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Engine Controls/fuel - 3.6l - DTC p0010 to DTC p0390 Buick LaCrosse II

Testing & Diagnostics ~36214 words

Diagnostic Instructions

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

Circuit/System Description

The camshaft position actuator system enables the Engine Control Module (ECM) to change the timing of the camshafts while the engine is operating. The Camshaft Position Actuator Solenoid Valve signal from the ECM is pulse width modulated (PWM). The ECM controls the Camshaft Position Actuator Solenoid Valve duty cycle by controlling the amount of solenoid valve ON time. The Camshaft Position Actuator Solenoid Valve controls the advance or the retard of each camshaft. The Camshaft Position Actuator Solenoid Valve controls the oil flow that applies the pressure to advance or retard the camshafts.

The ECM controls the Camshaft Position Actuator Solenoid Valve by supplying a 12 V pulse width modulated (PWM) signal. The ECM supplies a ground to the low reference circuit.

Conditions for Running the DTC

  1. The ignition voltage is greater than 11 V.
  2. The ignition switch is in the Crank or Run position.
  3. The ECM commanded the Camshaft Position Actuator Solenoid Valve ON.
  4. DTCs P0010, P0013, P0020, and P0023 run continuously when the above conditions are met.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

DTCs P0010, P0013, P0020, and P0023 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0010, P0013, P0020, and P0023 are Type B DTCs.

Diagnostic Aids

If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool circuit status parameters for the component. The circuit status parameters change from OK or Not Run to Malfunction if there is a condition with the circuit or a connection.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON.
  2. Verify DTC P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, or P0391 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If none of the DTCs are set
  3. Observe the appropriate control circuit status parameters listed below with a scan tool: The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit Low Voltage Test Status Bank 1 or 2 The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit Open Test Status Bank 1 or 2 The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit High Voltage Test Status Bank 1 or 2 If Malfunction is displayed Refer to Circuit/System Testing If OK or Not Run is displayed
  4. Engine idling, command the appropriate Camshaft Position Actuator from 0-25° and back to 0° while observing the appropriate control circuit status parameters listed below with a scan tool: The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit Low Voltage Test Status Bank 1 or 2 The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit Open Test Status Bank 1 or 2 The Intake/Exhaust Camshaft Position Actuator Solenoid Valve Control Circuit High Voltage Test Status Bank 1 or 2 If Malfunction is displayed Refer to Circuit/System Testing If OK or Not Run is displayed
  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 a DTC does not set. If any DTC sets Refer to Circuit/System Testing below for further diagnosis. If a DTCs does not set
  7. All OK.

Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate harness connector at the camshaft position actuator solenoid valve. 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 2 and ground. 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. Verify that a test lamp does not illuminate between the control circuit terminal 1 and ground. If the test lamp illuminates 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 less than 1 V, replace the K20 Engine Control Module If the test lamp does not illuminate
  5. Remove the test lamp.
  6. Command the CMP actuator solenoid ON and OFF with a scan tool. Verify the voltage changes. If the voltage does not change 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 or short to ground in the circuit If less than 2 ohms, replace the K20 Engine Control Module If the voltage changes
  7. Test or replace the appropriate camshaft position actuator solenoid valve.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate Q6 Camshaft Position Actuator Solenoid Valve.
  2. Test for 5-12 ohms between the control terminal 1 and the low reference circuit terminal 2. If not between 5-12 ohms Replace the Q6 Camshaft Position Actuator Solenoid Valve. If between 5-12 ohms
  3. Test for infinite resistance between each terminal and the Q6 Camshaft Position Actuator Solenoid Valve housing. If less than infinite resistance Replace the Q6 Camshaft Position Actuator Solenoid Valve. If infinite resistance
  4. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Exhaust»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Exhaust»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The camshaft position actuator system enables the Engine Control Module (ECM) to change the timing of the camshafts while the engine is operating. The camshaft position actuator solenoid signal from the ECM is pulse width modulated (PWM). The ECM controls the camshaft position actuator solenoid duty cycle by controlling the amount of solenoid ON time. The camshaft position actuator solenoid controls the advance or the retard of each camshaft. The camshaft position actuator solenoid controls the oil flow that applies the pressure to advance or retard the camshafts.

  1. DTC P0010, P0013, P0020, P0023, P0016, P0017, P0018, P0019, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, and P0391 is not set.
  2. The ignition voltage is greater than 11 V.
  3. The engine is running.
  4. The desired camshaft position is not changing greater than 4.5° for at least 1 s.
  5. Both of the desired and actual camshaft position actuator values cannot be greater than 20° or less than 5°.
  6. DTCs P0011, P0014, P0021, and P0024 run continuously when the above conditions are met.

P0011 and P0021

The ECM detects the difference between the desired and actual camshaft position angle is greater than 5° for greater 2.5 s.

P0014 and P0024

The ECM detects the difference between the desired and actual camshaft position angle is greater than 5° for greater 10 s.

DTCs P0011, P0014, P0021, and P0024 are Type B DTCs.

DTCs P0011, P0014, P0021, and P0024 are Type B DTCs.

Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft, camshaft position actuator solenoid, mechanical camshaft actuator, or timing chain can cause this DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool DTC information. Verify that DTC P0016, P0017, P0018, P0019, P0335, P0336, P0338, P0340, P0341, P0345, P0346, P0365, P0366, P0390, or P0391 is not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Engine Running, command the appropriate Camshaft Position Actuator from 0-25° and back to 0° while observing the appropriate scan tool Camshaft Position Variance parameters. The Camshaft Position Variance should be less than 2° in each of the commanded states.
  3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the appropriate Q6 Camshaft Position Actuator Solenoid Valve.
  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 2 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 1 and ground. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  4. Connect the DMM between control circuit terminal 1 and B+. Command the CMP actuator solenoid ON and OFF with a scan tool. The DMM should transition from a higher voltage to a lower voltage when commanded ON. If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 engine control module.
  5. Remove the Camshaft Position Actuator Solenoid Valve. Verify the following conditions do not exist with the Camshaft Position Actuator Solenoid Valve: Torn, restricted, mis-positioned, or missing screens at the CMP actuator solenoid Engine oil leak between the oil sealing lands of the CMP actuator solenoid. Inspect the lands of the CMP actuator solenoid for nicks. Oil seepage at the CMP actuator solenoid connector If a condition is found, replace Q6 Camshaft Position Actuator Solenoid Valve.
  6. Ignition OFF, swap the appropriate Camshaft Position Actuator Solenoid Valve with a Camshaft Position Actuator Solenoid Valve that is operating correctly.
  7. Engine idling. Command the appropriate Camshaft Position Actuator from 0-20° and back to 0° while observing the appropriate scan tool Camshaft Position Variance parameters. The Camshaft Position Variance should be less than 2° in each of the commanded states. If greater than the specified value, replace the mechanical camshaft position actuator.
  8. If all circuits/connections test normal, test or replace the Q6 Camshaft Position Actuator Solenoid Valve.
  1. Ignition OFF, disconnect the harness connector at the appropriate Q6 Camshaft Position Actuator Solenoid Valve.
  2. Test for 5-12 ohms between the ignition circuit terminal 1 and the control circuit terminal 2 of the Q6 Camshaft Position Actuator Solenoid Valve. If not within the specified range, replace the Q6 Camshaft Position Actuator Solenoid Valve.
  3. Test for infinite resistance between each terminal and the Q6 Camshaft Position Actuator Solenoid Valve housing. If not the specified value, replace the Q6 Camshaft Position Actuator Solenoid Valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Camshaft Position Actuator Replacement - Bank 1»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle__camshaft-position-actuator-replacement-bank)
  2. «Camshaft Position Actuator Replacement - Bank 2»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle__camshaft-position-actuator-replacement-bank)
  3. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Exhaust»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  6. «Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 2 (Left Side) Exhaust»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  7. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) uses the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor pulses to monitor the correlation between the crankshaft and the camshaft position. An improper relative position can be caused by either engine timing or improper indexing of the camshaft drive chain.

  1. P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0641, or P0642 are not set
  2. The engine is cranking or running.
  3. The crankshaft and camshaft position signals are synchronized.
  4. The camshaft position actuator is in the parked position.
  5. DTC P0016, P0017, P0018, and P0019 run continuously when the above conditions are met.

DTC P0016, P0017, P0018, or P0019

  1. The ECM detects that one camshaft is mis-aligned with the crankshaft. The ECM detects one of the following conditions: Bank 1 intake camshaft is greater than 9° retarded or 12° advanced in relationship to the crankshaft. Bank 1 exhaust camshaft is greater than 10° retarded or 13° advanced in relationship to the crankshaft. Bank 2 intake camshaft is greater than 11° retarded or 13° advanced in relationship to the crankshaft. Bank 2 exhaust camshaft is greater than 9° retarded or 13° advanced in relationship to the crankshaft.
  2. The ECM detects that all 4 camshafts are mis-aligned with the crankshaft. The ECM detects the following conditions: Bank 1 intake camshaft is greater than 9° retarded or 12° advanced in relationship to the crankshaft. Bank 1 exhaust camshaft is greater than 10° retarded or 13° advanced in relationship to the crankshaft. Bank 2 intake camshaft is greater than 6° retarded or 9° advanced in relationship to the crankshaft. Bank 2 exhaust camshaft is greater than 7° retarded or 9° advanced in relationship to the crankshaft.

DTC P0016 and P0017

The ECM detects that both camshafts on bank 1 are mis-aligned with the crankshaft. The ECM detects the following conditions

  1. Bank 1 intake camshaft is greater than 6° retarded or 12° advanced in relationship to the crankshaft.
  2. Bank 1 exhaust camshaft is greater than 10° retarded or 13° advanced in relationship to the crankshaft.

DTC P0018 and P0019

The ECM detects that both camshafts on bank 2 are mis-aligned with the crankshaft. The ECM detects the following conditions

  1. Bank 2 intake camshaft is greater than 6° retarded or 9° advanced in relationship to the crankshaft.
  2. Bank 2 exhaust camshaft is greater than 7° retarded or 9° advanced in relationship to the crankshaft.

DTCs P0016, P0017, P0018, and P0019 are type B DTCs.

DTCs P0016, P0017, P0018, and P0019 are type B DTCs.

  1. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed secondary timing chain can cause this DTC to set.
  2. This diagnostic algorithm is designed to detect an alignment condition between a primary intermediate sprocket and the secondary timing chain, or the alignment between a primary intermediate sprocket and the crankshaft. Either condition would cause the camshaft timing for both cams on one bank to be off an equal number of degrees.
  3. DTCs P0016, P0017, P0018, and P0019 set at the same time indicate a possible condition with the primary timing chain and the alignment between both intermediate sprockets and the crankshaft. Or, the crankshaft reluctor wheel has moved and is no longer referenced to top dead center (TDC).
  4. Observing the desired and actual camshaft angle parameters, with a scan tool before a DTC sets, may help to isolate whether a condition is specific to one camshaft, one bank, or caused by a condition with the primary crankshaft timing.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that none of the following DTCs are set. DTC P0010, P0013, P0020, P0023, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094 or P2095. If any of the DTCs listed are set refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Idle the engine at normal operating temperature. DTCs P0016, P0017, P0018, or P0019 should not set. If a DTC sets, inspect for the following and repair as necessary: The correct installation of the camshaft sensors The correct installation of the crankshaft sensor A timing chain tensioner condition An incorrectly installed timing chain Excessive play in the timing chain A mechanical cam actuator that is stuck in the full advance or retard position. A timing chain that jumped teeth A crankshaft reluctor wheel that has moved in relationship to top dead center (TDC) on the crankshaft
  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. «Timing Chain Alignment Diagram»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-timing-chain-alignment-routing-diagram)
  2. «Camshaft Timing Drive Components Cleaning and Inspection»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle)
  3. «Crankshaft and Bearing Cleaning and Inspection»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
HO2S High SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P1133, P1153, P2A00, P2A03
HO2S Low SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P1133, P1153, P2A00, P2A03
HO2S Heater Voltage SupplyP0030, P0036, P0050, P0056, P0132, P0135, P0138, P0141, P0152, P0155, P0158, P0161, *P0030, P0036, P0050, P0056, P0132, P0134, P0135, P0138, P0140, P0141, P0152, P0154, P0155, P0158, P0160, P0161P0030, P0036, P0050, P0056, P0132, P0134, P0135, P0138, P0140, P0141, P0152, P0154, P0155, P0158, P0160, P0161P0690P0135, P0141, P0155, P0161
HO2S Heater ControlP0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141, P0155, P0161P0030, P0036, P0050, P0056, P0132, P0134, P0135, P0138, P0140, P0141, P0152, P0154, P0155, P0158, P0160, P0161P0030, P0036, P0050, P0056, P0132, P0134, P0135, P0138, P0140, P0141, P0152, P0154, P0155, P0158, P0160, P0161P0030, P0036, P0050, P0056, P0132, P0134, P0135, P0138, P0140, P0141, P0152, P0154, P0155, P0158, P0160, P0161P0135, P0141, P0155, P0161
* Opens Fuse

Typical Scan Tool Data

CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 0.2-1.5 A
HO2S Heater Low Control0 A0 A0 A
HO2S Heater Voltage Supply0 A0 A0.2-2 A

HO2S Sensor 1 Current/HO2S Sensor 2 Current

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensors to reach operating temperature. Voltage is provided to the heater by an ignition voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit through a low side driver within the engine control module (ECM). The ECM uses pulse width modulation (PWM) to control the HO2S heater operation to maintain a specific HO2S operating temperature range.

P0030, P0036, P0050, or P0056

  1. The ignition voltage is between 11-32 V.
  2. The engine speed is greater than 400 RPM.
  3. The DTCs run continuously when the above conditions are met.

P0053, P0054, P0059, or P0060

  1. DTCs P0112, P0113, P0117, P0118, or P2610 are not set.
  2. The engine run time is greater than 20 s.
  3. The ignition voltage is less than 18 V.
  4. The ignition is OFF for greater than 8 h.
  5. The engine coolant temperature (ECT) is between -30 to +45°C (-22 to +113°F) at engine start-up.
  6. The ECT and the intake air temperature (IAT) are within 8°C (14°F) at engine start-up.
  7. The DTCs run once per drive cycle when the above conditions are met.

P0135, P0141, P0155, or P0161

  1. DTCs P0116, P0117, P0118, P0125, or P0128 are not set.
  2. The ignition voltage is between 10-32 V.
  3. The HO2S is at operating temperature.
  4. The HO2S is commanded ON.
  5. The DTCs run once per drive cycle when the above conditions are met for 120 s.

P0030, P0036, P0050, or P0056

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

P0053, P0054, P0059, or P0060

The ECM detects the HO2S heater is not within a specified resistance range at engine start-up.

P0135 or P0155

The ECM detects that the HO2S 1 heater current is greater than 3.1 amps, or less than 0.3 amps for greater than 8 s.

P0141 or P0161

The ECM detects that the HO2S 2 heater current is greater than 2.9 amps, or less than 0.3 amps for greater than 8 s.

DTCs P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141. P0155, and P0161 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0135, P0141. P0155, and P0161 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, command the appropriate HO2S Heater Bank 1 or 2 Sensor 1 or 2 ON and OFF with a scan tool while observing the HO2S Heater Control Circuit High Voltage, Open, and Low Voltage Test Status Bank 1 or 2 Sensor 1 or 2 parameters. The parameters should display OK or Not Run.
  2. Engine idling at operating temperature, observe the scan tool HO2S Heater parameter. The amperage should be within 0.2-2 A.
  3. Engine idling at operating temperature, move the related wiring and connectors while observing the HO2S Heater parameter with a scan tool. The parameter should not change with movement. If movement affects the parameter, repair the appropriate harness or connector.
  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 appropriate B52 HO2S.
  2. 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 B52 HO2S heater circuit fuse is open, test all components connected to the fuse and replace as necessary.
  3. Ignition ON, observe the appropriate scan tool HO2S Heater Control Circuit Open Test Status Bank 1 or 2 Sensor 1 or 2 parameter. The parameter should display Malfunction. If not the specified value, test the heater control circuit terminal E for a short to ground, or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Connect a 3 A fused jumper wire between the heater control circuit terminal E and ground. Observe the appropriate scan tool HO2S Heater Control Circuit Low Voltage Test Status parameter. The parameter should transition from OK to Malfunction. If not the specified value, test the heater control circuit terminal E for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  5. Ignition OFF, connect a 10 A fused jumper wire between the control circuit terminal E and the ignition voltage circuit terminal D.
  6. Engine idling, observe the appropriate HO2S Control Circuit High Voltage Test Status Bank 1 or 2 Sensor 1 or 2 parameter. The parameter should transition from Not Run to Malfunction. If not the specified value, test the control circuit and the ignition voltage circuit for high resistance. If the circuits test normal, replace the K20 ECM.
  7. If all circuits test normal, test or replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. Perform the scan tool Heated Oxygen Sensor Resistance Learn Reset after replacing an HO2S.
  6. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) compares actual airflow based on throttle position (TP) to a calculated airflow based on manifold absolute pressure (MAP) sensor, and mass air flow (MAF).

DTC P0068

  1. The engine speed is greater than 800 RPM.
  2. The ignition voltage is greater than 6.0 V.
  3. The throttle actuator control system is not in reduced power mode.
  4. The DTC runs continuously when the above conditions are met.

DTC P1101

  1. DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335, or P0336 are not set
  2. The engine speed is between 500-6, 800 RPM
  3. The engine coolant temperature (ECT) is between -7 and +125°C (+19 and +257°F).
  4. The intake air temperature (IAT) sensor 1 is between -20 and +125°C (-4 to +257°F).
  5. The DTC runs continuously when the above conditions are met.

The ECM detects that the actual airflow rate is greater than the calculated airflow.

  1. DTC P0068 is a type A DTC.
  2. DTC P1101 is a type B DTC.
  1. DTC P0068 is a type A DTC.
  2. DTC P1101 is a type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify none of the following conditions exist: The air intake duct system for loose clamps, cracks, or other damage The air intake duct system for being collapsed or restricted Restricted air filter Q38 throttle body for dirt, debris, and coking. Also, throttle body blade or shaft damage. Refer to «Throttle Body Inspection and Cleaning»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-cleaning) for further diagnosis. Splits, kinks, or improper connections at the vacuum hoses Missing, restricted, or leaking exhaust components-Refer to «Symptoms - Engine Exhaust»(/buick/lacrosse/ii-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) for further diagnosis. Vacuum leaks at the intake manifold and Q38 throttle body. If a condition exists, repair as necessary.
  2. Ignition ON, observe the diagnostic trouble code (DTC) information with a scan tool. Verify that DTC P0641, P0651, P0697, or P06A3 is not set. If any of the above DTCs are set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) for DTC P0641, P0651, P0697, or P06A3 diagnosis.
  3. Determine the current vehicle testing altitude. Compare the MAP Sensor pressure parameter to the reading in the «Altitude Versus Barometric Pressure»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__altitude-versus-barometric-pressure) table. The MAP sensor pressure parameter should be within the specified range indicated in the table. If the MAP sensor pressure is not within the range specified for your altitude, refer to «DTC P0106 (LF1, LFW, or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis.
  4. Engine idling, observe the MAP Sensor kPa parameter. The reading should be between 26-52 kPa (3.8-7.5 psi). If not within the specified range, refer to «DTC P0106 (LF1, LFW, or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis.
  5. Engine idling, observe the scan tool MAF Sensor parameter. The reading should be between 2.5-13.4 g/s depending on the engine coolant temperature (ECT) and barometric (BARO) pressure. If not within the specified range, refer to «DTC P0101»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis.
  6. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below. Engine idling Perform the scan tool snapshot function. Increase the engine speed slowly to 3, 000 RPM and then back to idle. Exit from the scan tool snapshot and review the data. Observe the MAF Sensor parameter frame by frame with a scan tool. If the MAF Sensor g/s parameter does not change smoothly and gradually, refer to «DTC P0101»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis.
  7. If all conditions test normal, test the engine for a mechanical condition. Refer to «Symptoms - Engine Mechanical»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) for further diagnosis.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Throttle Body Assembly Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-assembly-replacement-lfw-or)
  2. «Air Cleaner Element Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The high fuel pressure necessary for direct injection is supplied by the high pressure fuel pump. The pump is mounted on the rear of the engine and is driven by a three-lobe cam on the Bank 2 exhaust camshaft. This pump also regulates the fuel pressure using an actuator in the form of an internal solenoid-controlled valve. In order to keep the engine running efficiently under all operating conditions, the engine control module (ECM) requests pressure ranging from 2 to 15 MPa (290 to 2176 psi), depending on engine speed and load. Output drivers in the ECM provide the pump control circuit with a 12 V pulse-width modulated (PWM) signal, which regulates fuel pressure by closing and opening the control valve at specific times during pump strokes. This effectively regulates the portion of each pump stroke that is delivered to the fuel rail. When the control solenoid is NOT powered, the pump operates at maximum flow rate. In the event of pump control failure, the high pressure system is protected by a relief valve in the pump that prevents the pressure from exceeding 17.5 MPa (2538 psi).

The fuel rail fuel pressure sensor provides the feedback necessary to the ECM to control the pump and the injectors. This sensor is diagnosed separately from the fuel pressure control system.

The ECM monitors the fuel rail fuel pressure sensor and the high pressure fuel pump actuator to determine if the commanded and actual pressures are within a predetermined range during engine cranking and at all times while the engine is running. The ECM also monitors the fuel pump actuator to make sure it is operating within expected limits.

P0089, P228C, or P228D

  1. DTC P0016, P0017, P0018, P0019, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0111, P0112, P0113, P0116, P0117, P0118, P0128, P0192, P0193, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0627, P0628, or P0629 is not set.
  2. The ignition voltage is greater than 8 V.
  3. The low side fuel pressure is greater than 275 kPa (40 psi).
  4. The engine is running.
  5. The DTCs run continuously when the above conditions are met for 10 s.

P00C6

  1. DTC P0090, P0091, P0092, P00C8, P00C9, P00CA, P0116, P0117, P0118, P0128, P0192, P0193, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0627, P0628, P0629 are not set.
  2. The ignition voltage is more than 8 V.
  3. The engine coolant temperature is less than 65°C (149°F).
  4. The low side fuel pressure is greater than 300 kPa (44 psi).
  5. The diagnostic runs once for each engine start.

P0089

The high pressure fuel pump has exceeded it's control limits. This condition exists when the high pressure fuel pump actuator command is 0 ° or greater than 240 °. The condition exists for greater than 10 s.

P00C6

The ECM detects that the fuel rail pressure is not rising greater than 3 MPa (435 psi) or has fallen below 2 MPa (290 psi) during engine cranking, depending on initial pressure when cranking begins.

P228C

The actual fuel rail pressure is 3 MPa (435 psi) less than the desired fuel rail pressure. The condition exists for greater than 10 s.

P228D

The actual fuel rail pressure is 3 MPa (435 psi) greater than the desired fuel rail pressure. The condition exists for greater than 10 s.

  1. DTCs P0089 and P00C6 are Type B DTCs.
  2. DTCs P228C and P228D are Type A DTCs.
  3. A message center or an indicator displays Reduced Engine Power for P228C and P228D.
  1. DTCs P0089 and P00C6 are Type B DTCs.
  2. DTCs P228C and P228D are Type A DTCs.
  1. A leak in the high pressure fuel system may set a DTC.
  2. A faulty valve, plunger, or solenoid in the high pressure fuel pump may set a DTC. High pressure fuel pump damage will most likely be undetectable upon visual inspection.
  3. A restricted fuel feed pipe between the high pressure fuel pump and the fuel rail pressure sensor may set a DTC.
  4. Any problem with the Bank 2 exhaust cam may set fuel pressure DTCs due to the location and design of the high pressure fuel pump. If DTC P0019 or P0391 are current or in history, a cam control issue may be the root cause.
  5. A leaking or restricted fuel injector may set DTC P0089.
  6. For DTC P00C6, park the vehicle outdoors overnight and perform a start in the morning.
  7. A short to voltage in the crankshaft position signal circuit may set a DTC.
  8. As little as 2 ohms on either circuit of the high pressure fuel pump actuator will cause these DTCs to set. Test the circuits of the high pressure fuel pump actuator for a high resistance if you suspect a condition.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Attempt to start and idle the engine.
  2. Observe the DTC information with a scan tool. DTCs P0089, P00C6, P228C, and P228D should not set. If a DTC is set refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  3. Engine idling, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The pressure should be approximately 1.9-5.0 MPa (276-725 psi).
  4. Command an increase and decrease in Fuel Pressure with a scan tool. Observe the scan tool Fuel Rail Pressure Sensor parameter. The Fuel Rail Pressure Sensor parameter should increase or decrease with each commanded state.
  5. Road test the vehicle and perform a wide open acceleration from a stop until the transmission shifts into second gear. On manual transmission applications, shift to second gear or stop the test near 7000 RPM. Repeat the test at least three times. DTCs P0089, P228C, and P228D should not set.
  6. 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. Clear the DTCs.
  2. Road test the vehicle and perform a wide open acceleration from a stop until the transmission shifts into second gear. On manual transmission applications, shift to second gear or stop the test near 7000 RPM. Repeat the test at least three times. Observe the scan tool Fuel Rail Pressure Sensor parameter during the test. Near 7000 RPM the Fuel Rail Pressure Sensor parameter should reach 14-17 MPa (2031-2466 psi). If not the specified value, replace the G18 high pressure fuel pump.
  3. Remove the G18 high pressure fuel pump and visually inspect the lobes on the camshaft for unusual wear. If the lobes appear normal, replace the G18 high pressure fuel pump. If the lobes are worn, replace the camshaft.
  1. Ignition OFF, disconnect the harness connector at the G18 high pressure fuel pump.
  2. Test for 10 ohms plus/minus 1 ohms at 25°C (77°F) between the low control circuit terminal 1 and the high control circuit terminal 2. If not within the specified range, replace the G18 high pressure fuel pump.
  3. Test for infinite resistance between each terminal and the G18 high pressure fuel pump housing. If not the specified value, replace the G18 high pressure fuel pump.

Perform the Diagnostic Repair Verification after completing the repair

  1. «Camshaft Replacement - Left Side»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-on-vehicle__camshaft-replacement-left-side)
  2. «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Fuel Pump Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pump-replacement)
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
High Pressure Fuel Pump Actuator High ControlP0091, P00C9P0090, P00C8P0092, P00C9, P00CA
High Pressure Fuel Pump Actuator Low ControlP0091, P0092, P00C9P0090, P00C8P0092, P00CA

High pressure fuel is regulated by the high pressure fuel pump actuator, which is a part of the high pressure fuel pump. The high pressure fuel pump actuator is a solenoid valve. The ECM provides battery voltage on the actuator high control circuit and ground on the actuator low control circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the high control circuit driver energizes the high pressure fuel pump actuator and the low control circuit driver pulse-width modulates (PWM) the low control circuit to ground. The ECM monitors the voltage on the circuits to detect a failure.

  1. The ignition voltage is between 11-18 V.
  2. The DTCs run continuously within the enabling conditions.

P0090

  1. The ECM detects an open circuit in the high pressure fuel pump actuator low control circuit.
  2. The DTC sets when the above condition is present for 4 s.

P0091

  1. The ECM detects a short to ground in the high pressure fuel pump actuator low control circuit.
  2. The DTC sets when the above condition is present for 4 s.

P0092

  1. The ECM detects a short to voltage in the high pressure fuel pump actuator low control circuit.
  2. The DTC sets when the above condition is present for 4 s.

P00C8

  1. The ECM detects an open circuit in the high pressure fuel pump actuator high control circuit.
  2. The DTC sets when the above condition is present for 4 s.

P00C9

  1. The ECM detects a short to ground in the high pressure fuel pump actuator high control circuit.
  2. The DTC sets when the above condition is present for 4 s.

P00CA

  1. The ECM detects a short to voltage in the high pressure fuel pump actuator high control circuit.
  2. The DTC sets when the above condition is present for 4 s.
  1. DTCs P0090, P0091, P0092, P00C8, P00C9, and P00CA are Type A DTCs.
  2. A message center or an indicator displays Reduced Engine Power.

DTCs P0090, P0091, P0092, P00C8, P00C9, and P00CA are Type A DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Observe the DTC information with a scan tool. DTC P0090, P0091, P0092, P00C8, P00C9, P00CA, P0685, or P1682 should not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Ignition ON, command the Fuel Pressure Regulator ON and OFF with a scan tool while observing the following control circuit status parameters: Fuel Pressure Regulator Control Circuit High Voltage Test Status Fuel Pressure Regulator Control Circuit Open Test Status Fuel Pressure Regulator Control Circuit Low Voltage Test Status Fuel Pressure Regulator High Control Circuit High Voltage Test Status Fuel Pressure Regulator High Control Circuit Open Test Status Fuel Pressure Regulator High Control Circuit Low Voltage Test Status Each parameter should toggle between OK and Not Run or Not Run and OK.
  3. Engine idling, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The pressure should be approximately 1.9-5.0 MPa (276-725 psi).
  4. Command an increase and decrease in Fuel Pressure with a scan tool. Observe the scan tool Fuel Rail Pressure Sensor parameter. The Fuel Rail Pressure Sensor should increase or decrease with each command.
  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 harness connector at the G18 high pressure fuel pump.
  2. 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 engine control module.
  3. 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 engine control module.
  4. 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 engine control module.
  5. Ignition OFF, connect a test lamp between the low control circuit terminal 1 and B+.
  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 low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  7. If all circuits test normal, test or replace the G18 high pressure fuel pump.

Static Test

  1. Ignition OFF, disconnect the harness connector at the G18 high pressure fuel pump.
  2. Test for 9-11 ohms at 25°C (77°F) between the low control circuit terminal 1 and the high control circuit terminal 2. If not within the specified range, replace the G18 high pressure fuel pump.
  3. Measure the resistance between each terminal and the high pressure fuel pump housing. The DMM should display OL. If less than the specified value, replace the G18 high pressure fuel pump.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pump Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-pump-replacement)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0112, P0114, P2199P0111, P0113, P0114, P2199P0113, P0114, P2199*P0111, P2199
Low ReferenceP0111, P0113, P0114, P2199, P2229, P2230P0113, P0114, P2199, P2227, P2229*
*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 VoltageP0096, P0097, P0102, P0178, P0443, P11C2, P2199P0096, P0097, P0101, P0102, P0178, P11C2, P2199, P2230P0690P0096, P0101, P0103
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+.

IAT Sensor 2

CircuitShort to GroundOpen or High ResistanceShort to Voltage
Operating Conditions: Engine Running Parameter Normal Range: Varies with ambient temperature
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 temperature
Ignition Voltage40°C (-40°F) 10 Hz40°C (-40°F) 10 Hz
Signal40°C (-40°F) 10 Hz40°C (-40°F) 10 Hz40°C (-40°F)* 10 Hz
Ground40°C (-40°F) 10 Hz
*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
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 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 internal circuits for these sensors

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

The multifunction intake air sensor houses the following

  1. IAT sensor 1
  2. IAT sensor 2
  3. Humidity sensor
  4. MAF sensor
  5. BARO pressure sensor
IAT Sensor 1IAT Sensor 1 ResistanceIAT Sensor 1 Signal Voltage
ColdHighHigh
WarmLowLow
IAT Sensor 2IAT Sensor 2 FrequencyIAT Sensor 2 Temperature
Cold45 Hz40°C (-40°F)
Warm302 Hz104°C (219°F)

Conditions for Running the DTCs

P0096 and P0111

  1. DTCs P0097, P0098, P0112, P0113, P0116, P0117, P0118, P0119, or P1682 are not set.
  2. The vehicle has been OFF at least 8 hours.
  3. Ignition voltage is at least 11 V.
  4. These DTCs run once per ignition cycle when the enabling conditions are met.

Conditions for Setting the DTCs

P0096

  1. The ECM determines the absolute difference between IAT sensor 1 start-up temperature and the IAT sensor 2 start-up temperature is greater than 25°C (45°F). AND
  2. The absolute difference between ECT start-up temperature and the IAT sensor 2 start-up temperature is greater than the absolute difference between ECT start-up temperature and the IAT sensor 1 start-up temperature.
  3. This DTC runs once per ignition cycle when the enabling conditions are met.

P0111

  1. The ECM determines the absolute difference between IAT sensor 1 start-up temperature and the IAT sensor 2 start-up temperature is greater than 25°C (45°F). AND
  2. The absolute difference between ECT start-up temperature and the IAT sensor 1 start-up temperature is greater than the absolute difference between ECT start-up temperature and the IATsensor 2 start-up temperature.
  3. This DTC runs once per ignition cycle when the enabling conditions are met.

Action Taken When the DTCs Set

DTCs P0096 and P0111 are Type B DTCs.

Conditions for Clearing the DTCs

DTCs P0096 and P0111 are Type B DTCs.

  1. An IAT sensor 1 that is skewed, due to more resistance than is normal, can widen the spread between the 2 sensors and cause this DTC to set. Measure and record the resistance of the IAT sensor 1 at various ambient temperatures, and then compare those measurements to the Temperature vs. Resistance Table. Refer to «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitachi Sensor)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-intake-air) table.
  2. A slight to moderate resistance in the IAT sensor 1 signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor 1 signal circuit, which is interpreted by the ECM as a colder IAT sensor.
  3. Inspect the multifunction intake air sensor terminals for corrosion.
  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 also Humidity Sensor DTCs, check for a circuit problem.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

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

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

  1. Ignition ON, observe the following scan tool parameters. The readings should be within 25°C (45°F) of each other. Start-Up IAT Sensor 1 IAT Sensor 2
  2. Engine running, observe the scan tool IAT Sensor 1 and IAT Sensor 2 Sensor parameters. Depending on the current ambient temperature and the vehicle operating conditions, the readings should be between -39 and +149°C (-38 and +300°F
  3. Operate the vehicle within the conditions for running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the 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 2 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 OFF, all vehicle systems OFF, test for less than 2 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 engine control module.
  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 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.
  8. 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+
  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 engine control module.
  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 (Hitachi Sensor)»(/buick/lacrosse/ii-2009-2013/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, 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 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition VoltageP0096, P0097, P0102, P0178, P0443, P11C2, P2199P0096, P0097, P0101, P0102, P0178, P11C2, P2199, P2230P0690P0096, P0101, P0103
SignalP0096, P0097, P11C3, P2199P0096, P0097, P11C2, P2199P0096, P0097, P11C2, P2199*P0096
GroundP0096, P0097, P0102, P0178, P11C2, P2199, P2230P0096, P0102
*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
Ignition Voltage40°C (-40°F) 10 Hz40°C (-40°F) 10 Hz
Signal40°C (-40°F) 10 Hz40°C (-40°F) 10 Hz40°C (-40°F)* 10 Hz
Ground40°C (-40°F) 10 Hz
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 2

The intake air temperature (IAT) sensor 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 1 sensor signal circuit and a ground for the IAT 1 sensor 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 internal circuits for these sensors

  1. IAT sensor 2
  2. Humidity sensor
  3. Mass Air Flow (MAF) sensor

The multifunction intake air sensor houses the following

  1. IAT Sensor 1 sensor
  2. IAT sensor 2 sensor
  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)

P0097, P0098, and P0099

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

P0097

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

The ECM detects that the IAT sensor 2 signal is less than 13 Hz, colder than -60°C (-76°F), for greater than 5 s.

P0098

The ECM detects that the IAT sensor 2 signal is greater than 390 Hz, warmer than 150°C (302°F), for greater than 5 s.

P0099

The ECM detects that the IAT sensor 2 signal is intermittent or has abruptly changed for longer than 5 s.

  1. DTCs P0097, P0098, and P0099 are Type B DTCs.
  2. The ECM commands the cooling fans ON.

DTCs P0097, P0098, and P0099 are Type B DTCs.

  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 MAF sensor heating elements.
  2. Inspect the multifunction intake air sensor terminals for corrosion.
  3. 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 also Humidity Sensor DTCs, check for a circuit problem.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Signal Generator

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

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

  1. Ignition ON, observe the following scan tool parameters. The readings should be within 25°C (45°F) of each other. Start-Up IAT Sensor 1 IAT Sensor 2
  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).
  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 2 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 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 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 Duty Cycle switch to 50 % (Normal) Frequency switch to 30 Hz
  7. 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 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 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition VoltageP0096, P0097, P0102, P11C2, P2199P0096, P0097, P0101, P0102, P11C2, P2199P0690P0096, P0101, P0103
MAF Sensor SignalP0102P0102P0102*P0101, P0103, P1101
GroundP0096, P0097, P0102, P11C2, P2199P0096, P0102
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running at various operating conditions Parameter Normal Range: 2, 000-10, 000 Hz
Ignition Voltage0 Hz0 Hz
MAF Sensor Signal0 Hz0 Hz0 Hz*
Ground0 Hz

MAF Sensor

Circuit Description

The intake flow rationality diagnostic provides the within-range rationality check for the mass air flow (MAF), manifold absolute pressure (MAP), and the throttle position sensors. This is an explicit model-based diagnostic containing 4 separate models for the intake system.

The estimates of MAF and MAP obtained from this system of models and calculations are then compared to the actual measured values from the MAF, MAP, and the throttle position sensors and to each other to determine the appropriate DTC to fail.

  1. DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335 or P0336 are not set.
  2. The engine speed is greater than 500 RPM.
  3. The engine coolant temperature (ECT) is between -7 and +125°C (+19 and +257°F).
  4. The intake air temperature (IAT Sensor 1) is between -20 and +125°C (-4 and +257°F).
  5. The DTC runs continuously when the above conditions are met.

The engine control module (ECM) detects that the actual measured airflow from the MAF, MAP, and throttle position sensors is not within range of the calculated airflow that is derived from the system of models for greater than 2 s.

DTC P0101 is a Type B DTC.

DTC P0101 is a Type B DTC.

  1. A steady or intermittent high resistance of 15 ohms or greater on the ignition voltage circuit will cause the MAF sensor signal to be increased by as much as 60 g/s.
  2. Any type of contamination on the MAF sensor heating elements will degrade the proper operation of the sensor. Certain types of contaminants act as a heat insulator, which will impair the response of the sensor to airflow changes. Water or snow can create the opposite effect, and cause the signal to increase rapidly.
  3. Depending on the current ambient temperature, and the vehicle operating conditions, a MAF sensor signal circuit that is shorted to the IAT Sensor 1 signal circuit will cause the MAF sensor signal to be skewed or erratic. Additionally, it may cause a rapid fluctuation in the IAT Sensor 1 parameter.
  4. Certain aftermarket air filters may cause this DTC to set.
  5. Certain aftermarket air induction systems may cause this DTC to set.
  6. Modifications to the air induction system may cause this DTC to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Speed Generator

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

  1. Verify that the following DTCs are not set: 5 V reference circuits Camshaft position system performance Engine controls ignition relay circuits Ignition circuits-body control module (BCM) If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Verify that restrictions do not exist in the exhaust system. Refer to «Restricted Exhaust»(/buick/lacrosse/ii-2009-2013/remont/exhaust/#engine-exhaust-system__restricted-exhaust) for further diagnosis.
  3. Engine idling, observe the scan tool MAF Sensor parameter. The reading should be between 2.5-13.4 g/s depending on the engine coolant temperature (ECT) and barometric (BARO) pressure.
  4. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below. Engine idling Perform the scan tool snapshot function. Increase the engine speed slowly to 3, 000 RPM and then back to idle. Exit from the scan tool snapshot and review the data. Observe the MAF Sensor parameter frame by frame with a scan tool.
  5. Verify the proper operation of the ECT sensor and IAT sensor 1. A skewed or stuck ECT sensor and IAT sensor 1 will cause the calculated models to be inaccurate and may cause this DTC to run/fail when it should not. Refer to «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitachi Sensor)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-intake-air) table.
  6. Verify the proper operation of the MAP sensor. A skewed MAP sensor will cause the BARO value to be inaccurate. Refer to «DTC P0106 (LF1, LFW, or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis.
  7. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify the integrity of the entire air induction system by inspecting for the following conditions: Any damaged components Loose or improper installation An air flow restriction Any vacuum leaks Water intrusion In cold climates, inspect for any snow or ice buildup Inspect the B75C Multifunction Intake Air Sensor element for contamination.
  2. Ignition OFF, disconnect the harness connector at the B75C Multifunction Intake Air Sensor.
  3. Ignition OFF, all vehicle systems OFF, this may take up to 2 min, 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 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.
  5. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 6 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 OFF, connect the leads of the J 38522 variable speed generator as follows: Red lead to the signal circuit terminal 6 at the harness connector Black lead to ground Battery voltage supply lead to B+
  7. Set the J 38522 variable speed generator to the following specifications. Signal switch to 5 V Duty Cycle switch to 50 % (Normal) Frequency switch to 5 KHz
  8. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4, 950-5, 050 Hz. If the parameter is not within the specified range, replace the K20 engine control module.
  9. If all other circuits test normal, test or replace the B75C Multifunction Intake Air Sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Engine Coolant Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition VoltageP0096, P0097, P0102, P11C2, P2199P0096, P0097, P0101, P0102, P11C2, P2199P0690P0096, P0101, P0103
MAF Sensor SignalP0102P0102P0102*P0101, P0103, P1101
GroundP0096, P0097, P0102, P11C2, P2199P0096, P0102
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running at various operating conditions Parameter Normal Range: 2, 000-10, 000 Hz
Ignition Voltage0 Hz0 Hz
MAF Sensor Signal0 Hz0 Hz0 Hz*
Ground0 Hz
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

MAF Sensor

The mass air flow (MAF) sensor is integrated with the multifunction intake air sensor. The MAF sensor is an air flow meter that measures the amount of air in the sensor bore. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition.

The ECM applies 5 V to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a variable frequency signal based on the inlet air flow through the sensor bore. The signal varies with engine load and is displayed by the scan tool as Hertz (Hz) and grams per second (g/s). Ignition voltage and ground circuits are also supplied to the multifunction intake air sensor internal circuits for these sensors

  1. Intake Air Temperature (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
  1. The engine is running for greater than 1 s.
  2. The ignition signal is greater than 10 V.
  3. The above conditions are met for greater than 1 s.
  4. The DTC runs continuously when the above conditions are met.

P0102

The ECM detects that the MAF Sensor Signal is less than 800 Hz (about 0.90 g/s) for greater than 10 s.

P0103

The ECM detects that the MAF Sensor Signal parameter is greater than 14, 500 Hz (about 630 g/s) for greater than 10 s.

DTCs P0102 and P0103 are Type B DTCs.

DTCs P0102 and P0103 are Type B DTCs.

  1. Verify the integrity of the air induction system by inspecting for the following conditions: Loose or improper installation Damaged components Any water intrusion in the induction system Any contamination or debris on the sensing elements of the MAF sensor
  2. A steady or intermittent high resistance of 15 ohms or greater on the ignition voltage circuit will cause the MAF sensor signal to be increased by as much as 60 g/s.
  3. Depending on the current ambient temperature, and the vehicle operating conditions, a MAF sensor signal circuit that is shorted to the IAT sensor 1 signal circuit will cause the MAF sensor signal to be skewed or erratic. Additionally, it may cause a rapid fluctuation in the IAT Sensor 1 parameter.
  4. Verify that any electrical aftermarket devices are properly connected and grounded. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) for further diagnosis.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 38522 Variable Speed Generator

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

  1. Verify that the following DTCs are not set: P0685, P0690 or B1380. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Engine idling, observe the scan tool MAF Sensor parameter. The reading should be between 2.5-13.4 g/s depending on the engine coolant temperature (ECT) and barometric (BARO) pressure.
  3. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below. Engine idling Perform the scan tool snapshot function. Increase the engine speed slowly to 3, 000 RPM and then back to idle. Exit from the scan tool snapshot and review the data. Observe the MAF Sensor parameter frame by frame with a scan tool.
  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, 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 signal circuit terminal 6 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 speed generator as follows: Red lead to the signal circuit terminal 6 at the harness connector Black lead to ground Battery voltage supply lead to B+
  6. Set the J 38522 variable speed generator to the following specifications. Signal switch to 5 V Duty Cycle switch to 50 % (Normal) Frequency switch to 5 KHz
  7. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4, 950-5, 050 Hz. If the parameter is not within the specified range, replace the K20 engine control module.
  8. If all other 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 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
5 V ReferenceP0107, P0641P0106, P0697P0107P0106, P0697P0106, P0107
MAP Sensor SignalP0107P0106, P0107P0107P0108P0106, P0107, P1101
Low ReferenceP0106, P0108P0106, P0108P0106, P0108
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running, transmission in Park or Neutral Parameter Normal Range: 20-48 kPa (2.9-7 psi), varies with altitude
5 V Reference0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
MAP Sensor Signal0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Low Reference127 kPa (18.4 psi)

MAP Sensor

The intake flow rationality diagnostic provides the within-range rationality check for the mass air flow (MAF), manifold absolute pressure (MAP), and the throttle position sensors. This is an explicit model-based diagnostic containing 4 separate models for the intake system.

  1. The throttle model describes the flow through the throttle body and is used to estimate the MAF through the throttle body as a function of barometric pressure (BARO), throttle position, intake air temperature (IAT), and estimated MAP. The information from this model is displayed on the scan tool as the MAF Performance Test parameter.
  2. The first intake manifold model describes the intake manifold and is used to estimate MAP as a function of the MAF into the manifold from the throttle body and the MAF out of the manifold caused by engine pumping. The flow into the manifold from the throttle uses the MAF estimate calculated from the above throttle model. The information from this model is displayed on the scan tool as the MAP Performance Test 1 parameter.
  3. The second intake manifold model is identical to the first intake manifold model except that the MAF sensor measurement is used instead of the throttle model estimate for the throttle air input. The information from this model is displayed on the scan tool as the MAP Performance Test 2 parameter.
  4. The fourth model is created from the combination and additional calculations of the throttle model and the first intake manifold model. The information from this model is displayed on the scan tool as the Throttle Position Performance Test parameter.

The estimates of MAF and MAP obtained from this system of models and calculations are then compared to the actual measured values from the MAF, MAP, and the throttle position sensors and to each other to determine the appropriate DTC to fail. The following table illustrates the possible failure combinations and the resulting DTC or DTCs.

MAF Performance TestMAP Performance Test 1MAP Performance Test 2Throttle Position Performance TestDTCs PassedDTCs Failed
OKOKP0101, P0106, P0121, P1101None
OKOKMalfunctionOKP0101, P0106, P0121, P1101None
MalfunctionOKMalfunctionOKP0106, P0121, P1101P0101
OKMalfunctionMalfunctionOKP0101, P0121, P1101P0106
MalfunctionMalfunctionMalfunctionOKP0121, P1101P0101, P0106
OKMalfunctionP0101, P0106, P1101P0121
OKOKMalfunctionMalfunctionP0101, P0106, P0121, P1101None
MalfunctionOKMalfunctionMalfunctionP0101, P0106, P0121P1101
MalfunctionMalfunctionMalfunctionP0101, P0106, P0121P1101

Scan Tool Diagnostic Test Results

  1. DTC P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0128, P0335 or P0336 is not set.
  2. The engine speed is between 400-7, 000 RPM.
  3. The IAT Sensor parameter is between -20° to +125°C (-4° to +257°F).
  4. The ECT Sensor parameter is between 69-127°C (156-260°F).
  5. This DTC runs continuously within the enabling conditions.

The engine control module (ECM) detects that the actual measured airflow from MAF, MAP, and throttle position is not within range of the calculated airflow that is derived from the system of models for more than 2 s.

DTC P0106 is a Type B DTC.

DTC P0106 is a Type B DTC.

  1. A wide open throttle (WOT) acceleration from a stop should cause the MAP sensor parameter on the scan tool to increase rapidly to near the BARO parameter at the time of the 1-2 shift.
  2. The BARO that is used by the ECM to calculate the air flow models is initially based on the MAP sensor at ignition ON. When the engine is running, the ECM will continually update the BARO value near WOT using the MAP sensor and a calculation. A skewed MAP sensor will cause the BARO value to be inaccurate.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 23738-A Mityvac
  2. J 35555 Metal Mityvac
  3. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-special-tools-and-equipment__special-tools-diagnostic-tools) .
  1. Verify that DTC P0641, P0651, or P0697 is not set. If any of the DTCs are set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. Verify that restrictions do not exist in the exhaust system. Refer to «Restricted Exhaust»(/buick/lacrosse/ii-2009-2013/remont/exhaust/#engine-exhaust-system__restricted-exhaust) .
  3. Ignition OFF for 90 s, determine the current vehicle testing altitude.
  4. Ignition ON, engine OFF, observe the scan tool BARO parameter. Compare the parameter to the «Altitude Versus Barometric Pressure»(/buick/lacrosse/ii-2009-2013/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.
  5. Use the scan tool and compare the MAP Sensor parameter to a known good vehicle, under various operating conditions. The reading should be within 5 kPa of the known good vehicle.
  6. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify the integrity of the entire air induction system by inspecting for the following conditions: Any damaged components Loose or improper installation An air flow restriction Any vacuum leak Improperly routed vacuum hoses In cold climates, inspect for any snow or ice buildup Verify that restrictions do not exist in the MAP sensor port or vacuum source.
  2. Ignition OFF for 90 s, disconnect the harness connector at the B74 MAP sensor.
  3. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 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 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Verify the scan tool MAP Sensor parameter is less than 1 kPa (0.2 psi). If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1. Verify the scan tool MAP Sensor parameter is greater than 127 kPa (18.4 psi). If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  7. If the circuits test normal, test or replace the B74 MAP sensor.

Note. You must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

Skewed Signal Test

  1. Using the following steps and referencing the table below will determine if the MAP sensor is skewed.
  2. Ignition ON, engine OFF, observe the MAP Sensor scan tool parameter.
  3. Use the observed MAP Sensor scan tool parameter that is closest to a value that is indicated in the first column. THEN
  4. Using the J 23738-A Mityvac or the J 35555 Metal Mityvac to apply 5 in Hg of vacuum to the B74 MAP sensor, the parameter in the first column should decrease by 17 kPa (2.5 psi). The acceptable range is indicated in the second column.
  5. Using the J 23738-A Mityvac or the J 35555 Metal Mityvac to apply 10 in Hg of vacuum to the B74 MAP sensor, the parameter in the first column should decrease by 34 kPa (4.9 psi). The acceptable range is indicated in the third column.
Ignition ON, Engine OFF, MAP Sensor ParameterMAP Sensor Parameter With 5 Inches of Vacuum AppliedMAP Sensor Parameter With 10 Inches of Vacuum Applied
100 kPa (14.5 psi)79-87 kPa (11.5-12.6 psi)62-70 kPa (9-10.2 psi)
95 kPa (13.8 psi)74-82 kPa (10.7-11.9 psi)57-65 kPa (8.3-9.4 psi)
90 kPa (13.1 psi)69-77 kPa (10-11.2 psi)52-60 kPa (7.5-8.7 psi)
80 kPa (11.6 psi)59-67 kPa (8.6-9.7 psi)42-50 kPa (6.1-7.3 psi)
70 kPa (10.2 psi)49-57 kPa (7.1-8.3 psi)32-40 kPa (4.7-5.8 psi)
60 kPa (8.7 psi)39-47 kPa (5.7-6.8 psi)22-30 kPa (3.2-4.4 psi)

Erratic Signal Test

  1. Ignition OFF, remove the B74 MAP sensor.
  2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the corresponding terminal of the B74 MAP sensor.
  3. Install a jumper wire between the low reference circuit terminal 2 of the B74 MAP sensor and ground.
  4. Install a jumper wire at terminal 3 of the B74 MAP sensor.
  5. Connect a DMM between the jumper wire from terminal 3 of the B74 MAP sensor and ground.
  6. Ignition ON, with the J 23738-A Mityvac or J 35555 Metal Mityvac, slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 V, without any spikes or dropouts. If the voltage reading is erratic, replace the B74 MAP sensor.

Perform the Diagnostic Repair Verification after completing the repair

  1. «Manifold Absolute Pressure Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
5 V ReferenceP0106, P0107, P0108, P0697P0106, P0107P0107P0106, P0108, P0697P0106, P0107
MAP Sensor SignalP0107P0106, P0107P0107P0106, P0108P0106, P0107, P1101
Low ReferenceP0106, P0108P0108P0106, P0108
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running, transmission in Park or Neutral Parameter Normal Range: 20-48 kPa (2.9-7.0 psi), varies with altitude
5 V Reference0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
MAP Sensor Signal0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Low Reference127 kPa (18.4 psi)

MAP Sensor

The manifold absolute pressure (MAP) sensor has a 5 V reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5 V to the MAP sensor on the 5 V reference circuit, and provides a ground for the low reference circuit. The MAP sensor provides a voltage signal to the ECM on the signal circuit relative to the intake manifold pressure changes.

  1. DTC P0697 is not set.
  2. The engine is running.
  3. This DTC runs continuously within the enabling conditions.

P0107

The ECM detects that the MAP sensor voltage is less than 0.20 V for more than 5 s.

P0108

The ECM detects that the MAP sensor voltage is more than 4.80 V for more than 5 s.

DTCs P0107 and P0108 are Type B DTCs.

DTCs P0107 and P0108 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 23738-A Mityvac
  2. J 35555 Metal Mityvac
  3. For equivalent regional tools, refer to «Special Tools (Diagnostic Tools)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-special-tools-and-equipment__special-tools-diagnostic-tools) .
  1. Verify that DTC P0641, P0651, or P0697 is not set. If any of the DTCs are set refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. Ignition ON, observe the scan tool MAP Sensor parameter. The reading should be between 0.20-4.80 V.
  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 for 90 s, disconnect the harness connector at the B74 MAP sensor.
  2. Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 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 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Verify the scan tool MAP Sensor parameter is less than 1 kPa (0.2 psi). If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1. Verify the scan tool MAP Sensor parameter is greater than 127 kPa (18.4 psi). If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If the circuits test normal, test or replace the B74 MAP sensor.

Note. You must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

Erratic Signal Test

  1. Ignition OFF, remove the B74 MAP sensor.
  2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 and the corresponding terminal of the B74 MAP sensor.
  3. Install a jumper wire between the low reference circuit terminal 2 of the B74 MAP sensor and ground.
  4. Install a jumper wire at terminal 3 of the B74 MAP sensor.
  5. Connect a DMM between the jumper wire from terminal 3 of the B74 MAP sensor and ground.
  6. Ignition ON, with the J 23738-A Mityvac or the J 35555 Metal Mityvac, slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5 V without any spikes or dropouts. If the voltage reading is erratic, replace the B74 MAP sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Manifold Absolute Pressure Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
SignalP0112, P0114, P2199P0111, P0113, P0114, P2199P0113, P0114, P2199*P0111, P2199
Low ReferenceP0111, P0113, P0114, P2199, P2227, P2228, P2229P0113, P0114, P2199, P2227, P2229*
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

IAT Sensor 1

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running Parameter Normal Range: Varies with ambient temperature
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

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 multifunction intake air sensor houses the following

  1. IAT sensor 1
  2. IAT sensor 2
  3. Humidity sensor
  4. Mass Air Flow (MAF) sensor
  5. BARO pressure sensor
IAT Sensor 1IAT Sensor 1 ResistanceIAT Sensor 1 Signal Voltage
ColdHighHigh
WarmLowLow

P0112 and P0113

  1. The engine run time is greater than 1 s.
  2. The DTCs run continuously when the above conditions are met.

P0114

  1. The ignition is ON or the engine is running.
  2. This DTC runs continuously within the enabling conditions.

P0112

The ECM detects that the IAT sensor 1 signal is warmer than 149°C (300°F) for greater than 5 s.

P0113

The ECM detects that the IAT sensor 1 signal is colder than -60°C (-76°F) for greater than 5 s.

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

P0114

The ECM detects that the IAT sensor 1 signal is intermittent or has abruptly changed for greater than 5 s.

  1. DTCs P0112, P0113, and P0114 are Type B DTCs.
  2. The ECM commands the cooling fans ON.

DTCs P0112, P0113, and P0114 are Type B DTCs.

  1. With the ignition ON, the engine OFF, if the engine is cold, a properly functioning IAT sensor 1 will gradually increase the scan tool IAT Sensor 1 parameter. This is due to the heat that is generated by the MAF sensor heating elements.
  2. Depending on the ambient temperature, an IAT sensor 1 signal circuit or low reference circuit that is shorted to the MAF sensor signal circuit can cause a DTC P0113 and/or P0114 to set. This condition causes a rapid fluctuation in the IAT Sensor 1 parameter.
  3. An IAT sensor 1 signal circuit that is shorted to the MAF sensor ignition circuit can cause a DTC P0113 and/or P0114 to set.
  4. A MAF sensor ground circuit that is open will cause a DTC P0113 and/or a DTC P0114 to set.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine idling, DTC P0112, P0113, or P0114 should not set.
  2. Engine running, observe the scan tool IAT Sensor 1 parameter. The reading should be between -39 and +149°C (-38 and +300°F) depending on the current ambient temperature and the vehicle operating conditions.
  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 2 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 or for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  3. 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 terminal 1 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
  4. 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.
  5. 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 by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitachi Sensor)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-intake-air) table. The resistance values should be within the specified range. If not within the specified range, replace the B75C multifunction intake air sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions) for multifunction intake air sensor replacement.
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117, P0119P0118, P0119P0118, P0119P0116, P0128
Low ReferenceP0118P0118P0128
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running at various operating conditions Parameter Normal Range: Varies with coolant temperature
ECT Sensor150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 V to the ECT sensor signal circuit and a ground for the low reference circuit.

The ECM uses this high side coolant rationality diagnostic to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the ignition is OFF. If the calibrated ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT) to determine if the temperatures are within an acceptable operating range of each other.

  1. DTC P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0128, P0502, P0503, P0601, or P2610 is not set.
  2. The vehicle has had a minimum ignition OFF time of 8 h.
  3. The ignition is ON.
  4. The start-up IAT is warmer than -7°C (+19°F).
  5. The Fuel Level Sensor parameter is greater than 2.5%.
  6. This DTC runs once per ignition cycle within the enabling conditions.
  1. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30°C (54°F) warmer than the IAT sensor. OR
  2. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) warmer than the IAT sensor, and the time spent cranking the engine is greater than 30 s when the fuel level is greater than 2.5%. OR
  3. The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 16°C (29°F) warmer than the IAT sensor. Then the vehicle must be driven for greater than 6 min and 40 s at greater than 24 km/h (15 mph). If the IAT sensor then decreases greater than 5°C (9°F), an engine block heater was detected and the test is aborted. If the IAT sensor does not decrease, an engine block heater was not detected and DTC P0116 will set.
  1. DTC P0116 is a Type B DTC - with RPO NU5.
  2. DTC P0116 is a Type C DTC - with RPO NTA.
  1. DTC P0116 is a Type B DTC - with RPO NU5.
  2. DTC P0116 is a Type C DTC - with RPO NTA.
  1. Engine coolant that is leaking through the sensor will create a high resistance short to ground. This condition results in less voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a warmer ECT.
  2. An IAT sensor that is skewed colder at various ambient temperatures due to greater resistance than is normal will increase the range between these two sensors. Measure and record the resistance of the IAT sensor at various ambient temperatures, then compare those measurements to the «Temperature Versus Resistance - Intake Air Temperature Sensor (Hitachi Sensor)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-intake-air) table.
  3. A slight to moderate resistance in the IAT sensor signal circuit or low reference circuit will increase the range between these two sensors. This condition results in a greater voltage on the IAT sensor signal circuit, which is interpreted by the ECM as a colder IAT.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to «Cooling System Leak Testing»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) , and «Cooling System Draining and Filling (Static Fill)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) , «Cooling System Draining and Filling (GE 47716)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-ge) .
  2. Ignition OFF for 8 h or greater.
  3. Ignition ON, observe the scan tool ECT Sensor and IAT Sensor parameters. The ECT, IAT, and ambient temperature should be within 15°C (27°F) of each other.
  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 B34 engine coolant temperature sensor.
  2. Vehicle OFF, all 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 A 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, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F). If warmer than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 engine control module.
  4. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT Sensor parameter is warmer than 140°C (284°F). If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  5. If the circuits test normal, test or replace the B34 engine coolant temperature sensor.

Static Test

  1. Ignition off, remove the B34 engine coolant temperature sensor.
  2. Test the B34 engine coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) Temperature Versus Resistance table and verify that the resistance is within 5% of the specification. If not within the specified range, replace the B34 engine coolant temperature sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117, P0119P0118, P0119*P0118, P0119P0116, P0128
Low ReferenceP0118, P0119P0128
*ECM or sensor damage may occur if the circuit is shorted to B+.
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine running at various operating conditions Parameter Normal Range: Varies with coolant temperature
Signal150°C (302°F)40°C (-40°F)40°C (-40°F)
Low Reference40°C (-40°F)40°C (-40°F)

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 V to the ECT sensor signal circuit and a ground for the low reference circuit.

The purpose of this diagnostic is to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the engine is OFF. If the required engine OFF time is met at start-up, the ECM will compare the temperature difference between the actual measured ECT and IAT sensors.

P0117

  1. The ignition is ON. OR
  2. The engine is running for greater than 10 s.
  3. This DTC runs continuously within the enabling conditions.

P0118

  1. The ignition is ON. OR
  2. The engine is running for greater than 10 s. OR
  3. The engine run time is less than 10 s when the IAT is warmer than 0°C (32°F).
  4. This DTC runs continuously within the enabling conditions.

P0117

The ECM detects that the ECT is warmer than 149°C (300°F) for greater than 5 s.

P0118

The ECM detects that the ECT is colder than -39°C (-38°F) for greater than 5 s.

  1. DTC P0117 or P0118 are a Type B DTC.
  2. The cooling fans will be commanded ON.
  3. The Engine Coolant Temperature Gauge is inoperative.

DTC P0117 or P0118 are a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON.
  2. Verify the scan tool ECT Sensor parameter is between -39 to + 120°C (-38 to +248°F) and changes with engine run time. If not between -39 to + 120°C (-38 to +248°F) or does not change Refer to Circuit/System Testing below. If between -39 to + 120°C (-38 to +248°F) and changes
  3. All OK.
  1. Disconnect the B34 engine coolant temperature sensor harness connector at the 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 A and ground. 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. Verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F). If warmer than -39°C (-38°F) Ignition OFF, disconnect the harness connector at the K20 engine control module. Test for infinite resistance between the signal circuit terminal B 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 colder than -39°C (-38°F)
  5. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A.
  6. Verify the scan tool ECT sensor parameter is warmer than 149°C (300°F). If colder than the 149°C (300°F) Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON. 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 Ignition OFF 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 warmer than 149°C (300°F)
  7. Test or replace the B34 engine coolant temperature sensor.
  1. Ignition OFF, remove the B34 engine coolant temperature sensor.
  2. Test the B34 engine coolant temperature sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5% of the specification. If not within the specified range Replace the B34 engine coolant temperature sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) engine control module replacement, programming, and setup.

Repair Verification

  1. Ignition ON, observe the ECT Sensor parameter. The reading should be between -39 to + 120°C (-38 to +248°F).
  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.
  3. Verify a DTC does not set. If any DTC sets Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If no DTC sets
  4. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117, P0119P0116, P0118, P0119P0118*P0116, P0128
Low ReferenceP0116, P0118, P0119P0118*P0128
* Internal ECM or sensor damage may occur if the circuit is shorted to B+
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: -39 to +142°C (-38 to +288°F) Varies with coolant temperature.
ECT Sensor Signal143°C (289°F)40°C (-40°F)40°C (-40°F)*
Low Reference40°C (-40°F)40°C (-40°F)*
* Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the ECT sensor. If the ECM detects excessive noise or rapid fluctuations in the ECT signal, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

ECTECT ResistanceECT Signal Voltage
ColdHighHigh
WarmLowLow
  1. DTC P0117 or P0118 is not set.
  2. The ignition is ON or the engine is operating.
  3. DTC P0119 runs continuously once the above conditions are met.
  1. The ECM detects an abrupt ECT positive temperature change or negative temperature change ±10°C (±18°F) greater than the expected value.
  2. The condition exists for approximately 4-6 seconds.

DTC P0119 is a Type B DTC.

DTC P0119 is a Type B DTC.

  1. Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) .
  2. If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 5°C (41°F).
  3. After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
  4. Intermittent High resistance on either the ECT sensor signal circuit or the ECT sensor low reference circuit could set a DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Observe the scan tool engine coolant temperature (ECT) sensor parameter, while moving the ECT sensor connector and the K20 ECM connector. The ECT sensor parameter should not fluctuate while moving the related harnesses and connectors. Repair the suspected harness or connection if the ECT parameter fluctuates greater than 3°C (5°F) while moving the related harnesses and connectors.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature sensor.
  2. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 ohms between the low reference circuit terminal A 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, verify the scan tool ECT Sensor parameter is colder than -40°C (-40°F). If warmer than the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 engine control module.
  4. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT Sensor parameter is warmer than 140°C (284°F). If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  5. If all circuits test normal, test or replace the B34 engine coolant temperature sensor.
  1. Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature sensor.
  2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the B34 engine coolant temperature sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP06A3P0122*, P0222*, P16A0P06A3P0121*, P16A2, P2135*
Throttle Position Sensor SignalP0122*, P0222*, P16A0P0122*, P0222*, P16A1P0123*, P0223*, P16A1**P0121*, P16A2, P2135*
Low ReferenceP0123*, P0223*, P16A1P0121*, P16A2, P2135*
* This DTC set indicates an internal throttle body condition. ** A short to voltage causes P16A1 to set. If DTC P16A0, P16A1, and P16A2 set at the same time, an intermittent circuit condition exists.
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating with the throttle closed. All accessories OFF. Parameter Normal Range: Throttle Position Sensor 1 3.75-4.75 V
5 V Reference5.0 V5.0 V5.0 V
Throttle Position Sensor Signal5.0 V0.0 V0.0 V
Low Reference0.0 V

Throttle Position Sensor 1

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating with the throttle closed. All accessories OFF. Parameter Normal Range: Throttle Position Sensor 2 0.45-0.90 V
5 V Reference0.0 V0.0 V0.0 V
Throttle Position Sensor Signal0.0 V5.0 V5.0 V
Low Reference5.0 V

Throttle Position Sensor 2

The throttle body assembly contains a contact-less inductive throttle position sensing element that is managed by a customized integrated circuit. The throttle position 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 throttle position 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 throttle position 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 throttle position sensor 1 and 2.

P0121

  1. DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0335, or P0336 is not set.
  2. The engine speed is between 400-6, 200 RPM.
  3. The engine coolant temperature (ECT) is between -7 to +125°C (19-257°F).
  4. The intake air temperature (IAT) is between -20 to +125°C (-4 to +257°F).
  5. The DTC runs continuously when the above conditions are met.

P0122, P0123, P0222, P0223

  1. DTC P06A3 is not set.
  2. The ignition is ON or the engine is running.
  3. The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
  4. The DTCs run continuously when the above condition are met.

P16A0, P16A1, or P16A2

  1. The ignition is ON or the engine is operating.
  2. The run/crank voltage is greater than 6.4 V.
  3. The DTCs run continuously once the above conditions are met for greater than 1 s.

P2135

  1. DTCs P0122, P0123, P0222, P0223, or P06A3 are not set.
  2. The ignition is ON or the engine is running.
  3. The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
  4. The DTC runs continuously when the above conditions are met.

P0121

The ECM detects that the throttle position sensor 1 voltage is stuck in range for greater than 1 s.

P0122

The ECM detects the throttle position sensor 1 signal voltage is less than 0.32 V for greater than 1 s.

P0123

The ECM detects the throttle position sensor 1 signal voltage is greater than 4.7 V for greater than 1 s.

P0222

The ECM detects the throttle position sensor 2 signal voltage is less than 0.25 V for greater than 1 s.

P0223

The ECM detects the throttle position sensor 2 signal voltage is greater than 4.6 V for greater than 1 s.

P16A0

The ECM detects a low voltage circuit condition on the throttle position sensor signal circuit for greater than 1 s.

P16A1

The ECM detects a high voltage circuit condition on the throttle position sensor signal circuit for greater than 1 s.

P16A2

The ECM detects an incorrect message was received over the throttle position sensor signal circuit for greater than 1 s.

P2135

The ECM detects that throttle position sensor 1 and 2 disagree greater than 7-10 percent for greater than 1 s.

  1. DTCs P0121 is a Type B DTC.
  2. DTCs P0122, P0123, P0222, P0223, P16A0, P16A1, P16A2, and P2135 are Type A DTCs.
  3. The ECM commands the throttle actuator control (TAC) system to operate in a Reduced Engine Power mode.
  4. A message center or an indicator displays Reduced Engine Power.
  5. Under certain conditions, the ECM commands the engine OFF.
  1. DTCs P0121 is a Type B DTC.
  2. DTCs P0122, P0123, P0222, P0223, P16A0, P16A1, P16A2, and P2135 are Type A DTCs.
  1. A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.
  2. If the accelerator pedal is pressed to the wide open throttle position, the throttle blade angle or Throttle Position angle is limited to less than 40 percent.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON.
  2. Verify that DTC P0601-P0606, P06A3, and P16F3 is not set. If any of the DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If none of the DTCs are set
  3. Verify the scan tool Throttle Body Idle Airflow Compensation parameter is less than 90 %. 90 % or greater Refer to «Throttle Body Inspection and Cleaning»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-inspection-and-cleaning) . If less than 90 %
  4. Verify the scan tool Throttle Position Sensor 1 and Throttle Position Sensor 2 voltage parameters are greater than 0.0 V. If 0.0 V Refer to Circuit/System Testing below. If greater 0.0 V
  5. Verify the Throttle Position Sensors 1 and 2 Agree/Disagree parameter displays Agree while performing the Throttle Sweep Test with a scan tool. If Disagree Test or replace the Q38 throttle body assembly. If Agree
  6. Verify DTC P0121, P0122, P0123, P0222, P0223, P16A0, P16A1, P16A2, and P2135 is not set. If any of the DTCs are set Refer to Circuit/System Testing below. If none of the DTCs are set
  7. Determine the current vehicle testing altitude.
  8. Verify the scan tool MAP Sensor pressure parameter is within range specified in the «Altitude Versus Barometric Pressure»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__altitude-versus-barometric-pressure) table. The MAP Sensor pressure is not in range Refer to DTC P0106. The MAP Sensor pressure is within range
  9. Engine idling.
  10. Verify the scan tool MAP Sensor pressure parameter is between 26-52 kPa (3.8-7.5 psi) and changes with accelerator pedal input. If not between 26-52 kPa (3.8-7.5 psi) or does not change Refer to DTC P0106. If between 26-52 kPa (3.8-7.5 psi) and changes
  11. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below. Engine idling Perform the scan tool snapshot function. Increase the engine speed slowly to 3, 000 RPM and then back to idle. Exit from the scan tool snapshot and review the data. Observe the MAF Sensor parameter frame by frame with a scan tool. The MAF Sensor parameter does not change smoothly and gradually Refer to DTC P0101. The MAF Sensor parameter changes smoothly and gradually
  12. 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.
  13. Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing below. If the DTC does not set
  14. All OK
  1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at Q38 throttle body assembly. 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 4 and ground. 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 the 5 V reference circuit terminal 5 and ground. 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. Ignition ON.
  6. Test for 4.8-5.2 V between the signal circuit terminal 3 and ground. If less than 4.8 V Ignition OFF, disconnect the 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 Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON. 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
  7. Test or replace the Q38 throttle body assembly.
  1. «Throttle Body Assembly Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__throttle-body-assembly-replacement-lfw-or)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module 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 Throttle Position Sensors 1 and 2 Agree/Disagree parameter displays Agree while performing the Throttle Sweep Test with a scan tool. If Disagree Test or replace the Q38 throttle body assembly. If Agree
  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/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If no DTC sets
  8. All OK
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
ECT Sensor SignalP0117, P0119P0118P0118P0116, P0119, P0128
Low ReferenceP0118, P0119P0118P0119, P0128
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Engine Running at various operating conditions 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)

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT sensor signal circuit and a ground for the low reference circuit.

The purpose of this diagnostic is to analyze the performance of the thermostat, by using the ECT sensor to determine if the engine coolant will increase at the correct rate, and also meet the calibrated target temperatures under various operating conditions. The ECM uses the start-up ECT and the start-up intake air temperature (IAT) to begin the diagnostic calculation. The air flow into the engine is accumulated, and vehicle speed, distance, and engine run time are also factored in to determine if the ECT does increase normally and reach the calibrated target temperatures.

  1. DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0502, P0503, P1104, P16F3, P2101, or P2135 is not set.
  2. The start-up ECT is colder than 66°C (151°F).
  3. The start-up IAT is between -7 to +55°C (+19 to +131°F).
  4. The engine Not ran for greater than 30 minutes.
  5. The engine run time is greater than 30 seconds.
  6. The vehicle has traveled greater than 2.4 kilometers (1.5 miles) at greater than 8 km/h (5 mph).
  7. The Ethanol in the fuel is less than 87 %.
  8. The mass air flow (MAF) average is greater than 1 g/s.
  9. This DTC runs once per ignition cycle within the enabling conditions.

The ECM detects that the maximum amount of cumulative airflow has been attained, and the minimum ECT of 70°C (158°F) has not been met with a start-up IAT colder than 10°C (50°F).

OR

The ECM detects that the maximum amount of cumulative airflow has been attained, and the minimum ECT of 80°C (176°F) has not been met with a start-up IAT warmer than 10°C (50°F).

  1. DTC P0128 is a Type B DTC.
  2. The Engine Coolant Temperature Gauge is inoperative.
  3. The A/C is commanded OFF and inoperative.
  4. The Cooling Fans are commanded ON.

DTC P0128 is a Type B DTC.

  1. DTC P0128 occurring with insufficient vehicle interior heating is an indication of improper thermostat operation.
  2. Corrosion in the ECT sensor terminals or the ECT harness connector results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.
  3. A slight to moderate resistance in the ECT sensor signal circuit or low reference circuit will affect this diagnostic. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to «Cooling System Leak Testing»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-leak-testing) , and «Cooling System Draining and Filling (Static Fill)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-static) , «Cooling System Draining and Filling (GE 47716)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__cooling-system-draining-and-filling-ge) .
  2. Ignition OFF for 8 hours or greater.
  3. Ignition ON, observe the scan tool ECT Sensor and IAT Sensor parameters. The ECT, IAT and ambient temperatures should be within 15°C (27°F) of each other.
  4. Use the scan tool to verify the proper operation of the engine cooling system fans.
  5. Verify the proper heat range, and the operation of the thermostat. Refer to «Thermostat Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis) .
  6. 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 B34 engine coolant temperature sensor.
  2. Vehicle OFF, all 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 A 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, verify the scan tool ECT Sensor parameter is colder than -39°C (-38°F). If warmer than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 engine control module.
  4. Install a 3A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool ECT Sensor parameter is warmer than 149°C (300°F). If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  5. If the circuits test normal, test or replace the B34 engine coolant temperature sensor.

Measure and record the resistance of the ECT sensor at various ambient temperatures, then compare those measurements to the Temperature Versus Resistance - Engine Coolant Temperature Sensor table.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Engine Coolant Temperature Sensor Replacement (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Engine Coolant Thermostat Replacement (LUK)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__engine-coolant-thermostat-replacement-luk) , «Engine Coolant Thermostat Replacement (V6)»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system)
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
HO2S High SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P015A, P015B, P015C, P015D
HO2S Low SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P015A, P015B, P015C, P015D
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal0.00 VApproximately 1.9 VApproximately 1.9 V
HO2S Low Signal0.00 VApproximately 1.9 VApproximately 1.9 V

HO2S Sensor 1 Voltage, HO2S Sensor 2 Voltage

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

P0131, P0137, P0151, or P0157

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
  2. The engine is operating in Closed Loop.
  3. The Ignition voltage is between 10-32 V.
  4. The fuel level is greater than 10 percent.
  5. The throttle position (TP) is between 3-70 percent.
  6. The DTCs run continuously when the above conditions are met for 2 s.

P0132, P0138, P0152, or P0158

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
  2. The engine is operating in Closed Loop.
  3. The Ignition voltage is between 10-32 V.
  4. The fuel level is greater than 10 percent.
  5. The throttle position (TP) is between 0-70 percent.
  6. The DTCs run continuously when the above conditions are met for 3 s.

P0134, P0140, P0154, or P0160

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
  2. The ignition voltage is between 10-32 V.
  3. The engine run time is greater than 150 s.
  4. The fuel system is in Closed Loop.
  5. The DTCs run continuously when the above conditions are met.

P0131, P0137, P0151, or P0157

  1. The ECM detects that the HO2S voltage is less than 50 mV.
  2. The DTCs set within 50 s when the above condition is met.

P0132, P0138, P0152, or P0158

  1. The ECM detects that the HO2S voltage is greater than 1, 050 mV.
  2. The DTCs set within 50 s when the above condition is met.

P0134 or P0154

  1. The ECM detects that the HO2S 1 voltage is between 350-550 mV.
  2. The HO2S heater warm-up cycle is complete.
  3. The DTCs set within 15 s when the above conditions are met.

P0140 or P0160

  1. The ECM detects that the HO2S 2 voltage is not varying.
  2. The HO2S heater warm-up cycle is complete.
  3. The DTCs set within 15 s when the above conditions are met.

DTCs P0131, P0132, P0134, P0137, P0138, P0140, P0151, P0152, P0154, P0157. P0158, and P0160 are Type B DTCs.

DTCs P0131, P0132, P0134, P0137, P0138, P0140, P0151, P0152, P0154, P0157, P0158, and P0160 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify no HO2S heater DTCs are set. If a HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Engine running, observe the appropriate scan tool HO2S voltage parameter. The reading should be within the range of 50-1, 050 mV.
  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 appropriate B52 HO2S harness connector.
  2. Ignition ON, observe the appropriate scan tool HO2S voltage parameter. The parameter should display 1.9 V. If less than the specified range, test the high and low signal circuits for a short to ground. If both signal circuit test normal, replace the K20 ECM.
  3. Ignition ON, test for 2.5-3.0 V between the high signal circuit terminal B and ground. If less than the specified range, test the high signal circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the high signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition OFF, connect a 3 A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A.
  5. Ignition ON, verify the scan tool HO2S parameter displays 0.0 V. If greater than the specified range, test the low signal circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Verify none of the following conditions exist: Water intrusion in the B52 HO2S harness connector Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks Engine vacuum leaks If any of the above conditions exist, repair as necessary. If all circuits test normal, test or replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. Perform the scan tool Heated Oxygen Sensor Resistance Learn Reset after replacing an HO2S.
  6. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
HO2S High SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P015A, P015B, P015C, P015D
HO2S Low SignalP0131, P0137, P0151, P0157P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P015A, P015B, P015C, P015D
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal0.00 VApproximately 1.9 VApproximately 1.9 V
HO2S Low Signal0.00 VApproximately 1.9 VApproximately 1.9 V

HO2S Sensor 1 Voltage, HO2S Sensor 2 Voltage

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

P0133 or P0153

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
  2. The engine coolant temperature (ECT) is greater than 54°C (129°F).
  3. The intake air temperature (IAT) is warmer than -40°C (-40°F)
  4. The ignition voltage is between 10-32 V.
  5. The fuel level is greater than 10 percent.
  6. The engine run time is greater than 60 s.
  7. The engine speed is between 1, 000-3, 000 RPM.
  8. The barometric (BARO) pressure is greater than 70 kPa.
  9. The mass airflow (MAF) is between 15-43 g/s.
  10. The fuel system is in Closed Loop.
  11. The throttle position (TP) is greater than 5 percent.
  12. The DTCs run once per drive cycle when the above conditions are met.

P013A P013C, P013E, or P014A

  1. Before the ECM can report DTC P013A, or P013C failed, DTCs P013E, P014A, P2270, and P2272 must run and pass.
  2. Before the ECM can report DTC P013E, or P014A failed, DTCs P2270 and P2272 must run and pass.
  3. DTCs P0030, P0036, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0120, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1174, P1516, P2101, P2119, P2135, P2176, P2270, P2271, P2A00 are not set.
  4. The ignition voltage is between 10-32 V.
  5. The learned heater resistance is valid.
  6. The fuel level is greater than 10 percent.
  7. The engine run time is equal to or greater than 5 min.
  8. The accelerator pedal (APP) is steady.
  9. The torque converter clutch (TCC) is applied.
  10. The DTCs run once per ignition cycle, during decel fuel cut-off (DFCO), when the above conditions are met.

P013B P013D, P013F, or P014B

  1. Before the ECM can report DTC P013B, or P013D failed, DTCs P013A, P013C, P013E, P013F, P014A, P014B, P2270, P2271, P2272, and P2273 must run and pass.
  2. Before the ECM can report DTC P013F, or P014B failed, DTCs P013A, P013C, P013E, P014A, P2270, P2271, P2272, and P2273 must run and pass.
  3. DTCs P0030, P0036, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0120, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1174, P1516, P2101, P2119, P2135, P2176, P2270, P2271, P2A00 are not set.
  4. The ignition voltage is between 10-32 V.
  5. The learned heater resistance is valid.
  6. The fuel level is greater than 10 percent.
  7. The engine run time is equal to or greater than 5 min.
  8. The DTCs run once per ignition cycle when the above conditions are met.

P015A, P015B, P015C or P015D

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
  2. The engine coolant temperature (ECT) is warmer than 54°C (129°F).
  3. The intake air temperature (IAT) is warmer than -40°C (-40°F)
  4. The ignition voltage is between 10-32 V.
  5. The fuel level is greater than 10 percent.
  6. The engine run time is greater than 60 s.
  7. The engine speed is between 1, 025-2, 325 RPM.
  8. The vehicle speed is between 70 km/h (44 mph).
  9. The mass airflow (MAF) is between 3-12 g/s.
  10. The fuel system is in Closed Loop.
  11. The DTCs run once per drive cycle when the above conditions are met.

P013B P013D, P013F, or P014B

  1. Before the ECM can report DTC P2270, P2271, P2272, or P2273 failed, DTCs P013A, P013B, P013C, P013D, P013E, P013F, P014A, and P014B must run and pass.
  2. DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.
  3. The ignition voltage is between 10-32 V.
  4. The engine speed is between 1, 025-2, 325 RPM.
  5. The mass air flow (MAF) is between 3-12 g/s.
  6. The vehicle speed is between 64-128 km/h (40-80 mph).
  7. The fuel level is greater than 10 percent.
  8. The fuel system is in Closed Loop.
  9. The predicted catalytic converter temperature is between 500-980°C (932-1, 796°F).
  10. The HO2S heater is ON for more than 180 s.
  11. The DTCs run once per ignition cycle, during decel fuel cut-off, when the above conditions are met.

P2270 or P2272

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P013A, P013B, P013E, P013F, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0411, P0412, P0418, P1174, P1516, P2101, P2119, P2135, P2176, P2270, P2271 are not set.
  2. The system voltage is between 10-32 V.
  3. The fuel level is greater than 10 percent.
  4. The engine speed is between 1, 100-2, 300 RPM.
  5. The engine airflow is between 3-11 g/s.
  6. The vehicle speed is between 64 km/h (39.8 mph) and 120 km/h (74 mph).
  7. The fuel state is in Closed Loop.
  8. The evaporative emission (EVAP) diagnostics are not in control of purge.
  9. The heated oxygen sensor heaters are ON for more than 180 s.
  10. The predicted catalytic converter temperature is between 600-900°C (1, 112-1, 652°F).
  11. This DTC runs once per trip when all of the above conditions have been met for 3 s.

P2271 or P2273

  1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P013A, P013B, P013E, P013F, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0411, P0412, P0418, P1174, P1516, P2101, P2119, P2135, P2176, P2270 are not set.
  2. The system voltage is between 10-32 V.
  3. The fuel level is greater than 10 percent.
  4. The engine speed is 1, 150-2, 300 RPM.
  5. The engine airflow is between 3-11 g/s.
  6. The vehicle speed is between 70-120 km/h (44-74 mph).
  7. The fuel state is in Closed Loop.
  8. The EVAP is not in control of purge.
  9. Power take-off is not active.
  10. The heated oxygen sensor heaters have been on more than 180 s.
  11. The predicted catalyst temperature is between 500-980°C (1, 112-1, 652°F).
  12. DTCs P013A, P013E, and P2270 have run and passed. THEN
  13. DFCO is active.
  14. The accelerator pedal position is stable.
  15. This DTC runs once per trip when the above conditions are met for 3 s.

P0133, P0153, P015A, P015B, P015C or P015D

  1. The ECM detects that the HO2S 1 rich-to-lean or lean-to-rich average response time is greater than a calibrated value.
  2. The DTCs set within 60 s when the above condition is met.

P013A or P013C

The ECM detects that the accumulated mass air flow monitored during rich-to-lean transitions between 450-150 mV is greater than 75 grams.

P013B or P013D

The ECM detects that the accumulated mass air flow monitored during lean-to-rich transitions between 350-650 mV is greater than 75 grams.

P013E or P014A

The ECM detects that the O2 sensor voltage has not decreased below 450 mV within a calibrated value of accumulated air flow.

P013F or P014B

The ECM detects that the O2 sensor voltage has not increased above 350 mV within a calibrated value of accumulated air flow.

P2270 or P2272

The ECM does not detect a HO2S voltage greater than 800 mV before accumulated mass air flow exceeds a calibrated value.

P2271 or P2273

The ECM does not detect an HO2S voltage less than 100 mV before accumulated mass air flow exceeds a calibrated value.

  1. DTCs P0133, P013E, P013F, P014A, P014B, P0153, P2270, P2271, P2272, and P2273 are Type B DTCs.
  2. DTCs P013A, P013B, P013C, P013D, P015A, P015B, P015C, and P015D are Type A DTCs.
  1. DTCs P0133, P013E, P013F, P014A, P014B, P0153, P2270, P2271, P2272, and P2273 are Type B DTCs.
  2. DTCs P013A, P013B, P013C, P013D, P015A, P015B, P015C, and P015D are Type A DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify no HO2S heater DTCs are set. If a HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Verify none of the following conditions exist: Lean or rich fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Water intrusion in the HO2S harness connector Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks Engine vacuum leaks Engine oil consumption-Refer to «Oil Consumption Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures__oil-consumption-diagnosis) . Engine coolant consumption-Refer to «Loss of Coolant»(/buick/lacrosse/ii-2009-2013/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) . If you find any of the above conditions, repair as necessary.
  3. If all conditions test normal, test or replace the appropriate HO2S.
  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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  5. Perform the scan tool Heated Oxygen Sensor Resistance Learn Reset after replacing an HO2S.
  6. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) controls a Closed Loop air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The ECM monitors the heated oxygen sensor (HO2S) signal voltage, and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The long term fuel trim values change in response to trends in the short term fuel trim The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. The ideal fuel trim values are around 0 %. A positive fuel trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0178, P0179, P0201-P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0275, P0277, P0300-P0306, P0442, P0443, P0446, P0449, P0451-P0455, P0496, P0506, P0507, P1248, P1249, P124A, P124B, P124C, P124D, P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, P216F, P2227-P2230, P2269 are not set.
  2. The engine is in Closed Loop status.
  3. The catalyst monitor diagnostic intrusive test, post 02 diagnostic intrusive test, device control, and EVAP diagnostic Tank Pull Down test are not active.
  4. The engine coolant temperature (ECT) is between -38 and +150°C (-36 and +302°F).
  5. The intake air temperature (IAT) is between -38 and +150°C (-36 and +302°F).
  6. The manifold absolute pressure (MAP) is between 5-255 kPa (1.45-37 psi).
  7. The engine speed is between 400-6, 600 RPM.
  8. The mass air flow (MAF) is between 0.5-510 g/s.
  9. The barometric pressure (BARO) is greater than 70 kPa (10.2 psi).
  10. The fuel level is greater than 10 %.
  11. This diagnostic runs continuously when the above conditions have been met.
  1. The average long term fuel trim weighted average value is greater or less than a calibrated value.
  2. The above condition is present for approximately 3 min after the Conditions for Running the DTC have been met.

DTCs P0171, P0172, P0174, and P0175 are Type B DTCs.

DTCs P0171, P0172, P0174, and P0175 are Type B DTCs.

  1. Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S value should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
  2. The normal Short Term Fuel Trim and Long Term Fuel Trim parameters should be between +10 and -10 % with 0 % the optimum, with the engine running at operating temperature.
  3. An HO2S will not cause this DTC to set without the occurrence of the circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.
  4. Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
  5. A MAF sensor condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor parameters will appear to be within range.
  6. Inspect the air filter for being the correct one for this application. Make sure that the engine oil fill cap is in place and that it is tight. Verify that the engine oil dip stick is fully seated.
  7. Certain aftermarket air filters may cause a DTC to set.
  8. Certain aftermarket air induction systems or modifications to the air induction system may cause a DTC to set.
  9. Certain aftermarket exhaust system components may cause a DTC to set.

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Observe the DTC information with a scan tool. DTC P0171, P0172, P0174, or P0175 should not be set.
  2. Engine running, observe the DTC information with a scan tool. Verify there are no HO2S DTCs set. If any HO2S DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  3. Ignition ON, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to «Altitude Versus Barometric Pressure»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__altitude-versus-barometric-pressure) . If not the specified range, refer to «DTC P0106 (LF1, LFW, or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) .
  4. Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term Fuel Trim parameter with a scan tool. The value should be between -20 % and +20 %. If not the specified range, inspect for the following: P0171 or P0174 Mass air flow (MAF) sensor signal skewed-If the Short Term Fuel Trim parameters for both banks changes greater than 20 % when the MAF sensor is disconnected, refer to «DTC P0101»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Missing, restricted, or leaking exhaust components-Refer to «Symptoms - Engine Exhaust»(/buick/lacrosse/ii-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . Malfunctioning fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Vacuum hoses for splits, kinks, and improper connections Insufficient fuel in the tank Low fuel pressure-Refer to «Fuel System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings. Air induction system and air intake ducts for leaks, or missing air filter element Cracked EVAP canister Evaporative pipes obstructed or leaking Crankcase ventilation system for leaks P0172 or P0175 Mass air flow (MAF) sensor signal skewed-If the Short Term Fuel Trim parameters for both banks changes greater than 20 % when the MAF sensor is disconnected, refer to «DTC P0101»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Missing, restricted, or leaking exhaust components-Refer to «Symptoms - Engine Exhaust»(/buick/lacrosse/ii-2009-2013/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . Malfunctioning fuel injectors-Refer to «Fuel Injector Solenoid Coil Test»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) , Air intake duct collapsed or restricted Excessive fuel pressure - Refer to «Fuel System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) Air filter dirty or restricted Objects blocking the throttle body Evaporative emissions control system not operating properly. Excessive fuel in the crankcase-Change the oil as necessary.
  5. If all conditions test normal, test the engine for a mechanical condition. Refer to «Symptoms - Engine Mechanical»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .
  6. 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/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Alcohol content information is supplied to the ECM from the fuel composition sensor. The fuel composition sensor has a battery positive circuit, a signal circuit, and a ground circuit. The fuel composition sensor uses a microprocessor inside the sensor to measure the ethanol percentage and changes the output signal accordingly. The signal circuit carries the ethanol percentage via the frequency signal. The ECM provides an internal pull up to 5 V on the signal circuit, and the fuel composition sensor pulls the 5 V to ground in pulses. The normal range of operating frequency is between 50-150 Hz. The microprocessor inside the sensor is capable of a certain amount of self-diagnosis. An output frequency between 180 Hz and 190 Hz indicates that the fuel is contaminated.

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

The ECM detects that the fuel composition sensor output frequency is less than 45 Hz for greater than 6 s.

DTC P0178 is a Type B DTC.

DTC P0178 is a Type B DTC.

  1. The Fuel Composition Sensor scan tool parameter reacts immediately to any change in the fuel composition sensor circuits, but may not react long enough to set a DTC.
  2. An intermittent condition may not be detected because the sensor does not immediately power down and the connection may be restored before voltage drops below the operating threshold.
  3. If this DTC will not reset and the parameters are steady, thoroughly inspect all fuel composition sensor circuits for an intermittent open.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 38522 Variable Signal Generator
  2. J 44175-A Fuel Composition Tester
  1. Engine running, verify the scan tool Fuel Composition Sensor parameter is between 50-150 Hz.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
  1. Ignition OFF, disconnect the harness connector at the B198 fuel composition 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 ground circuit terminal 2 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 B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the circuit, and repair or replace as necessary.
  4. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 3 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.
  5. Ignition OFF, connect the red lead of the J 38522 Variable Signal Generator to the signal circuit terminal 3 at the B198 fuel composition sensor harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  6. Set the J 38522 Variable Signal Generator Signal to 5 V, the Frequency to 60 Hz, and the Duty Cycle to Normal.
  7. Ignition ON, verify the scan tool Fuel Composition Sensor parameter is at 60 Hz. If not at the specified value, replace the K20 engine control module.
  8. If all circuits test normal, test or replace the B198 fuel composition sensor.
  1. Test the fuel composition using the J 44175-A Fuel Composition Tester and the J 44175-A Instruction Manual. Record the frequency.
  2. Compare the special tool test frequency and the scan tool Fuel Composition Sensor frequency parameter. The difference between the tool and the sensor should be less than 12 Hz. If greater than the specified value, replace the B198 fuel composition sensor.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for ECM replacement, programming, and setup

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

Alcohol content information is supplied to the ECM from the fuel composition sensor. The fuel composition sensor has a battery positive circuit, a signal circuit, and a ground circuit. The fuel composition sensor uses a microprocessor inside the sensor to measure the ethanol percentage and changes the output signal accordingly. The signal circuit carries the ethanol percentage via the frequency signal. The ECM provides an internal pull up to 5 V on the signal circuit, and the fuel composition sensor pulls the 5 V to ground in pulses. The normal range of operating frequency is between 50-150 Hz. The microprocessor inside the sensor is capable of a certain amount of self-diagnosis. An output frequency between 180 Hz and 190 Hz indicates that the fuel is contaminated.

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

The ECM detects that the fuel composition sensor output frequency is between 155-185 Hz for greater than 6 s.

DTC P0179 is a Type B DTC.

DTC P0179 is a Type B DTC.

A momentary slug of water in the fuel system may set this DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

  1. J 38522 Variable Signal Generator
  2. J 44175-A Fuel Composition Tester
  1. Engine running, verify the scan tool Fuel Composition Sensor parameter is between 50-150 Hz.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify that there are no contaminants, water, or too high of a concentration of ethanol in the fuel. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) and the J 44175-A Instruction Manual.
  2. Ignition OFF, disconnect the harness connector at the B198 fuel composition sensor.
  3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the ground circuit terminal 2 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the circuit, and repair or replace as necessary.
  5. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 3 and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Ignition OFF, connect the red lead of the J 38522 Variable Signal Generator to the signal circuit terminal 3 at the B198 fuel composition sensor harness connector. Connect the battery voltage supply to B+, and the black lead to ground.
  7. Set the J 38522 Variable Signal Generator Signal to 5 V, the Frequency to 60 Hz, and the Duty Cycle to Normal.
  8. Ignition ON, verify the scan tool Fuel Composition Sensor parameter is at 60 Hz. If not at the specified value, replace the K20 ECM.
  9. If all circuits test normal, test or replace the B198 fuel composition sensor.
  1. Test the fuel composition using the J 44175-A Fuel Composition Tester and the J 44175-A Instruction Manual. Record the frequency.
  2. Compare the special tool test frequency and the scan tool Fuel Composition Sensor frequency parameter. The difference between the tool and the sensor should be less than 12 Hz. If greater than the specified value, replace the B198 fuel composition sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel System Cleaning»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-system-cleaning)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V ReferenceP018C, P0641P018CP018D, P0641P06A6
SignalP018CP018CP018DP018B
Low ReferenceP018DP06A6

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

  1. The engine is running.
  2. DTC 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 engine has been running for at least 5 seconds.

The fuel pump control module does not detect a change in the fuel pressure of at least 30 kPa (4.4 psi) when the fuel pump is operating. The fuel pressure sensor performance diagnostic provides a means to detect fuel pressure sensor output that is stuck within the normal operating range of the sensor.

DTC P018B, P018C and P018D are Type A DTCs.

DTC P018B, P018C and P018D are Type A DTCs.

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC P018B resets before proceeding with the circuit system testing. If the DTC does not reset, refer to diagnostic aids qbove.

  1. Ignition OFF, disconnect the harness connector at the B47 fuel pressure 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 10 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.
  3. Ignition ON, test for 4.8-5.2 V between the B47 fuel pressure sensor 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.
  4. Verify the scan tool fuel pressure sensor voltage is less than 1 V. If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.
  5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the 5 V reference circuit terminal 3. Wait 15 seconds. Verify the scan tool fuel pressure sensor voltage is greater than 4.8 V. 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 K27 fuel pump flow control module.
  6. If all circuits test normal, replace the B47 fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel Pressure Sensor Replacement - Fuel Feed Pipe»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V Reference VoltageP0192, P0193, P0340, P0345, P0365, P0390, P0506, P0641, P2227P0192P0193, P0641, P2227, P2229P0191
Fuel Rail Pressure Sensor SignalP0192P0192, P0193P0193P0191
Low ReferenceP0193P0193P0191

The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail fuel pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

Condition 1

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0122, P0123, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301-P0306, P0351-P0356, P0506, P0507, P0722, P0723, P1248, P1249, P124A, P124B, P2122, P2123, P2127, P2128, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157 are not set.
  2. The engine is running.
  3. The accelerator pedal position is 0 percent for 4 s.
  4. The ignition voltage is greater than 11 V.
  5. The low side fuel pressure is greater than 275 kPa (40 psi).
  6. The vehicle speed is less than 1 km/h (0.62 mph).
  7. The diagnostic runs continuously when the above conditions are met.

Condition 2 and 3

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0122, P0123, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301-P0306, P0351-P0356, P0506, P0507, P0722, P0723, P1248, P1249, P124A, P124B, P2122, P2123, P2127, P2128, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157 are not set.
  2. The ignition voltage is greater than 11 V.
  3. The low side fuel pressure is greater than 275 kPa (40 psi).
  4. The desired fuel rail pressure is between 4-6 MPa (580-870 psi).
  5. The engine speed is between 1000-3000 RPM.
  6. The vehicle speed is greater than 30 km/h (18.64 mph).
  7. The diagnostic runs continuously when the above conditions are met.

Condition 4

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0122, P0123, P0201-P0206, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0300, P0301-P0306, P0351-P0356, P0506, P0507, P0722, P0723, P1248, P1249, P124A, P124B, P2122, P2123, P2127, P2128, P2135, P2147, P2148, P2150, P2151, P2153, P2154, P2156, or P2157 are not set.
  2. The engine speed is greater than 2000 RPM.
  3. The vehicle speed is greater than 30 km/h (18.64 mph).
  4. DTC P0191 runs once an ignition cycle at engine start up when the above conditions have been met.

Condition 1

The difference between the low side fuel pressure and the high side fuel pressure is less than or equal to -0.8 MPa (-116 psi) or greater than or equal to 0.3 MPa (44 psi) with the high pressure fuel pump actuator commanded OFF. The condition exists for greater than 3 s.

Condition 2

The difference between the relief pressure and the measured high pressure is less than or equal to -2 MPa (-290 psi) for greater than 3 s.

Condition 3

The difference between the desired fuel rail pressure and the actual fuel rail pressure is greater than 2 MPa (290 psi) for 3 s.

Condition 4

The difference between the measured maximum high pressure and the measured minimum high pressure is less than or equal to 0.1 MPa (14.5 psi) for greater than 10 s.

  1. DTC P0191 is a Type A DTC.
  2. A message center or an indicator may display Reduced Engine Power.

DTC P0191 is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Observe the scan tool DTC information, verify DTC P0627, P0628, P0629, P069E or U0109 is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Engine idling, observe the scan tool Fuel Rail Pressure Sensor parameter. The pressure should be approximately 1.9-5.0 MPa (276-725 psi).
  3. Engine idling, the scan tool Fuel Rail Pressure Sensor should be close to the scan tool Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
  4. Move related harnesses/connectors of the B47B fuel rail fuel pressure sensor and verify the engine does not stumble, stall, or change engine speed. If the engine stumbles, stalls, or changes engine speed, test or repair the suspected harness or connection.
  5. Observe the DTC information with a scan tool, DTC P0191 should not set.
  6. 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 B47B fuel rail pressure sensor 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 less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A 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 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, replace the B47B fuel rail pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V Reference VoltageP0192, P0193, P0340, P0345, P0365, P0390, P0506, P0641, P2227P0192P0193, P0641, P2227, P2229P0191
Fuel Rail Pressure Sensor SignalP0192P0192, P0193P0193P0191
Low ReferenceP0193P0193P0191

The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the reference ground circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail fuel pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

  1. The engine is running.
  2. The ignition voltage is between 11-18 V.
  3. The DTCs run continuously within the enabling conditions.

P0192

The ECM detects that the fuel rail fuel pressure sensor signal voltage is low.

P0193

The ECM detects that the fuel rail fuel pressure sensor signal voltage is high.

  1. DTCs P0192 and P0193 are Type A DTCs.
  2. A message center or an indicator may display Reduced Engine Power.

DTCs P0192 and P0193 are Type A DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool, DTC P0641 should not be set. If a DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  2. Engine idling, observe the DTC information with a scan tool. DTC P0192 or P0193 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the B47B fuel rail pressure sensor 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 less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A 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 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, replace the B47B fuel rail pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to 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 4P2156P0204P0270, P2157P124B
Direct Fuel Injector High Voltage Control Cylinder 4P0270, P2156P0204P0271, P2157P124B
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 once the above conditions are met.

P0201, P0202, P0203, P0204, P0205, or P0206

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

P0261, P0264, P0267, P0270, P0273, or P0276

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

P0262, P0265, P0268, P0271, P0274, or P0277

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

DTCs P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, and P0277 are Type A DTCs.

DTCs P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, and P0277 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/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-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 Control Circuit Status parameters. An Injector Control Circuit Status parameter will change from OK or Not Run to Malfunction 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/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/buick/lacrosse/ii-2009-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. 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/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Engine operating, observe the DTC information with a scan tool. DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, or P0277 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 Control Circuit Status parameters. Verify the Injector Control Circuit Status parameters display OK or Not Run.
  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 Control 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 engine control module.
  3. Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The Cylinder 1-6 Injector Control 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 engine control module.
  4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL. 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 2-3 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/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures)
  2. «Fuel Injector Balance Test»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-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 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-injection-fuel-rail-assembly-replacement)
  2. «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LFW or LFX)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__fuel-injection-fuel-rail-assembly-replacement)
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
ControlP0231P023FP0232P023F, P2635
Low ReferenceP023FP023F, P2635

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

P0231, P023F

The ignition voltage is between 9-18 V.

P0232

The control enable voltage signal supplied for the ECM to fuel pump control module is inactive for 4 seconds after engine has been shut off.

The fuel pump control module detects a fault on the fuel pump voltage circuit that is less than 4 V or greater than 4.5 V.

DTCs P0231, P0232, and P023F are Type A DTCs.

DTCs P0231, P0232, and P023F are Type A DTCs.

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

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

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

  1. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
  2. Test for less than 5 ohms between the low reference terminal 2 and ground. If greater than the specified value test the low reference circuit for an open or high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  3. Connect a test lamp between the control circuit terminal 1 and ground.
  4. Ignition ON, command the G12 fuel pump ON and OFF with a scan tool. 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.
  5. If all circuits test normal, replace the G12 fuel pump.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Fuel Tank Fuel Pump Module Replacement (NT7)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-repair-instructions__fuel-tank-fuel-pump-module-replacement) , «Fuel Tank Fuel Pump Module Replacement (NU6)»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-24l-repair-instructions__fuel-tank-fuel-pump-module-replacement)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
FPCM ControlP025AP025A

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

The ignition is ON.

The GMLAN serial data message from the ECM to the fuel pump control module does not agree with the state of the control enable voltage signal supplied from the ECM to the fuel pump control module for more than 2 seconds.

DTC P025A is a Type A DTC.

DTC P025A is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC resets before proceeding with the circuit system testing. If the DTC does not reset, refer to diagnostic aids above.

  1. Ignition OFF, disconnect the harness connector at the K27 fuel pump control module.
  2. Ignition OFF, connect a test lamp between the control circuit terminal 13 and ground.
  3. 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 K20 engine 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 K20 engine control module.
  4. If all circuits test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the repair.

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

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

The engine control module (ECM) uses information from the crankshaft position sensor and the camshaft position sensors in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM detects individual misfire events. A misfire rate that is high enough can cause 3-way catalytic converter damage. The malfunction indicator lamp (MIL) flashes ON and OFF when the conditions for catalytic converter damage are present.

DTCs P0301 through P0306 correspond to cylinders 1 through 6. If the ECM is able to determine that a specific cylinder is misfiring, the DTC for that cylinder is set, and the corresponding fuel injector is disabled. To retest for a misfire, the ECM re-enables the fuel injector(s) after 4 crankshaft revolutions or after 8 crankshaft revolutions for manual transmission equipped vehicles. For catalyst damaging misfires the ECM re-enables the fuel injector(s) after a 30 second delay to retest for a misfire. This 30 second periodic re-enabling occurs until the end of the drive cycle or until no further catalyst damaging misfire events are present.

  1. DTC P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0068, P00C8, P00C9, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0122, P0123, P0191, P0192, P0193, P0222, P0223, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P0601, P0604, P0606, P0651, P1104, P1682, P160D, P160E, P16A0, P16A1, P16A2, P16F3, P2100, P2101, P2102, P2103, P2135, P2227, P2228, P2229, or P2230 is not set.
  2. The engine speed is between 350 and 7, 000 RPM. OR
  3. The engine speed is greater than 1, 000 RPM and DTC P0315 is set.
  4. The engine coolant temperature (ECT) is between -7 and +127°C.
  5. If the ECT is colder than -7°C (+19°F) at start-up, this diagnostic will not run until the ECT is more than +21°C (+69°F).
  6. The ignition voltage is between 9 and 32 V.
  7. The evaporative emissions (EVAP) leak detection is not active.
  8. The ECM is not in fuel cut-off or decel fuel cut-off mode.
  9. The fuel level is greater than 10 %.
  10. Torque Converter Clutch (TCC) is not applied/active.
  11. DTCs P0300 through P0306 run continuously when the above conditions exist for at least 1, 000 engine revolutions.
  12. DTCs P0300 through P0306 run continuously when the above conditions exist and the ECT is warmer than 47°C (117°F) for at least 1, 000 engine revolutions for the first failure occurrence, 200 engine revolutions after the fist failure occurrence for catalyst damaging misfire(s).

P0300

The ECM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed a predetermined value.

P0301, P0302, P0303, P0304, P0305, P0306

The ECM detects a crankshaft rotation speed variation indicating a single cylinder misfire rate sufficient to cause emissions levels to exceed mandated standards.

  1. DTCs P0300-P0306 are Type B DTCs.
  2. The ECM disables the fuel injector of the misfiring cylinder when a misfire is present.

DTCs P0300-P0306 are Type B DTCs.

  1. A misfire DTC could be caused by an excessive vibration from sources other than the engine. Inspect for the following possible sources: A tire or wheel that is out of round or out of balance Variable thickness brake rotors An unbalanced drive shaft Certain rough road conditions Transmission operation A damaged accessory drive component or belt; remove the belt and safely operate the engine to evaluate
  2. High resistance in the circuits of the injectors may set a misfire DTC without setting an injector DTC. Test the injector circuits of the affected cylinder(s) for a high resistance if you suspect a condition.
  3. If the condition is intermittent, observing the scan tool IC Circuit Test and Fuel Injector Circuit Test Status parameters may help isolate the condition. The circuit test status parameters will change from OK or Not Run to Fault/Malfunction if a condition exists.
  4. A condition in the heated O2 sensor (HO2S) heater control circuits may set a DTC P0300.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 26792 HEI Spark Tester

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

  1. Engine idling at the normal operating temperature. If there is an abnormal engine noise, refer to «Symptoms - Engine Mechanical»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .
  2. Verify that no other DTCs are set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  3. Observe the scan tool Misfire Current Cyl. 1-6 parameters. The Misfire Current Counters should not be incrementing.
  4. Engine idling, perform the Cylinder Power Balance Test with a scan tool to isolate the misfiring cylinder. The engine speed should change when each injector is disabled.
  5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Verify that the following conditions do not exist: Vacuum hose splits, kinks, and incorrect connections Engine vacuum leaks Crankcase ventilation system for vacuum leaks Fuel pressure that is too low or too high-Refer to «Fuel System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Contaminated Fuel-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . Exhaust system restrictions If you find any of the above conditions, repair as necessary.
  2. Ignition OFF, remove the T8 ignition coil of the misfiring cylinder, but leave the electrical connector connected.
  3. Inspect the ignition coil boot for the following conditions: Holes Tears Carbon tracking Oil contamination Water intrusion If you find any of the above conditions, repair as necessary.
  4. Install the J 26792 HEI Spark Tester to the boot of the appropriate T8 ignition coil and ground.
  5. Attempt to start the engine and observe the J 26792 HEI Spark Tester. The spark tester should spark. If there is no spark, refer to «Electronic Ignition System Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) for diagnosis of the ignition coil.
  6. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the spark plug does not exhibit the following conditions: Gas, coolant, or oil fouled-Refer to «Spark Plug Inspection»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__spark-plug-inspection) . Cracked, worn, incorrectly gapped-Refer to «Ignition System Specifications»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__ignition-system-specifications) . If there is a condition with the spark plug, replace the spark plug.
  7. Exchange the suspected spark plug with another cylinder that is operating correctly.
  8. Engine idling, observe the scan tool Misfire Current Counter parameters. The misfire should not follow the spark plug exchange. If the misfire follows the spark plug, replace the spark plug.
  9. If all conditions test normal, test or inspect for the following: A lean or rich Q17 fuel injector-Refer to «Fuel Injector Solenoid Coil Test»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) . An engine mechanical condition-Refer to «Symptoms - Engine Mechanical»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) .
  1. «Spark Plug Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Ignition Coil Replacement - Bank 1»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Ignition Coil Replacement - Bank 2»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  1. Perform the «Diagnostic Repair Verification»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-repair-verification) after completing the repair.
  2. To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair Verification for DTC P0420 or P0430. Refer to «DTC P0420 or P0430»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0341-to-dtc-p2635-and-diagnostic-information-and-procedures) .
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The crankshaft position system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the crankshaft position sensor. The calculated error allows the engine control module (ECM) to accurately compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load conditions.

The crankshaft position system variation compensating values are stored in ECM memory after a learn procedure has been performed and the ignition switch is turned to the OFF position for at least 30 s. If the actual variation is not within the crankshaft position system variation compensating values stored in the ECM, DTC P0300 may set.

If the crankshaft position system variation values are not stored in the ECM memory or a proper ECM power down does not occur after completing the Crankshaft Position Learn Procedure, DTC P0315 sets.

DTC P0315 runs continuously.

The ECM detects that the crankshaft position system variation values are not stored in memory.

DTC P0315 is a Type A DTC.

DTC P0315 is a Type A DTC.

This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test .

Schematic Reference

Connector End Views

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. The Crankshaft Position System Variation Learn Procedure may have to be repeated up to 5 times before the procedure is successful.

  1. Perform the «Crankshaft Position System Variation Learn»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions__crankshaft-position-system-variation-learn) procedure. The scan tool should display Learned Successful. If, after 5 Crankshaft Position System Variation Learn Procedure attempts, the scan tool did not display Learned Successful; inspect for the following conditions: Worn crankshaft main bearings A damaged or misaligned reluctor wheel Excessive crankshaft runout A damaged crankshaft-Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-repair-instructions-off-vehicle) . Interference in the signal circuit of the crankshaft position sensor The ignition switch is in the ON position until there is insufficient system voltage. An ECM power disconnect with the ignition ON that may have erased the crankshaft position system variation values and set DTC P0315 Debris between the crankshaft position sensor and the reluctor wheel If a condition is found Repair or replace the affected component as necessary. Perform the Crankshaft Position System Variation Learn Procedure. If no condition is found Replace the K20 engine control module. Perform the Crankshaft Position System Variation Learn Procedure.
  2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records data.
  3. Verify the DTC is not set. If any of DTC sets Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) If none of the DTCs set
  4. All OK

Perform the Diagnostic Repair Verification after using this diagnostic procedure.

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

  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Knock Sensor 1 SignalP0327P0325P0328P0326
Knock Sensor 2 SignalP0332P0330P0333P0331
Knock Sensor 1 Low ReferenceP0327P0325, P06B6P0328P0326
Knock Sensor 2 Low ReferenceP0332P0330, P06B7P0333P0331

The knock sensors enable the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The knock sensors produce an alternating current (AC) voltage signal that varies depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the two knock sensor signals. The ECM receives the two knock sensor signals through 2 isolated circuits. The ECM learns a minimum knock sensor noise level for all of the engine speed ranges. The ECM monitors for a normal knock sensor signal. The ECM monitors the two internal knock sensor processors by verifying a 20 KHz signal generated on the signal circuits is detected on the sensors' low reference circuits.

P0324, P0326, and P0331-Condition 1

  1. Engine speed is between 400 and 8, 500 RPM.
  2. Engine is running for greater than 2 s.
  3. The engine coolant temperature (ECT) is warmer than -40°C (-40°F).
  4. The intake air temperature (IAT) sensor 1 is warmer than -40°C (-40°F).
  5. The DTCs run continuously when the above conditions are met.

P0326 and P0331-Condition 2

  1. Engine speed is greater than 2, 200 RPM.
  2. Engine is running for greater than 1 s.
  3. The ECT is warmer than -40°C (-40°F).
  4. The IAT sensor 1 is warmer than -40°C (-40°F).
  5. The DTCs run continuously when the above conditions are met.

P06B6 and P06B7

  1. Engine speed is between 400 and 5, 000 RPM.
  2. Engine is running greater than 2 s.
  3. The DTCs run continuously when the above conditions are met.

P0324

The ECM detects that the knock sensor signal's performance is out of the normal expected range due to an excessive engine knock, or abnormal noise, or a flat signal; in at least a single cylinder.

P0326 and P0331

  1. The ECM detects that the knock sensor signal indicates the sensor harness is connected, but the sensor is not properly bolted to the engine. OR
  2. The ECM detects that the knock sensor signal indicates an excessive engine knock is present.

P06B6 and P06B7

The ECM has detected an internal knock sensor processor fault.

  1. DTCs P0324, P0326, P0331, P06B6, and P06B7 are Type B DTCs.
  2. The ignition timing is retarded to reduce the potential of engine damaging spark knock.

DTCs P0324, P0326, P0331, P06B6, and P06B7 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine running, observe the DTC information with a scan tool. Verify DTC P0325, P0327, P0328, P0330, P0332, P0333, P06B6, and P06B7 is not set. If DTC P0325, P0327, P0328, P0330, P0332, or P0333 is set with P06B6 or P06B7 refer to «DTC P0325, P0327, P0328, P0330, P0332, or P0333»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-dtc-p0010-to-dtc-p0390) for further diagnosis. If only DTC P06B6 or P06B7 is set, and no external knock sensor circuit issues exist, replace the K20 engine control module.
  2. Vehicle OFF, inspect for the following: The affected B68 knock sensor for physical damage. A sensor that is dropped or damaged may cause a DTC to set. The sensor for proper installation. A sensor that is loose or not at the correct torque may cause a DTC to set. Refer to «Fastener Tightening Specifications»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__fastener-tightening-specifications) . The sensor mounting surface for burrs, casting flash, and foreign material. The sensor must be clear of hoses, brackets, and engine electrical wiring. Loose brackets Loose or broken accessory drive belts, brackets, components An engine mechanical condition-Refer to «Symptoms - Engine Mechanical»(/buick/lacrosse/ii-2009-2013/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures) . If a condition is found, repair as necessary.
  3. If there is no mechanical condition, test or replace the B68 knock sensor.
  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.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Knock Sensor Replacement - Bank 1»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Knock Sensor Replacement - Bank 2»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Knock Sensor 1 SignalP0327P0325P0328P0326
Knock Sensor 2 SignalP0332P0330P0333P0331
Knock Sensor 1 Low ReferenceP0327P0325, P06B6P0328P0326
Knock Sensor 2 Low ReferenceP0332P0330, P06B7P0333P0331

The knock sensors enable the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The knock sensors produce an alternating current (AC) voltage signal that varies depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the two knock sensor signals. The ECM receives the two knock sensor signals through 2 isolated circuits. The ECM learns a minimum knock sensor noise level for all of the engine speed ranges. The ECM monitors for a normal knock sensor signal. The ECM monitors the two internal knock sensor processors by verifying a 20 KHz signal generated on the signal circuits is detected on the sensors' low reference circuits.

P0325 and P0330

  1. Engine speed is between 400 and 8, 500 RPM.
  2. Engine is running at least 2 s.
  3. The ECT is warmer than -40°C (-40°F).
  4. The IAT sensor 1 is warmer than -40°C (-40°F).
  5. The DTCs run continuously when the above conditions are met.

P0327, P0328, P0332, and P0333

  1. Engine speed is less than 8, 500 RPM.
  2. The DTCs run continuously when the above condition is met.

P0325 and P0330

The ECM detects that a knock sensor signal circuit is open for longer than 6 s.

P0327 and P0332

The ECM detects that a knock sensor signal circuit is shorted to ground for longer than 6 s.

P0328 and P0333

The ECM detects that a knock sensor signal circuit is shorted to voltage for longer than 6 s.

  1. DTCs P0325, P0327, P0328, P0330, P0332, and P0333 are Type B DTCs.
  2. The ignition timing is retarded to reduce the potential of engine damaging spark knock.

DTCs P0325, P0327, P0328, P0330, P0332, and P0333 are Type B DTCs.

  1. Inspect the affected knock sensor for physical damage. A sensor that is dropped or damaged may cause a DTC to set.
  2. The sensor mounting surface must be free of burrs, casting flash, and foreign material.
  3. The sensor must be clear of hoses, brackets, and engine electrical wiring.

Schematic Reference

Connector End View Reference

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Engine running, observe the DTC information with a scan tool. Verify DTC P0325, P0327, P0328, P0330, P0332, P0333, P06B6, and P06B7 are not set. If DTC P0325, P0327, P0328, P0330, P0332, or P0333 is set with P06B6 or P06B7 continue with Circuit/System Testing. If only DTC P06B6 or P06B7 is set, and no external knock sensor circuit issues exist, replace the K20 engine control module.
  2. Move the related harnesses and connectors for the affected knock sensor circuits while observing the scan tool parameters listed below. The parameters should display NO. Cylinder 1 Knock Detected Cylinder 2 Knock Detected Cylinder 3 Knock Detected Cylinder 4 Knock Detected Cylinder 5 Knock Detected Cylinder 6 Knock Detected If the parameters change, repair the wiring or the harness connectors.
  3. Observe the DTC information with a scan tool. DTC P0325, P0327, P0328, P0330, P0332, or P0333 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. Verify the affected B68 knock sensor is properly tightened, refer to «Fastener Tightening Specifications»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-specifications__fastener-tightening-specifications) . If not the specified value, correct the condition as appropriate.
  2. Vehicle OFF, disconnect the harness connector at the B68 knock sensor.
  3. Ignition ON, measure for 1-4 V between each of the following circuits and ground on the K20 engine control module side of the harness connector: The signal circuit, terminal 1 The low reference circuit, terminal 2 If less than the specified range, test the circuits for a short to ground or an open/high resistance. If the circuits test normal, replace the K20 engine control module. If greater than the specified range, test the circuits for a short to voltage. If the circuits test normal, replace the K20 engine control module.
  4. If all circuits test normal, replace the B68 knock sensor.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Knock Sensor Replacement - Bank 1»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Knock Sensor Replacement - Bank 2»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup.
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V Reference CircuitP0651P0335P0651, P2135
Crankshaft Position Sensor Signal CircuitP0335P0335P0335P0336
Low Reference and Ground CircuitP0335P0335

The crankshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit and an output signal circuit. The crankshaft 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 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The crankshaft position sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the crankshaft position sensor output depends on the velocity of the crankshaft. The crankshaft position sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the crankshaft position sensor. The ECM uses each crankshaft position signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses crankshaft position sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and to detect cylinder misfire.

Condition 1

  1. Engine is cranking starter is engaged.
  2. DTCs P0101, P0102, P0103, are not set.
  3. The airflow into the engine is greater than 3 g/s.

Condition 2

  1. Engine is running starter is not engaged.
  2. DTC P0651 not set.

Condition 3

  1. Engine is running or starter is engaged.
  2. DTCs P0365, P0366, P0641, or P0651 are not set.

The DTC runs continuously when the above conditions are met.

  1. The ECM detects that the starter is commanded ON and the engine has been cranking for more than 4 seconds without a crankshaft position sensor pulse.
  2. The ECM detects that the engine has been running but has not received a crankshaft position sensor pulse for 2 of 10 engine revolutions.
  1. DTC P0335 is a Type B DTC.
  2. The camshaft position actuator is commanded to the Home or Parked position.

DTC P0335 is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Electronic Ignition System Description»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__electronic-ignition-system-description)
  2. «Engine Control Module Description»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__engine-control-module-description)

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

  1. Engine idling, observe the scan tool Crankshaft Position Active Counter parameter. The parameter should be incrementing.
  2. Engine idling, observe the DTC information with a scan tool. DTC P0335 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the B26 crankshaft position sensor connector.
  2. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes, test for less than 5 ohms between low reference circuit terminal 1 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  3. Ignition ON, engine OFF, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for an open/high resistance or short to ground. 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. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground. If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 engine control module. 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 a 3 A fused jumper wire to signal circuit terminal 2.
  6. Ignition ON, momentarily touch the other end of the fused jumper wire to ground repeatedly while monitoring the scan tool Crankshaft Position Sensor Active Counter parameter. The Crankshaft Position Active Counter should increment. If the Crankshaft Position Active Counter does not increment, replace the K20 engine control module.
  7. If the crankshaft position active counter increments, test or replace the B26 crankshaft position sensor.

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

  1. Inspect the B26 crankshaft position sensor for looseness and correct installation. Remove the crankshaft position sensor from the engine and inspect the sensor and the O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, repair or replace the B26 crankshaft position sensor.
  2. Connect the crankshaft position sensor connector to the crankshaft position sensor. Turn ON the ignition, with the engine OFF.
  3. Observe the Crankshaft Position Active Counter parameter with a scan tool. Pass a flat steel object by the tip of the sensor repeatedly. The crankshaft position active counter parameter should increment. If the function does not perform as specified, replace the B26 crankshaft position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Crankshaft Position Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V Reference CircuitP0651P0335P0651, P2135
Crankshaft Position Sensor Signal CircuitP0335P0335P0335P0336
Low Reference CircuitP0335P0335

The crankshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit and an output signal circuit. The crankshaft 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 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The crankshaft position sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the crankshaft position sensor output depends on the velocity of the crankshaft. The crankshaft position sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the crankshaft position sensor. The ECM uses each crankshaft position signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses crankshaft position sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and to detect cylinder misfire.

  1. DTCs P0101, P0102, P0103, P0340, P0341, P0641, or P0651 are not set.
  2. The engine is cranking or running.
  3. The airflow into the engine is greater than 3 g/s.
  4. The DTC runs continuously when the above conditions are met.
  1. The ECM detects that the engine is running, but receives less than 51 or more than 65 crankshaft position sensor pulses each engine revolution for 8 of 10 engine revolutions.
  2. The ECM detects that the engine is running, but more than 19 resyncs occur within 25 seconds.
  3. The ECM detects that the engine has been running, but the crankshaft does not sync for 0.4 second.
  1. DTC P0336 is a Type B DTC.
  2. The camshaft position actuator is commanded to the Home or Parked position.

DTC P0336 is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

  1. «Electronic Ignition System Description»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__electronic-ignition-system-description)
  2. «Engine Control Module Description»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-description-and-operation__engine-control-module-description)

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

  1. Engine idling, observe the scan tool Crankshaft Position Active Counter parameter. The parameter should be incrementing.
  2. Engine idling, observe the DTC information with a scan tool. DTC P0335 should not set.
  3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the B26 crankshaft position sensor connector.
  2. Ignition OFF, vehicle systems OFF, this may take 2 minutes, test for less than 3 ohms between low reference circuit terminal 1 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground. If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, engine OFF, using a 3 A jumper wire connected to ground, momentarily touch the crankshaft position sensor signal circuit terminal 2 repeatedly. The Crankshaft Position Active Counter parameter should increment. If the Crankshaft Position Active Counter parameter does not increment, replace the K20 ECM. If the Crankshaft Position Active Counter increments, test or replace the B26 crankshaft position sensor.

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

  1. Inspect the B26 crankshaft position sensor for looseness and correct installation. Remove the crankshaft position sensor from the engine and inspect the sensor and the O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, repair or replace the B26 crankshaft position sensor.
  2. Connect the crankshaft position sensor connector to the crankshaft position sensor. Turn ON the ignition, with the engine OFF.
  3. Observe the Crankshaft Position Active Counter parameter with a scan tool. Pass a steel object by the tip of the sensor repeatedly. The Crankshaft Position Active Counter parameter should increment. If the function does not perform as specified, replace the B26 crankshaft position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Crankshaft Position Sensor Replacement»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/buick/lacrosse/ii-2009-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5 V Reference CircuitP0641, P0452, P0107, P0532, P0522P0340, P0345, P0365, P0390P0641
Camshaft Position Sensor Signal CircuitP0340, P0345, P0365, P0390P0340, P0345, P0365, P0390P0340, P0345, P0365, P0390P0341, P0346, P0366, P0391
Low Reference CircuitP0340, P0345, P0365, P0390P0340, P0345, P0365, P0390

The 4X camshaft position sensor circuits consist of an engine control module (ECM) supplied 5 V reference circuit, low reference circuit, and an output signal circuit. The camshaft position sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 4-tooth reluctor wheel attached to the camshaft. As each reluctor wheel tooth rotates past the camshaft position sensor, the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The sensor returns a digital ON/OFF DC voltage pulse of varying frequency, with 4 varying width output pulses per camshaft revolution that represent an image of the camshaft reluctor wheel. The frequency of the camshaft position sensor output depends on the velocity of the camshaft. The ECM decodes the narrow and wide tooth pattern to identify camshaft position. The ECM uses the cylinder 1 intake camshaft position sensor to determine injector and ignition system synchronization. Also, the cylinder 1 intake camshaft position sensor is used to determine camshaft to crankshaft relationship. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses camshaft position sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and for limp-home operation.

Note. The ECM detects engine movement by sensing the airflow through the MAF sensor when airflow is greater than 3 g/s, or by sensing crankshaft position sensor pulses.

  1. DTC P0102, P0103, P0335, P0336, P0641, P0651, or P0697 is not set.
  2. The engine is cranking or running.
  3. The DTC runs continuously when the above conditions are met.
  1. The ECM detects that the starter is commanded ON and the engine has been cranking for more than 4 seconds without a camshaft position sensor pulse.
  2. The ECM detects that the engine has started, but did not receive a camshaft position sensor pulse during the first engine revolution.
  3. The ECM detects that the engine is running, but does not receive a camshaft position sensor pulse for 800 of 1, 000 engine cycles.
  1. DTCs P0340, P0345, P0365, and P0390 are Type B DTCs.
  2. The camshaft position actuator is commanded to the Home or Parked position.

DTCs P0340, P0345, P0365, and P0390 are Type B DTCs.

  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

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

DTC Type Reference

Scan Tool Reference

  1. With the ignition OFF, inspect the engine wiring harnesses carrying the B23 camshaft position sensor circuits for the following conditions: Close routing of aftermarket electrical equipment Close to solenoids, motors, and relays Correct any wire harness routing or component placement conditions if it is determined to be a possible source of electrical interference.
  2. Observe the following scan tool parameters are all incrementing: Exhaust Camshaft Position Active Counter Bank 1 Intake Camshaft Position Active Counter Bank 1 Exhaust Camshaft Position Active Counter Bank 2 Intake Camshaft Position Active Counter Bank 2
  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, all vehicle systems OFF, this may take 2 minutes, disconnect the affected B23 camshaft position sensor connector.
  2. Test for less than 3 ohms between the low reference circuit terminal 1 and ground. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground. If less than the specified range, test the affected signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the affected signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, using a 3 A fused jumper wire connected to ground; momentarily touch the camshaft position sensor signal circuit terminal 2 repeatedly. The appropriate camshaft position active counter parameter should increment. If the camshaft position active counter does not increment, replace the K20 ECM. If the circuits test normal, replace the B23 camshaft position sensor.

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

  1. Inspect the B23 crankshaft position sensor for looseness and correct installation. Remove the crankshaft position sensor from the engine and inspect the sensor and the O-ring for damage. If the sensor is loose, incorrectly installed, or damaged, repair or replace the B23 crankshaft position sensor.
  2. Connect the crankshaft position sensor connector to the crankshaft position sensor.
  3. Ignition ON, observe the applicable camshaft position active counter parameter with a scan tool. Pass a steel object by the tip of the sensor repeatedly. The camshaft position active counter parameter should increment. If the function does not perform as specified, replace the B23 camshaft position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  2. «Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  3. «Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake»(/buick/lacrosse/ii-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-36l-repair-instructions)
  4. «Control Module References»(/buick/lacrosse/ii-2009-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for K20 ECM replacement, setup, and programming

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics (LFX)
• COMPONENT CONNECTOR END VIEWS - INDEX
• Camshaft Actuator System Description
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Trouble Code (DTC) List - Vehicle
• Diagnostic Repair Verification
• Camshaft Position Actuator Solenoid Valve Solenoid Replacement - Bank 1 (Right Side) Intake
• Oil Pressure Diagnosis and Testing
• Camshaft Position Actuator Replacement - Bank 1
• Timing Chain Alignment Diagram
• Camshaft Timing Drive Components Cleaning and Inspection
• Throttle Body Inspection and Cleaning
• Symptoms - Engine Exhaust
• DTC P0641, P0651, P0697, or P06A3 (ECM)
• Altitude Versus Barometric Pressure
• Symptoms - Engine Mechanical
• Throttle Body Assembly Replacement (LFW or LFX)
• Fuel System Description
• Camshaft Replacement - Left Side
• Fuel Pump Replacement
• Temperature Versus Resistance - Intake Air Temperature Sensor (Hitachi Sensor)
• Special Tools (Diagnostic Tools)
• Restricted Exhaust
• Checking Aftermarket Accessories
• Cooling System Leak Testing
• Cooling System Draining and Filling (Static Fill)
• Cooling System Draining and Filling (GE 47716)
• Temperature Versus Resistance - Engine Coolant Temperature Sensor
• Thermostat Diagnosis
• Engine Coolant Thermostat Replacement (LUK)
• Engine Coolant Thermostat Replacement (V6)
• Oil Consumption Diagnosis
• Loss of Coolant
• Fuel System Cleaning
• Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LFW or LFX)
• Fuel Tank Fuel Pump Module Replacement (NT7)
• Engine Controls Schematics (LUK)
• Powertrain Component Views
• Spark Plug Inspection
• Ignition System Specifications
• Battery Inspection/Test
• Crankshaft Position System Variation Learn
• Fastener Tightening Specifications
• Electronic Ignition System Description
• Engine Control Module Description
• Engine Control Module Scan Tool Information (LFX or LFW)
• Engine Control Module Scan Tool Information (LUK)
• DTC P0106 (LF1, LFW, or LFX)

More articles — Engine Performance