 46-X1 for a short to ground. If the circuit tests normal, replace the P16 instrument panel cluster.
  3. Connect a 3 A fused jumper wire between the MIL control circuit terminal 46-X1 and ground. The MIL should illuminate. If the MIL illuminates, replace the ECM. If the MIL does not illuminate, test the MIL control circuit for a short to voltage or an open/high resistance. If the MIL control circuit tests OK, test the instrument cluster ignition voltage circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the instrument cluster/bulb.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Instrument Cluster Replacement»(/buick/regal/v-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to Voltage
Relay Coil Supply VoltageP0685, P0689, P1682
Relay Control CircuitP0690P1682P0685, P0689, P1682
Relay Feedback CircuitP0689, P1682P0689, P1682P0690

Engine Controls Ignition Relay

CircuitShort to GroundOpen/High ResistanceShort to Voltage
Ignition 1 Signal, Ignition Run Relay112
1. No Crank condition. 2. Engine continues to operate with ignition OFF.

Ignition Run Relay

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Component commanded OFF Parameter Normal Range: The following illustrates the normal parameter state with no circuit conditions: Component OFF - OK for Open/Low Voltage test and Not Run for High Voltage test Component ON - Not Run for Open/Low Voltage test and OK for High Voltage test
Battery VoltageMalfunctionMalfunction
Engine Controls Ignition Relay Control CircuitMalfunctionMalfunctionNot Run

Engine Controls Ignition Relay Control Circuit Low Voltage, Open, and High Voltage Test Status - Component Commanded OFF

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Component commanded ON Parameter Normal Range: The following illustrates the normal parameter state with no circuit conditions: Component OFF - OK for Open/Low Voltage test and Not Run for High Voltage test Component ON - Not Run for Open/Low Voltage test and OK for High Voltage test
Battery VoltageNot RunNot Run
Engine Controls Ignition Relay Control CircuitNot RunNot RunMalfunction

Engine Controls Ignition Relay Control Circuit Low Voltage, Open, and High Voltage Test Status - Component Commanded ON

There are 2 ignition voltage circuits supplied to the engine control module (ECM). One is supplied by the engine controls ignition relay and the other is supplied by the ignition run relay. The ECM monitors and compares the ignition voltage supplied by the two relays.

P0685

The DTC runs continuously when the ignition voltage is greater than 11 V.

P0689

  1. The engine controls ignition relay is commanded ON.
  2. The ignition voltage is greater than 11 V.
  3. DTC P0685 is not set.
  4. The DTC runs continuously when the above conditions are met.

P0690

  1. The engine controls ignition relay is commanded ON.
  2. DTC P0685 is not set.
  3. The DTC runs continuously when the above conditions are met.

P1682

  1. The engine controls ignition relay is commanded ON.
  2. The ignition voltage is greater than 5.5 V.
  3. The DTC runs continuously when the above conditions are met.

P0685

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 2 s.

P0689

The engine controls ignition relay voltage is less than 5 volts for greater than 5 s.

P0690

  1. The ECM detects the engine controls ignition relay feedback circuit is greater than 4 V when the relay is commanded OFF.
  2. The condition is present for greater than 5 s.

P1682

The ECM detects that there is greater than 3 V difference between the ignition run relay signal and the engine controls ignition relay signal circuits for less than 1 s.

  1. DTC P1682 is a Type A DTC.
  2. DTCs P0685 and P0690 are Type B DTCs.
  3. DTC P0689 is a Type C DTC.
  1. DTC P1682 is a Type A DTC.
  2. DTCs P0685 and P0690 are Type B DTCs.
  3. DTC P0689 is a Type C DTC.

The engine controls ignition relay may also be labeled the powertrain relay, the engine control module relay, or the main relay. The ignition run relay may also be labeled the run/crank relay, the ignition 1 relay, the ignition main relay, or the ignition relay.

Schematic Reference

  1. «Engine Controls Schematics»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-wiring-schematic-diagrams)
  2. «Power Distribution Schematics»(/buick/regal/v-2009-2013/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Electrical Center Identification Views»(/buick/regal/v-2009-2013/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)
  4. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  5. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, command the Engine Controls (EC) Ignition Relay ON and OFF with a scan tool while observing the parameters listed below: Engine Controls Ignition Relay Control Circuit Low Voltage Test Status Engine Controls Ignition Relay Control Circuit Open Test Status Engine Controls Ignition Relay Control Circuit High Voltage Test Status Each parameter should display OK or Not Run in each commanded state.
  2. Ignition ON, observe the DTC information with a scan tool. DTC P0685, P0689, P0690, or P1682 should not set.
  3. Ignition ON, observe the scan tool Ignition 1 Voltage Signal and the Engine Controls Ignition Relay Feedback Signal parameters. There should be less than 3 V difference between the two parameters.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Note. You must perform the Circuit/System Verification before proceeding with Circuit/System Testing unless sent here from Engine Cranks But Does Not Run.

  1. Ignition OFF, disconnect the KR75 engine controls ignition relay.
  2. Verify that a test lamp illuminates between ground and the relay circuit terminals listed below: Terminal 85 Terminal 30 If the test lamp does not illuminate, test the relay battery voltage circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground. If the test lamp illuminates, test the ignition voltage circuit for a short to voltage.
  4. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
  5. Ignition ON, observe the scan tool Engine Controls Ignition Relay Feedback Signal parameter. The ECM should communicate, and the parameter should display B+. If not the specified value, or the ECM does not communicate, test the ignition voltage circuit between the engine controls ignition relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
  6. Ignition OFF, connect a DMM set to the diode setting between control circuit terminal 86 and ground. Verify the DMM displays OL. If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  7. Ignition ON, verify the DMM displays less than 1 V. If not the specified range, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  8. If all circuits test normal, replace the KR75 engine controls ignition relay.
  1. Remove the KR75 engine controls ignition relay.
  2. Test for one of the following resistance specifications between terminals 85 and 86 of the KR75 engine controls ignition relay: 70-110 ohms 200-250 ohms If not within the specified range, replace the KR75 engine controls ignition relay.
  3. Test for infinite resistance between the following terminals of the KR75 engine controls ignition relay: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the KR75 engine controls ignition relay.
  4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the KR75 engine controls ignition relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) , «Relay Replacement (Attached to Wire Harness)»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The fuel pump control module uses the serial data network to signal the engine control module (ECM) that the fuel pump control module is requesting malfunction indicator lamp (MIL) illumination. A DTC is set in the fuel pump control module, and the request for MIL illumination is sent when the fuel pump control module determines that a failure that affects emissions has occurred in the fuel pump control system. When the ECM receives the message from the fuel pump control module, DTC P069E will set in the ECM.

The ignition is ON, or the engine is running for greater than 3 s.

The fuel pump control module requests the ECM to illuminate the MIL.

  1. DTC P069E is a Type A DTC.
  2. DTC P069E will continue to be current or active as long as the fuel pump control module is requesting MIL illumination.

DTC P069E is a Type A DTC.

Communication codes, U-codes, as well as powertrain codes, P-codes, set in the fuel pump control module will cause the fuel pump control module to request DTC P069E to be set in the ECM.

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. DTC P069E is an informational DTC. If there are no engine controls or communication DTCs, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for diagnosis of fuel pump control module DTCs. Do not replace the ECM for this DTC.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each of the diagnostic category.

Diagnostic trouble code (DTC) P0700 is an informational DTC that indicates that an emission related transmission DTC has set in the transmission control module (TCM). The engine control module (ECM) turns ON the malfunction indicator lamp (MIL) when the TCM sends a message over the serial data circuit requesting MIL illumination. The DTC information for the ECM will only display DTC P0700, and the ECM Freeze Frame/Failure Records data will display the engine operating conditions that were present when the transmission DTC was set. The TCM Freeze Frame/Failure records data is available from the DTC that was set in the TCM.

  1. The ignition is ON or the engine is operating.
  2. DTC P0700 runs continuously.

The ECM receives a serial data message from the TCM requesting the ECM to turn ON the MIL.

DTC P0700 is a Type A DTC.

DTC P0700 is a Type A DTC.

Communication codes, U-codes, as well as powertrain codes, P-codes, set in the TCM can cause the TCM to request DTC P0700 to be set in the ECM.

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that there are no engine controls or communication DTCs set. If a DTC is set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for diagnosis of engine control or communications DTCs. If a DTC is not set
  2. Verify that there are no transmission control module DTCs set. If a DTC is set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for diagnosis of transmission control module DTCs. If a DTC is not set
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  4. Verify the DTC does not set. If the DTC sets Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If the DTC does not set
  5. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
IAT Sensor 3 SignalP112C, P112DP112B, P112D, P112EP112D*, P112EP112B
Low ReferenceP112B, P112D, P112EP112D*, P112E
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 3

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
IAT Sensor 1 SignalP0112, P0114, P2199P0111, P0113, P0114, P2199P0113*, P0114, P2199P0111, P2199
Low ReferenceP0111, P0113, P0114, P2199P0113*, P0114
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 1

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition 1 VoltageP0096, P0097, P0102, P11C2, P2199P0096, P0097, P0102, P11C2, P2199P0096
IAT Sensor 2 SignalP0096, P0097, P11C3, P2199P0096, P0097, P11C2, P2199P0096*, P0097, P11C2, P2199P0096
GroundP0096, P0097, P0102, P11C2, P2199P0096
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 2

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient temperature; and engine bay conditions
IAT Sensor 3 Signal150°C (302°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 3

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient temperature; and engine bay conditions
IAT Sensor 1 Signal150°C (302°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 1

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient humidity and temperature; and engine bay conditions
Ignition 140°C (-40°F)40°C (-40°F)
IAT Sensor 2 Signal40°C (-40°F)40°C (-40°F)40°C (-40°F)*
Ground40°C (-40°F)
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 2

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient humidity and temperature; and engine bay conditions
Ignition 110 Hz10 Hz
IAT Sensor Signal 210 Hz10 Hz10 Hz*
Ground10 Hz
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 2

The intake air temperature (IAT) sensor 3 is a variable resistor that measures the temperature of the air in the sensor bore located before the throttle body. The IAT sensor 3 is integrated with the throttle inlet absolute pressure sensor. The engine control module (ECM) supplies 5 V to the IAT sensor 3 signal circuit and a ground for the IAT sensor 3 low reference circuit. The signal varies with inlet air temperature at the throttle body and is displayed by the scan tool as °C (°F).

IAT Sensor 3IAT Sensor 3 ResistanceIAT Sensor 3 Signal Voltage
ColdHighHigh
WarmLowLow

P112B

  1. DTCs P0097, P0098, P0112, P0113, P0117, P0118, P0119, P112C, or P112D are not set.
  2. The vehicle has been OFF at least 8 hours.
  3. Ignition 1 voltage is at least 11 V.
  4. These DTCs run once per ignition cycle when the enabling conditions are met.

P112B-Condition 1

  1. The ECM determines the absolute difference between IAT sensor 1 start-up temperature and the IAT sensor 2 start-up temperature is less or equal to 30°C (54°F). AND
  2. The ECM determines the absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 1 start-up temperature is greater than 25°C (77°F). AND
  3. The ECM determines the absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 2 start-up temperature is greater than 25°C (77°F). AND

P112B-Condition 2

  1. The ECM determines the IAT sensor 1 start-up temperature is between the IAT sensor 3 start-up temperature and the IAT sensor 2 start-up temperature AND
  2. The ECM determines the absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 2 start-up temperature is greater than 25°C (77°F). AND
  3. The absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 1 start-up temperature is greater than the absolute difference between IAT sensor 2 start-up temperature and the IAT sensor 1 start-up temperature.

P112B-Condition 3

  1. The ECM determines the IAT sensor 2 start-up temperature is between the IAT sensor 3 start-up temperature and the IAT sensor 1 start-up temperature AND
  2. The ECM determines the absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 1 start-up temperature is greater than 25°C (77°F). AND
  3. The absolute difference between IAT sensor 3 start-up temperature and the IAT sensor 2 start-up temperature is greater than the absolute difference between IAT sensor 2 start-up temperature and the IAT sensor 1 start-up temperature.

DTC P112B is a Type B DTC.

Conditions for Clearing the DTCs

DTC P112B is a Type B DTC.

  1. An IAT sensor 3 that is skewed, due to more resistance than is normal, can widen the spread between the 3 sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor 3 at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-intake-air) .
  2. A slight to moderate resistance in the IAT sensor 3 signal circuit or low reference circuit will increase the range between these sensors. This condition results in a greater voltage on the IAT sensor 3 signal circuit, which is interpreted by the ECM as a colder IAT sensor 3.
  3. Inspect the intake air sensor 3 terminals for corrosion.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment)
  2. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-special-tools-and-equipment__special-tools-diagnostic-tools) .

Note. Perform Step 1 of this verification procedure only if the ignition has been OFF for 8 hours or more.

  1. Ignition ON, observe the following scan tool parameters. The readings should be within 30°C (54°F) of each other. IAT Sensor 3 Start-Up IAT Sensor 1 IAT Sensor 2
  2. Engine running, observe the scan tool IAT Sensor 1, IAT Sensor 2. and IAT Sensor 3 parameters. Depending on the current ambient temperature and the vehicle operating conditions, the readings should be between -38 and +149°C (-36 and +300°F).
  3. Operate the vehicle within the conditions for running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the B111B turbocharger boost/intake air temperature sensor.
  2. Ignition OFF, all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the low reference circuit terminal 1 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, verify the scan tool IAT Sensor 3 parameter is colder than -39°C (-38°F). If warmer than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool IAT Sensor 3 parameter is warmer than 149°C (300°F). If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, test for 4.8-5.2 V between the IAT sensor 3 signal circuit terminal 2 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, test or replace the B111B turbocharger boost/intake air temperature sensor.
  1. Ignition OFF, disconnect the harness connector at the B111B turbocharger boost/intake air temperature sensor.
  2. Test the IAT sensor 3 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-intake-air) table. The resistance values should be in range of the table values. If not within the specified range, replace the B111B turbocharger boost/intake air temperature sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Intake Air Pressure and Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for turbocharger boost/intake air temperature sensor.
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
IAT Sensor 3 SignalP112CP112DP112DP112B, P112E
Low ReferenceP112DP112D, P112EP112B, P112E
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running Parameter Normal Range: Varies with ambient temperature
IAT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor

The intake air temperature (IAT) sensor 3 is a variable resistor that measures the temperature of the air in the sensor bore located before the throttle body. The IAT sensor 3 is integrated with the throttle inlet absolute pressure sensor. The engine control module (ECM) supplies 5 V to the IAT sensor 3 signal circuit and a ground for the IAT sensor 3 low reference circuit. The signal varies with inlet air temperature at the throttle body and is displayed by the scan tool as °C (°F).

IAT Sensor 3IAT Sensor 3 ResistanceIAT Sensor 3 Signal Voltage
ColdHighHigh
WarmLowLow

P112C, P112D, and P112E

  1. The ignition is ON, or the engine is running.
  2. The DTCs run continuously when the above conditions are met.

P112C

The ECM detects that the IAT sensor signal is warmer than 149°C (300°F) for at least 5 s.

P112D

The ECM detects that the IAT sensor signal is colder than -60°C (-76°F) for at least 5 s.

Note. The scan tool display range is between -40 and +150°C (-40 and +302°F).

P112E

The ECM detects that the IAT sensor signal is intermittent or has abruptly changed for at least 5 s.

Action Taken When the DTCs Set

  1. DTCs P112C, P112D, and P112E are Type B DTCs.
  2. The ECM commands the cooling fans ON.

DTCs P112C, P112D, and P112E are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine running, observe the scan tool IAT Sensor 3 parameter. The reading should be between -40 and +149°C (-40 and +300°F) depending on the current ambient temperature and the vehicle operating conditions.
  2. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the B111B turbocharger boost/intake air temperature sensor.
  2. Ignition OFF, all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the low reference circuit terminal 1 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, verify the scan tool IAT Sensor 3 parameter is colder than -39°C (-38°F). If warmer than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool IAT Sensor 3 parameter is warmer than 149°C (300°F). If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, test for 4.8-5.2 V between the IAT sensor 3 signal circuit terminal 2 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, test or replace the B111B turbocharger boost/intake air temperature sensor.
  1. Ignition OFF, disconnect the harness connector at the B111B turbocharger boost/intake air temperature sensor.
  2. Test the IAT sensor 3 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-intake-air) table. The resistance values should be in range of the table values. If not within the specified range, replace the B111B turbocharger boost/intake air temperature sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Intake Air Pressure and Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for turbocharger boost/intake air temperature sensor replacement.
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition 1 VoltageP0096, P0097, P0102, P11C2, P2199P0096, P0097, P0102, P11C2, P2199P0096
Intake Air Humidity Sensor SignalP0096, P0097, P11C3, P2199P0096, P0097, P11C2, P2199P0096*, P0097, P11C2, P2199P0096
GroundP0096, P0097, P0102, P11C2, P2199P0096
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

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CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient humidity and temperature; and engine bay conditions
Ignition 10 %0 %
Intake Air Humidity Signal100 %0 %0 %*
Ground0 %
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

Intake Air Humidity

The humidity sensor measures the Intake Air humidity of the air in the sensor bore. The signal varies with intake air humidity and is displayed by the scan tool as duty cycle %. The ECM applies 5 V to the circuit. The signal circuit is shared by the humidity sensor and the intake air temperature (IAT) sensor 2. Ignition voltage and ground circuits are also supplied to the multifunction intake air sensor's internal circuits for these sensors

  1. IAT sensor 2
  2. Humidity sensor
  3. MAF sensor

The multifunction intake air sensor houses the following

  1. IAT sensor 1
  2. IAT sensor 2
  3. Humidity sensor
  4. MAF sensor
  5. BARO pressure sensor

P11C2, P11C3, and P11C4

  1. The ignition is ON.
  2. The Ignition 1 voltage is at least 11 V.
  3. These DTCs run continuously within the enabling conditions.

P11C2

The ECM detects that the humidity sensor signal is less than or equal to 5 % for greater than 5 s.

P11C3

The ECM detects that the humidity sensor signal is greater than or equal to 95 % for greater than 5 s.

P11C4

The ECM detects that the humidity sensor signal is intermittent or has abruptly changed over a period of time greater than 5 s.

DTCs P11C2, P11C3, P11C4 are Type B DTCs.

DTCs P11C2, P11C3, P11C4 are Type B DTCs.

  1. The Intake Air Humidity Signal parameter displays the measured humidity within the air intake system and may differ from atmospheric humidity measured outside the air intake system.
  2. With the ignition ON, the engine OFF, if the engine is cold, a properly functioning humidity sensor will gradually increase the scan tool Intake Air Humidity Signal parameter. This is due to the heat that is generated by the multifunction intake air sensor heating elements.
  3. The humidity sensor and the IAT sensor 2 signals are sent to the ECM on the same circuit. If the Intake Air Humidity parameter displays the value: 0 % or 100 %, and there are also IAT Sensor 2 DTCs, check for a circuit problem.
  4. With the ignition ON, the engine OFF, if the engine is cold, a properly functioning IAT sensor 2 will gradually increase the scan tool IAT Sensor 2 parameter. This is due to the heat that is generated by the multifunction intake air sensor heating elements.

Schematic Reference

Engine Controls Schematics Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References Control Module References for scan tool information

Special Tools

  1. «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment) Variable Speed Generator
  2. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-special-tools-and-equipment__special-tools-diagnostic-tools) .
  1. Ignition ON. Observe the scan tool IAT Sensor 1 and 2 parameters. The readings should be within 30°C (54°F) of each other.
  2. Engine running, observe the scan tool Intake Air Humidity parameter. Depending on the current ambient humidity and temperature; engine bay conditions; and the vehicle operating conditions, the reading should be between 5 and 90 %.
  3. Operate the vehicle within the conditions for running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
  2. Ignition OFF, all vehicle systems OFF, test for less than 5 ohms between the ground circuit terminal 7 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the circuit and repair or replace as necessary.
  4. Ignition ON, test for 4.8-5.2 V between the humidity signal circuit terminal 8 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module. NOTE: If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  5. Ignition OFF, connect the red lead of the «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment) to the signal circuit terminal 8 at the harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  6. Set the «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment) to the following specifications. Signal switch to 5 V Frequency switch to 250 Hz Duty Cycle switch to 50 % (Normal)
  7. Ignition ON, observe the scan tool Intake Air Humidity parameter. The scan tool parameter should be between 45-55 %. If the parameter is not within the specified range, replace the K20 engine control module.
  8. If all circuits test normal, test or replace the B75C multifunction intake air sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

The engine is running.

The fuel pump control module detects an over-temperature fault.

DTCs P064A and P1255 are Type A DTCs.

DTCs P064A and P1255 are Type A DTCs.

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that DTC P0231, P0232 or P023F are not set. If any of those codes are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ensure that the entire undercarriage of the vehicle is clean, especially around the area where the K27 fuel pump control module is located. Clear all codes from the K27 fuel pump control module and test drive the vehicle. Verify that DTC P1255 or P064A do not set. If DTC P1255 or P064A reset, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for fuel pump control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition Coil Supply Voltage Bank 1P0201, P0203, P0205, P0300, P0351, P0353, P0355, P135AP0201, P0203, P0205, P0300, P0351, P0353, P0355, P135A

The ignition system on this engine uses an individual module/coil for each cylinder. The engine control module (ECM) monitors the ignition voltage from the fuse of each bank of coils to the ECM. The ECM uses this information to determine if the misfire is ignition coil voltage related.

  1. The ignition is ON.
  2. The ignition module supply voltage is less than 2.5 V.
  3. The DTCs run continuously when the above condition is met.

The ECM detects a fault in an ignition coil control circuit for 50 out of 63 samples. Each sample runs on a 6.25 ms loop.

DTC P135A is a Type A DTC.

DTC P135A is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Electronic Ignition System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation)
  2. «Engine Control Module Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation__engine-control-module-description)

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

With the ignition ON, observe the Ignition Coil Supply Voltage Bank 1 parameter for each cylinder.

  1. The parameter should display ON.

Note. The ignition circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components for being shorted that share the ignition circuit.

  1. Ignition OFF, disconnect the harness connector at the appropriate T8 ignition coil.
  2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground of each T8 ignition coil. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, with the ignition OFF, disconnect the harness connector at each T8 ignition coil and monitor the fuse while individually connecting each T8 ignition coil. If the fuse opens, replace the appropriate T8 ignition coil.
  3. Ignition OFF, disconnect the K20 ECM harness connector X1.
  4. Ignition ON, connect a test lamp between the X1 67 ignition voltage circuit and ground. The test lamp should illuminate on each circuit. If the test lamp does not illuminate, test the ignition circuit for an open/high resistance.
  5. If all circuits/connections test normal, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ignition Coil Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for K20 ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The catalytic converter must be warmed to efficiently reduce the emissions. The cold start strategy is to reduce the amount of time it takes to warm the catalytic converter. During a cold start, the engine idle speed is elevated and spark timing is retarded to allow the catalyst to warm quickly. This diagnostic monitors the following to build an exhaust energy model

  1. Engine speed
  2. Spark advance
  3. Throttle position
  4. Engine airflow
  5. Engine coolant temperature
  6. Engine run time
  7. Park/Neutral position
  8. Vehicle speed

The actual model is then compared to the expected exhaust energy model.

  1. The engine is running, and a cold start has been detected.
  2. The vehicle speed is less than 2 km/h (1 mph).
  3. The catalyst temperature is greater than 1, 000°C (1, 832°F).
  4. The coolant temperature is greater than 56°C (133°F).
  5. The engine run time is greater than 18 s.
  6. The engine is at idle with no input from the accelerator pedal for greater than 5 s.
  7. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0201, P0202, P0203, P0204, P0300, P0335, P0336, P0351, P0352, P0353, P0506, P0507, P0601, P0602, P0603, P0604, P0606, P0607, P062F, P0641, P0651, P1516, P1682, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176, P2610 are not set.
  8. This DTC runs within 15 seconds within the first 2 minutes of start-up. This diagnostic runs once per trip when a cold start has been determined.

The actual exhaust energy model does not match the expected exhaust energy model.

DTC P1400 is a Type A DTC.

DTC P1400 is a Type A DTC.

Any loading of the engine that lowers engine RPM, such as partial application of the clutch, A/C cycling, etc. during the first 120 seconds of the engine run time may set this DTC.

  1. Allow the engine to cool until the catalyst temperature is less than 500°C (932°F) and the engine coolant is greater than -10°C (+14°F).
  2. Idle the engine for greater than 2 minutes.
  3. Observe the scan tool DTC information. DTC P1400 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Inspect the air intake system for the following: Modified, damaged, or restricted Dirty or deteriorating air filter element Crankcase ventilation system for correct operation. Water intrusion Vacuum leak and other unmetered air downstream of the MAF sensor Intake manifold leak
  2. Inspect the exhaust system for the following: Water intrusion Exhaust leak Damaged, restricted, modified or enhanced exhaust system.
  3. Inspect the engine mechanical for items that could alter the air flow into the combustion chamber.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
TAC Motor Control ClosedP1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P0690, P1516, P2101, P2176P1516, P2101, P2176
TAC Motor Control OpenP1516, P2101, P2119, P2176P1516, P2101, P2176P1516, P2101, P2176P0690, P1516, P2101, P2176P1516, P2101, P2176

The throttle body assembly contains a contact-less inductive throttle position sensing element that is managed by a customized integrated circuit. The TP sensor is mounted within the throttle body assembly and is not serviceable. The engine control module (ECM) supplies the throttle body with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and an asynchronous signal/serial data circuit. The asynchronous signal means communication is only going from the throttle body to the ECM. The throttle body cannot receive data from the ECM over the signal/serial data circuit. The TP sensor provides a signal voltage that changes relative to throttle blade angle. The customized integrated circuit translates the voltage based position information into serial data using the Society of Automotive Engineers (SAE) J2716 Single Edge Nibble Transmission (SENT) protocol. The TP sensor information is transmitted between the throttle body and the ECM on the signal/serial data circuit. The ECM decodes the serial data signal and is used as voltages for TP sensor 1 and 2.

The ECM controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the TP sensor signal/serial data circuit to determine the actual throttle valve position.

P1516

  1. The run/crank or powertrain relay voltage is greater than 6.4 V and reduced power is not active.
  2. DTC P1516 runs continuously when the above conditions are met.

P2101

  1. DTC P1682 is not set.
  2. The run/crank or powertrain relay voltage is greater than 6.4 V and reduced power is not active.
  3. The engine is running or the following conditions are met: The engine is not running. The ignition voltage is greater than 11 V. The TAC system is not in the Battery Saver mode. The ECM is commanding the throttle. The ECM has learned the minimum throttle position.
  4. DTC P2101 runs continuously when the above conditions are met.

P2119

  1. DTCs P0122, P0123, P0222, P0223, or P06A3 is not set.
  2. The run/crank or powertrain relay voltage is greater than 6.4 V and reduced power is not active.
  3. The system is not in the Battery Save mode.
  4. The ECM is not commanding the throttle.
  5. DTC P2119 runs continuously when the above conditions are met.

P2176

  1. The run/crank or powertrain relay voltage is greater than 6.4 V and reduced power is not active.
  2. DTC P2176 runs continuously when the above conditions are met.

P1516

The ECM detects an unstable throttle position for greater than 1 s.

P2101

  1. The ECM detects the actual throttle position does not match the predicted throttle position for greater than 1 s. Or
  2. The ECM detects the throttle control is driving the throttle in the incorrect direction or exceed the reduced power limit.

P2119

The ECM determines that the throttle blade did not return to the rest position within 1 s.

P2176

The ECM detects that both throttle position (TP) sensors were greater than a predetermined voltage during the minimum throttle learn procedure for greater than 2 s.

  1. DTCs P1516, P2101, and P2176 are type A DTCs.
  2. DTC P2119 is a type C DTC.
  3. The ECM commands the TAC system to operate in the Reduced Engine Power mode.
  4. A message center or an indicator displays Reduced Engine Power.
  5. Under certain conditions, the control module commands the engine OFF.
  1. DTCs P1516, P2101, and P2176 are type A DTCs.
  2. DTC P2119 is a type C DTC.
  1. Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close.
  2. A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.
  3. A low battery condition may cause a DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON.
  2. Verify DTC P0121, P0122, P0123, P0222, P0223, P0562, P0621, P0622, or P2135 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If none of the DTCs are set
  3. Verify the scan tool Throttle Body Idle Airflow Compensation parameter is less than 90 %. 90 % or greater Refer to «Throttle Body Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__throttle-body-cleaning) . If less than 90 %
  4. Clear the DTCs with a scan tool.
  5. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
  6. Ignition ON.
  7. Verify the scan tool TAC Motor parameter displays Enabled. If Disabled Refer to Circuit/System Testing If Enabled
  8. Verify DTC P1516, P2101, P2119, or P2176 is not set. If any of the DTCs are set Refer to Circuit/System Testing If none of the DTCs are set
  9. Verify the scan tool TAC Motor parameter displays Enabled while performing the Throttle Sweep Test with a scan tool. If Disabled NOTE: Before replacing the throttle body assembly, make sure the TAC motor control circuits are not shorted to B+. Test or replace the Q38 throttle body assembly. If Enabled
  10. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  11. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing If the DTC does not set
  12. All OK
  1. Ignition OFF.
  2. Verify the conditions listed below do not exist with the Q38 throttle body assembly: A throttle blade that is not in the rest position A throttle blade that is binding open or closed A throttle blade that is free to move open or closed without spring pressure If a condition is found Test or replace the Q38 throttle body assembly. If a condition is not found
  3. Ignition OFF.
  4. Disconnect the harness connector at the Q38 throttle body assembly, ignition ON.
  5. Verify that a test lamp does not illuminate continuously between each motor control circuit listed below and ground. TAC Motor Control Open circuit terminal 1 TAC Motor Control Closed circuit terminal 2 If the test lamp illuminates continuously Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If the test lamp is always OFF
  6. Verify that a test lamp does not illuminate between each motor control circuit listed below and B+. TAC Motor Control Open circuit terminal 1 TAC Motor Control Closed circuit terminal 2 If the test lamp illuminates Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 engine control module. If the test lamp is always OFF
  7. Ignition OFF, set the DMM to the 40 V scale, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms.
  8. Verify the Max voltage is within 1 V of B+ while using DMM Min/Max Recording Mode function on each control circuit listed below as the ignition is turned ON. TAC Motor Control Open circuit terminal 1 TAC Motor Control Closed circuit terminal 2 If not within 1 V of B+ Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 engine control module. If within 1 V of B+
  9. Test or replace the Q38 throttle body assembly.
  1. «Throttle Body Assembly Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Install any components that have been removed or replaced during diagnosis.
  2. Perform any adjustments, programming or setup procedures that are required when a component is removed or replaced.
  3. Clear the DTCs with a scan tool.
  4. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
  5. Ignition ON.
  6. Verify the scan tool TAC Motor parameter displays Enabled while performing the Throttle Sweep Test with a scan tool. If Disabled Test or replace the Q38 throttle body assembly. If Enabled
  7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If any DTC sets Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If no DTCs set
  8. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM) or an out of range high pressure fuel pump actuator current.

  1. DTCs P0016, P0017, P0090, P0091, P0092, P0096, P0097, P0098, P00C8, P00C9, P00CA, P0111, P0112, P0113, P0116, P0117, P0118, P0128, P0178, P0179, P0192, P0193, P0335, P0336, P0340, P0341, P0365, P0366, P0627-P0629, P1682, P2269 are not set.
  2. The engine is running.
  3. The ignition voltage is greater than 11 V.
  4. The low side fuel pressure is greater than 275 kPa (40 psi).
  5. DTC P163A runs continuously when the conditions are met for greater than 500 mS.

The ECM detects a condition with the integrated circuits of the high pressure fuel pump actuator driver module or the ECM detects that the current used to drive the high pressure fuel pump actuator is out of range for greater than 4 s.

DTC P163A is a Type B DTC.

DTC P163A is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the G18 high pressure fuel pump.
  2. Test for 9-11 ohms at 25°C (77°F) between the low control circuit terminal 1 and the high control circuit terminal 2. If not within the specified range, replace the G18 high pressure fuel pump.
  3. Measure the resistance between each terminal and the high pressure fuel pump housing. The DMM should display OL. If less than the specified value, replace the G18 high pressure fuel pump.
  4. Ignition ON, verify that a test lamp does not illuminate between the high control circuit terminal 2 and ground and the low control circuit terminal 1 and ground. If the test lamp illuminates, test the appropriate control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Verify that a test lamp does not illuminate between the high control circuit terminal 2 and B+ and the low control circuit terminal 1 and B+. If the test lamp illuminates, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  6. Connect a 3 A fused jumper wire between the high control circuit terminal 2 and ground. The Fuel Pressure Regulator High Control Circuit Open Test Status should transition from Malfunction to OK and the Fuel Pressure Regulator High Control Circuit Low Voltage Test Status should transition from OK to Malfunction. If not the specified value, test the high control circuit for an open/high resistance.
  7. Connect a 3 A fused jumper wire between the low control circuit terminal 1 and B+. The Fuel Pressure Regulator Control Circuit Open Test Status should transition from Malfunction to OK and the Fuel Pressure Regulator Control Circuit High Voltage Test Status should transition from OK to Malfunction. If not the specified value, test the low control circuit for an open/high resistance.
  8. If all circuits and the high pressure fuel pump test normal, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pump Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit Description

Fuel trim bias is used to keep the post catalyst air/fuel ratio within a predetermined range. This allows optimal catalyst efficiency under various operating conditions. The engine control module (ECM) constantly monitors how lean or rich the fuel trim bias is commanded, to determine if the fuel trim bias is greater than a calibrated amount.

  1. DTC P0016, P0017, P0018, P0019, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0178, P0179, P0201, P0202, P0203, P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0301, P0302, P0303, P0304, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1221, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P219A, P2227, P2228, P2229, P2230, P2269, P2270, P2271, P2440, P2444, or P2A00 is not set.
  2. The barometric pressure (BARO) is greater than 70 kPa (10.2 PSI).
  3. The manifold absolute pressure (MAP) is between 0-200 kPa (0-29 PSI).
  4. The intake air temperature (IAT) is between -20 and +200°C (-4 and +392°F).
  5. The engine coolant temperature is greater than -20°C (-4°F).
  6. The engine is in Closed Loop status.
  7. The fuel control intrusive diagnostics are not active.
  8. The engine is operating under light acceleration, heavy acceleration, or cruise.
  9. DTC P2096 runs continuously when the conditions above have been met for greater than 40 seconds.

The lean correction limit for a condition causing a rich air/fuel ratio has been exceeded.

  1. DTCs P2096 is a Type B DTC.
  2. The ECM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the ECM stores this information in the Failure records. If the diagnostic reports a failure on the second ignition cycle, the ECM records the operating conditions at the time of the failure. The ECM writes the operating conditions to the Freeze Frame and updates the Failure records. The ECM illuminates the malfunction indicator lamp (MIL) when one of the following occurs: The ECM detects the same fuel trim failure during 2 consecutive trips. The ECM detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria: The engine load is within 20 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.
  1. DTCs P2096 is a Type B DTC.
  2. The ECM turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.
  3. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  1. It is very unlikely that an HO2S will cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC without first performing all the steps in Circuit/System Verification.
  2. The post catalyst fuel trim diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may cause a DTC to set.
  3. Certain aftermarket air filters may cause a DTC to set.
  4. Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.
  5. Certain aftermarket exhaust system components may cause a DTC to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set. If any other HO2S or fuel trim DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Verify that none of the following conditions exist: The air intake duct for being collapsed or restricted. The air filter for biting dirty or restricted. Objects blocking the throttle body. Excessive fuel in the crankcase. Change engine oil as necessary. Rich fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Excessive fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Fuel saturation of the evaporative emissions (EVAP) canister Stuck open or leaking EVAP purge valve Restricted exhaust-Refer to «Symptoms - Engine Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) Incorrect PCV system operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc) If you find any of the above conditions, repair as necessary.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Fuel trim bias is used to keep the post catalyst air/fuel ratio within a predetermined range. This allows optimal catalyst efficiency under various operating conditions. The engine control module (ECM) constantly monitors how lean or rich the fuel trim bias is commanded, to determine if the fuel trim bias is greater than a calibrated amount.

  1. DTC P0016, P0017, P0018, P0019, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0178, P0179, P0201, P0202, P0203, P0204, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0301, P0302, P0303, P0304, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1221, P1248, P1249, P124A, P124B, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P219A, P2227, P2228, P2229, P2230, P2269, P2270, P2271, P2440, P2444, or P2A00 is not set.
  2. The barometric pressure (BARO) is greater than 70 kPa (10.2 PSI).
  3. The manifold absolute pressure (MAP) is between 0-200 kPa (0-29 PSI).
  4. The intake air temperature (IAT) is between -20 and +200°C (-4 and +392°F).
  5. The engine coolant temperature is greater than -20°C (-4°F).
  6. The engine is in Closed Loop status.
  7. The fuel control intrusive diagnostics are not active.
  8. The engine is operating under light acceleration, heavy acceleration, or cruise.
  9. DTC P2097 runs continuously when the conditions above have been met for greater than 40 seconds.

The rich correction limit for a condition causing a lean air/fuel ratio has been exceeded.

  1. DTCs P2097 is a Type B DTC.
  2. The ECM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the ECM stores this information in the Failure records. If the diagnostic reports a failure on the second ignition cycle, the ECM records the operating conditions at the time of the failure. The ECM writes the operating conditions to the Freeze Frame and updates the Failure records. The ECM illuminates the malfunction indicator lamp (MIL) when one of the following occurs: The ECM detects the same fuel trim failure during 2 consecutive trips. The ECM detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria: The engine load is within 20 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.
  1. DTCs P2097 is a Type B DTC.
  2. The ECM turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the diagnostic runs and does not fail.
  3. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  1. It is very unlikely that an HO2S will cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC without first performing all the steps in Circuit/System Verification.
  2. The post catalyst fuel trim diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may cause a DTC to set.
  3. An exhaust system leak that may not be audible can set this DTC.
  4. Certain aftermarket air filters may cause a DTC to set.
  5. Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.
  6. Certain aftermarket exhaust system components may cause a DTC to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set. If any other HO2S or fuel trim DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Verify that none of the following conditions exist: Exhaust system leaks-Refer to «Symptoms - Engine Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) Vacuum hoses for splits, kinks, and proper connections Insufficient fuel in the tank The air induction system and the air intake ducts for leaks or for a missing air filter element A cracked evaporative canister Evaporative pipes plugged, obstructed, or leaking The crankcase ventilation system for leaks. Refer to «Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc) Engine vacuum leaks Low fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Lean fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . If you find any of the above conditions, repair as necessary.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Accelerator Pedal Position (APP) Sensor 1 5 V Reference CircuitP06A3P2138P2122P06A3P2138
Accelerator Pedal Position (APP) Sensor 2 5 V Reference CircuitP0108, P0107, P0697P2138P2127P0106, P0108, P0697P2138
Accelerator Pedal Position (APP) Sensor 1 SignalP2122P2138P2122P2123, P2138P2138
Accelerator Pedal Position (APP) Sensor 2 SignalP2127P2138P2127P2128, P2138P2138
Accelerator Pedal Position (APP) Sensor 1 Low ReferenceP2138P2123P2138
Accelerator Pedal Position (APP) Sensor 2 Low ReferenceP2138P2128P2138
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 1 0.88-1.08 V
APP Sensor 1 5 V Reference0.00 V0.00 V2-3 V
APP Sensor 1 Signal0.00 V0.00 V4-5 V
APP Sensor 1 Low Reference4-5 V

APP Sensor 1

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 2 0.39-0.59 V
APP Sensor 2 5 V Reference0.00 V0.00 V1-3 V
APP Sensor 2 Signal0.00 V0.00 V2-5 V
APP Sensor 2 Low Reference4-5 V

APP Sensor 2

The accelerator pedal assembly contains 2 accelerator pedal position (APP) sensors. The APP sensors are mounted to the accelerator pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to pedal position. The engine control module (ECM) supplies each APP sensor with a 5 V reference circuit, a low reference circuit, and a signal circuit.

Both the APP sensors 1 and 2 signal percentages increase as the pedal is depressed, from approximately 0 percent at rest to above 95 percent when fully depressed.

P2122, P2123, P2127, or P2128

  1. DTC P06A3 or P0697 are not set.
  2. The ignition is ON or the engine is operating.
  3. The ignition voltage is greater than 6 V.
  4. The ECM is not commanding reduced power.
  5. The DTCs run continuously when the above conditions are met.

P2138

  1. DTCs P06A3, P0697, P2122, P2123, P2127, or P2128 are not set.
  2. The ignition is ON or the engine is operating.
  3. The ignition voltage is greater than 6 V.
  4. The ECM is not commanding reduced power.
  5. The DTC runs continuously when the above conditions are met.

P2122

The ECM detects that the APP sensor 1 voltage is less than 0.46 V for less than 1 s.

P2123

The ECM detects that the APP sensor 1 voltage is greater than 4.7 V for less than 1 s.

P2127

The ECM detects that the APP sensor 2 voltage is less than 0.32 V for less than 1 s.

P2128

The ECM detects that the APP sensor 2 voltage is greater than 2.6 V for less than 1 s.

P2138

The ECM detects that APP sensor 1 and APP sensor 2 disagree greater than 10 percent for less than 1 s.

OR

The ECM detects that both APP sensor 1 and APP sensor 2 are 5 percent greater than the learned minimum position for less than 1 s.

  1. DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.
  2. The ECM commands the TAC system to operate in a Reduced Engine Power mode.

DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.

  1. A high resistance condition on the accelerator pedal position circuits could cause a DTC to set.
  2. Ensure that the in-line harness connector seals are installed correctly. Improper installation could result in water intrusion into the connector and cause a DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON.
  2. Verify DTC P0697 or P06A3 is not set. If any of the DTCs are set Refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) for further diagnosis. If none of the DTCs are set
  3. Verify the APP Sensor 1 Circuit Status and APP Sensor 2 Circuit Status displays OK. If Malfunction is displayed Refer to Circuit/System Testing If OK is displayed
  4. Verify the scan tool APP Sensor 1 and 2 Agree/Disagree parameter displays Agree while performing the tests listed below: Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. If Disagree Refer to Circuit/System Testing If Agree
  5. Verify that DTC P2122, P2123, P2127, P2128, or P2138 is not set. If any of the DTCs are set Refer to Circuit/System Testing If none of the DTCs set
  6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  7. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing If the DTC does not set
  8. All OK
  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B107 accelerator pedal assembly. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between each low reference circuit terminal listed below and ground. Low reference circuit terminal 4 Low reference circuit terminal 5 If 5 ohms or greater Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 engine control module. If less than 5 ohms
  3. Ignition ON.
  4. Test for 4.8-5.2 V between each 5 V reference circuit terminal listed below and ground. 5 V reference circuit terminal 1 5 V reference circuit terminal 2 If less than 4.8 V Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 engine control module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 engine control module. If between 4.8-5.2 V
  5. Verify each APP sensor voltage parameter is less than 0.2 V. If 0.2 V or greater Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON. Test for less than 1 V between the signal circuit terminal listed below and ground. APP sensor 1 signal circuit terminal 3 APP sensor 2 signal circuit terminal 6 If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 engine control module. If less than 0.2 V
  6. Install a 3 A fused jumper wire between each signal circuit terminal listed below and the 5 V reference circuit terminal 1. APP sensor 1 signal circuit terminal 3 APP sensor 2 signal circuit terminal 6
  7. Verify the scan tool APP sensor voltage parameter is greater than 4.8 V. If 4.8 V or less Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for infinite resistance between the signal circuit terminal and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 engine control module. If greater than 4.8 V
  8. Test or replace the B107 accelerator pedal assembly.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Accelerator Pedal Position Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
IAT Sensor 1 SignalP0112, P0114, P2199P0111, P0113, P0114, P2199P0113*, P0114, P2199P0111, P2199
Low ReferenceP0111, P0113, P0114, P2199P0113*, P0114
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 1

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition 1 VoltageP0096, P0097, P11C3, P2199P0096, P0097, P0102, P11C2, P2199P0096
IAT Sensor 2 SignalP0096, P0097, P0102, P11C2, P2199P0096, P0097, P11C2, P2199P0096*, P0097, P11C2, P2199P0096
GroundP0096, P0097, P0102, P11C2, P2199P0096
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 2

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient temperature; and engine bay conditions
IAT Sensor 1 Signal150°C (302°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 1

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient humidity and temperature; and engine bay conditions
Ignition 140°C (-40°F)40°C (-40°F)
IAT Sensor 2 Signal40°C (-40°F)40°C (-40°F)40°C (-40°F)*
Ground40°C (-40°F)
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

IAT Sensor 2

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with coolant temperature
ECT Sensor Signal150°C (302°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+

ECT Sensor

The intake air temperature (IAT) sensor 1 is a variable resistor that measures the temperature of the air in the sensor bore. The engine control module (ECM) supplies 5 V to the IAT sensor 1 signal circuit and a ground for the IAT sensor 1 low reference circuit. The signal varies with inlet air temperature and is displayed by the scan tool as °C (°F).

The IAT sensor 2 produces a frequency signal based on the inlet air temperature very close to the humidity sensor within the sensor bore. The signal varies with inlet air temperature and is displayed by the scan tool as °C (°F) and Hertz (Hz). The ECM applies 5 V to the circuit. The signal circuit is shared by the IAT sensor 2 and the humidity sensor. Ignition voltage and ground circuits are also supplied to the multifunction intake air sensor's internal circuits for these sensors

  1. IAT sensor 2
  2. Humidity sensor
  3. MAF sensor

The multifunction intake air sensor houses the following

  1. IAT sensor 1
  2. IAT sensor 2
  3. Humidity sensor
  4. MAF sensor
  5. BARO pressure sensor
IAT Sensor 1IAT Sensor 1 ResistanceIAT Sensor 1 Signal Voltage
ColdHighHigh
WarmLowLow
IAT Sensor 2IAT Sensor 2 FrequencyIAT Sensor 2 Temperature
Cold45 Hz40°C (-40°F)
Warm302 Hz104°C (219°F)
  1. The ignition is ON.
  2. Ignition 1 voltage is at least 11 V.
  3. This DTC runs continuously within the enabling conditions.

The ECM detects that the absolute difference between the IAT sensor 1 and the IAT sensor 2 temperatures is greater than 55°C (99°F) for longer than 5 s.

DTC P2199 is a Type B DTC.

DTC P2199 is a Type B DTC.

  1. With the ignition ON, the engine OFF, if the engine is cold, a properly functioning IAT sensor 2 will gradually increase the scan tool IAT Sensor 2 parameter. This is due to the heat that is generated by the multifunction intake air sensor heating elements.
  2. Depending on the ambient temperature, an IAT sensor 1 signal circuit that is shorted to the MAF sensor signal circuit can cause either a rapid fluctuation in the IAT Sensor 1 parameter or cause it to become stuck at a given value.
  3. An IAT sensor 1 low reference circuit that is open can cause the IAT Sensor 1 parameter response to be sluggish.
  4. The humidity sensor and the IAT sensor 2 signals are sent to the ECM on the same circuit. If the IAT Sensor 2 parameter displays the values: 10 Hz; -40°C (-40°F), and there are Humidity Sensor DTCs, check for a circuit problem.

Schematic Reference

Engine Controls Schematics Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References Control Module References for scan tool information

Special Tools

  1. «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment)
  2. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-special-tools-and-equipment__special-tools-diagnostic-tools) .

Note. Perform Step 1 of this verification procedure only if the ignition has been OFF for 8 hours or more.

  1. Ignition ON, observe the following scan tool parameters. The readings should be within 30°C (54°F) of each other. Start-Up IAT Sensor 1 IAT Sensor 2 Start-Up ECT
  2. Engine running, observe the scan tool IAT Sensor 1 and IAT Sensor 2 parameters. Depending on the current ambient temperature, engine bay conditions, and the vehicle operating conditions, the readings should be between: -38 and +149°C (-36 and +300°F) for IAT Sensor 1 -38 and +149°C (-36 and +300°F) for IAT sensor 2
  3. Operate the vehicle within the conditions for running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
  2. Ignition OFF, all systems OFF. It may take up to for 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the low reference circuit terminal 3 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition OFF, all vehicle systems OFF, test for less than 5 ohms between the ground circuit terminal 7 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool IAT Sensor 1 parameter is colder than -39°C (-38°F). If warmer than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool IAT Sensor 1 parameter is warmer than 149°C (300°F). If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the circuit and repair or replace as necessary.
  7. Ignition ON, test for 4.8-5.2 V between the IAT sensor 2 signal circuit terminal 8 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. NOTE: If the signal circuit is shorted to a voltage the ECM or the sensor may be damaged. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  8. Ignition OFF, connect the red lead of the «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment) to the signal circuit terminal 8 at the harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  9. Set the «J 38522»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-6t406t456t50-special-tools-and-equipment) to the following specifications. Signal switch to 5 V Duty Cycle switch to 50 % (Normal) Frequency switch to 30 Hz
  10. Ignition ON, observe the scan tool IAT Sensor 2 parameter. The scan tool parameter should be between 28-32 Hz. If the parameter is not within the specified range, replace the K20 ECM.
  11. If all circuits test normal, test or replace the B75C multifunction intake air sensor.
  1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
  2. Test the IAT sensor 1 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-intake-air) table. The resistance values should be in range of the table values. If not within the specified range, replace the B75C multifunction intake air sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The Air Fuel Imbalance diagnostic detects a rich or lean cylinder to cylinder air/fuel ratio imbalance. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal's frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0122, P0123, P0128, P0201-P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301-P0304, P0411, P0442, P0443, P0455, P0496, P1248, P1249, P124A, P124B, P2101, P2135, P2147, P2148, P2150. P2151, P2153, P2154, P2156, P2157, P2440, P2444 are not set.
  2. The device control is not active.
  3. The intrusive diagnostics are not active.
  4. The engine overspeed protection is not active.
  5. The engine is in closed loop status.
  6. The system voltage is greater than 11 V for greater than 2 s.
  7. The engine coolant temperature (ECT) is warmer than -20°C (-4°F).
  8. The engine speed is between 900-4, 200 RPM.
  9. The mass air flow is between 7-200 g/s.
  10. The AIR pump is not ON.
  11. Engine run time is greater than 30 s.
  12. Fuel level is greater than 10% and no fuel level sensor fault is present.
  13. The DTC runs continuously when the above conditions have been met.

Multiple samples of the pre-catalyst HO2S accumulated voltage are consistently greater than the desired value.

DTC P219A is a Type A DTC.

DTC P219A is a Type A DTC.

  1. The air fuel imbalance diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may cause a DTC to set.
  2. Monitoring the misfire current counters, or misfire graph, may help to isolate the cylinder that is causing the condition.
  3. Certain aftermarket air filters may cause a DTC to set.
  4. Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.
  5. Certain aftermarket exhaust system components may cause a DTC to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Troubleshooting with a Test Lamp»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__troubleshooting-with-a-test-lamp)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Read and record the Freeze Frame/Failure Records data taking note of the speed and load at which the DTC set.
  2. Diagnose any other DTCs that are set. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  3. With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 20-48 kPa. If the MAP sensor parameter is not between 20-48 kPa, refer to «DTC P0106»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) .
  4. Inspect the air induction system for modified, damaged, leaking, or restricted components.
  5. Inspect the crankcase ventilation system for improper operation. Refer to «Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc) .
  6. Inspect the vacuum hoses for splits, kinks, and improper connections.
  7. Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to «Symptoms - Engine Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  8. Test the fuel injectors for improper operation. Refer to «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  9. Test for fuel contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  10. Test for excessive fuel in the crankcase due to leaking injectors. Change engine oil as necessary.
  11. Test the ignition system for improper operation. Refer to «Electronic Ignition System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  12. Test the engine for any mechanical conditions such as sticking valves, lifters, etc., which could alter the flow into the combustion chamber. Refer to «Symptoms - Engine Mechanical»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verify the repair under the same speed and load as noted in the Freeze Frame/Failure Records data recorded during testing.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0651, P2227, P2228P2228P0651, P2229P2227, P2230
SignalP2227, P2228P2227, P2228P2227, P2229P2227, P2230
Low ReferenceP2227, P2229P2227, P2230
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, Engine OFF Parameter Normal Range: 56-105 kPa (8.1-15.2 psi), varies with altitude
5 V Reference0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Signal0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Low Reference127 kPa (18.4 psi)

BARO

The Barometric Pressure (BARO) sensor is integral to the multifunction intake air sensor and responds to changes in altitude and atmospheric conditions. This gives the engine control module (ECM) an indication of barometric pressure. The ECM uses this information to calculate fuel delivery. The BARO sensor provides a voltage signal to the ECM relative to the atmospheric pressure changes. The ECM monitors the BARO sensor signal for a voltage outside of the normal range.

P2227

  1. DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0121, P0122, P0123, P0222, P0223, P2101, P2135, P2228, or P2229 is not set.
  2. The engine is running for greater than 30 s. OR
  3. DTC P0106, P0107, P0108, P0237, P0238, P2228, P2229, P2230, or P2610 is not set.
  4. DTC P0107, P0108, P0237, P0238, P2228, or P2229 is not pending.
  5. The ignition is ON, the engine is OFF.
  6. The time between the current ignition cycle and the last time the engine was running is greater than 7 min.
  7. DTC P2227 runs continuously when the above conditions are met.

P2228 or P2229

  1. The engine is running for greater than 30 s.
  2. The DTCs run continuously when the above condition is met.

P2230

  1. DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0121, P0122, P0123, P0222, P0223, P2101, P2135, P2228, or P2229 is not set.
  2. The ignition is ON.
  3. DTC P2230 runs continuously when the above conditions are met.

P2227

  1. Engine running, the ECM detects that the difference between the BARO signal and the calculated BARO is greater than 9 kPa (1.3 psi) for 5 s, when the vehicle has traveled no more than 2.0 km (1.2 mi) since the last calculated BARO update, or if the difference is greater than 20 kPa (2.9 psi) for 5 s, when the vehicle has traveled greater than 2.0 km (1.2 mi) since the last calculated BARO update.
  2. Ignition ON, engine OFF, the ECM detects that the BARO pressure is less than 50 kPa (7.3 psi) or greater than 115 kPa (16.7 psi).

P2228

The ECM detects that the BARO sensor voltage is less than 2.0 V for greater than 5 s.

P2229

The ECM detects that the BARO sensor voltage is greater than 4.5 V for greater than 5 s.

P2230

The ECM detects that the difference between the current BARO sensor reading and the previous BARO sensor reading is greater than a calibrated threshold for greater than 5 s.

DTCs P2227, P2228, P2229, and P2230 are Type B DTCs.

DTCs P2227, P2228, P2229, and P2230 are Type B DTCs.

Inspect the inlet port on the BARO sensor (multifunction intake air sensor) for moisture or debris and attempt to dry or clean the inlet, if contaminated.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0641 or P0651 is not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Ignition ON, observe the scan tool BARO parameter. Compare the parameter to the «Altitude Versus Barometric Pressure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__altitude-versus-barometric-pressure) table. The BARO parameter should be within the specified range indicated in the table.
  3. Engine running observe the DTC information with a scan tool. DTC P2227, P2228, P2229, or P2230 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the B75C multifunction intake air sensor.
  2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the low reference circuit terminal 3 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  4. Verify the scan tool BARO Sensor parameter is less than 1 kPa (0.2 psi). If greater than the specified range, test the signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 2. Verify the scan tool BARO Sensor parameter is greater than 127 kPa (18.4 psi). If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  6. If the circuits test normal, replace the B75C multifunction intake air sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

System Description

The BorgWarner™ dual-scroll turbocharger incorporates a wastegate that is controlled by the engine control module (ECM) by means of a pulse width modulation (PWM) solenoid, to regulate the pressure ratio of the compressor. An ECM controlled compressor bypass valve, which uses a remotely mounted solenoid, is integrated into the unit to prevent compressor surging and damage from vibrations by opening during abrupt closed throttle conditions. The bypass valve is open during closed throttle deceleration conditions to allow air to recirculate in the turbocharger and maintain compressor speed. The valve closes during open throttle commands, to optimize turbo response.

Front wheel drive platforms also incorporate a bypass valve vacuum tank. The purpose of the tank is to provide an instant source of vacuum to the bypass valve, when it is commanded open by the ECM. This results in less pressure buildup under closed throttle conditions, thereby reducing compressor noise and surge.

The purpose of this diagnostic is to determine if the bypass valve is stuck closed. The ECM will first verify the integrity of the following sensors. The ECM then compares the actual measured mass air flow (MAF) to a modeled airflow that is derived from these inputs

  1. Throttle position
  2. Engine speed
  3. Boost pressure sensor
  4. Manifold absolute pressure (MAP) sensor
  1. DTC P0033, P0034, P0035, P0101, P0102, P0103, P0236, P0237, or P0238 is not set.
  2. The boost pressure versus the BARO pressure ratio is between 1.1-3.3.
  3. The turbocharger bypass valve has been commanded Open greater than 6% for greater than 1 s immediately after an abrupt closed throttle has occurred and the resulting pressure ratio across the compressor exceeds the calibrated pressure ratio limit.
  4. The DTC runs continuously when the above conditions have been met.

The ECM has detected a series of pulsations in the induction system that exceed a calibrated threshold.

DTC P2261 is a Type B DTC.

DTC P2261 is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information.

  1. Verify that DTC P0033, P0034, or P0035 is not set If a DTC is set, refer to «DTC P0033-P0035»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) for further diagnosis.
  2. Engine running, command the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool. A click should be heard and felt.
  3. Set up the scan tool for a snapshot of the induction data list. With the emergency brake on, the vehicle transmission in neutral, and the engine idling, perform a wide open throttle and then quickly release the accelerator. Review the Boost Pressure Sensor parameter. There should not be any abnormal pulsations of the parameter.
  4. With the parking brake ON and the engine idling in neutral, perform an audible test of the valve by depressing the throttle wide open, then quickly releasing it to a closed throttle position. A valve that is stuck shut will generate a rapid pulsating or fluttering sound. There should not be any unusual noise.
  5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify the conditions listed below do not exist: Vacuum leaks Vacuum line restrictions Bypass solenoid valve damage or sticking Bypass valve assembly damage. Refer to «Turbocharger Cleaning and Inspection (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__turbocharger-cleaning-and-inspection-ldk-lhu) Improper routing or connecting of the vacuum hoses on the turbocharger bypass valve solenoid, the bypass valve, and the bypass valve vacuum tank If a condition is found, repair or replace the affected component as necessary.
  2. If all inspections are normal, test or replace the charge air bypass valve.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Charge Air Bypass Valve Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Turbocharger Control Solenoid Valve Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) for turbocharger bypass valve solenoid replacement.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Alcohol content and fuel temperature information is supplied to the ECM from the fuel composition sensor. The fuel composition sensor has a battery positive circuit, a signal circuit, and a ground circuit. The fuel composition sensor uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes output signals accordingly. The signal circuit carries both the ethanol percentage, and the fuel temperature within the same signal. The signal is both variable frequency and variable pulse width. The frequency signal indicates the ethanol percentage, and the pulse width indicates fuel temperature. The ECM provides an internal pull up to 5 V on the signal circuit, and the fuel composition sensor pulls the 5 V to ground in pulses. The normal range of operating frequency is between 50-150 Hz. The normal pulse width ranges between 1-5 milliseconds. The microprocessor inside the sensor is capable of a certain amount of self-diagnosis. An output frequency of 180 Hz indicates that the fuel is contaminated or an internal sensor fault has been detected.

  1. The ignition voltage is greater than 11 V.
  2. The DTC runs continuously when the above condition is met.

The ECM detects that the fuel composition sensor output frequency is greater than 185 Hz for greater than 6 s.

DTC P2269 is a Type B DTC.

DTC P2269 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 38522 Variable Signal Generator
  2. J 44175-A Fuel Composition Tester

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) .

  1. Engine running, verify the scan tool Fuel Composition Sensor parameter is between 50-150 Hz.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify that there are no contaminants, water, or too high of a concentration of ethanol in the fuel. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) and the J 44175-A Instruction Manual.
  2. Ignition OFF, disconnect the harness connector at the B198 fuel composition sensor.
  3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the circuit, and repair or replace as necessary.
  5. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 3 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Ignition OFF, connect the red lead of the J 38522 Variable Signal Generator to the signal circuit terminal 3 at the B198 fuel composition sensor harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  7. Set the J 38522 Variable Signal Generator Signal to 5 V, the Frequency to 60 Hz, and the Duty Cycle to Normal.
  8. Ignition ON, verify the scan tool Fuel Composition Sensor parameter is at 60 Hz. If not at the specified value, replace the K20 ECM.
  9. If all circuits test normal, test or replace the B198 fuel composition sensor.
  1. Test the fuel composition using the J 44175-A Fuel Composition Tester and the J 44175-A Instruction Manual. Record the frequency.
  2. Compare the special tool test frequency and the scan tool Fuel Composition Sensor frequency parameter. The difference between the tool and the sensor should be less than 12 Hz. If greater than the specified value, replace the B198 fuel composition sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel System Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__fuel-system-cleaning)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
IGN VoltageP2534P2534

The fuel pump control module monitors the ignition voltage circuit in order to determine if the voltage is within the normal operating range.

The engine is running.

The FPCM detects that the IGN voltage is less than 6.0 V.

DTC P2534 is a Type A DTC.

DTC P2534 is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that DTC P0562 is not set. If DTC P0562 is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition OFF, disconnect the harness connector of the K27 fuel pump control module.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 15 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. If all circuits test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) , «Relay Replacement (Attached to Wire Harness)»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for a overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

To improve shift feel, the transmission control module (TCM) is constantly sending the engine control module (ECM) serial data messages with information regarding it's request for modifying engine speed or torque. The serial data messages are sent through two circuits which are part of a communication network called the controller area network (CAN). The ECM sets DTC P2544 when it detects a discrepancy in the structure of the message causing the integrity of the message to be questioned.

An intermittent fault in the CAN circuits will cause the ECM to set DTC P2544.

  1. The engine run time is greater than 0.5 s.
  2. No other CAN errors are present.

The ECM detects that the engine speed and torque modification messages from the TCM are either corrupted or intermittently missing for greater than 4 s.

  1. DTC P2544 is a Type B DTC.
  2. The TCM commands maximum line pressure during shifts, which results in harsh shifts.
  3. The TCM freezes adaptive functions.

DTC P2544 is a Type B DTC.

DTC Type Reference

  1. DTC P2544 is an informational DTC. Diagnose all other engine control DTCs prior to DTC P2544. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. If there are no other engine controls DTCs, diagnosis is accomplished by looking for an intermittent CAN circuit fault. Refer to «Scan Tool Does Not Communicate with High Speed GMLAN Device»(/buick/regal/v-2009-2013/remont/communication-devices/#data-communications-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for TCM replacement, setup, and programming.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ControlP0231P023FP0232P023F, P2635
Low ReferenceP023FP023F, P2635

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

  1. DTC P018B, P018C, P018D, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active.
  2. DTC P0641 has not failed this ignition cycle.
  3. Fuel pump control is enabled and the fuel pump control state is normal.
  4. The system voltage is greater than 11 V.
  5. The engine has been running for more than 30 seconds.

This DTC sets when the fuel pump control module detects a predetermined fuel pressure performance degradation between the desired fuel rail pressure and the current fuel rail pressure.

DTC P2635 is a Type B DTC.

DTC P2635 is a Type B DTC.

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

On vehicles equipped with a high pressure mechanical pump on Direct Fuel Injection engines, the vehicle may continue to run even though the pump in the fuel tank is not operating.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Do not replace the fuel pump control module based on a history DTC P2635. The DTC P2635 may be stored but that does not indicate a failure of the fuel pump control module. Refer to Strategy Based Diagnosis for further history DTC diagnostics.

  1. Verify that DTCs P018C, P018D, P0231, P0232, or P023F are not set. If any of the DTC are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
  3. Ignition OFF, test for less than 5.0 ohms between the G12 fuel pump low reference circuit terminal 2 and ground. If greater than the specified range, test the G12 fuel pump low reference circuit for a high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  4. Ignition OFF, install a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
  5. Ignition ON, command the ECM Fuel Pump Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  6. Perform the «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) to verify proper fuel pressure. If the fuel pressure is not normal, replace the G12 fuel pump
  7. If all circuits test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel Tank Fuel Pump Module Replacement (NU6)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) , «Fuel Tank Fuel Pump Module Replacement (NT7)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.

Symptoms Description

Symptoms covers conditions that are not covered by DTCs. Certain conditions can cause multiple symptoms. These conditions are listed together under Symptoms Testing. Conditions that may only cause specific symptoms are listed separately under Additional Symptoms Testing. Perform the Symptoms Testing before using the Additional Symptoms Testing.

Symptoms Verification

Before using the Symptom tables, perform the following inspections

  1. Verify the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
  2. Verify there are no DTCs that are stored.
  3. Verify the scan tool data is within a normal operating range. Refer to «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for scan tool information.
  4. Verify the customer concern.
  5. Perform the Visual/Physical Inspection in this section. The visual/physical inspection is extremely important, and can lead to correcting a condition without additional testing. It may also help reveal the cause of an intermittent condition.

Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movements of a component. Refer to the following for a list of issues that may cause an intermittent condition

  1. Moisture and water intrusion in connectors, terminals, and components
  2. Incomplete connector mating
  3. Poor terminal contact
  4. High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
  5. Harness that is too short or tight
  6. Wire insulation that is chaffed or cut
  7. High or low ambient temperature
  8. High or low engine coolant temperatures
  9. High underhood temperatures
  10. Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
  11. High or low system voltage
  12. High vehicle load conditions
  13. Rough road surfaces
  14. Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
  15. Incorrect installation of aftermarket, add on accessories

Visual/Physical Check

  1. Verify the control module grounds are clean, tight, and correctly located.
  2. Verify the vacuum hoses are not split or kinked, and are properly connected, as shown on the Vehicle Emission Control Information label.
  3. Verify the air filter is clean and free from restrictions.
  4. Verify there is no water intrusion in connectors terminals and components.
  5. Inspect the air intake ducts for the following conditions: Collapsed Damaged areas Looseness Incorrect installation Leaking
  6. Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
  7. Inspect the wiring harness for the following conditions: Poor connections Pinches Cuts
  8. Inspect for loose, damaged, unseated, or missing sensors/components.
  9. Inspect the terminals for corrosion and correct contact.

Symptoms Testing

Backfire, Cuts Out/Misses, Detonation/Spark Knock, Dieseling/Run-On, Hard Start, Hesitation/Sag/Stumble, Lack of Power/Sluggishness/Sponginess, Poor Fuel Economy, Rough, Unstable, or Incorrect Idle and Stalling, or Surges/Chuggles

  1. Test the fuel system for the following: Correct fuel system operation and pressure-Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Poor fuel quality condition-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Improperly operating fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  2. Test the ignition system for the following: Spark plugs with incorrect heat range or an abnormal condition-Refer to «Spark Plug Inspection»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__spark-plug-inspection) , and «Ignition System Specifications»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__ignition-system-specifications) . Coolant or oil fouled spark plugs-for diagnosis, refer to «Coolant in Combustion Chamber (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__coolant-in-combustion-chamber-ldk-lhu) , or «Oil Consumption Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Secondary ignition system susceptible to water. Engine running, wet down the secondary ignition system with water from a spray bottle to help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied. Weak spark using the «J 26792»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-special-tools-and-equipment__special-tools-diagnostic-tools) Spark Tester-Refer to «Electronic Ignition System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  3. Inspect for the following conditions: On vehicles equipped with automatic transmission, improper operation of the transmission torque converter clutch (TCC)-The scan tool should indicate an engine speed drop when the TCC is commanded ON. Refer to «Torque Converter Diagnosis»(/buick/regal/v-2009-2013/remont/automatic-trans/#automatic-transmission-af40-6__torque-converter-diagnosis) . Improper operation of the A/C compressor. An engine that runs lean or rich. Observe the Fuel Trim parameters with a scan tool and refer to «DTC P0171 or P0172»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) for more information. Slow responding heated oxygen sensors (HO2S). The HO2S should respond quickly to different throttle positions. Refer to «DTC P0131, P0132, P0134, P0137, P0138, or P0140»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) . CAUTION: Refer to «Heated Oxygen and Oxygen Sensor Caution»(/buick/regal/v-2009-2013/remont/oem-general-information/#dangers-warnings-and-cautions__heated-oxygen-and-oxygen-sensor-caution) . Water intrusion in the HO2S connector NOTE: The embossed arrows on the mass air flow (MAF) sensor indicate the direction of the intake air flow. The arrows must point toward the engine. Improper MAF sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Install the MAF in the proper direction. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) . Improper mass air flow (MAF) sensor connections. Engine oil contaminated by fuel Split or kinked vacuum hoses-Verify that the routing and connections are as shown on the Vehicle Emission Control Information label. Excessive knock sensor spark retard activity-Observe the Knock Retard parameter on the scan tool for activity more than 0°.
  4. Inspect the exhaust system components for the following: Physical damage or possible internal failure Restricted three-way catalytic converters For more information, refer to «Symptoms - Engine Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  5. Inspect for electromagnetic interference (EMI) on the reference circuit, which can cause a misfire condition. You can usually detect EMI with a scan tool by monitoring the Engine Speed parameter. A sudden increase in the engine RPM with little change in actual engine speed indicates that EMI is present. Inspect the high voltage components near the ignition control circuit if a condition exists.
  6. Inspect the crankcase ventilation valve for improper operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc) .
  7. Inspect for a stuck open evaporative emission (EVAP) canister purge solenoid.
  8. Inspect the engine cooling system for the following conditions: A thermostat with incorrect heat range. Refer to «Thermostat Diagnosis»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) . Improper engine coolant level-If the level is low, refer to «Loss of Coolant»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
  9. Inspect the crankshaft position sensor for an intermittent condition-Observe the scan tool Crankshaft Position Resync Counter parameter. The Resync Counter parameter should remain at 0 during all operating conditions, and when moving the related harnesses and connectors between the crankshaft position sensor and the ECM.
  10. Inspect the engine for the following mechanical failures: Refer to «Symptoms - Engine Mechanical»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures) . Excessive oil in the combustion chamber or leaking valve seals Oil Consumption Incorrect cylinder compression Sticking or leaking valves Worn camshaft lobes Incorrect valve timing Worn rocker arms Broken valve springs Excessive carbon buildup in the combustion chambers-Clean the chambers with top engine cleaner, if necessary. Follow the instructions on the can. Incorrect engine parts
  11. If the above conditions do not address the symptom, refer to the additional symptoms tests.

Additional Symptoms Tests

Detonation/Spark Knock

  1. Test for an engine overheating condition. Refer to «Engine Overheating»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
  2. Verify that the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LUK)»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information-all-systems__engine-control-module-scan-tool-information) , «Engine Control Module Scan Tool Information (LEA)»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information-all-systems__engine-control-module-scan-tool-information) , list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance (ECT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-ect) , «Temperature Versus Resistance (IAT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat) , «Temperature Versus Resistance (IAT 2)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat-2) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  3. Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner, if necessary. Follow the instructions on the can.
  4. If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle minimum octane requirements.

ECM Commanded Reduced Engine Power

Under certain conditions the ECM may limit engine power by reducing engine torque and, for some vehicles, fuel pressure as well. For most, but not all of the conditions, the ECM will illuminate the reduced engine power lamp on the instrument panel cluster, however a DTC may not be set. Observe the scan tool Reduced Engine Power History parameter, if applicable, or refer to Engine Control Module Scan Tool Information (LUK) , Engine Control Module Scan Tool Information (LEA) to determine the reason for the reduced engine power event.

Verify or inspect for the following

  1. Vehicle being operated at sustained high engine speeds, or, towing heavy loads up an incline for an extended period of time, which may cause the engine oil or coolant to overheat. A repair may not be necessary. Inspect the airflow passageways in front of the engine for obstructions and clear away any debris or foreign material that is found. If no obstructions are found, review approved driving habits with the customer. The customer may need to operate the vehicle at a higher engine speed to improve cooling system performance, or, at a slower engine speed to reduce engine load.
  2. A cooling fan condition which may cause the ECM to reduce engine power. Refer to «Cooling Fan Description and Operation (LAF, LEA, LUK)»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-description-and-operation-24l) , «Cooling Fan Description and Operation (LDK or LHU)»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-fan-description-and-operation-20l) , and «Cooling System Description and Operation»(/buick/regal/v-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-description-and-operation) to verify correct operation of the cooling fan.
  3. Temporarily reduced engine power. Under extremely cold ambient temperatures some SIDI equipped vehicles may experience ECM commanded reduced engine power for a few minutes during engine warm-up. This would be a normal condition, noticeable only at wide open throttle, and the reduced engine power lamp would not be illuminated.
  4. Reduced engine power due to OnStar® remote command. Verify the vehicle is not in the OnStar® initiated Stolen Vehicle Slowdown mode. Refer to «OnStar Stolen Vehicle Slowdown Active»(/buick/regal/v-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system) , and «Remote Vehicle Speed Limiting Description and Operation»(/buick/regal/v-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__remote-vehicle-speed-limiting-description-and) for additional information.
  5. Excessively high fuel pressure condition. Refer to «Fuel System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) , and «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) to verify fuel system operation.
  6. Maximum recommended engine oil life exceeded. Refer to the Owners Manual for scheduled maintenance recommendations.
  7. High transmission oil temperature, if equipped with a manual transmission, may cause the ECM to command reduced engine power. Observe the Manual Transmission Over-temperature Protection Mode and the Manual Transmission Over-temperature Activation Counter parameters with a scan tool for any activity.
  8. Turbocharger boost pressure out of range. Refer to «Turbocharger System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) .
  9. Intake air temperature out of range too high. Observe the scan tool IAT Sensor 1 and IAT Sensor 2 parameters. The readings should be within 9°C (16°F) of a each other. Refer to DTC P0096 or P0111 for more information.
  10. Fuel temperature out of range too high. Observe the scan tool Fuel Temperature Sensor parameter and refer to DTC P0178 and DTC P0179 for more information.

Hard Start

  1. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__throttle-body-cleaning)
  2. Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance (ECT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-ect) , «Temperature Versus Resistance (IAT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat) , «Temperature Versus Resistance (IAT 2)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat-2) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  3. Verify that the fuel system has adequate pressure for engine start-up. Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) for fuel pressure specifications.
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__crankshaft-and-bearing-cleaning-and-inspection) .

Hesitation, Sag, Stumble

  1. Test the fuel pressure. Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  3. Test the generator. Refer to «Symptoms - Engine Electrical»(/buick/regal/v-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-non-hybrid__symptoms-engine-electrical) . Repair the charging system if the generator output voltage is less than 9 V or more than 16 V.
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position sensor reluctor wheel to move out of alignment with the crankshaft position sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__crankshaft-and-bearing-cleaning-and-inspection) .
  5. Test the manifold absolute pressure (MAP) sensor. Refer to «DTC P0106»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) .
  6. Engine warm and idling, verify the correct operation of the camshaft actuator system. Command the intake and exhaust camshaft actuators from 0 degrees to 25 degrees and back to zero while observing the scan tool Intake and Exhaust Camshaft Position Variance parameters. The variance should be less than 2 degrees in each of the commanded states. If the variance is greater than 2 degrees, inspect the suspect camshaft actuator and camshaft actuator solenoid valve and valve bore for contamination, obstruction, and damage. Refer to «Camshaft Position Actuator Solenoid Valve Replacement (Intake)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) , «Camshaft Position Actuator Solenoid Valve Replacement (Exhaust)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) , and «Camshaft Actuator System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) .

Fuel Odor

  1. Inspect for a saturated EVAP canister-Refer to «Evaporative Emission Control System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) .
  2. Inspect for a condition with the internal components of the fuel tank assembly-Refer to «Fuel System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) .
  3. Inspect for damaged, leaking, or deteriorated fuel lines.

Lack of Power, Sluggishness, or Sponginess

  1. Verify that each injector harness is connected to the correct injector.
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  3. Verify the turbocharger air inlet and outlet ducts are tightly sealed and that the air passages are not obstructed. Inspect the turbocharger moving components for looseness, binding, wear, and damage. Refer to «Turbocharger System Description»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-description-and-operation) , and «Turbocharger Cleaning and Inspection (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__turbocharger-cleaning-and-inspection-ldk-lhu) .
  4. Inspect for excessive turbocharger noise. Refer to «Turbocharger Whine Noise (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-whine-noise-ldk-lhu) , or «Turbocharger Hissing Noise (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-hissing-noise-ldk-lhu) .
  5. Inspect the engine electrical system for correct operation. Refer to «Symptoms - Engine Electrical»(/buick/regal/v-2009-2013/remont/charging-system/#battery-charging-system-and-starting-system-non-hybrid__symptoms-engine-electrical) .

Poor Fuel Economy

  1. Inspect for heavy loads being carried or towed
  2. Inspect for acceleration rate too much or too often
  3. Inspect the brake system for brake drag.
  4. Inspect for incorrect operation of the speedometer.
  5. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__throttle-body-cleaning)
  6. Verify the engine coolant temperature (ECT) has not shifted in value. Allow the engine to run and reach operating temperature. Observe the ECT Sensor parameter with a scan tool and compare the reading to that parameter listed on the «Engine Control Module Scan Tool Information (LUK)»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information-all-systems__engine-control-module-scan-tool-information) , «Engine Control Module Scan Tool Information (LEA)»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-scan-tool-information-all-systems__engine-control-module-scan-tool-information) , list. If the reading is not in the range specified in the list, test the resistance of the ECT sensor. Refer to «Temperature Versus Resistance (ECT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-ect) , «Temperature Versus Resistance (IAT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat) , «Temperature Versus Resistance (IAT 2)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat-2) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  7. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .

Rough, Unstable, or Incorrect Idle and Stalling

  1. Observe the TB Idle Airflow Compensation parameter with a scan tool. A value greater than 80 % may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to «Throttle Body Cleaning»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__throttle-body-cleaning)
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  3. Inspect the engine mounts-Refer to «Engine Mount Inspection»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-on-vehicle__engine-mount-inspection) .
  4. Inspect the intake and exhaust manifolds for casting flash.

Surges/Chuggles

  1. Verify that each injector harness is connected to the correct injector.
  2. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  3. Inspect for slow responding heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The PCM reduces the amount of fuel delivered to the engine, causing a driveability condition. Refer to «DTC P0131, P0132, P0134, P0137, P0138, or P0140»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) .
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The malfunction indicator lamp (MIL) illuminates to inform the driver that an emission system fault has occurred and the engine control system requires service. Ignition voltage is supplied directly to the MIL and, when the emission system fault occurs, the engine control module (ECM) turns the MIL ON by grounding the MIL control circuit. Under normal operating conditions, the MIL should be ON only when the ignition is ON and the engine is OFF.

If the condition is intermittent, move the related harnesses and connectors with the ignition ON and the engine OFF, and with the engine operating while monitoring the scan tool MIL control circuit status parameters. The MIL control circuit status parameters will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

  1. «Engine Controls Schematics»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-wiring-schematic-diagrams)
  2. «Instrument Cluster Schematics»(/buick/regal/v-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Note. Any MIL requesting DTCs that may be set should be diagnosed first.

  1. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
  2. Command the MIL ON and OFF while observing the following control circuit status parameters: The MIL Control Circuit Low Voltage Test Status The MIL Control Circuit Open Test Status The MIL Control Circuit High Voltage Test Status Each parameter should display OK or Not Run.
  3. Engine running, command the MIL ON and OFF while observing the following control circuit status parameters: The MIL Control Circuit Low Voltage Test Status The MIL Control Circuit Open Test Status The MIL Control Circuit High Voltage Test Status Each parameter should display OK or Not Run.
  1. Ignition OFF, disconnect the X1 harness connector at the K20 ECM.
  2. Ignition ON, the MIL should not illuminate. If the MIL is illuminated, test the MIL control circuit terminal 46-X1 for a short to ground. If the circuit tests normal, replace the P16 instrument panel cluster.
  3. Connect a 3 A fused jumper wire between the MIL control circuit terminal 46-X1 and ground. The MIL should illuminate. If the MIL illuminates, replace the ECM. If the MIL does not illuminate, test the MIL control circuit for a short to voltage or an open/high resistance. If the MIL control circuit tests OK, test the instrument cluster ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the instrument panel cluster/bulb.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Instrument Cluster Replacement»(/buick/regal/v-2009-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  2. «Control Module References»(/buick/regal/v-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for replacement. setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This Engine Cranks but Does Not Run diagnostic is an organized approach to identify a condition which causes the engine to crank but not start. This diagnostic directs the technician to the appropriate system diagnosis.

Inspect for any of the following conditions

  1. When attempting to start the engine, the mechanical portion of the vehicle key must be locked in the fully extended position with the fob parallel to the key. Leaving the key partially retracted or folded over when starting may interrupt transponder authentication and result in an intermittent no-start condition. In such instances, DTC B3055 may also be set. If an intermittent no-start complaint is received, it may be necessary to discuss with the customer their starting habits and verify they are locking the key in the fully extended position, fob parallel to the key, before starting.
  2. Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
  3. The fuel injectors are calibrated to begin operating at 0.8 MPa (116 psi) at 20-32°C (68-90°F). This specification will vary when the temperature is outside of this range.
  4. Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid, can cause a no start condition. Refer to «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) , and «Fuel Injector Balance Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  5. There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the values indicated with the expected values or the values from a known good vehicle.
  6. Check the crankshaft position sensor engine reference signal with a scan tool. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200-300 RPM while cranking. If erratic values, such as sudden spikes in the engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run properly.
  7. Inspect the engine for good secure electrical grounds.
  8. If the engine almost starts and then stalls, check for an open in the ground circuits of the crankshaft position sensor and the camshaft position sensor.
  9. Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 min in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
  10. A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. «CH-48027»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-24l) Digital pressure Gauge.
  2. «J 26792»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-special-tools-and-equipment__special-tools-diagnostic-tools) HEI Spark Tester.

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) .

Note. This diagnostic assumes the following: The battery is completely charged. Refer to Battery Inspection/Test . The engine cranking speed is acceptable. Refer to Engine Cranks Slowly . There is adequate fuel in the fuel tank.

  1. Engine cranking, observe the DTC information with a scan tool. The following DTCs should not be set: DTC P0201-P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0335, P0336, P0601-P0604, P0606, P0627, P062B, P062F, P0630, P0685, P0686, P0687, P0689, P0690, P1248, P1249, P124A, P124B, P1682, P2147-P2157, or P2610 If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition ON, observe the Theft Deterrent LED located on the instrument panel cluster. The LED should illuminate momentarily and then go out. If the LED stays ON or is flashing, review the scan tool DTC information for Immobilizer system DTCs--refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . For more information, refer to «Immobilizer Description and Operation»(/buick/regal/v-2009-2013/remont/door-locks-anti-theft-systems/#immobilizer-system__immobilizer-description-and-operation) .
  3. Engine cranking, observe the scan tool Engine Speed parameter. The scan tool should indicate an engine speed greater than 0 RPM. If the engine speed is 0 RPM, refer to «DTC P0335 or P0336»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0010-to-dtc-p0336) for further diagnosis.
  4. Ignition OFF, disconnect theT8 ignition coil from the cylinder and spark plug.
  5. Connect the «J 26792»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-special-tools-and-equipment__special-tools-diagnostic-tools) spark tester to the boot of the T8 ignition coil and ground.
  6. Engine cranking, verify that the spark tester sparks. If there is no spark for any cylinder tested, refer to «Electronic Ignition System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  7. Ignition OFF, install the «CH-48027»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-24l) gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  8. Ignition ON, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is running. Verify the fuel pressure is between 345-690 kPA (50-100 psi). If the fuel pump does not run, refer to «Fuel Pump Electrical Circuit Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) for further diagnosis. If the fuel pump runs but the fuel pressure is not within the specified range, refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  9. Verify that the fuel pressure, after the pump has turned off, decreases to 500-599 kPA (72-87 psi) and does not decrease greater than 34 kPa (5 psi) in 1 minute from that point. If the fuel pressure is not within the range specified, refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  10. Verify that the following conditions do not exist: Collapsed air intake duct to the throttle body Restricted air filter element Spark plugs gas or coolant fouled-Refer to «Spark Plug Inspection»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__spark-plug-inspection) . A skewed B74 manifold absolute pressure (MAP) sensor-Compare the B74 MAP Sensor parameter to the Altitude Versus Barometric Pressure table. Refer to «Altitude Versus Barometric Pressure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__altitude-versus-barometric-pressure) . A skewed B34 engine coolant temperature (ECT) sensor-Compare the B34 ECT Sensor parameter to the Temperature Versus Resistance table. Refer to «Temperature Versus Resistance (ECT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-ect) , «Temperature Versus Resistance (IAT)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat) , «Temperature Versus Resistance (IAT 2)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-specifications__temperature-versus-resistance-iat-2) . Exhaust system restricted-Refer to «Restricted Exhaust»(/buick/regal/v-2009-2013/remont/exhaust/#engine-exhaust-system) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) . Engine mechanical condition, for example, worn timing chain and gears or low compression-Refer to «Symptoms - Engine Mechanical»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures) . If you find any of the above conditions, repair as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Fuel Pump High SignalP0231P023FP0232P023F, P2635
Fuel Pump Low SignalP023FP023F, P2635

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for two seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the fuel pump ON and OFF using the scan tool ECM output control. The fuel pump should turn on and off.

  1. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
  2. Connect a test lamp between the control circuit terminal 1 and ground.
  3. Ignition ON, command the G12 fuel pump ON and OFF using a scan tool ECM fuel pump output control. The test lamp should turn ON and OFF, as commanded. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  4. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
  5. Ignition ON, command the G12 fuel pump ON using a scan tool. The test lamp should illuminate. If the test lamp does not illuminate, test the low reference circuit terminal 1 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  6. If all circuits test normal, replace the G12 fuel pump.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for fuel pump control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies voltage to the fuel pump flow control module when the ECM detects that the ignition is ON. The voltage signal from the ECM to the fuel pump flow control module remains active for 2 s, unless the engine is in Crank or Run. While this voltage is being received, the fuel pump flow control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

The fuel system is an electronic returnless on-demand design. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

The fuel tank stores the fuel supply. An electric turbine style fuel pump attaches to the fuel tank fuel pump module inside the fuel tank. The fuel pump supplies fuel through the fuel feed pipe to the high pressure fuel pump. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel tank fuel pump module. The function of the venturi pump is to fill the fuel tank fuel pump module reservoir. The fuel tank fuel pump module contains a reverse flow check valve. The check valve maintains fuel pressure in the fuel feed pipe in order to prevent long cranking times.

The fuel injectors are calibrated to begin operating at these pressures

  1. 0.8 Mpa (116 psi) at 20-32°C (68-90°F) with nonblended gasoline
  2. 2.45 Mpa (355 psi) at 20°C (68°F) with E85 blended gasoline
  3. 2.35 Mpa (341 psi) at 24°C (75°F) with E85 blended gasoline
  4. 2.2 Mpa (319 psi) at 32°C (90°F) with E85 blended gasoline

These specifications will vary when the temperature is outside of this range.

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. CH 48027 Digital Pressure Gauge
  2. J 37287 Fuel Line Shut-Off Adapter

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) .

Note. Repair all fuel system related DTCs before performing this diagnostic. Inspect the fuel system for damage or external leaks before proceeding. Verify that adequate fuel is in the fuel tank before proceeding. The Fuel Pump Enable may need to be commanded ON a few times in order to obtain the highest possible fuel pressure. Before proceeding with this test, review the User Manual CH 48027-5 for Safety Information and Instruction.

  1. Ignition OFF, all accessories OFF, install a CH 48027 Digital Pressure Gauge. Refer to «Fuel Pressure Gauge Installation and Removal»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
  2. Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool. Verify the fuel pressure is between 345-690 kPa (50-100 psi) with the fuel pump running.
  3. Engine idling at normal operating temperature, the Fuel Pump Flow Control Module Fuel Pressure Sensor parameter should read between 300-400 kPa (43-58 psi).
  1. Ignition ON, engine OFF, command the Fuel Pump Enable ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating. Verify the fuel pressure is between 345-690 kPa (50-100 psi). If the fuel pressure is greater than the specified range, replace the fuel tank fuel pump module. If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank fuel pump module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
  2. Verify that the fuel pressure, after the fuel pump is turned off, decreases to 500-599 kPa (72-87 psi), and does not decrease more than 34 kPa (5 psi) in 1 minute from that point. If the fuel pressure stays above 600 kPa (87 psi), replace the fuel tank fuel pump module. If the fuel pressure decreases greater than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__fuel-pressure-relief) . Disconnect the chassis fuel feed hose from the engine compartment fuel pipe. Install the J 37287 Fuel Line Shut-Off Adapter between the chassis fuel hose and the engine compartment fuel pipe. Open the valve on the J 37287 Fuel Line Shut-Off Adapter. Ignition ON, command the Fuel Pump Enable ON with a scan tool and bleed the air from the CH 48027 Digital Pressure Gauge. Command the Fuel Pump Enable ON and then OFF with a scan tool. Close the valve on the J 37287 Fuel Line Shut-Off Adapter. Monitor the fuel pressure for 1 minute. If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s). If the fuel pressure does not decrease greater than 34 kPa (5 psi) within the specified time, replace the fuel tank fuel pump module.
  3. Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease greater than 14 kPa (2 psi) in 5 minutes. If the fuel pressure decreases greater than the specified value, replace the fuel tank fuel pump module.
  4. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027 Digital Pressure Gauge. The fuel pressure should not drop off during acceleration, cruise, or hard cornering. If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank fuel pump module. Restricted fuel feed pipe Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
  5. If the fuel system tests normal, refer to «Symptoms - Engine Controls»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) ,, «Fuel Injector Solenoid Coil Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) ,, and «Fuel Injector Balance Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Direct Fuel Injector Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Fuel Feed Pipe Replacement (LDK)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) , «Fuel Feed Pipe Replacement (LTD)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  3. «Fuel Tank Fuel Pump Module Replacement (NU6)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) , «Fuel Tank Fuel Pump Module Replacement (NT7)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a separate high voltage supply circuit and a high voltage control circuit for each fuel injector. The injector high voltage supply circuit and the high voltage control circuit are both controlled by the ECM. The ECM energizes each fuel injector by grounding the control circuit. The ECM controls each fuel injector with 65 V. This is controlled by a boost capacitor in the ECM. During the 65 V boost phase, the capacitor is discharged through an injector, allowing for initial injector opening. The injector is then held open with 12 V. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

  1. Monitoring the Current Misfire Counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
  2. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. The resistance test must be performed at the fuel injector or mis-diagnosis will occur. The DMM and test leads must be calibrated to 0 ohms in order to prevent mis-diagnosis.

  1. Verify the resistance of each Q17 fuel injector with one of the following methods: If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each Q17 fuel injector should be 1.25-1.75 ohms. If not within the specified range, replace the Q17 fuel injector. If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each Q17 fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 0.45 ohms. If the difference is more than 0.45 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the Q17 fuel injector that displays the greatest difference above or below the average.
  2. If the injectors measure OK, perform the Fuel Injector Balance Test. Refer to «Fuel Injector Balance Test»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The fuel injector balance test is performed while the engine is running at idle. The scan tool pressurizes the fuel rail to a predetermined pressure before each injector is pulsed for a precise amount of time allowing a measured amount of the fuel to be injected. This causes a drop in the system fuel pressure that is recorded and used to compare each injector.

  1. Monitoring the Current Misfire Counters may help to isolate the fuel injector that is causing the condition.
  2. Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.

Note. DO NOT perform this test if the engine coolant temperature (ECT) is above 60°C (140°F). Irregular fuel pressure readings may result due to hot soak fuel boiling. Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.

Fuel Injector Balance Test

  1. Verify the correct low side fuel pressure. Refer to «Fuel System Diagnosis»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  2. Engine running at normal operating temperature. With a scan tool, select the Fuel Injector Balance function within the Output Controls menu.
  3. Select and test an injector. Repeat for each injector in order to obtain a pressure drop value for each injector.
  4. After all injectors are tested, record the fuel pressure drops.
  5. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  6. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop.
  7. Multiply the average pressure drop by 0.20. This is the acceptable variance from the average pressure drop, 20 percent. If the difference between any individual pressure drop and the average pressure drop is more than the acceptable variance, replace the fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Test Description

Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.

Ethanol concentrations of greater than 10 percent in nonblended gasoline or greater than 85 percent with E85 blended gasoline for flexible fuel applications can cause driveability conditions such as hesitation, lack of power, stalling, or no start. Excessive concentrations of ethanol used in vehicles not designed for it may cause fuel system corrosion, deterioration of rubber components, and fuel filter restriction.

Special Tools

J 44175-A Fuel Composition Tester

System Verification

The fuel sample should be drawn from the bottom of the tank so that any water present in the tank will be detected. The sample should be bright and clear.

  1. If the sample appears cloudy, or contaminated with water, as indicated by a water layer at the bottom of the sample, perform the Particulate Contaminants in Fuel Testing Procedure.
  2. If alcohol contamination is suspected, perform the Alcohol in Fuel Testing procedure.

Alcohol in Fuel Testing with Special Tool

  1. Test the fuel composition using J 44175-A Tester and Instruction Manual.
  2. If water appears in the fuel sample, clean the fuel system.
  3. Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample.
  4. If the nonblended gasoline fuel sample measures more than 15 percent ethanol, or if the E85 blended gasoline fuel sample measures more than 91 percent ethanol, add fresh regular gasoline to the vehicle's fuel tank.
  5. Test the fuel composition.
  6. If additional testing indicates that the ethanol percentage is still above 15 percent for a nonblended gasoline sample, drain and replace the vehicle's fuel. Refer to «Fuel Tank Draining (Non E-85)»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions__fuel-tank-draining-non-e-85) . If additional testing indicates that the E85 blended gasoline sample still measures above 91 percent, continue adding fresh, regular gasoline until the ethanol content is 85 percent or less.

Alcohol in Fuel Testing without Special Tool

  1. Using a 100 ml (3.38 oz) specified cylinder with 1 ml (0.034 oz) graduation marks, fill the cylinder with fuel to the 90 ml (3.04 oz) mark.
  2. Add 10 ml (0.34 oz) of water in order to bring the total fluid volume to 100 ml (3.38 oz) and install a stopper.
  3. Shake the cylinder vigorously for 10-15 seconds.
  4. Carefully loosen the stopper in order to release the pressure.
  5. Re-install the stopper and shake the cylinder vigorously again for 10-15 seconds.
  6. Put the cylinder on a level surface for approximately 5 minutes in order to allow adequate liquid separation. If alcohol is present in the fuel, the volume of the lower layer, which would now contain both alcohol and water, will be more than 10 ml (0.34 oz). For example, if the volume of the lower layer is increased to 15 ml (0.51 oz), this indicates at least 5 percent alcohol in the fuel. The actual amount of alcohol may be somewhat more because this procedure does not extract all of the alcohol from the fuel.

Particulate Contaminants in Fuel Testing Procedure

  1. Using an approved fuel container, draw approximately 0.5 liter (0.53 qt) of fuel.
  2. Place the container on a level surface for approximately 5 minutes in order to allow settling of the particulate contamination. Particulate contamination will show up in various shapes and colors. Sand will typically be identified by a white or light brown crystals. Rubber will appear as black and irregular particles.
  3. Observe the fuel sample. If any physical contaminants or water are present, clean the fuel system.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The ignition system uses individual ignition coil/module assemblies for each cylinder. The engine control module (ECM) controls the individual coils by transmitting timing pulses on the ignition control circuit of each ignition coil/module to enable a spark event.

  1. Depending on location in the spliced ignition voltage circuit, a slight resistance can cause a misfire or a crank/no start concern. A voltage drop test will pinpoint this condition.
  2. A slight to moderate resistance on any ignition control circuit can cause a misfire before DTC P0351-P0354 sets.
  3. Extended engine cranking time, may foul the spark plugs with excessive fuel.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/regal/v-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 26792 HEI Spark Tester

  1. Ignition OFF, disconnect the harness connector at the affected T8 ignition coil/modules.
  2. Ignition OFF, all vehicle systems OFF. This may take up to 2 minutes. Test for less than 5 ohms between the ground circuit terminal A/1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Test for less than 5 ohms between the low reference circuit terminal B/2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal D/4 and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  5. Exchange the affected T8 ignition coil/module with the T8 ignition coil/module of a good cylinder.
  6. Start the engine, and observe the scan tool Misfire Current Cylinder parameters. If the misfire transfers with the suspect T8 ignition coil/module, replace as needed.
  7. If the circuits test normal, test or replace the spark plug/s.

Use the J 26792 Spark Tester to verify the output of each ignition coil/module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ignition Coil Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)
  2. «Spark Plug Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions)

Special Tools

EN 41413-VLV EVAP Service Port Vent Fitting

Operating Instructions for the Evaporative Emission System Tester (EEST)

Vehicle Setup

  1. Engine OFF, open the hood. Position a large fan to blow air under the vehicle onto the fuel tank area.
  2. Connect the red battery clip from the tester to the positive battery terminal.
  3. Connect the black battery clip from the tester to chassis ground.

Flow Meter Test - Leak Detection

  1. Open the Nitrogen tank valve and turn the NITROGEN/SMOKE valve on the front control panel to NITROGEN.
  2. Connect the hose to the correct test orifice on the bottom front of the tester. For orifice size, refer to the vehicle specific information found in service procedures for DTCs that relate to evaporative emission (EVAP) system leaks.
  3. Press and release the remote switch to activate the tester.
  4. Position the sliding red flag on the flow meter to align with the floating indicator. When the red flag is set, press and release the remote switch to deactivate the tester.
  5. Remove the hose from the test orifice and install the hose onto the vehicle. For proper connection location, and the special tool numbers for any adapters that may be required, refer to the service procedures for DTCs that relate to EVAP system leaks.
  6. Ignition ON, seal the EVAP system per instructions in the service procedures for DTCs that relate to EVAP system leaks. Most systems can be sealed using a scan tool output control for the EVAP vent solenoid valve, other systems require that the vent system be plugged.
  7. Press and release the remote switch to activate the nitrogen flow and fill the system.
  8. Compare the stable floating indicator position to the red flag. Below the red flag, the result is acceptable, Pass. Test complete Above the red flag, the result is unacceptable, Fail. Go to the Smoke Procedure
  9. Press and release the remote switch to deactivate the tester.

Smoke Procedure - Locate the Leak

  1. Turn OFF any fans that may cause air movement around or near the vehicle.
  2. Connect the nitrogen/smoke hose to the vehicle as directed in the service procedures. Some vehicles require that the nitrogen/smoke hose be connected at the front of the EVAP system at the EVAP service port. An adapter may be necessary. Other vehicles require the connection be made at the rear of the system using an adapter at the fuel fill cap. Consult the service procedures for DTCs that relate to evaporative emission (EVAP) system leaks for vehicle specific instructions regarding connection location and adapters.
  3. Open the nitrogen tank valve and turn the nitrogen/smoke valve on the control panel to smoke.
  4. Press and release the remote switch to activate the tester and inject smoke into the EVAP system.
  5. Verify smoke has filled the EVAP system by opening the system opposite the end where smoke is injected. When injecting smoke at the service port, remove the fuel fill cap until smoke is observed. Then close the system and continue testing. If using a special tool fuel fill cap adapter at the filler neck, vent the system at the service port, with special tool EN 41413-VLV EVAP Service Port Vent Fitting, until smoke is observed then remove the vent fitting tool and close the system to continue with the test.
  6. Press and release the remote switch to deactivate the tester.
  7. Introduce smoke into the system for an additional 60 s. Continue introducing smoke at 15 s intervals, as necessary.
  8. Using a high-intensity white light, inspect the entire EVAP system path, and look for the source of the leak indicated by the exiting smoke. Introduce smoke at 15 s intervals, as needed, until leak source is identified.

Temperature Variation Instructions

The Concern

Ideal circumstances for conducting the EVAP flow meter test require equal temperatures between the nitrogen gas and the vehicle EVAP system. Significant differences in temperature between them can result in a flow or pressure change during testing, causing misleading results. Typically, the EEST is stored indoors, approximately 21°C (70°F). Vehicles brought in for diagnosis may have an EVAP system at significantly different temperatures.

For Example

Note. With no temperature difference between the nitrogen gas and EVAP system, the resulting vehicle EVAP system pressure will remain stable at 3.2 kPa, 13 in. H2O (0.5 PSI) once pressurized, providing no leaks are present.

When the EVAP flow meter tests are performed with significant differences in temperature between the nitrogen gas and the vehicle EVAP system, the following results can occur

  1. An increase in flow during the flow meter test can be caused by a vehicle's warm EVAP system cooling down.
  2. A decrease in flow during the flow meter test can be caused by a vehicle's cool EVAP system warming up.

The Solution

When working on a vehicle with significant temperature differences between the vehicle EVAP system and the nitrogen gas, allow the vehicle EVAP system temperature to stabilize as close as possible to the temperature of the nitrogen gas before conducting the Flow Meter Test.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Description

Several states require that a vehicle pass on-board diagnostic (OBD) system tests and the inspection/maintenance (I/M) emission inspection in order to renew license plates. This is accomplished by viewing the I/M System Status display on a scan tool. Using a scan tool, the technician can observe the I/M System Status in order to verify that the vehicle meets the criteria that complies with the local area requirements. While testing in the I/M System Status mode, some DTCs may occur that are called I/M Test DTCs. An I/M Test DTC is defined as a fault code that is currently commanding the MIL ON, and is stored in non-volatile memory. The intended use of this data is to prevent vehicles from passing I/M inspection without proper repair to the vehicle. These fault codes are not erasable from any scan tool command or erasable by disconnecting power to the controller. The I/M Test DTCs will be supported by all emissions related ECUs such as ECMs, TCMs, FPCMs, etc. An I/M Test DTC will not be stored or erased from the ECU except at the end of trip processing which occurs 5 s after ignition OFF.

Conditions for Updating the I/M System Status

Each system requires at least one, and sometimes several, diagnostic tests. The results of these tests are reported by a diagnostic trouble code (DTC). A system monitor is complete when either all of the DTCs comprising the monitor have Run and Passed, or any one of the DTCs comprising the monitor have illuminated the malfunction indicator lamp (MIL). Once all of the tests are completed, the I/M System Status display will indicate YES in the Completed column.

For example, when the HO2S Heater Status indicates YES, either all of the oxygen sensor heater tests have passed or one of the tests has illuminated the MIL. If the vehicle has four heated oxygen sensors, either all four heater circuit tests have passed or one of the heater circuit tests has illuminated the MIL. The I/M System Status will indicate NO under the Completed column when any of the required tests for that system have not run. The following is a list of conditions that would set the I/M System Status indicator to NO

  1. The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
  2. The battery has been disconnected or discharged below operating voltage.
  3. The control module power or ground has been interrupted.
  4. The control module has been reprogrammed.
  5. The control module DTCs have been cleared as part of a service procedure.

Conditions for Clearing I/M Test DTCs

  1. Only the OBD II System can erase the I/M Test DTC. The OBD II system must determine that the malfunction that caused the I/M Test DTC to be stored is no longer present and is not commanding the MIL. Each of the following represents ways to clear an I/M Test DTC: If the MIL goes out due to 3 passing drive cycles, scan tool code clear is not used, the I/M Test DTC is erased at power down of the last drive cycle. If a scan tool code clear is used to turn OFF the MIL, the I/M Test DTC is not erased, the DTC must PASS and not FAIL. The I/M Test DTC is erased at power down of the drive cycle. If the controller is reflashed/reprogrammed, all I/M Test DTCs are erased.
  2. For the OBD II System to run a single drive cycle for clearing an I/M Test DTC, all of the following conditions must occur: Cumulative time of engine run time is greater than 600 s. Cumulative vehicle operation above 41 kPa (25 mph) for over 300 s. Continuous vehicle idle for greater than 30 s. Turn ignition OFF for 5 s and allow the code to clear.

Monitored Emission Control Systems

The OBD II system monitors all emission control systems that are on-board. Not all vehicles need every possible emission control system. For example, a vehicle may not be equipped with secondary air injection (AIR) or exhaust gas recirculation (EGR). The OBD II regulations require monitoring of the following; if equipped

  1. The air conditioning system
  2. The catalytic converter efficiency
  3. Comprehensive component monitoring-Emission related inputs and outputs
  4. The evaporative emission (EVAP) system
  5. The fuel delivery system
  6. Heated catalyst monitoring
  7. Misfire monitoring
  8. The oxygen sensor system (O2S or HO2S)
  9. The oxygen sensor heater system (HO2S heater)

For the specific DTCs required for each system, refer to Inspection/Maintenance (I/M) Test DTC Table . Systems such as misfire and comprehensive components may not be listed in a system status list. These tests run continuously and do not require an I/M System Status indicator.

The I/M System Status display provides an indication of when the control module has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the failure. If a failure indication is present for a DTC associated with one of the I/M regulated systems, it may prevent other required tests from running. For example, a DTC for the control circuit of the EVAP purge solenoid may not be listed in the Inspection/Maintenance System DTC Table because it is a continuous test. If this DTC is set, the Active Tests for the EVAP system may not run.

The I/M System Status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Review the I/M System Status indicators. All I/M System Status indicators should report YES, and no I/M Test DTCs should be present.

  1. Observe the Engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Review applicable service bulletins for software updates that would prevent the I/M System Status tests from completing. If a control module re-program or other repair is required, perform the «Inspection/Maintenance Complete System Set Procedure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  3. Observe the I/M System Status indicators. If any I/M System Status indicators report NO, perform the «Inspection/Maintenance Complete System Set Procedure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  4. Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set and all of the I/M System Status indicators are Yes, there is no need to perform the Complete System Set Procedure. Diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) and refer to Conditions for Clearing the I/M Test DTCs. If an I/M Test DTC is set and the I/M System Status indicators are NO, diagnosis the DTC and perform the «Inspection/Maintenance Complete System Set Procedure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The purpose of the Inspection/Maintenance (I/M) complete system set procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the trips for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance (I/M) Complete System Set Procedure if any I/M System Status indicators are set to NO.

Conditions for Meeting a Cold Start

  1. The ignition voltage between 10 and 15 V.
  2. The barometric pressure (BARO) is more than 75 kPa (10.9 psi).
  3. The engine coolant temperature (ECT) at start-up is less than 42°C (108°F).
  4. The intake air temperature (IAT) is between 2-32°C (36-90°F).
  5. The engine is OFF for greater than 6 hours or the following conditions must be met: The start-up IAT minus start-up ECT are within 12°C (22°F). The start-up ECT minus start-up IAT are within 50°C (90°F).
  6. Fuel level is between 25 and 75 %.

Review the Inspection/Maintenance (I/M) System Status indicators. All I/M System Status indicators should report YES, and no I/M Test DTCs should be present.

Inspection/Maintenance (I/M) System Set Procedure

  1. Ensure that the vehicle meets the conditions for a cold start listed above. If the EVAP I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable.
  2. Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc., and open the hood.
  3. Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
  4. Start and idle the engine for 2 min.
  5. Close the hood, release the parking brake and Accelerate at part throttle to 72-80 km/h (45-50 mph) with this speed maintained until the engine reaches operating temperature, 8-10 min.
  6. Continue operation under these conditions for an additional 6 min.
  7. Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained for 2 min.
  8. Release the accelerator pedal for at least 10 s. This will allow the vehicle to enter the decel fuel cut off.
  9. Safely stop the vehicle, with the engine in drive for automatic or neutral with the clutch pedal depressed and parking brake applied for manual. Allow the vehicle to idle for 2 min.
  10. Shift the vehicle to park for automatic and neutral for manual. Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 min.
  11. Observe the Inspection/Maintenance (I/M) System Status with a scan tool. All of the I/M System Status indicators should display YES. If the EVAP I/M System Status indicator displays NO, turn OFF the ignition, ensure that the vehicle meets the conditions for a cold start, and repeat steps 6-11 three more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the «Inspection/Maintenance (I/M) Test DTC Table»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis__inspectionmaintenance-im-test-dtc-table) to identify the DTCs that did not run. If any of the I/M System Status indicators display NO, refer to the «Inspection/Maintenance (I/M) Test DTC Table»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis__inspectionmaintenance-im-test-dtc-table) for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.
  12. Observe the I/M Test DTC information with a scan tool. Verify there are no I/M Test DTCs present. If an I/M Test DTC is set, diagnose the DTC using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) , and refer to «Inspection/Maintenance System Check»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) .
  13. Observe the engine DTC information with a scan tool. Verify no DTCs are present. If a DTC is set, diagnose using the «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/regal/v-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . After repairs, perform the «Inspection/Maintenance Complete System Set Procedure»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-dtc-p0340-through-dtc-p2635-and-symptom-troubleshooting-diagnosis) to verify no further DTCs are set.

Inspection/Maintenance (I/M) Test DTC Table

SystemDTCs Required to Set System Status to YES
If an I/M System Status indicator did NOT update to YES during the Inspection/Maintenance Complete System Set Procedure , review each indicator and reference this table to determine each DTC associated with the I/M System Status Indicator. Each DTC listed below has specific conditions that must be met for the diagnostic to run. Included within the conditions are additional DTCs, which if set, may inhibit the DTCs listed below from running. Reviewing and operating the vehicle within the Conditions for Running for each DTC listed below will allow the I/M System Status Indicators to transition to YES.
CatalystDTC P0420
EVAPDTC P0442 DTC P0446 DTC P0451-P0454 DTC P0455 Fuel Gauge Malfunction - DTC P0461-P0464 DTC P0496
Oxygen SensorDTC P0030, P0036, P0053, P0054, P0135, or P0141 DTC P0131, P0132, P0134, P0137, P0138, or P0140 DTC P0133, P013A, P013B, P013E, P013F, P015A, P015B, P2270, P2271, or P2A00
Oxygen Sensor HeaterDTC P0030, P0036, P0053, P0054, P0135, or P0141
Camshaft SystemDTC P0011 or P0014

Inspection/Maintenance (I/M) Test DTC Table

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• COMPONENT CONNECTOR END VIEWS -- INDEX
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Camshaft Position Sensor Replacement - Exhaust
• Camshaft Timing Chain and Sprocket Cleaning and Inspection (LDK, LHU)
• Camshaft Cleaning and Inspection (LDK, LHU)
• Diagnostic Trouble Code (DTC) List - Vehicle
• Heated Oxygen Sensor Wiring Repairs
• Three-Way Catalytic Converter Damage Caution
• Heated Oxygen Sensor Resistance Learn Reset Caution
• Restricted Exhaust
• Exhaust Leakage
• Evaporative Emission Control System Description
• Special Tools (Diagnostic Tools)
• Troubleshooting with a Test Lamp
• Throttle Body Cleaning
• Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)
• Battery Inspection/Test
• Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
• Input and Output Speed Sensor Installation
• Instrument Cluster Schematics
• Power Distribution Schematics
• Electrical Center Identification Views
• Relay Replacement (Within an Electrical Center)
• Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)
• J 38522
• Engine Control Module Description
• Engine Control Module Scan Tool Information (LUK)
• Symptoms - Engine Exhaust
• Road Test Warning
• DTC P0106
• Symptoms - Engine Mechanical
• Altitude Versus Barometric Pressure
• Turbocharger Cleaning and Inspection (LDK, LHU)
• Fuel System Cleaning
• Scan Tool Does Not Communicate with High Speed GMLAN Device
• Spark Plug Inspection
• Ignition System Specifications
• Coolant in Combustion Chamber (LDK, LHU)
• Oil Consumption Diagnosis
• J 26792
• Torque Converter Diagnosis
• Heated Oxygen and Oxygen Sensor Caution
• Thermostat Diagnosis
• Loss of Coolant
• Engine Overheating
• Temperature Versus Resistance (ECT)
• Temperature Versus Resistance (IAT)
• Temperature Versus Resistance (IAT 2)
• Cooling Fan Description and Operation (LAF, LEA, LUK)
• Cooling Fan Description and Operation (LDK or LHU)
• Cooling System Description and Operation
• OnStar Stolen Vehicle Slowdown Active
• Remote Vehicle Speed Limiting Description and Operation
• Crankshaft and Bearing Cleaning and Inspection
• Symptoms - Engine Electrical
• Turbocharger Whine Noise (LDK, LHU)
• Turbocharger Hissing Noise (LDK, LHU)
• Engine Mount Inspection
• CH-48027
• Immobilizer Description and Operation
• Fuel Pressure Relief
• Fuel Tank Draining (Non E-85)
• Fuel and Evaporative Emission Pipe Warning
• Clean, Dry, Low Pressure Gas Source Caution
• Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Caution
• DTC P0420
• Inspection/Maintenance (I/M) Test DTC Table

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