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Engine Controls/fuel - 3.6l - DTC p0340 to DTC p2635 and Diagnostic Information and Procedures Buick Enclave I

Testing & Diagnostics ~36671 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0107, P0192, P0345, P0452, P0522, P0532, P0641, P2228P0340, P0345, P0365, P0390P0193, P0345, P0453, P0641, P2227
SignalP0340, P0345, P0365, P0390P0340, P0345, P0365, P0390P0340, P0345, P0365, P0390P0341, P0346, P0366, P0391
Low ReferenceP0340, P0345, P0365, P0390P0340, P0345, P0365, P0390

Circuit/System Description

The 4 camshaft position sensors each have 3 circuits consisting 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 uses the cylinder 1 intake camshaft position sensor to determine injector and ignition system synchronization. The cylinder 1 intake camshaft position sensor is also used to determine camshaft to crankshaft relationship. The ECM also uses camshaft position sensor output information to determine the camshaft relative position to the crankshaft to control camshaft phasing and limp-home operation.

Conditions for Running the DTC

Condition 1

  1. The starter is engaged and the engine control module detects camshaft position sensor pulses. OR
  2. DTCs P0101, P0102 and P0103 are not set and the airflow into the engine is greater than 3 g/s.

Condition 2

  1. DTC P0651 is not set.
  2. The engine is running.
  3. The starter is not engaged.

Condition 3

  1. DTC P0335, P0641, or P0651, is not set.
  2. The starter is engaged.
  3. The crankshaft is synchronized.

The DTCs run continuously once the above conditions are met.

Conditions for Setting the DTC

Condition 1

The ECM does not detect a camshaft position sensor pulse for greater than 5.5 s or greater than 4.0 s since the time the starter has been engaged.

Condition 2

The ECM detects less than 4 camshaft position sensor pulse for greater than 3.0 s.

Condition 3

The ECM does not detect a camshaft position sensor pulse for 8 out of 10 engine revolutions.

Action Taken When the DTC Sets

  1. DTCs P0340, P0341, P0345, P0346, P0365, P0366, P0391, and P0390 are Type B DTCs.
  2. The camshaft position actuator is commanded to the Home or Parked position.
  3. The ignition system defaults to a failed camshaft position sensor limp home mode.
  4. With a DTC set, the engine may crank for an extended period of time at start-up.

Conditions for Clearing the MIL/DTC

DTCs P0340, P0341, P0345, P0346, P0365, P0366, P0391, and P0390 are Type B DTCs.

Diagnostic Aids

  1. With a DTC set, the engine may crank for an extended period of time at start-up
  2. The cylinder 1 intake camshaft position sensor is used for injector and ignition system synchronization. A stalling condition will occur if the CMP sensor signal is intermittent and a DTC will not set. Inspect all cylinder 1 intake camshaft position sensor circuits for poor connections.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. Ignition ON.
  2. Verify DTC P0641 or P0651 is not set. If any of the DTCs are set Refer to «DTC P0641, P0651, P0697, or P06A3»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . If none of the DTCs are set
  3. Engine running.
  4. Verify the scan tool parameters listed below increment: Exhaust Camshaft Position Active Counter Bank 1 Exhaust Camshaft Position Active Counter Bank 2 Intake Camshaft Position Active Counter Bank 1 Intake Camshaft Position Active Counter Bank 2 If any counter does not increment Refer to Circuit/System Testing. If all counters increment
  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.
  6. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing. If the DTC does not set
  7. All OK.

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate B23 Camshaft Position Sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 5 ohms between the low reference circuit terminal 1 and ground. If 5 ohms or greater Ignition OFF, disconnect the X2 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 2 ohms or less, replace the K20 Engine Control Module. If less than 5 ohms
  3. Ignition ON.
  4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than 4.8 V Ignition OFF, disconnect the X2 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 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. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground. If less than 4.8 V Ignition OFF, disconnect the X2 harness connector at the K20 Engine Control Module. Test for infinite resistance between the signal 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 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 5.2 V Test for less than 1 V between the signal 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
  6. Verify DTC P0341, P0346, P0366, or P0391 is not set. If any of the DTCs are set Inspect for the conditions listed below: Excessive play or looseness of the B23 Camshaft Position Sensor or the reluctor wheel Improper installation of the B23 Camshaft Position Sensor Foreign material passing between the B23 Camshaft Position Sensor and the reluctor wheel Damaged reluctor wheel Excessive air gap between the B23 Camshaft Position Sensor and the reluctor wheel Engine oil for debris Timing chain, tensioner, and sprockets for wear or damage If any of the conditions above are found, repair as necessary. If all components test normal, test or replace the B23 Camshaft Position Sensor. If none of the DTCs are set
  7. Test or replace the B23 Camshaft Position Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition Voltage - Bank 1P0300-P0306, P2300, P2306, P2312P0300-P0306, P0351, P0353, P0355P0300, P0301, P0303, P0305
Ignition Voltage - Bank 2P0300-P0306, P2303, P2309, P2315P0300-P0306, P0352, P0354, P0356P0300, P0302, P0304, P0306
Ignition Coil 1 Control CircuitP2300P0301, P0351P2301P0300, P0301
Ignition Coil 2 Control CircuitP2303P0302, P0352P2304P0300, P0302
Ignition Coil 3 Control CircuitP2306P0303, P0353P2307P0300, P0303
Ignition Coil 4 Control CircuitP2309P0304, P0354P2310P0300, P0304
Ignition Coil 5 Control CircuitP2312P0305, P0355P2313P0300, P0305
Ignition Coil 6 Control CircuitP2315P0306, P0356P2316P0300, P0306
Low Reference and GroundP0351, P0356P0351, P0356

The ignition system on this engine uses individual ignition coils and ignition control (IC) circuits for each cylinder. Ignition voltage is supplied to each bank of ignition coils. The engine control module (ECM) controls the ignition system operation. The ECM controls each coil using the IC circuits. The ECM commands the IC circuit low when a spark event is requested.

The sequencing and timing are ECM controlled.

  1. The engine is operating.
  2. The ignition voltage is between 10-18 volts.
  3. The engine speed is less than 6,000 RPM.
  4. The DTCs run continuously once per crankshaft revolution after the above conditions are met.

P0351-P0356

The ECM detects the ignition control circuit is open for greater than 4 seconds or a cumulative of 30 seconds.

P2300, P2303, P2306, P2309, P2312, or P2315

The ECM detects the ignition control circuit is shorted to ground for greater than 4 seconds or a cumulative of 30 seconds.

P2301, P2304, P2307, P2310, P2313, or P2316

The ECM detects the ignition control circuit is shorted to voltage for greater than 4 seconds or a cumulative of 30 seconds.

DTCs P0351, P0352, P0353, P0354, P0355, P0356, P2300, P2301, P2303, P2304, P2306, P2307, P2309, P2310, P2312, P2313, P2315, and P2316 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0351, P0352, P0353, P0354, P0355, P0356, P2300, P2301, P2303, P2304, P2306, P2307, P2309, P2310, P2312, P2313, P2315, and P2316 are Type B DTCs.

  1. Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may cause this DTC to set.
  2. If the condition is intermittent, moving the related harnesses and connectors, with the engine operating, while monitoring the appropriate scan tool Misfire Current Cylinder, or the IC Circuit Test Status parameter may help to isolate the condition. An IC Circuit Test Status parameter will change from OK or Not Run to Fault if a condition is present.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. Operate the engine for 30 seconds. Observe the DTC information with a scan tool. DTC P0351, P0352, P0353, P0354, P0355, P0356, P2300, P2301, P2303, P2304, P2306, P2307, P2309, P2310, P2312, P2313, P2315, or P2316 should not set.
  2. Engine operating, observe the scan tool IC Circuit Test Status parameters, the IC Circuit Test Status parameters should display OK or Not Run.
  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. Engine running, observe the Ignition Coil 1-6 Control Circuit Low Voltage Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Fault test for open or short to ground.
  2. Engine running, observe the Ignition Coil 1-6 Control Circuit Open Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Fault test for open circuit.
  3. Engine running, observe the Ignition Coil 1-6 Control Circuit High Voltage Test Status on the scan tool. Test Status should be Ok or Not Run. If test status is Fault test for short to voltage.
  4. Ignition OFF, disconnect the harness connector at the appropriate T8 ignition coil.
  5. 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 circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition voltage circuit and replace as necessary.
  6. Connect a test lamp between the each of the ground circuits terminal A, and terminal B, and B+. The test lamp should illuminate on each circuit. If the test lamp does not illuminate, test the suspected circuit for an open/high resistance.
  7. If all circuits test normal, replace the appropriate T8 ignition coil.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Ignition Coil Replacement - Bank 1»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Ignition Coil Replacement - Bank 2»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

A 3-way catalytic converter (TWC) controls emissions of hydrocarbons, CO and NOx. The catalyst within the converter promotes a chemical reaction, which oxidizes the hydrocarbons and the CO that are present in the exhaust gas. This process converts the hydrocarbons and the CO into water vapor and CO2, and reduces the NOx, converting the NOx into nitrogen. The TWC also stores oxygen. The ECM monitors this process by using a heated oxygen sensor (HO2S) that is in the exhaust stream after the TWC. The HO2S 2 produces an output signal that the ECM uses to calculate the oxygen storage capacity of the catalyst. This indicates the ability of the catalyst to convert the exhaust emissions efficiently. The ECM monitors the efficiency of the catalyst by allowing the catalyst to heat, then wait for a stabilization period while the engine is idling. The ECM then adds and removes fuel while monitoring the HO2S 2. When the catalyst is functioning properly, the HO2S 2 response to the extra fuel is slow compared to the response of the HO2S 1, which is located before the TWC. When the HO2S 2 response is near that of the HO2S 1, the oxygen storage capability and efficiency of the catalyst may be degraded below an acceptable threshold.

  1. DTC P0016, P0017, P0018, P0019, P0053, P0054, P0059, P0060, P0068, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0135, P0137, P0138, P013A, P013B, P013C, P013D, P013E, P013F, P0140, P0141, P014A, P014B, P0151, P0152, P0153, P0155, P0157, P0158, P0160, P0161, P0171, P0172, P0174, P0175, P0191, P0192, P0193, P0222, P0223, P0300, P0301. P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0443, P0506, P0507, P0606, P1153, P16F3, P2101, P2122, P2123, P2127, P2128, P2135, P2138, P2227, P2228, P2229, P2230, P2270, P2271, P2272, or P2273 is not set.
  2. Before the ECM performs the idle test, the vehicle must be driven under the following conditions: The engine speed is greater than 965 RPM The engine run time is greater than a calibrated value Both conditions exist for greater than 15 s
  3. The throttle is in the rest position.
  4. The Intake Air Temperature (IAT) is between -20 to +250°C (-4 to +482°F).
  5. The ignition voltage is greater than 11 V.
  6. The Engine Coolant Temperature (ECT) is between 40-127°C (104-261°F).
  7. The Barometric Pressure (BARO) is greater than 70 kPa.
  8. The engine has been idling less than 50 s.
  9. The vehicle speed is less than 2 km/h (1 mph).
  10. The short term fuel trim is learned.
  11. The air flow into the engine is between 3-13 g/s.
  12. The Evaporative Emission (EVAP) purge concentration is learned.
  13. The catalytic converter calculated temperature is between 450-850°C (842-1,562°F).
  14. The engine is operating in Closed Loop.
  15. The transmission is not in P/N (automatic transmission only).

This diagnostic attempts one test during each valid idle period once the above conditions have been met. This diagnostic attempts up to 8 tests during each drive cycle.

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

DTC P0420 and P0430 are Type A DTCs.

DTC P0420 and P0430 are Type A DTCs.

Inspect for the following conditions, which may cause a catalytic converter to degrade

  1. An engine misfire
  2. High engine oil or high coolant consumption
  3. Retarded spark timing
  4. A weak or poor spark
  5. A lean fuel mixture
  6. A rich fuel mixture
  7. A damaged oxygen sensor or wiring harness

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that no other DTCs are set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Operate the vehicle within the Conditions for Running the DTC while observing the scan tool TWC Mon. Off Idle Test Conditions Met parameter. The parameter will change to Yes when the Off Idle Conditions have been met. If not the specified value, operate the vehicle within the Off Idle Conditions.
  3. When the parameter has changed to Yes and the conditions are safe, stop and idle the vehicle in gear.
  4. Apply the service brake.
  5. Monitor the scan tool TWC Monitor Test State parameter. When the parameter indicates Active, the TWC Monitor Test is running.
  6. Continue to monitor the parameter. When the parameter indicates Inactive, the TWC Monitor Test has completed.
  7. When the test has completed, the TWC Monitor Test Count parameter will increment by one and the TWC Monitor Test Result parameter will indicate Passed, Failed or No Decision. If No Decision is indicated, repeat steps 2-6 until the Test Result parameter indicates Passed or Failed.
  1. Verify the following conditions do not exist with the appropriate catalytic converter: Dents Severe discoloration caused by excessive temperatures Road damage Internal rattles caused by damaged catalyst substrate Restrictions If a condition is found, replace the catalytic converter.
  2. Verify the following conditions do not exist with the exhaust system: Leaks Physical damage Loose or missing hardware If a condition is found, repair the exhaust system.
  3. Verify the following conditions do not exist with the appropriate B52B heated oxygen sensor 2: The HO2S is not at the correct torque Damage If a condition is found, replace the B52B heated oxygen sensor 2 as necessary.
  4. If all physical conditions test normal, test or replace the catalytic converter.

Note. A new converter with less than 100 miles on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.

  1. «Exhaust Leakage»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__exhaust-leakage)
  2. «Restricted Exhaust»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__restricted-exhaust)
  3. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. Perform the HO2S Heater Learn procedure with a scan tool after replacing the Heated Oxygen Sensor.
  6. «Catalytic Converter Replacement - Left Side»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system)
  7. «Catalytic Converter Replacement - Right Side»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system)

Repair Verification

  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. Turn OFF the ignition for 60 s
  5. Operate the vehicle within the Conditions for Running the DTC while observing the scan tool TWC Mon. Off Idle Test Conditions Met parameter. The parameter will change to Yes when the Off Idle Conditions have been met. If not the specified value, operate the vehicle within the Off Idle Conditions.
  6. When the parameter has changed to Yes and the conditions are safe, stop and idle the vehicle in gear.
  7. Apply the service brake.
  8. Monitor the scan tool TWC Test State parameter. When the parameter indicates Active, the TWC Monitor Test is running.
  9. Continue to monitor the parameter. When the parameter indicates Inactive, the TWC Monitor Test has completed.
  10. When the test has completed, the TWC Monitor Test Count parameter will increment by one and the TWC Monitor Test Result parameter will indicate Passed, Failed or No Decision. If No Decision is indicated, repeat steps 5-9 until the Test Result parameter indicates Passed or Failed.
  11. 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for further diagnosis.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 engine control module (ECM) using the fuel tank pressure (FTP) sensor input. With a leak in the system, the amount of pressure change will be less than that of a sealed system.

  1. DTCs P010C, P010D, P012B, P012C, P012D, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0222, P0223, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0502, P0503, P0722, P0723, P1221, P2227, P2228, P2229, P2610 are not set.
  2. The barometric pressure (BARO) is greater than 70 kPa.
  3. The fuel level is between 10-90 %.
  4. The start-up engine coolant temperature (ECT) and the start-up intake air temperature (IAT) are between 0-40°C (32-104°F).
  5. The engine run time before engine shut-off was greater than 10 min.
  6. The drive distance before engine shut-off was more than 8.4 km (5.2 mi).
  7. The ignition is OFF.
  8. The ambient air temperature at the end of the drive cycle is between 0-34°C (32-93°F).
  9. DTC P0442 runs once per drive cycle during the hot soak period after the ignition is turned OFF and may require up to 40 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 h.
  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.

DTC P0442 is a Type A DTC.

  1. The EVAP 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 GE-41413-A evaporative emissions system tester (EEST) , move all EVAP components while observing smoke with the GE-41413-SPT high intensity white light.
  3. Individual components can be isolated and tested using adapters in the GE-41413-300 EVAP cap and plug kit.
  4. A condition may exist where a leak in the EVAP 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 EVAP system and then observe the FTP parameter for vacuum decay.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 EVAP Service Port Access Tool
  2. GE-41413-A Evaporative Emissions System Tester (EEST)
  3. GE-41413-300 EVAP Cap and Plug Kit
  4. GE-41413-SPT High Intensity White Light

For equivalent regional tools, refer to Special Tools .

Note. Refer to the GE-41413-A evaporative emissions system tester (EEST) operation manual for detailed instructions in Evaporative Emission System Diagnosis . 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 EVAP canister side of the Q12 evaporative emission purge solenoid valve and install the CH-48096 EVAP service port access tool.
  2. Connect the GE-41413-A evaporative emissions system tester (EEST) to the CH-48096 EVAP service port access tool.
  3. Using a scan tool close the EVAP vent solenoid valve to seal the EVAP system.
  4. Use the flow meter on the GE-41413-A evaporative emissions system tester (EEST) , calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system. If a leak is detected, use the GE-41413-A evaporative emissions system tester (EEST) to apply smoke to the EVAP system at the purge tube until the leak is located using the GE-41413-SPT high intensity white light.
  1. Seal the EVAP system and use the flow meter on the GE-41413-A evaporative emissions system tester (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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen / High ResistanceShort to Voltage
Ignition 1 Voltage - Purge SupplyP0030, P0031, P0033, P0036, P0050, P0051, P0102, P0132, P0135, P0152, P0155, P0443P0030, P0031, P0050, P0051, P0443
Battery Positive - Vent SupplyP0449P0449
EVAP Purge Solenoid ControlP0443P0443
EVAP Vent Solenoid ControlP0449P0449P0449

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 ON (Not Venting) or OFF (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 0.25 s.

DTC P0443 and P0449 are Type B DTCs.

DTC P0443 and P0449 are Type B DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. For P0443, the audible clicking intensity will vary depending on mounting locations and interference with the fuel injectors clicking. You may also feel a change in the frequency of clicking.

P0443

  1. Ignition ON, engine OFF, you should hear or feel a clicking sound when the EVAP purge solenoid valve is commanded to 50 % with a scan tool. The clicking sound or feel 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 ON (Not Venting) and OFF (Venting) with a scan tool. Listen or feel for a click when the valve operates.
  2. Verify that both the ON (Not Venting) and the OFF (Venting) states are commanded with a scan tool while observing their parameter status. EVAP Vent Solenoid Valve Control Circuit High Voltage Test Status EVAP Vent Solenoid Valve Control Circuit Low Voltage Test Status EVAP Vent Solenoid Valve Control Circuit Open Test Status Each parameter should display OK or Not Run.
  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, Q12 evaporative emission purge solenoid valve for P0443 Q13 evaporative emission vent solenoid valve for P0449
  2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit, Terminal 1 or A and ground for the purge solenoid valve Terminal 2 or B or A and ground for the vent solenoid valve 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 all components connected to the voltage supply circuit and replace as necessary.
  3. Connect a test lamp between the voltage supply circuit and the control circuit.
  4. With a scan tool command the, EVAP purge solenoid valve to 50 % EVAP vent solenoid valve ON (Not Venting) and OFF (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 engine control module. 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 engine control module.
  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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «EVAPORATIVE EMISSION CANISTER VENT SOLENOID VALVE REPLACEMENT»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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.

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
  1. Before the ECM can report DTC P0446 failed, DTCs P0450, P0451, P0452, and P0453 must run and pass.
  2. DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0128, P0221, P0222, P0223, P0443, P0449, P0451, P0452, P0453, P0458, P0459, P0496, P0497, P0498, P0499, P0560, P0562, P0563, P0700, P2122, P2123, P2127, P2128 or P2138 is not set.
  3. The ignition voltage is 10-18 volts.
  4. The Closed Loop fuel control is enabled.
  5. The engine run time is greater than 10 minutes or the fuel trim is stable.
  6. The engine is idling.
  7. The Fuel Tank Pressure is between -18.7 and +9.8 mm Hg (-10.0 and +5.2 in. H2O).
  8. The ambient air temperature (AAT) is between 2-32°C (35-90°F).
  9. The ECT and the IAT are within 10°C (18°F) of each other at engine start-up.
  10. The barometric pressure (BARO) is greater than 68 kPa.
  11. The long term fuel trim remains steady, less than 3 percent change in 200 ms over a period of 8 seconds.
  12. The fuel level is between 11-88 percent.
  13. The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).
  14. The above conditions exist for greater than 5 seconds.
  15. DTC P0446 will attempt to run up to 10 times or until the test completes successfully once per ignition cycle.
  1. The Fuel Tank Pressure Sensor is less than -7.5 mm Hg (-4.0 in. H2O).
  2. The condition is exists for greater than 4 seconds or a cumulative of 30 seconds.

DTC P0446 is a Type B DTC.

DTC P0446 is a Type B DTC.

An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP vent valve inlet or a pinched vent hose. A blockage in the vent system may also cause a poor fuel fill problem.

Schematic Reference

Connector End View Reference

Description and Operation

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.
IMPORTANTPerform 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.

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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
FTP Sensor 5 V ReferenceP0452, P0532, P0641P0451P0446, P0452P0453, P0641
FTP Sensor SignalP0452P0451P0452P0453P0451, P0454
FTP Sensor Low ReferenceP0446, P0451P0446, P0453, P0463P0451
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, Engine OFF Parameter Normal Range: 1.3-1.7 V
FTP Sensor 5 V Reference0 V0 V4.2-5 V
FTP Sensor Signal0 V0 V5 V
FTP Sensor Low Reference4.5 V

FTP Sensor Voltage

The FTP 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 FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The ECM also uses this FTP 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 min.

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 min.
  3. A refueling event is not detected. A refueling event is confirmed if the fuel level has a persistent change of 10 % for 30 s.

P0451

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

P0452

The FTP sensor voltage is less than 0.15 V for more than 10 s.

P0453

The FTP sensor voltage is more than 4.9 V for more than 10 s.

P0454

If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt FTP signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of 0.45 in.H2O in the span of 1 s but less than 1 in H2O in 12.5 ms.

  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 FTP sensor is unobstructed.
  3. A FTP 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 %, 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 GE 41413-A evaporative emission system tester (EEST) while taking a snapshot.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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

GE 41413-A Evaporative Emission System Tester (EEST)

For equivalent regional tools, refer to Special Tools

  1. Remove the fuel cap.
  2. Ignition ON, engine OFF.
  3. Observe the FTP sensor parameter with a scan tool.
  4. The FTP 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 and all vehicle systems OFF. this may take up to 2 min for all vehicle systems to power down. 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 K20 engine control module.
  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 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 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 engine control module.
  5. Install a 3A fused jumper wire between the signal circuit terminal and the 5 V reference circuit terminal. Verify the scan tool FTP 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 engine control module.
  6. If all circuits test normal, test or replace the B150 fuel tank pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Tank Pressure Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 EVAP vent solenoid valve ON and the purge solenoid valve ON, allowing vacuum into the EVAP system. The ECM monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time.

  1. DTCs P00C8, P00C9, P16F3, P0068, P0101, P0102, P0103, P010C, P010D, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0128, P160E, P160D, P0191, P0192, P0193, P0220, P0222, P0223, P0442, P0443, P0449, P0451, P0452, P0453, P0454, P0464, P0496, P0502, P0503, P0606, P0608, P0609, P0641, P0651, P0722, P0723, P1104, P1516, P2100, P2101, P2102, P2103, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2227, P2228, P2229, P2230 is not set.
  2. The ignition voltage is greater than 11 V.
  3. The barometric pressure (BARO) is greater than 70 kPa.
  4. The fuel level is between 10-90 %.
  5. The purge flow is greater than 1.5 %
  6. The start-up engine coolant temperature (ECT) is less than 35°C (95°F).
  7. The start-up 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.
  1. The EVAP system is not able to achieve or maintain a calibrated level of vacuum within a set amount of time.
  2. 2 L (0.5 gal) of fuel must be consumed before setting this DTC a second 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 EVAP purge solenoid valve, purge pipe, canister, or vapor pipe, can cause this DTC to set.
  4. The EVAP 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 GE 41413-A evaporative emissions system tester (EEST) , move all EVAP components while observing smoke with the J 41413-SPT high intensity white light.
  6. Individual components can be isolated and tested using adapters in the J 41413-300 evaporative emissions cap and plug kit.
  7. A condition may exist where a leak in the EVAP 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 EVAP system and then observe the FTP sensor parameter for vacuum decay.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. GE 41413-A Evaporative Emissions System Tester (EEST)
  4. GE 41413-300 Evaporative Emissions Cap and Plug Kit
  5. GE 41413-SPT High Intensity White Light
  6. J 41413-VLV Evaporative Emissions Service Port Vent Tool

For equivalent regional tools, refer to Special Tools

Note. Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize or produce smoke from a leak. Refer to the GE 41413-A evaporative emissions system tester (EEST) operation manual for detailed instructions in Evaporative Emission System Diagnosis .

  1. Disconnect the purge tube at the quick connector on the EVAP canister side of the Q12 evaporative emission purge solenoid valve. Install the CH 48096 evaporative emissions service access port tool between the disconnected purge tube and the purge solenoid valve. Connect the GE 41413-A Evaporative Emissions System Tester (EEST) to the service access port tool.
  2. Use a scan tool to seal the EVAP system.
  3. Use the flow meter on the GE 41413-A evaporative emissions system tester (EEST) , calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system. If a leak is detected, use the GE 41413-A evaporative emissions system tester (EEST) to apply smoke to the EVAP system at the purge tube until the leak is located using the GE 41413-SPT high intensity white light.
  4. To test for a restriction, install the J 41415-30 fuel tank adapter to the fuel tank filler neck. Connect the GE-41413-A evaporative emissions system tester (EEST) to the adapter.
  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 %.
  8. The vacuum/pressure gauge on the GE-41413-A evaporative emissions system tester (EEST) and the FTP parameter on the scan tool should both show vacuum. If the vacuum/pressure gauge shows vacuum, but the FTP parameter does not show vacuum, replace the B150 fuel tank pressure sensor. If neither the FTP 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 GE-41413-A evaporative emissions system tester (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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit Description

This DTC tests for continuous intake manifold vacuum flow to the Evaporative Emission (EVAP) System. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is greater than a predetermined value within a predetermined time, this DTC sets.

FTP Sensor Signal VoltageFuel Tank Pressure
High, Approximately 1.5 Volts or MoreNegative Pressure/Vacuum
Low, Approximately 1.5 Volts or LessPositive Pressure
  1. Before the engine control module (ECM) can report DTC P0496 failed, DTCs P0450, P0451, P0452, and P0453 must run and pass.
  2. DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0443, P0446, P0449, P0450, P0451, P0452, P0453, P0458, P0459, P0498, P0499, P0560, P0562, P0563, P0700, P2122, P2123, P2127, P2128, P2138, P2227, P2228, or P2229 is not set.
  3. The fuel system is in closed loop.
  4. The engine run time is greater than 10 minutes.
  5. The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).
  6. The engine is idling.
  7. The ignition voltage is between 10-18 volts.
  8. The Closed Loop fuel control is enabled.
  9. The long term fuel trim remains steady, less than 3 percent change in 200 ms over a period of 8 seconds.
  10. The fuel tank pressure (FTP) is between -10.0 and +5.0 in. H2O (-18.7 and +9.8 mm Hg).
  11. The ambient air temperature is between 2-32°C (36-90°F).
  12. The start-up engine coolant temperature (ECT) is within 10°C (18°F) of ambient air temperature
  13. The fuel tank level is between 11-88 percent.
  14. The barometric pressure (BARO) is greater than 68 kPa.
  15. The above conditions are met for greater than 30 seconds.
  16. DTC P0496 will attempt to run up to 10 times or the test completes successfully once per ignition cycle.
  1. The control module detects vacuum during a non-purge condition.
  2. The condition exists for greater than 4 seconds or for a cumulative of 30 seconds.

DTC P0496 is a Type A/B DTC.

DTC P0496 is a Type A/B DTC.

  1. Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set . This may assist in diagnosing the condition.
  2. The EVAP system tests run when engine is first started and meets The Conditions for Running the DTC. An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge solenoid valve , or by a temporary blockage or restriction in the EVAP canister purge solenoid valve.

Schematic Reference

Connector End View Reference

Description and Operation

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Disconnect the EVAP purge solenoid valve electrical harness connector.
  2. Start the engine.
  3. Command the EVAP vent closed with a scan tool.
  4. Increase the engine speed to 1,200-1,500 RPM.
  5. Observe the scan tool fuel tank pressure (FTP) sensor parameter. Verify the scan tool FTP sensor parameter is -0.9 to +0.9 mm Hg (-0.5 to +0.5 in. H2O). If not within the specified range, replace the EVAP purge solenoid valve.
  6. Ignition ON, engine OFF, disconnect the EVAP purge solenoid valve pipe.
  7. Observe the scan tool FTP sensor parameter. Verify the FTP sensor parameter is -0.9 to +0.9 mm Hg (-0.5 to +0.5 in. H2O). If not within the specified range, replace the FTP sensor.
  1. «Evaporative Emission Canister Purge Solenoid Valve Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Tank Pressure Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming
  1. Start the engine.
  2. Command the EVAP vent solenoid closed with a scan tool.
  3. Increase the engine idle to 1,200-1,500 RPM.
  4. Observe the scan tool FTP sensor parameter. Verify the FTP sensor parameter is -0.9 to +0.9 mm Hg (-0.5 to +0.5 in. H2O).
  5. Clear the DTCs with a scan tool.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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, P0174, P0175, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268. P0270, P0271, P0273, P0274, P0276, P0277, P0300-P0306, P0351-P0356, P0461-P0464, P0496, P0627, P0628, P0629, P0722, P1516, P2066-P2068, 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

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 Inspection and Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-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»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) . 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0089, P0090-P0092, P00C6, P00C8, P00C9, P00CA, P0101-P0103, P0106-P0108, P0112-P0114, P0116-P0118, P0121-P0123, P0128, P0192, P0193, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0315, P0335, P0336, P0351-P0356, P0627-P0629, P069E, P0716, P0717, P0722, P0723, P0850-P0852, P1248, P1249, P124A, P124B, P124C, P124D, P1258, P135A, P135B, P150C, P163A, P1762, P1763, P1915, P2122, P2123, P2127, P2128, P2135, P2138, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, P216F, P228C, P228D, U0109 are not set.
  2. The catalyst temperature is less than 100°C (212°F).
  3. The engine coolant temperature is warmer than 10°C (14°F).
  4. The barometric pressure is greater than 70 kPa.
  5. The engine speed is between 450-1800 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 1-6 Current Misfire Counters during the first 500 engine cycles. The Cylinder 1-6 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Contaminated fuel-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. If all conditions test normal, replace fuel injectors as indicated by high misfire counts.
  1. «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)

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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
  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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) 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/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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

The FPCM 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 FPCM 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.

  1. This DTC may be stored as a history DTC without affecting the operation of the module.
  2. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module.
  3. If this DTC is retrieved as both a current and history DTC, replace the module that the DTC set for.

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

IMPORTANTThis 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 FPCM.

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

  1. If the DTCs are set, program the FPCM. If the DTCs reset, replace the FPCM.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for FPCM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Fuel Pump EnableP0628, P069EP0627, P069EP0629

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 between 11-18 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 Enable 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. 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
5-Volt ReferenceP0641P0641, P06A6P0641P06A6
Fuel Rail Pressure (FRP) Sensor SignalP0192P0191, P0192P0193P0191
Fuel Line Pressure Sensor Low ReferenceP0641, P06A6P06A6

The fuel pressure sensor is mounted on the fuel line. Fuel pressure is measured by the fuel pressure sensor. The fuel pump flow control module (FPCM) monitors the voltage signal from the fuel pressure sensor and also supplies the voltage and the ground of the fuel pressure sensor.

The ignition is on.

The FPCM detects that the fuel pressure 5-volt reference is above or below a predetermined voltage threshold.

DTC P0641 and P06A6 are A type DTCs.

DTC P0641 and P06A6 are A type 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 fuel line pressure sensor.
  2. Ignition OFF, test for less than 1.0 ohm 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 FPCM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FPCM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the FPCM.
  4. If all circuits test normal, replace the fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pressure Sensor Replacement - Fuel Feed Pipe»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for FPCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 other components connected to the same internal 5 V reference circuit.

  1. Ignition voltage is greater than 6.4 V.
  2. DTCs P0641, P0651, P0697, and P06A3 run continuously when the above condition is met.

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 sensor
  2. Multifunction intake air sensor
  3. Fuel rail pressure sensor
  4. A/C refrigerant pressure sensor
  5. All four camshaft position sensors

DTC P0651

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

  1. Crankshaft position sensor
  2. Brake pedal position sensor

DTC P0697

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

  1. Manifold absolute pressure 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 5 V reference circuit while viewing the 5 V Reference Circuit parameter on the scan tool. The scan tool parameter will change from Fault 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 the voltage is 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 the voltage is 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 Voltage parameter. Verify the voltage remains 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement»(/buick/enclave/i-2007-2013/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning)
  3. «Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  6. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  7. «Crankshaft Position Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  8. «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  9. «Fuel Tank Pressure Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  10. «Manifold Absolute Pressure Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  11. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  12. «Throttle Body Assembly Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  13. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 that 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 ignition voltage is between 10-32 V.
  2. The ECM has commanded the MIL ON at least once.
  3. The DTC runs 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.

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 Malfunction if there is a condition with the circuit or a connection.

Schematic Reference

  1. «Engine Controls Schematics»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-wiring-schematic-diagrams)
  2. «Instrument Cluster Schematics»(/buick/enclave/i-2007-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 with a scan tool while observing the control circuit status parameters listed below: 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 with a scan tool while observing the control circuit status parameters listed below: 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 illuminates, test the MIL control circuit terminal 54-X1 for a short to ground. If the circuit tests normal, replace the P16 instrument cluster.
  3. Connect a 3 A fused jumper wire between the MIL control circuit terminal 54-X1 and ground. The MIL should illuminate. If the MIL illuminates, replace the K20 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 normal, test the instrument cluster ignition voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the P16 instrument panel cluster/bulb.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  2. «Instrument Cluster Replacement (Traverse)»(/buick/enclave/i-2007-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges) , «Instrument Cluster Replacement (Enclave)»(/buick/enclave/i-2007-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges) , «Instrument Cluster Replacement (Acadia)»(/buick/enclave/i-2007-2013/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 CircuitP0690P0685, P0689, P1682P0685, P0689, P1682
Relay Feedback CircuitP0689, P1682P0689, P1682P0690

Powertrain Relay

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

Ignition Main 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/Short Gnd test and Not Run for Short To Volts test Component ON - Not Run for Open/Short Gnd test and OK for Short To Volts test
Battery VoltageFaultFault
Engine Controls Ignition Relay Control CircuitFaultFaultNot 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/Short Gnd test and Not Run for Short To Volts test Component ON - Not Run for Open/Short Gnd test and OK for Short To Volts test
Battery VoltageNot RunNot Run
Engine Controls Ignition Relay Control CircuitNot RunNot RunFault

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 powertrain relay and the other is supplied by the ignition main relay. The ECM monitors and compares the ignition voltage supplied by the two relays.

P0685

  1. The ignition is ON.
  2. The ignition voltage is greater than 11 V.
  3. The DTC runs continuously when the above conditions are met.

P0689, P0690

  1. The powertrain relay is commanded ON.
  2. DTC P0685 is not set.
  3. These DTCs run continuously when the above conditions are met.

P1682

  1. The powertrain 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 ECM detects that the engine controls ignition relay feedback circuit is less than 5 V.

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 2 s.

P1682

The ECM detects that there is greater than 3 V difference between the ignition main relay signal and the powertrain 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.

Schematic Reference

  1. «Engine Controls Schematics»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-wiring-schematic-diagrams)
  2. «Power Distribution Schematics»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Electrical Center Identification Views»(/buick/enclave/i-2007-2013/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)
  4. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  5. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 following Engine Controls Ignition Relay control circuit status parameters: 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 powertrain 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 powertrain 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 powertrain relay.

Component Testing

  1. Remove the KR75 powertrain relay.
  2. Test for one of the following resistance specifications between terminals 85 and 86 of the KR75 powertrain relay: 70-110 ohms 200-250 ohms If not within the specified range, replace the KR75 powertrain relay.
  3. Test for infinite resistance between the following terminals of the KR75 powertrain relay: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the KR75 powertrain 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 powertrain relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) Prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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. 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 fuel pump control module DTCs set. If a DTC is set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for diagnosis of fuel pump 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition VoltageP0096, P0097, P0102, P0178, P0443, P11C2, P2199P0096, P0097, P0101, P0102, P0178, P11C2, P2199P0690P0096, P0101, P0103
Intake Air Humidity Sensor SignalP0096, P0097, P11C3, P2199P0096, P0097, P11C2, P2199P0096, P0097, P11C2, P2199*P0096
GroundP0096, P0097, P0102, P0178, P11C2, P2199P0096, P0102
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.
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
Ignition0 %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 ambient 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

Conditions for Running the DTCs

P11C2, P11C3, and P11C4

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

Conditions for Setting the DTCs

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

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 38522 Variable Signal Generator

For equivalent regional tools, refer to Special Tools .

  1. Ignition ON. Observe the scan tool IAT Sensor 1 and 2 parameters. The readings should be within 25°C (45°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, this may take up to 2 minutes, 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 leads of the J 38522 Variable Signal Generator as follows: Red lead to the signal circuit terminal 8 at the harness connector Black lead to ground Battery voltage supply lead to B+
  6. Set the J 38522 Variable Signal Generator 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageShort from Supply Circuit to Control Circuit
Direct Fuel Injector High Voltage Supply Cylinder 1P2147P0201P2148P1248
Direct Fuel Injector High Voltage Control Cylinder 1P0261P0201P0262P1248
Direct Fuel Injector High Voltage Supply Cylinder 2P2150P0202P2151P1249
Direct Fuel Injector High Voltage Control Cylinder 2P0264P0202P0265P1249
Direct Fuel Injector High Voltage Supply Cylinder 3P2153P0203P2154P124A
Direct Fuel Injector High Voltage Control Cylinder 3P0267P0203P0268P124A
Direct Fuel Injector High Voltage Supply Cylinder 4P2156P0204P2157P124B
Direct Fuel Injector High Voltage Control Cylinder 4P0270P0204P0271P124B
Direct Fuel Injector High Voltage Supply Cylinder 5P216BP0205P216CP124C
Direct Fuel Injector High Voltage Control Cylinder 5P0273P0205P0274P124C
Direct Fuel Injector High Voltage Supply Cylinder 6P216EP0206P216FP124D
Direct Fuel Injector High Voltage Control Cylinder 6P0276P0206P0277P124D

The engine control module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of the fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled.

  1. The engine is running.
  2. The ignition voltage is between 11-18 V.
  3. The DTCs run continuously when the above conditions are met.

The ECM detects the injector high voltage supply circuit is shorted to the injector high voltage control circuit for greater than 2 s.

DTCs P1248, P1249, P124A, P124B, P124C, and P124D are Type A DTCs.

DTCs P1248, P1249, P124A, P124B, P124C, and P124D are Type A DTCs.

  1. Performing the fuel injector coil test may help isolate an intermittent condition. Refer to «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Circuit Status parameters. An Injector Circuit Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. Observe the DTC information with a scan tool. DTC P0685 or P1682 should not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. Engine operating, observe the DTC information with a scan tool. DTC P1248, P1249, P124A, P124B, P124C, or P124D should not set.
  3. Observe the scan tool Misfire Current Counter parameters. The Misfire Current Counters should not increment.
  4. Ignition ON, observe the scan tool Cylinder 1-6 Injector Circuit Status parameters. Verify the Injector Circuit Status parameters display OK.
  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. Ignition OFF, disconnect the appropriate multi-way harness connector X160 or X161, at the rear of the intake manifold.
  2. Ignition ON, observe the appropriate scan tool Cylinder 1-6 Injector Circuit Status. The parameter should display Open. If not the specified value, test the appropriate high voltage supply circuit, ECM side, for a short to ground or the appropriate high voltage control circuit, ECM side, for a short to voltage. If the circuits test normal, replace the K20 ECM.
  3. Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The Injector Circuit Status should transition from Open to OK. If not the specified value, test for the following conditions in the ECM side of the harness: An open/high resistance in the high voltage supply circuit An open/high resistance in the high voltage control circuit A short to ground in the high voltage control circuit A short to voltage in the high voltage supply circuit If the circuits test normal, replace the K20 ECM.
  4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohms. If less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
  5. Test for 1.5-2.5 ohms between the appropriate high voltage supply circuit and high voltage control circuit. If less than the specified range, test for a short between the high voltage supply circuit and high voltage control circuit. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s). If greater than the specified range, test the high voltage supply circuit and high voltage control circuit for an open/high resistance. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector.
  1. «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures)
  2. «Fuel Injector Balance Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures)

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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

The engine is running.

The FPCM detects an overtemperature fault.

DTC P064A and P1255 are A type DTCs.

DTC P064A and P1255 are A type 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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

IMPORTANTVerify that DTC P0231, P0232 or P023F are not set as current or history before performing this diagnostic. If any of those codes are set as current or history, go to DTC P0231, P0232, or P023F .
  1. Check that the entire undercarriage of the vehicle is clean, especially around the spare tire area where the FPCM is located. Clear all codes from the FPCM and test drive the vehicle. Verify that DTC P1255 or P064A do not set as current. If DTC P1255 or P064A reset as current, replace the FPCM.
  2. If the DTCs do not set in the FPCM again, the system is okay. Do not replace the FPCM.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for FPCM replacement, programming and setup

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide 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 coolant temperature
  5. Engine runtime
  6. Park/neutral position
  7. 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. Vehicle speed is less than 3 km/h (2 mph).
  3. The engine is at idle with no input from the accelerator pedal.
  4. The calculated catalyst temperature is less than 350°C (662°F).
  5. Engine coolant is greater than -10°C (50°F) and less than 56°C (132°F).
  6. Barometric pressure is greater than 74 kPa (10.7 psi).
  7. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0335, P0336, P0351, P0352, P0353, P0501, P0502, P0506, P0507, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, P0641, P0651, P1101, P1516, P1682, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176, P2610 are not set.
  8. This DTC runs for 10 s within the first 18 s of start-up, or until the calculated catalyst temperature is greater than 900°C (1,652°F). 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.

Description and Operation

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Any loading of the engine that lowers engine RPM, such as with partial application of the clutch, A/C cycling etc., during the first 18 s of engine run time may set this DTC.

  1. Allow the engine to cool to meet the conditions for running.
  2. Start and idle the engine for at least 2 min.
  3. DTC P1400 should run and pass.
  1. Inspect the air intake system for the following: Damage, restriction, or modification Dirty or deteriorating air filter element Crankcase ventilation system for correct operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) . Water intrusion Vacuum leak and other un-metered air downstream of the mass air flow (MAF) sensor Intake manifold leak
  2. Inspect the exhaust system for the following: Water intrusion Exhaust leak Damaged, restricted, modified or enhanced exhaust system-Refer to «Symptoms - Engine Exhaust»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  3. Inspect the engine mechanical for items that could alter the air flow into the combustion chamber. Refer to «Symptoms - Engine Mechanical»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
TAC Motor Control ClosedP2101P2101P2101P1516, P2101, P2176
TAC Motor Control OpenP2119P2101P2101P1516, P2101, P2176

The throttle body assembly contains a contact-less inductive throttle position sensing element that is managed by a customized integrated circuit. The throttle position (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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 Inspection and Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-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.
  5. Ignition ON.
  6. 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
  7. 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
  8. Ignition OFF, set the DMM to the 40 V scale or higher, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms or faster.
  9. Verify the Max voltage is within 3 V of B+ while using DMM Min/Max Recording Mode function on each control circuit listed below and ground as the ignition is turned ON. TAC Motor Control Open circuit terminal 1 TAC Motor Control Closed circuit terminal 2 If not within 3 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 3 V of B+
  10. Test or replace the Q38 throttle body assembly.
  1. «Throttle Body Assembly Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) for further diagnosis. If no DTCs set
  8. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM).

  1. The engine is running or cranking.
  2. The ignition voltage is between 8-18 V.
  3. 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 C DTC.

DTC P163A is a Type C DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 0.3-0.6 ohms at 20°C (68°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 OFF, verify that a test lamp does not illuminate between B+ and the low control circuit terminal 1. If the test lamp illuminates, test the low control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, verify that a test lamp does not illuminate between ground and the high control circuit terminal 2. If the test lamp illuminates, test the high control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Ignition ON, command the Fuel Pressure Regulator ON with a scan tool. Verify that the test lamp illuminates. If the test lamp does not illuminate, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  7. Ignition OFF, connect a test lamp between the low control circuit terminal 1 and B+.
  8. Ignition ON, command the Fuel Pressure Regulator ON with a scan tool. Verify that the test lamp illuminates. If the test lamp does not illuminate, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  9. 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 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pump-replacement-llt)
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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, P0059, P0060, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013C, P013D, P013E, P013F, P0140, P0141, P014A, P014B, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0178, P0179, P0201, P0202, P0203, P0204, P0205, P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0301, P0302, P0303, P0304, P0305, P0306, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1153, P1221, P1248, P1249, P124A, P124B, P124C, P124D, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P219A, P2227, P2228, P2229, P2230, P2269, P2270, P2271, P2272, P2273, P2440, or P2444 is not set.
  2. The barometric pressure (BARO) is greater than 70 kPa (10.2 PSI).
  3. The manifold absolute pressure (MAP) is between 0-255 kPa (0-37 PSI).
  4. The intake air temperature (IAT) is between -20 and +150°C (-4 and +302°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. DTCs P2096 and P2098 run continuously when the conditions above have been met.

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

  1. DTCs P2096 and P2098 are Type B DTCs.
  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 and P2098 are Type B DTCs.
  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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . High fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel saturation of the evaporative emissions (EVAP) canister Stuck open or leaking EVAP purge valve Restricted exhaust Incorrect PCV system operation 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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, P0059, P0060, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013C, P013D, P013E, P013F, P0140, P0141, P014A, P014B, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0178, P0179, P0201, P0202, P0203, P0204, P0205, P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0301, P0302, P0303, P0304, P0305, P0306, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1153, P1221, P1248, P1249, P124A, P124B, P124C, P124D, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P219A, P2227, P2228, P2229, P2230, P2269, P2270, P2271, P2272, P2273, P2440, or P2444 is not set.
  2. The barometric pressure (BARO) is greater than 70 kPa (10.2 PSI).
  3. The manifold absolute pressure (MAP) is between 0-255 kPa (0-37 PSI).
  4. The intake air temperature (IAT) is between -20 and +150°C (-4 and +302°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. DTCs P2097 and P2099 run continuously when the conditions above have been met.

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

  1. DTCs P2097 and P2099 are Type B DTCs.
  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 and P2099 are Type B DTCs.
  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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. Verify that none of the following conditions exist: Exhaust system leaks-Refer to «Symptoms - Engine Exhaust»(/buick/enclave/i-2007-2013/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»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) Engine vacuum leaks Low fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Lean fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . 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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 CircuitP0106, P0108, 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) 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 or A Low reference circuit terminal 5 or D 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 or C 5 V reference circuit terminal 2 or F 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 or E APP sensor 2 signal circuit terminal 6 or B 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 or C. APP sensor 1 signal circuit terminal 3 or E APP sensor 2 signal circuit terminal 6 or B
  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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageShort from Supply Circuit to Control Circuit
Direct Fuel Injector High Voltage Supply Cylinder 1P2147P0201P2148P1248
Direct Fuel Injector High Voltage Control Cylinder 1P0261P0201P0262P1248
Direct Fuel Injector High Voltage Supply Cylinder 2P2150P0202P2151P1249
Direct Fuel Injector High Voltage Control Cylinder 2P0264P0202P0265P1249
Direct Fuel Injector High Voltage Supply Cylinder 3P2153P0203P2154P124A
Direct Fuel Injector High Voltage Control Cylinder 3P0267P0203P0268P124A
Direct Fuel Injector High Voltage Supply Cylinder 4P2156P0204P2157P124B
Direct Fuel Injector High Voltage Control Cylinder 4P0270P0204P0271P124B
Direct Fuel Injector High Voltage Supply Cylinder 5P216BP0205P216CP124C
Direct Fuel Injector High Voltage Control Cylinder 5P0273P0205P0274P124C
Direct Fuel Injector High Voltage Supply Cylinder 6P216EP0206P216FP124D
Direct Fuel Injector High Voltage Control Cylinder 6P0276P0206P0277P124D

The engine control module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of the fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled.

  1. The engine is running.
  2. The ignition voltage is between 11-18 V.
  3. The DTCs run continuously when the above conditions are met.

P2147, P2150, P2153, P2156, P216B, or P216E

The ECM detects the injector high voltage supply circuit is shorted to ground for greater than 2 s.

P2148, P2151, P2154, P2157, P216C, or P216F

The ECM detects the injector high voltage supply circuit is shorted to voltage for greater than 2 s.

DTCs P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, and P216F are Type A DTCs.

DTCs P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, and P216F are Type A DTCs.

  1. Performing the fuel injector coil test may help isolate an intermittent condition. Refer to «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Circuit Status parameters. An Injector Circuit Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. Observe the DTC information with a scan tool. DTC P0685 or P1682 should not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. Engine operating, observe the DTC information with a scan tool. DTC P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, or P216F should not set.
  3. Observe the scan tool Misfire Current Counter parameters. The Misfire Current Counters should not increment.
  4. Ignition ON, observe the scan tool Cylinder 1-6 Injector Circuit Status parameters. Verify the Injector Circuit Status parameters display OK.
  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. Ignition OFF, disconnect the appropriate multi-way harness connector X160 or X161, at the rear of the intake manifold.
  2. Ignition ON, observe the appropriate scan tool Cylinder 1-6 Injector Circuit Status. The parameter should display Open. If not the specified value, test the appropriate high voltage supply circuit, ECM side, for a short to ground or the appropriate high voltage control circuit, ECM side, for a short to voltage. If the circuits test normal, replace the K20 ECM.
  3. Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The Injector Circuit Status should transition from Open to OK. If not the specified value, test for the following conditions in the ECM side of the harness: An open/high resistance in the high voltage supply circuit An open/high resistance in the high voltage control circuit A short to ground in the high voltage control circuit A short to voltage in the high voltage supply circuit If the circuits test normal, replace the K20 ECM.
  4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohms. If less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
  5. Test for 1.5-2.5 ohms between the appropriate high voltage supply circuit and high voltage control circuit. If less than the specified range, test for a short between the high voltage supply circuit and high voltage control circuit. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s). If greater than the specified range, test the high voltage supply circuit and high voltage control circuit for an open/high resistance. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector.
  1. «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures)
  2. «Fuel Injector Balance Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures)

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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)
Warm306 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

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. 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 25°C (45°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 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. Ignition ON. Test for 4.8-5.2 V between the IAT sensor 1 signal circuit terminal 1 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.
  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 variable signal generator 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 variable signal generator 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-intake-air) table. The resistance values should be in range of the table values. If not within the specified range, 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 in each bank. 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 P0016, P0017, P0018, P0019, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0122, P0123, P0128, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0300, P0301-P0306, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0411, P0442, P0443, P0455, P0496, P1248, P1249, P124A, P124B, P124C, P124D, P16F3, P2101, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, P216F, P2440, or P2444 are not set.
  2. The EVAP device controls and intrusive diagnostics are not active .
  3. The engine overspeed protection is not active.
  4. Engine run time is greater than 120 s.
  5. The engine is in Closed Loop status for greater than 5 s.
  6. The fuel level is greater than 10% and no fuel level sensor fault is present.
  7. The system voltage is greater than 11 V for greater than 0.2 s.
  8. The engine coolant temperature (ECT) is warmer than -20°C (-4°F).
  9. The engine speed is between 1,600-4,000 RPM.
  10. The mass air flow is between 0-1,000 g/s.

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

DTCs P219A and P219B are Type A DTCs.

DTCs P219A and P219B are Type A DTCs.

  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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  3. «Wiring Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  4. «Connector Repairs»(/buick/enclave/i-2007-2013/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. Diagnose any other DTCs that are set. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. 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 (2.9-7.0 psi). If the MAP Sensor parameter is not between 20-48 kPa (2.9-7.0 psi), refer to «DTC P0106»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0338) , or «DTC P0107 or P0108»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0338) .
  3. Inspect the air induction system for modified, damaged, leaking, or restricted components.
  4. Inspect the crankcase ventilation system for improper operation.
  5. Inspect the vacuum hoses for splits, kinks, and improper connections.
  6. Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.
  7. Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to «Symptoms - Engine Exhaust»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  8. Test the fuel injectors for improper operation. Refer to «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  9. Test for fuel contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  10. Test for excessive fuel in the crankcase due to leaking injectors.
  11. Test the ignition system for improper operation. Refer to «Electronic Ignition System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  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/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP0641, P2227, P2228P2227, P2228P0193, P0641, P2227, P2229P2227
SignalP2227, P2228P2227, P2228P2227, P2229P2227
Low ReferenceP0113, P2199, P2227, P2228, P2229P2227
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)128 kPa (18.6 psi)
Signal0 kPa (0 psi)0 kPa (0 psi)128 kPa (18.6 psi)
Low Reference128 kPa (18.6 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 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. OR
  3. DTC P0106, P0107, P0108, P2228, P2229, P2230, or P2610 is not set and P0107, P0108, P2228, or P2229 is not pending.
  4. Ignition ON, engine OFF
  5. The time between the current ignition cycle and the last time the engine was running is greater than 7 min.
  6. DTC P2227 runs continuously when the above conditions are met.

P2228 or P2229

  1. The engine is running.
  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. The engine is running.
  2. The ECM detects that the difference between the BARO signal and the calculated BARO is greater than 15 kPa (2.2 psi) if the vehicle has traveled at most 2.0 km (1.2 mi) since the last calculated BARO update, or the ECM detects that the difference between the BARO signal and the calculated BARO is greater than 20 kPa (2.9 psi) if the vehicle has traveled greater than 2.0 km (1.2 mi) since the last calculated BARO update. OR
  3. Ignition ON, engine OFF
  4. 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 4 s.

P2229

The ECM detects that the BARO sensor voltage is greater than 4.5 V for greater than 4 s.

P2230

The ECM detects that the cumulative difference between BARO sensor readings, over a specific length of time, is greater than a calibrated threshold.

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 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 is not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-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 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 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 repair.

  1. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement
  2. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
IGN VoltageP2534P2534

The fuel pump flow control module (FPCM) 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 volts.

DTC P2534 is an A type DTC.

DTC P2534 is an A type DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. Ignition OFF, disconnect the harness connector of the FPCM.
  3. Ignition ON, test for greater than 11 volts between the IGN voltage circuit terminal 15 and ground. If less than the specified voltage, test the IGN voltage circuit for a short to ground or an open/high resistance. If the circuit test normal and the ECM - IGN fuse 58 is open, test the voltage circuit for a short to ground. If the circuit tests normal, test or replace the Run/Crank relay.
  4. If all circuits test normal, replace the FPCM.

Relay Test

  1. Ignition OFF, disconnect the RUN/CRANK relay.
  2. Test for 60-180 ohms between terminals 85 and 86. If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If less than infinite resistance, replace the RUN/CRANK relay.
  4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohms between terminals 30 and 87. If greater than 2.0 ohms, replace the RUN/CRANK relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Within an Electrical Center)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions__relay-replacement-within-an-electrical-center) , «Relay Replacement (Attached to Wire Harness)»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/buick/enclave/i-2007-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for FPCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for a overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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

Note. DTC P2544 is an informational DTC. Diagnose all other engine control module DTCs prior to DTC P2544.

  1. Verify there are no other engine control module or communication DTCs set. If a DTC is set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) If a DTC is not set
  2. Complete the diagnosis by looking for an intermittent CAN circuit fault. Refer to «Scan Tool Does Not Communicate with High Speed GMLAN Device»(/buick/enclave/i-2007-2013/remont/communication-devices/#data-communications-system) . If an intermittent CAN circuit fault is found Repair as necessary. If an intermittent CAN circuit fault is not found
  3. All OK.

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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or 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 flow 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 pressure.

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

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

DTC P2635 is an A type DTC.

DTC P2635 is an A type 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/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 fuel pump control module output control. The fuel pump should turn on and off.

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.

Note. Verify that DTCs P018B, P018C, P018D, P0231, P0232, or P023F are not set as current or history before performing this diagnostic. If any of those codes are set as current or history, refer to DTC P018B-P018D , or DTC P0231, P0232, or P023F .

  1. Ignition OFF, disconnect the harness connector at the fuel tank pump module.
  2. Ignition ON, test for 5.0 ohms or less between the fuel pump module low reference circuit terminal 2 and ground. If greater than the specified range, test the fuel pump module low reference circuit for a high resistance. If the circuit tests normal, replace the fuel pump control module.
  3. Ignition OFF, install a test lamp between the control circuit terminal 1 and the control circuit terminal 2.
  4. Ignition ON, command the fuel pump 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 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 fuel pump control module.
  5. Perform the «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) to verify proper fuel pressure. If the fuel pressure is not normal, replace the fuel tank fuel pump module.
  6. If the fuel system components test normal, refer to «Symptoms - Engine Controls»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the repair.

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

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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. Ensure that the malfunction indicator lamp (MIL) is operating correctly. Use the scan tool to command the lamp ON and OFF.
  2. Ensure that there are no DTCs that are stored.
  3. Ensure that the scan tool data is within a normal operating range. Refer to «Control Module References»(/buick/enclave/i-2007-2013/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. Ensure that the control module grounds are clean, tight, and correctly located.
  2. Ensure that the vacuum hoses are not split or kinked, and are properly connected.
  3. Ensure that the air filter is clean and free from restrictions.
  4. Ensure that 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: The fuel system for correct operation and pressure-Refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . The fuel injectors for proper operation-Refer to «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . A fuel quality condition-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. Test ignition system for the following: Spark plugs for incorrect heat range or an abnormal condition-Refer to «Spark Plug Inspection»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__spark-plug-inspection) , and «Ignition System Specifications»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__ignition-system-specifications) . For diagnosis of coolant or oil fouled spark plugs-Refer to «Coolant in Combustion Chamber»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures__coolant-in-combustion-chamber) , or «Oil Consumption Diagnosis»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Wet down the secondary ignition system with water from a spray bottle-Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied. Weak spark using the J 26792 spark tester -Refer to «Electronic Ignition System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  3. Inspect for the following conditions: The proper 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/enclave/i-2007-2013/remont/automatic-trans/#automatic-transmission-6t75-diagnostic-information-and-procedures) . The proper operation of the A/C compressor An engine that runs lean or rich-Observe the Fuel Trim parameters with a scan tool. Slow responding heated oxygen sensors (HO2S)-The HO2S should respond quickly to different throttle positions. CAUTION: Refer to «Heated Oxygen and Oxygen Sensor Caution»(/buick/enclave/i-2007-2013/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. Inspect the 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) . Inspect the mass air flow (MAF) sensor connections. Engine oil contaminated by fuel Vacuum hoses for splits or kinks-Verify that the routing and connections are correct. Knock sensor (KS) system for excessive spark retard activity-Observe the scan tool Knock Retard parameter for activity greater than 0°.
  4. The exhaust system components for the following: Physical damage or possible internal failure The three-way catalytic converters for a restriction For more information, refer to «Symptoms - Engine Exhaust»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  5. Electromagnetic interference (EMI) on a reference circuit 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 speed parameter 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. The crankcase ventilation valve for proper operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .
  7. Evaporative emission (EVAP) canister purge solenoid that is stuck open
  8. The engine cooling system for the following conditions: A thermostat with an incorrect heat range-Refer to «Thermostat Diagnosis»(/buick/enclave/i-2007-2013/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) . Improper engine coolant level-If the level is low, refer to «Loss of Coolant»(/buick/enclave/i-2007-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
  9. The crankshaft position (CKP) sensor for an intermittent condition-Observe the scan tool CKP Resync parameter. The Resync parameter should remain at 0 during all operating conditions, and when moving the related harnesses and connectors between the CKP sensor and the ECM.
  10. Inspect the engine for the following mechanical failures: Refer to «Symptoms - Engine Mechanical»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-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. 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

Hard Start

  1. Inspect the throttle body for excessive carbon deposits and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-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 - Engine Coolant Temperature Sensor»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-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. With a scan tool, compare the Fuel Pressure Sensor parameter value to the Desired Fuel Pressure parameter value when the ignition key is first turned to ON. Refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle) , and «Engine Mechanical Specifications (LLT)»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-specifications__engine-mechanical-specifications-llt) .

Hesitation, Sag, Stumble

  1. Test the fuel pressure. Refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  3. Test the generator. Refer to «Symptoms - Engine Electrical»(/buick/enclave/i-2007-2013/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) . Repair the charging system if the generator output voltage is less than 9 volts or more than 16 volts.
  4. Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle) , and «Engine Mechanical Specifications (LLT)»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-specifications__engine-mechanical-specifications-llt) .
  5. Engine warm and idling, verify the correct operation of the camshaft actuator system. Command the intake and exhaust camshaft actuators for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake CMP Variance and Exhaust CMP Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters 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 Timing Drive Components Cleaning and Inspection»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle) , and «Camshaft Actuator System Description»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__camshaft-actuator-system-description) for additional information.

Poor Fuel Economy

  1. Heavy loads being carried or towed
  2. Acceleration rate too much or too often
  3. Inspect the brake system for brake drag.
  4. Inspect for incorrect operation of the speedometer.
  5. 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 the parameter listed in the «Engine Control Module Scan Tool Information (LLT)»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 - Engine Coolant Temperature Sensor»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  6. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  7. Inspect the throttle body for excessive carbon deposits and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-cleaning) .

Detonation/Spark Knock

  1. Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner. Follow the instructions on the can.
  2. Test for an engine overheating condition. Refer to «Engine Overheating»(/buick/enclave/i-2007-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-overheating) .
  3. 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 (LLT)»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 - Engine Coolant Temperature Sensor»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) , for resistance specifications. Replace the ECT sensor if the resistance is not within specification. Refer to «Engine Coolant Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) . If the sensor is within the specification, test the ECT sensor circuits for high resistance.
  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.

Lack of Power, Hesitation, or Cut Out

  1. Inspect the engine electrical system for correct operation. Refer to «Symptoms - Engine Electrical»(/buick/enclave/i-2007-2013/remont/charging-system/#battery-charging-system-and-starting-system__symptoms-engine-electrical) .
  2. Verify that each injector harness is connected to the correct injector.
  3. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  4. Engine warm and idling, verify the correct operation of the camshaft actuator system. Command the intake and exhaust camshaft actuators for each cylinder bank from 0 degrees to 25 degrees and back to zero while observing the appropriate scan tool Intake CMP Variance and Exhaust CMP Position Variance parameters. Each parameter should be less than 2 degrees in each of the commanded states. If any of the parameters 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 Timing Drive Components Cleaning and Inspection»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle) , and «Camshaft Actuator System Description»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__camshaft-actuator-system-description) for additional information.

Rough, Unstable, or Incorrect Idle and Stalling

  1. Inspect the throttle body for excessive carbon deposits and clean, if necessary. Refer to «Throttle Body Inspection and Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  3. Inspect the engine mounts. Refer to «Engine Mount Inspection»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle__engine-mount-inspection) .
  4. Inspect the intake and exhaust manifolds for casting flash.
  5. Inspect all bank 1 intake camshaft position sensor wiring for poor connections. Start the engine and observe for engine stalling while wiggling the bank 1 intake camshaft position sensor wiring harness. Refer to «Inducing Intermittent Fault Conditions»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__inducing-intermittent-fault-conditions) for further diagnosis.

Surges/Chuggles

  1. Inspect the mass air flow (MAF) sensor for obstruction, contamination, and damage. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  2. Test the 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.
  3. Verify that each injector harness is connected to the correct injector.

Fuel Odor

  1. Saturated EVAP canister-Refer to «Evaporative Emission Control System Description»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation) .
  2. A condition with the internal components of the fuel tank assembly-Refer to «Fuel System Description»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation) .
  3. Inspect for damaged or deteriorated fuel lines.

ECM Commanded Reduced Engine Power

Refer to Engine Control Module Scan Tool Information (LLT) for various conditions that can cause reduced engine power.

Poor Fuel Fill Quality

ProblemCauses
DEFINITION: During the fueling process a continual, occasional, or no-fuel nozzle shut-off condition has occurred.
Difficult to fillFuel fill limiter vent valve stuck closed Evaporative emission (EVAP) canister restricted EVAP vent valve stuck closed Hose between canister and canister vent solenoid twisted or kinked if applicable High fuel temperature Fuel filler hose is kinked Faulty dispensing nozzle Ignition switch ON, vent valve closed
Over fillFill limiter vent valve stuck open or leaking Fuel inlet check valve stuck open
Pre-mature shut-off of the fuel dispensing nozzle occurs immediately after engaging dispensing nozzle, tank emptyRestricted vapor lines or fuel fill pipe High fuel temperature Inlet check valve at tank stuck closed, fill pipe full of fuel Fuel tank full, gauge not accurate
Pre-mature shut-off of the fuel dispensing nozzle, more than 1/8 of tank capacity dispensedKinked, pinched or plugged lines in fuel tank vent system EVAP vent valve stuck closed or restricted EVAP canister restricted Fuel limiting vent valve stuck closed or obstruction at top of fuel tank
Fuel SpitbackRestricted EVAP canister High fuel temperature Ignition switch ON, EVAP vent valve closed

Poor Fuel Fill Quality

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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. The engine control module (ECM) uses the camshaft position (CMP) sensors to determine engine speed and position when there is a crankshaft position (CKP) sensor condition.
  2. The engine will operate with a CKP sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a CKP sensor condition in the signal circuit, the engine will go into a limp home mode after a restart. The ECM then calculates engine speed from one of the CMP sensors.
  3. The fuel pump flow control module (FPCM) controls and monitors the operation of the in-tank fuel pump. If the FPCM detects a fault, a DTC sets in the FPCM. The FPCM will then send a serial data message to the engine control module (ECM) requesting the illumination of the malfunction indicator lamp (MIL).
  4. 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.
  5. 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  6. 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.
  7. Inspect the engine for good secure electrical grounds.
  8. 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 minutes 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.
  9. 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

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 26792 Spark Tester

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. Crank or start the engine. Observe the DTC information with a scan tool. Verify that DTCs P0116, P0118, P0119, P0335, P0336, P0338, P0351-P0356, P0601, P0602, P0604, P0606, P062B, P069E, P0627, P0628, P0629, P0641, P167D, P1629, P1631, P1632, P2105 or U0109 does not set. If any of the listed DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  2. Observe the fuel pump control module (FPCM) DTC information with a scan tool. Verify FPCM DTC P0191, P0192, P0193, P0231, P0232, P023F, P025A, P0601-P0604, P0606, P06A6, P062F, P0641, P064A, P1255, P2534, or P2635 is not set. If a DTC is set refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  3. Ignition ON, observe the Theft Deterrent parameter with a scan tool. The parameter should display Disabled. If Enabled is displayed, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) .
  4. Test the ignition system for spark. Refer to «Electronic Ignition System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  5. Ignition ON, command the in-tank fuel pump ON with a scan tool. You should hear the fuel pump turn ON. If the fuel pump does not turn ON, refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  6. Ignition ON, observe the FPCM fuel line pressure sensor scan tool parameter. Command an increase in the fuel line pressure with a scan tool. Verify the fuel line pressure increases to greater than 410 kPa (60 psi) as commanded. If less than the specified range, refer to «Fuel System Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  7. Disconnect the MAF sensor. The engine control module (ECM) will ignore the MAF sensor and default to the calculated air flow. If disconnecting the MAF sensor corrects the condition and the sensor connections are OK, replace the MAF sensor. Refer to «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) .
  8. Verify that the following conditions do not exist: Collapsed air intake duct to the throttle body Restricted air filter element Spark plugs for being gas or coolant fouled-Refer to «Spark Plug Inspection»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__spark-plug-inspection) . A skewed engine coolant temperature (ECT) sensor-Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) . Exhaust system restricted-Refer to «Restricted Exhaust»(/buick/enclave/i-2007-2013/remont/exhaust/#engine-exhaust-system__restricted-exhaust) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) . Engine mechanical condition, for example, worn timing chain and gears, low compression-Refer to «Symptoms - Engine Mechanical»(/buick/enclave/i-2007-2013/remont/mechanical/#engine-mechanical-36l-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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provide an overview of each diagnostic category.
CircuitShort to GroundOpen or 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 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 pressure.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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 B 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 B and the low reference circuit terminal A.
  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 B 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 repair.

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

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 s, 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 line 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 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 module. The function of the venturi pump is to fill the fuel tank module reservoir. The fuel tank 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.

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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. EN 37287 Fuel Line Shut-Off Adapter

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 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 Instructions.

  1. Ignition OFF, all accessories OFF, install a CH 48027 Gauge.
  2. Ignition ON, engine OFF, command the fuel pump 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 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 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 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 pump module. If the fuel pressure decreases more than the specified value, perform the following procedure: Ignition OFF, relieve the fuel pressure. Refer to «Fuel Pressure Relief (Without CH-48027)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pressure-relief-without-ch-48027) , «Fuel Pressure Relief (CH-48027)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pressure-relief-ch-48027) , «Fuel Pressure Relief (High Side)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pressure-relief-high-side) . Disconnect the chassis fuel feed hose from the engine compartment fuel pipe. Install the EN 37287 Shut-Off Adapter between the chassis fuel hose and the engine compartment fuel pipe. Open the valve on the EN 37287 Shut-Off Adapter. Ignition ON, command the fuel pump ON with a scan tool and bleed the air from the CH 48027 Gauge. Command the fuel pump ON and then OFF with a scan tool. Close the valve on the EN 37287 Shut-Off Adapter. Monitor the fuel pressure for 1 min. 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 more than 34 kPa (5 psi) within the specified time, replace the fuel tank 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 min. If the fuel pressure decreases greater than the specified value, replace the fuel tank module.
  4. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027 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 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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) , , «Fuel Injector Solenoid Coil Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) , , and «Fuel Injector Balance Test»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Feed Pipe Replacement (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Fuel Injector Replacement (LLT)»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-injector-replacement-llt)
  3. «Fuel Line Replacement - Chassis»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Fuel Pump Fuel Feed Hose Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. «Fuel Tank Module Replacement»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-tank-module-replacement)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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.

Schematic Reference

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 can cause driveability conditions and fuel system deterioration. Fuel with more than 10 percent ethanol could result in 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 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 fuel composition 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 fuel sample contains more than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank .
  5. Test the fuel composition.
  6. If testing shows the ethanol percentage is still more than 15 percent, replace the fuel in the vehicle.

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. «Fuel System Cleaning»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-system-cleaning)
  2. «Fuel Tank Draining»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-tank-draining)

Evaporative Emission System Diagnosis

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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ignition system on this engine uses individual ignition coils and ignition control circuits for each cylinder. Ignition voltage is supplied to each bank of ignition coils. The engine control module (ECM) controls the ignition system operation. The ECM controls each coil using the ignition control circuits. The ECM commands the ignition control circuit low when a spark event is requested. The sequencing and timing are controlled by the ECM.

  1. The ignition coils for each bank are fused separately. If a fuse opens or the ignition voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground circuit opens at the engine block, the ignition coils would be inoperative for one bank of the engine.
  2. Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may cause a condition with the ignition coils.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/enclave/i-2007-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/enclave/i-2007-2013/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

EL 26792 Spark Tester

For equivalent regional tools, refer to Special Tools .

  1. Ignition OFF, disconnect the harness connector of the affected T8 ignition coil.
  2. Ignition OFF, and 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 K20 engine control module.
  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. Reconnect harness connector, Engine running, observe the Ignition Coil 1-6 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 1-6 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 6 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.

Perform the Diagnostic Repair Verification after completing the diagnostic repair.

  1. «Ignition Coil Replacement - Bank 1»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Ignition Coil Replacement - Bank 2»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/enclave/i-2007-2013/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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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 km/h (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) System 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 I/M DTCs are present. If an I/M DTC is set that would prevent the I/M System Status tests from completing, diagnose that DTC before continuing. Refer to «Inspection/Maintenance (I/M) System DTC Table»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures__inspectionmaintenance-im-system-dtc-table) .
  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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  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/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__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.

Inspection/Maintenance Data List

To determine if the inspection/maintenance readiness diagnostic tests can be run this ignition cycle, use a scan tool to observe the inspection/maintenance monitor enabled parameters in the inspection/maintenance Data List.

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) System DTC Table»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures__inspectionmaintenance-im-system-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) System DTC Table»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures__inspectionmaintenance-im-system-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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) , and refer to «Inspection/Maintenance System Check»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  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/enclave/i-2007-2013/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-trouble-code-dtc-list) , . After repairs, perform the «Inspection/Maintenance Complete System Set Procedure»(/buick/enclave/i-2007-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0340-to-dtc-p2635-and-diagnostic-information-and-procedures) to verify no further DTCs are set.

Inspection/Maintenance (I/M) System 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 or P0430
EVAPDTC P0442 DTC P0446 DTC P0455
Fuel SystemDTC P219A or P219B
Oxygen SensorDTC P0131, P0132, P0134, P0137, P0138, P0140, P0151, P0152, P0154, P0157, P0158, or P0160 DTC P0133, P013A-P013F, P014A, P014B, P0153, P015A, P015B, P015C, P015D, P2270, P2271, P2272, or P2273
Oxygen Sensor HeaterDTC P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141, P0155, or P0161
Camshaft SystemDTC P0011, P0014, P0021, or P0024

Inspection/Maintenance (I/M) System DTC Table

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• COMPONENT CONNECTOR END VIEWS - INDEX
• Electronic Ignition System Description
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust
• Diagnostic Trouble Code (DTC) List - Vehicle
• Exhaust Leakage
• Restricted Exhaust
• Catalytic Converter Replacement - Left Side
• Evaporative Emission Control System Description
• Special Tools
• Throttle Body Inspection and Cleaning
• Crankcase Ventilation System Inspection/Diagnosis
• Battery Inspection/Test
• Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
• Instrument Cluster Schematics
• Power Distribution Schematics
• Electrical Center Identification Views
• Relay Replacement (Within an Electrical Center)
• Relay Replacement (Attached to Wire Harness)
• DTC P0231, P0232, or P023F
• Engine Control Module Description
• Symptoms - Engine Exhaust
• Fuel Pump Replacement (LLT)
• Temperature Versus Resistance - Intake Air Temperature Sensor (Hitatchi Sensor)
• Altitude Versus Barometric Pressure
• Scan Tool Does Not Communicate with High Speed GMLAN Device
• Spark Plug Inspection
• Ignition System Specifications
• Coolant in Combustion Chamber
• Oil Consumption Diagnosis
• Torque Converter Diagnosis
• Heated Oxygen and Oxygen Sensor Caution
• Thermostat Diagnosis
• Loss of Coolant
• Temperature Versus Resistance - Engine Coolant Temperature Sensor
• Crankshaft and Bearing Cleaning and Inspection
• Engine Mechanical Specifications (LLT)
• Symptoms - Engine Electrical
• Camshaft Actuator System Description
• Engine Control Module Scan Tool Information (LLT)
• Engine Overheating
• Engine Mount Inspection
• Inducing Intermittent Fault Conditions
• Fuel Pressure Relief (Without CH-48027)
• Fuel Pressure Relief (CH-48027)
• Fuel Pressure Relief (High Side)
• Fuel Injector Replacement (LLT)
• Fuel Tank Module Replacement
• Fuel System Cleaning
• Fuel Tank Draining
• Fuel and Evaporative Emission Pipe Warning
• Clean, Dry, Low Pressure Gas Source Caution
• Fuel and Evaporative Emission Hose/Pipe Connection Cleaning Caution
• Road Test Warning
• DTC P0641, P0651, P0697, or P06A3
• Evaporative Emission System Diagnosis
• Inspection/Maintenance (I/M) System DTC Table

More articles — Engine Performance