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Engine Control System & Fuel System - 2.8l, 3.0l - DTC p1516 to DTC p2433 Cadillac SRX II

Testing & Diagnostics ~19215 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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
TAC Motor Control ClosedP1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P0690, P1516, P2101, P2176P1516, P2101, P2176
TAC Motor Control OpenP1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176

Circuit/System Description

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.

  1. The ignition voltage is greater than 6 V and reduced power is not active.
  2. The engine is running.
  3. DTCs P1516 runs continuously when the above conditions are met.

P2101

  1. DTC P1682 not set.
  2. The engine is running.
  3. The ECM has learned the minimum throttle position.
  4. The ignition voltage is greater than 6 V and reduced power is not active.
  5. DTCs P2101 run continuously when the above conditions are met.

P2119

  1. DTCs P0121, P0122, P0123, P0222, P0223, P0641, P0651, P0697, P06A3, or P2135 are not set.
  2. The ignition is ON.
  3. The ignition voltage is greater than 6 V.
  4. DTC P2119 runs continuously when the above conditions are met.

P2176

  1. DTCs P0068, P0122, P0123, P0222, P0223 are not set.
  2. The ignition is ON.
  3. The ignition voltage is greater than 6 V and reduced power is not active.
  4. DTC P2176 runs continuously when the above conditions are met.

The ECM detect an inability to maintain a steady state throttle position for 4 s.

The ECM detects the difference between the actual throttle position, and the desired position is greater than 7 percent.

  1. The ECM detects that the throttle blade did not return to the default position, during power down, within a calibrated amount of time. or
  2. The ECM detects the throttle control is driving the throttle in the incorrect direction or exceeds the reduced power limit.

The ECM detects that both throttle position sensors were greater than 0.95 V during the minimum learn procedure.

Action Taken When the DTC Sets

  1. DTCs P1516, P2101, and P2176 are type A DTCs.
  2. DTC P2119 is a type C DTC.

Conditions for Clearing the MIL/DTC

  1. DTCs P1516, P2101, and P2176 are type A DTCs.
  2. DTC P2119 is a type C DTC.

Diagnostic Aids

  1. Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close.
  2. A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.
  3. A low battery condition may cause a DTC to set.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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, observe the DTC information with a scan tool. DTC P0121, P0122, P0123, P0222, P0223, P0562, P0621, P0622, or P2135 should not set. If a DTC sets, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Clear the DTCs with a scan tool. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
  3. Ignition ON, observe the scan tool TAC Motor parameter. The reading should display Enabled.
  4. Observe the DTC information with a scan tool. DTC P1516, P2101, P2119, or P2176 should not set.
  5. Perform the scan tool Throttle Sweep Test while observing the TAC Motor parameter with a scan tool. The TAC Motor parameter should display Enabled while the Throttle Sweep Test is in progress. NOTE: Before replacing the throttle body assembly, make sure the TAC motor control circuits are not shorted to B+. If not the specified value, replace the throttle body assembly.
  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.

Circuit/System Testing

  1. Ignition OFF, verify the following conditions do not exist with the Q38 throttle body assembly: A throttle blade that is not in the rest position A throttle blade that is binding open or closed A throttle blade that is free to move open or closed without spring pressure If a condition is found, replace the Q38 throttle body assembly.
  2. Ignition OFF, disconnect the harness connector at the Q38 throttle body assembly.
  3. Ignition ON, verify that a test lamp does not illuminate between each motor control circuit listed below and ground. Motor control circuit terminal A Motor control circuit terminal B If test lamp illuminates, test the motor control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, verify that a test lamp does not illuminate between each motor control circuit listed below and B+. Motor control circuit terminal A Motor control circuit terminal B If the test lamp illuminates, test the motor control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition OFF, set the DMM to the 40 V scale, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms.
  6. Ignition OFF, measure the voltage using the DMM Min/Max Recording Mode function on each circuit listed below as the ignition is turned ON. The Max voltage should be within 1 V of B+. Motor control circuit terminal A Motor control circuit terminal B If not within the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  7. If all circuits and connections test normal, replace the Q38 throttle body assembly.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Throttle Body Assembly Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) .
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming, and setup
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position sensors 1 and 2 to determine the actual throttle valve position.

Conditions for Running the DTC

  1. The vehicle speed is 0 km/h (0 mph).
  2. The engine speed is less than 40 RPM.
  3. The engine coolant temperature (ECT) is between 5-100°C (41-212°F).
  4. The intake air temperature (IAT) is between 5-143°C (41-290°F).
  5. The ignition voltage is greater than 10 volts.
  6. The accelerator pedal position (APP) is less than 15 percent.
  7. DTC P1551 runs when the conditions above have been met for greater than 5 seconds.

Conditions for Setting the DTC

  1. The ECM detects the TP sensor angle is less than 2 percent or greater than 13 percent when the throttle actuator control motor is deactivated.
  2. The condition exists for greater than 1 second or for a cumulative of 10 seconds.

DTC P1551 is a type A DTC.

Conditions for Clearing the DTC

DTC P1551 is a type A DTC.

  1. The scan tool has the ability to operate the throttle actuator control system using Special Functions. This function operates the throttle through the entire range in order to determine if the throttle body and system operate correctly.
  2. Inspect for a condition in which the throttle valve may have been held open.
  3. Inspect for conditions in which ice may have formed in the throttle bore.
  4. The throttle valve is spring loaded to a slightly open position. This is referred to as the rest position. The throttle valve should not be completely closed, nor should it be open any greater than predetermined amount. The throttle valve should move open and to the closed position without binding under the normal spring pressure. The throttle should NOT be free to move open or closed WITHOUT spring pressure.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0121, P0122, P0123, P0221, P0222, P0223, P2100, P2101, or P2119 is not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Start the engine. Observe the DTC information with a scan tool for 30 seconds. DTC P1551 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.

Ignition OFF, disconnect the air intake duct at the Q38 throttle body and inspect for the following

  1. Throttle valve that is NOT in the rest position
  2. Throttle valve that is binding open or closed
  3. Throttle valve that is free to move open or closed WITHOUT spring pressure
  1. If a condition is found, replace the Q38 throttle body assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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
Fuel Economy Mode Switch 5 V ReferenceP159FP159F, P15A1P159FP15A0P15A1
Fuel Economy Mode Switch SignalP159FP159FP159FP15A0P15A1
Fuel Economy Mode Switch GroundP15A0, P15A1P15A0P15A1

Circuit Description

The ECM supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the S87 fuel economy mode switch. The 5 V reference voltage causes current to flow through a series of resistors in the switch to the switch ground circuit. The ECM monitors the reference voltage through a discrete fuel economy mode switch signal circuit. When the switch button is momentarily pressed, the switch contacts allow the 5 V reference voltage to by-pass one of the resistors. The ECM detects the resulting voltage drop as a fuel economy mode request and sends a GMLAN message to the transmission control module (TCM) indicating the request. When the TCM receives the request, throttle progressions and transmission shift points are modified to optimize fuel efficiency. The instrument panel cluster (IPC) also receives the fuel economy mode request message from the ECM and illuminates the fuel economy mode indicator lamp. The fuel economy mode switch must be pressed for between 0.094-1.5 s to activate the fuel economy mode.

  1. Ignition key must be turned to ON.
  2. DTCs P159F and P15A0 run continuously when the above condition is met.

The ECM detects that the voltage on the fuel economy mode switch signal wire is either too low or too high out of range.

DTCs P159F and P15A0 are Type B DTCs

DTCs P159F and P15A0 are Type B DTCs

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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, verify the fuel economy mode indicator lamp on the instrument panel cluster is not illuminated.
  2. Ignition ON, verify the fuel economy mode indicator lamp on the instrument panel cluster illuminates when the fuel economy mode switch button is pressed.
  3. Engine running, observe the scan tool DTC information. DTCs P159F and P15A0 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.

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

  1. Ignition OFF, disconnect the harness connector at the S87 fuel economy mode switch.
  2. Ignition OFF and all vehicle systems OFF, test for less than 5 ohms between ground circuit terminal 2 of the harness connector and ground. If greater than the specified value, test the ground circuit for an open/high resistance and repair as necessary.
  3. Ignition ON, test for 4.8-5.2 V between 5 V reference circuit terminal 9 of the harness connector 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, test for 0.060-0.250 V between signal circuit terminal 10 of the harness connector 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.
  5. If all circuits test normal, test or replace the S87 fuel economy mode switch.

Component Testing

  1. Ignition OFF, disconnect the S87 fuel economy mode switch.
  2. Test for 266-294 ohms between 5 V reference voltage circuit terminal 9 and signal circuit terminal 10 of the S87 fuel economy mode switch. If not within the specified range, replace the S87 fuel economy mode switch.
  3. Test for 1,414-1,562 ohms between 5 V reference voltage circuit terminal 9 and ground circuit terminal 2 of the S87 fuel economy mode switch. If not within the specified range, replace the S87 fuel economy mode switch.
  4. With the S87 fuel economy mode switch button depressed, test for 486-538 ohms between 5 V reference voltage circuit terminal 9 and ground circuit terminal 2 of the S87 fuel economy mode switch. If not within the specified range, replace the S87 fuel economy mode switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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
Fuel Economy Mode Switch 5 V ReferenceP159FP159F, P15A1P159FP15A0P15A1
Fuel Economy Mode Switch SignalP159FP159FP159FP15A0P15A1
Fuel Economy Mode Switch GroundP15A0, P15A1P15A0P15A1

The ECM supplies 5 V reference voltage, through the 5 V reference voltage circuit, to the S87 fuel economy mode switch. This 5 V reference voltage causes current to flow through a series of resistors in the switch to the switch ground circuit. The ECM monitors the 5 V reference voltage through a discrete fuel economy mode switch signal circuit. When the switch button is momentarily pressed, the switch contacts allow the 5 V reference voltage signal to by-pass one of the resistors. The ECM detects the resulting voltage drop as a fuel economy mode request and sends a GMLAN message to the transmission control module (TCM) indicating the request. When the TCM receives the request, throttle progressions and transmission shift points are modified to optimize fuel efficiency. The instrument panel cluster (IPC) also receives the fuel economy mode request message from the ECM and illuminates the fuel economy mode indicator lamp. The fuel economy mode switch button must be pressed for between 0.094-1.5 s to activate the fuel economy mode.

  1. The ignition key is turned to ON.
  2. DTC P15A1 runs continuously when the above condition is met.

The ECM detects that the voltage on the fuel economy mode switch signal wire is in an indeterminate range.

DTC P15A1 is a Type B DTC.

DTC P15A1 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Verify that DTCs P159F and P15A0 are not set. If either or both of the DTCs are set, diagnose those DTCs first.
  2. Ignition ON, verify the fuel economy mode indicator lamp on the instrument panel cluster is not illuminated.
  3. Ignition ON, verify the fuel economy mode indicator lamp on the instrument panel cluster illuminates when the fuel economy mode switch button is pressed.
  4. Engine running, observe the DTC information with a scan tool. DTC P15A1 should not set.
  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.

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

  1. Ignition OFF, disconnect the harness connector at the S87 Fuel Economy Mode switch.
  2. Ignition OFF, and all vehicle systems OFF, test for less than 5 ohms between ground circuit terminal 2 of the harness connector and ground. If greater than the specified value, test the ground circuit for an open/high resistance and repair as necessary.
  3. Test for 266-294 ohms between 5 V reference voltage circuit terminal 9 and signal circuit terminal 10 of the S87 fuel economy mode switch. If not the specified range, replace the S87 fuel economy mode switch.
  4. Test for 1,414-1,562 ohms between 5 V reference voltage circuit terminal 9 and ground circuit terminal 2 of the S87 fuel economy mode switch. If not the specified range, replace the S87 fuel economy mode switch.
  5. With the fuel economy mode switch button depressed, test for 486-538 ohms between 5 V reference voltage circuit terminal 9 and ground circuit terminal 2 of the S87 fuel economy mode switch. If not the specified range, replace the S87 fuel economy mode switch.
  6. Disconnect the X2 harness connector at the ECM.
  7. Test for less than 5 ohms between 5 V reference voltage circuit terminal 14 of the ECM harness connector and 5 V reference voltage circuit terminal 9 of the fuel economy mode switch harness connector. If greater than the specified value, repair the 5 V reference voltage circuit as necessary.
  8. Test for less than 5 ohms between signal circuit terminal 29 of the ECM harness connector and signal circuit terminal 10 of the fuel economy mode switch harness connector. If greater than the specified value, repair the signal circuit as necessary.
  9. If all circuits test normal, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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

  1. The engine is running or cranking.
  2. The ignition voltage is between 8-18 V.
  3. DTC P163A runs continuously when the conditions are met for greater than 500 mS.

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

DTC P163A is a Type C DTC.

DTC P163A is a Type C DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the G18 high pressure fuel pump.
  2. Test for 9-11 ohms at 25°C (77°F) between the low control circuit terminal 1 and the high control circuit terminal 2. If not within the specified range, replace the G18 high pressure fuel pump.
  3. Measure the resistance between each terminal and the high pressure fuel pump housing. The DMM should display OL. If less than the specified value, replace the G18 high pressure fuel pump.
  4. Ignition OFF, verify that a test lamp does not illuminate between B+ and the low control circuit terminal 1. If the test lamp illuminates, test the low control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, verify that a test lamp does not illuminate between ground and the high control circuit terminal 2. If the test lamp illuminates, test the high control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  6. Ignition ON, command the Fuel Pressure Regulator ON with a scan too. Verify that the test lamp illuminates. If the test lamp does not illuminate, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  7. Ignition OFF, connect a test lamp between the low control circuit terminal 1 and B+.
  8. Ignition ON, command the Fuel Pressure Regulator ON with a scan tool. Verify that the test lamp illuminates. If the test lamp does not illuminate, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  9. If all circuits and the high pressure fuel pump test normal, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Pump Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to Voltage
Engine Controls Ignition Relay Feedback Signal, Powertrain RelayP1682P1682P0690
Ignition 1 Signal, Run/Crank Relay112
1. A short to ground or open/high resistance will cause a No Crank condition. 2. A short to voltage will cause the engine to continue to run with ignition OFF.

Typical Scan Tool Data

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, engine OFF, and run/crank and powertrain relay are commanded ON
Ignition 1 Signal, Run/Crank Relay0 V0 VB+
Engine Controls Ignition Relay Feedback Signal, Powertrain Relay0 V0 VB+

Ignition 1 Signal

There are 2 ignition voltage circuits supplied to the engine control module (ECM). The first ignition circuit is provided by the engine controls ignition relay, or powertrain relay, through a fuse. This ignition voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition voltage circuit is supplied by the run/crank relay through a fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition voltage circuits, DTC P1682 will set.

  1. The ignition is ON.
  2. System voltage is more than 6 V.
  3. The powertrain relay is commanded ON.
  4. DTC P1682 runs continuously.

The ECM detects that the voltage level difference is greater than 3 V between the 2 ignition voltage circuits for less than 1 s.

DTC P1682 is a Type A DTC.

DTC P1682 is a Type A DTC.

Schematic Reference

  1. «Engine Controls Schematics (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams) or «Engine Controls Schematics (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-schematic-routing-diagrams)
  2. «Power Distribution Schematics»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Electrical Center Identification Views»(/cadillac/srx/ii-2009-2012/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)
  4. «Probing Electrical Connectors»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  5. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  6. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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. On the scan tool, the powertrain relay is referred to as the engine controls ignition relay.

  1. If DTC P0685 or P0690 is set, diagnose that DTC first.
  2. Ignition ON, observe the scan tool Ignition 1 Voltage signal and the Engine Controls Ignition Relay Feedback signal parameters. There should be no more than 3 V difference between the two parameters.
  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.

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

  1. Ignition ON, observe the Ignition 1 Signal and the Engine Controls Ignition Relay Feedback scan tool parameter to determine which is more than 3 V lower than the other.
  2. Ignition OFF, remove the relay that corresponds to the scan tool parameter that is more than 3 V lower.
  3. Connect a 20 A fused jumper wire between B+ and the applicable ignition voltage circuit terminal 30. Ignition ON, verify that the applicable scan tool parameter displays between 9-14 V. If the applicable scan tool parameter is less than the specified value, test the ignition voltage circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  4. Ignition OFF, connect a DMM set to the diode setting between the control circuit terminal 85 and ground. Verify the DMM displays OL. If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, verify the DMM displays less than 1 V. If not the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, replace the applicable relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/srx/ii-2009-2012/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Fuel trim bias is used by the engine control module (ECM) to keep the post catalyst HO2S voltage within a range of 580-665 mV. This allows optimal catalyst efficiency under light load conditions, such as at idle or a steady cruise. The ECM constantly monitors how lean or rich the fuel trim bias is commanded, to determine if the fuel trim bias is greater than a calibrated amount.

  1. Before the ECM can report DTC P2096, DTCs P0030, P0031, P0032, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P2232, P2235, P2270, P2271, P2272, and P2273 must run and pass.
  2. DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0420, P0443, P0458, or P0459 is not set.
  3. The engine speed is 1,080-3,480 RPM.
  4. The engine load is 17-20 % and steady.
  5. The Closed Loop fuel control is active for greater than 1 s.
  6. The front and rear HO2S are in Closed Loop.
  7. The calculated exhaust gas temperature is greater than 250°C (482°F).
  8. DTC P2096 runs continuously when the conditions above have been met for greater than 200 s.

The lean correction limit for a condition causing a rich air/fuel mixture has been exceeded for a predetermined amount of time. The condition exists for greater than 4 s or for a cumulative of 30 s.

DTC P2096 is a Type B DTC.

DTC P2096 is a Type B DTC.

An HO2S will not cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set. If any other HO2S or fuel trim DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Verify that none of the following conditions exist: Rich fuel injectorsto «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . High fuel system pressure - Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Fuel saturation of the evaporative emissions (EVAP) canister Stuck open or leaking EVAP purge valve Restricted exhaust Incorrect PCV system operation If you find any of the above conditions, repair as necessary.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Fuel trim bias is used by the engine control module (ECM) to keep the post catalyst HO2S voltage within a range of 580-665 mV. This allows optimal catalyst efficiency under light load conditions, such as at idle or a steady cruise. The ECM constantly monitors how lean or rich the fuel trim bias is commanded, to determine if the fuel trim bias is greater than a calibrated amount.

  1. Before the ECM can report DTC P2097 failed, DTCs P0030, P0031, P0032, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P2232, P2235, P2270, P2271, P2272, and P2273 must run and pass.
  2. DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0420, P0443, P0458, or P0459 is not set.
  3. The engine speed is 1,080-3,480 RPM.
  4. The engine load is 17-20 % and steady.
  5. The Closed Loop fuel control is active for greater than 1 s.
  6. The front and rear HO2S are in Closed Loop.
  7. The calculated exhaust gas temperature is greater than 250°C (482°F).
  8. DTC P2097 runs continuously when the conditions above have been met for greater than 200 s.

The rich correction limit for a condition causing a lean air/fuel mixture has been exceeded for a predetermined amount of time. The condition exists for greater than 4 s or for a cumulative of 30 s.

DTC P2097 is a Type B DTC.

DTC P2097 is a Type B DTC.

  1. An HO2S will not cause this DTC to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.
  2. An exhaust system leak that may not be audible can set this DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool DTC information. Verify there is no other HO2S or fuel trim DTC set. If any other HO2S or fuel trim DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Verify that none of the following conditions exist: Exhaust system leaks - Refer to «Exhaust Leakage»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) Engine vacuum leaks Low fuel system pressure - Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Lean fuel injectors - Refer to «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . If you find any of the above conditions, repair as necessary.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position sensors 1 and 2 to determine the actual throttle valve position.

  1. The engine speed is greater than 1200 RPM.
  2. The ECM power down process in the last drive cycle was completely finished.
  3. DTC P2105 runs continuously when the above condition is met for greater than 5 s.
  1. The ECM detects an incorrect voltage level at the internal ignition voltage supply circuits. OR
  2. The ECM detects an internal communication error.
  3. Either condition exists for greater than 5 s.

DTC P2105 is a Type A DTC.

DTC P2105 is a Type A DTC.

  1. If DTC P2105 sets, the engine will stall and not restart until the ignition is cycled OFF and then ON.
  2. Additional DTCs set when P2105 sets.
  3. The ignition key will not be able to be removed from the ignition switch until another ignition cycle occurs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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. Start the engine. Rapidly move the accelerator pedal from the rest position, to wide open throttle position, back to the rest position. Repeat the procedure a few times. DTC P2105 should not set.
  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, remove the fuse that supplies voltage to terminal 5 X2 of the K20 engine control module. Verify the fuse is OK. NOTE: This DTC will only set if the fuse is open and the circuits are not grounded. The ignition voltage circuits must be tested thoroughly for an intermittent short to ground. If the fuse is open, test the ignition voltage circuit between the open fuse and the K20 engine control module terminal 5 X2 for an intermittent short to ground.
  2. Install the fuse.
  3. Disconnect the harness connectors of the K20 engine control module.
  4. Ignition ON, load test for B+ on the ignition circuit terminal 5 X2 of the K20 engine control module connector. If less than B+, repair the ignition circuit for an open/high resistance.
  5. If all circuits/connections test OK, replace the K20 engine control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Accelerator Pedal Position (APP) Sensor 1 5-Volt Reference CircuitP06A3, P2122P2138P2122P06A3, P2135P2138
Accelerator Pedal Position (APP) Sensor 1 SignalP2122P2138P2122P06A3, P2123P2138
Accelerator Pedal Position (APP) Sensor 1 Low ReferenceP2138P2123P2138
Accelerator Pedal Position (APP) Sensor 2 5-Volt Reference CircuitP0107, P0697P2138P2127P0106, P0108, P0697P2138
Accelerator Pedal Position (APP) Sensor 1 SignalP2122P2138P2122P06A3, P2123P2138
Accelerator Pedal Position (APP) Sensor 2 Low ReferenceP2138P2128P2138
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 1 0.88-1.08 V Parameter Normal Range: APP Sensor 2 0.39-0.59 V
APP Sensor 1 5-Volt Reference0.00 V0.00 V2.75 V
APP Sensor 1 Signal0.00 V0.00 V4.98 V
APP Sensor 1 Low Reference4.94 V
APP Sensor 2 5-Volt Reference0.00 V0.00 V1.35 V
APP Sensor 2 Signal0.00 V0.00 V4.98 V
APP Sensor 2 Low Reference4.92 V

APP Sensor 1 and 2

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

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

P2122, P2123, P2127, or P2128

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

P2138

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

P2122

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

P2123

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

P2127

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

P2128

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

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

OR

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

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

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

  1. If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.
  2. The scan tool 5 volt reference parameter should display between 4.8-5.2 volts.
  3. A high resistance condition on the accelerator pedal position circuits could cause a DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 DTCs P0697 or P06A3 are not set. If a DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0455-to-dtc-p150cp1400) for further diagnosis.
  2. Ignition ON, observe the scan tool Accelerator Pedal Position percentage parameter. The scan tool should display 0 percent.
  3. Observe the scan tool APP Sensor 1 and 2 Agree/Disagree parameter while performing the following tests: Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. The APP Sensor 1 and 2 Agree/Disagree parameter should display Agree.
  4. Observe the DTC information with a scan tool. DTCs P2122, P2123, P2127, P2128, or P2138 should not set.
  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 B107 accelerator pedal assembly.
  2. Ignition OFF for 1 minute, test for less than 5 ohms between the low reference circuit terminals listed below and ground. Low reference circuit terminal 4 Low reference circuit terminal 5 If greater than the specified range, test the appropriate low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between both 5-volt reference circuit terminals listed below and ground. 5 volt reference circuit terminal 1 5 volt reference circuit terminal 2 If less than the specified range, test the appropriate 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Verify the appropriate APP sensor voltage parameter is at 0 V. If greater than the specified range, test the appropriate signal circuit terminal listed below for a short to voltage. If the circuit tests normal, replace the K20 ECM. APP sensor 1 signal circuit terminal 3 APP sensor 2 signal circuit terminal 6
  5. Install a 3 A fused jumper wire between the appropriate signal circuit listed below and the 5-volt reference circuit terminal 1. Verify the appropriate APP sensor voltage parameter is greater than 4.8 V. APP sensor 1 signal circuit terminal 3 APP sensor 2 signal circuit terminal 6 If less than the specified range, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, replace the B107 accelerator pedal assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accelerator Pedal with Position Sensor Assembly Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
Accelerator Pedal Position (APP) Sensor 1 5-Volt Reference CircuitP0343, P0348, P0368, P0393, P0652, P2122P2122, P2138P0651, P2122P0653, P2138, P2123P0651, P0652, P0653, P2138
Accelerator Pedal Position (APP) Sensor 2 5-Volt Reference CircuitP0122, P0222, P0335, P0642, P0698, P0700P2127, P2138P0697, P2127P0123, P0221, P0699, P2138, P2128, P0700P0697, P0698, P0699, P2138
Accelerator Pedal Position (APP) Sensor 1 SignalP2122P2138P2122P2123P2138
Accelerator Pedal Position (APP) Sensor 2 SignalP2127P2138P2127P2128P2138
Accelerator Pedal Position (APP) Sensor 1 Low ReferenceP2123, P2138P2123P2138
Accelerator Pedal Position (APP) Sensor 2 Low ReferenceP2127, P2138P2128P2138
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 1 0%/1 Volts Parameter Normal Range: APP Sensor 2 0%/0.5 Volts
5-Volt Reference0%/0.00 Volts0%/0.00 Volts0%/4.98 Volts
APP Sensor 1 Signal0%/0.00 Volts0%/0.00 Volts0%/4.98 Volts
APP Sensor 2 Signal0%/0.00 Volts0%/0.00 Volts0%/4.98 Volts
APP Sensor 1 Low Reference0%/4.98 Volts
APP Sensor 2 Low Reference0%/4.98 Volts

APP Sensor

The accelerator pedal assembly contains two accelerator pedal position (APP) sensors. The APP sensors are mounted in the pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to the position of the accelerator pedal. The engine control module (ECM) supplies a separate 5-volt reference and low reference circuit for each of the APP sensors.

The APP sensor 1 signal voltage increases as the pedal is depressed, from approximately 1.0 volt at rest to approximately 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volt at rest to approximately 2 volts with the accelerator pedal fully depressed.

Conditions for Running the DTCs

  1. The ignition is ON or the engine is operating.
  2. The ignition voltage is greater than 8 volts.
  3. The DTCs run continuously once the above conditions are met for greater than 200 ms.
  1. The APP sensor 1 voltage is less than 0.74 volt and APP sensor 2 voltage is less than 0.62 V for greater than 1 s or for a cumulative time of 4 s. OR
  2. The APP sensor 1 voltage is less than 0.74 volt for greater than 1 s or for a cumulative time of 4 s.

The APP sensor 1 voltage is greater than 4.82 volts for greater than 1 s or for a cumulative time of 4 s.

The APP sensor 2 voltage is less than 0.63 volt for greater than 1 s or for a cumulative time of 4 s.

The APP sensor 2 voltage is greater than 4.82 volts for greater than 1 s or for a cumulative time of 4 s.

  1. The ECM detects that the voltage difference between APP sensor 1 and 2 is greater than 0.25 volts when the sensor voltages are between 1.91-1.25 V.
  2. The ECM detects that the voltage difference between APP sensor 1 and 2 is greater than 0.31 volts when the sensor voltages are between 1.91-2.63 V.
  3. The ECM detects that the voltage difference between APP sensor 1 and 2 is greater than 1.7 volts when the sensor voltages are greater than 2.63 V.
  4. DTC P2138 sets if any of the above conditions exist for greater than 1 s or for a cumulative time of 4 s.

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

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

Test the current output of the 5-volt reference circuits if you suspect high resistance in the circuit. The current output should be greater than 80 mA for APP 1 and greater than 50 mA for APP 2.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 P0651, P0652, P0653, P0697, P0698, or P0699 should not be set. If a DTC is set, refer to «DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0455-to-dtc-p150cp1400) .
  2. Observe the scan tool APP Sensor voltage parameters. Verify both of the APP sensor voltages are between 0.4-4.5 V.
  3. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. DTCs P2122, P2123, P2127, P2128, or P2138 should not set.
  4. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs P2122, P2123, P2127, P2128, or P2138 should not set.
  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. Disconnect the harness connector at the B107 accelerator pedal assembly.
  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 appropriate low reference circuit listed below and ground. B107 APP sensor 1 terminal 4 B107 APP sensor 2 terminal 5 If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2 V between the appropriate 5-volt reference circuit listed below and ground. B107 APP sensor 1 terminal 2 B107 APP sensor 2 terminal 1 If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the K20 ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
  4. Observe the scan tool APP sensor 1 voltage parameter. Verify the voltage is less than 0.3 V. If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
  5. Observe the scan tool APP sensor 2 voltage parameter. Verify the voltage is less than 0.3 V. If greater than the specified range, test the signal circuit terminal 6 for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
  6. Connect a 3 A fused jumper wire between the APP sensor 1 signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the APP sensor 1 voltage parameter 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/connections test normal, replace the K20 ECM.
  7. Connect a 3 A fused jumper wire between the APP sensor 2 signal circuit terminal 6 and the 5-volt reference circuit terminal 1. Verify the APP sensor 2 voltage parameter 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/connections test normal, replace the K20 ECM.
  8. If all circuits/connections test normal, test or replace the B107 accelerator pedal assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accelerator Pedal with Position Sensor Assembly Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 4P2156P0204P2157P124B
Direct Fuel Injector High Voltage Control Cylinder 4P0270P0204P0271P124B
Direct Fuel Injector High Voltage Supply Cylinder 5P216BP0205P216CP124C
Direct Fuel Injector High Voltage Control Cylinder 5P0273P0205P0274P124C
Direct Fuel Injector High Voltage Supply Cylinder 6P216EP0206P216FP124D
Direct Fuel Injector High Voltage Control Cylinder 6P0276P0206P0277P124D

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

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

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

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

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

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

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

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

  1. Performing the fuel injector coil test may help isolate an intermittent condition. Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  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 Fault if there is a condition with the circuit or a connection.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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»(/cadillac/srx/ii-2009-2012/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 P2147, P2148, P2150, P2151, P2153, P2154, P2156, P2157, P216B, P216C, P216E, or P216F should not set.
  3. Observe the scan tool Current Misfire Counter parameters. The Current Misfire 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.
  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 X198 or X199, 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 ECM.
  3. Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The 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 ECM.
  4. Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohms. If less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
  5. Test for 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 (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis)
  2. «Fuel Injector Balance Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis)

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Injection Fuel Rail Assembly Replacement - Bank 1 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Fuel Injection Fuel Rail Assembly Replacement - Bank 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  3. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 the throttle valve by applying a varying voltage to the throttle actuator control (TAC) motor. The ECM monitors the actual throttle valve position using throttle position sensor 1 and 2.

  1. The engine speed is less than 40 RPM.
  2. The vehicle speed is 0 km/h (0 mph).
  3. The engine coolant temperature (ECT) is between 5-101°C (41-214°F).
  4. The intake air temperature (IAT) is between 5-144°C (41-291°F).
  5. The accelerator pedal position (APP) sensor angle is less than 15 percent.
  6. The ignition voltage is greater than 10 volts.
  7. DTC P2176 runs once per ignition cycle, when the ignition is ON and the above conditions are met for greater than 1 second.
  1. The ECM detects that the TP sensor 1 voltage is not between 4.12-4.55 V after the throttle learn procedure, with the throttle at rest.
  2. The ECM detects that the TP sensor 2 voltage is not between 0.34-0.99 V after the throttle learn procedure, with the throttle at rest.
  3. The minimum throttle position is not learned after an ECM replacement.
  4. Either condition exists fro greater than 1 second, or a cumulative 10 seconds.

DTC P2176 is a Type A DTC.

DTC P2176 is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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, rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release the pedal. Repeat the procedure several times. Observe the DTC information with a scan tool. Verify that DTC P0121, P0122, P0123, P0221, P0222, P0223, P0638, or P2101 do not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. DTC P2176 is an informational DTC. Perform the throttle learn procedure, refer to «Throttle/Idle Learn (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) or «Throttle/Idle Learn (Without LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . If DTC P2176 resets after performing the throttle learn procedure, replace the Q38 throttle body.
  3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the HO2S inputs are added and used by the ECM to calculate short and long term fuel delivery adjustments. If the HO2S indicate a lean condition, fuel trim values will be above 0 %. If the HO2S indicate a rich condition, fuel trim values will be below 0 %. Short term fuel trim values change rapidly in response to the HO2S signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

P2177

  1. Before the ECM can report DTC P2177 failed, DTCs P0008, P0009, P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
  2. The engine speed is between 1,200-3,400 RPM.
  3. The mass air flow is between 7-83 g/s.
  4. The throttle angle is less than 100 %.
  5. The engine load is between 17-55 %.
  6. The fuel system is in Closed Loop.
  7. The engine is not in decel fuel cut-off.
  8. The long term fuel trim is active.
  9. The engine coolant temperature (ECT) is greater than 60°C (140°F).
  10. The intake air temperature (IAT) is less than 61°C (142°F).
  11. The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
  12. The fuel level is greater than 12 %.
  13. The amount of air flow into the engine is greater than 7,000 g.
  14. DTC P2177 runs continuously when the above conditions are met for at least 300 s.

P2187

  1. Before the ECM can report DTC P2187 failed, DTCs P0008, P0009, P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
  2. The engine speed is between 480-1,001 RPM.
  3. The engine load is between 7-32 %.
  4. The MAF is between 1-8 g/s.
  5. The fuel system is in Closed Loop.
  6. The engine is not in decel fuel cut-off.
  7. The long term fuel trim is active.
  8. The engine coolant temperature (ECT) is greater than 60°C (140°F).
  9. The intake air temperature (IAT) is less than 61°C (142°F).
  10. The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
  11. The fuel level is greater than 12 %.
  12. The amount of air flow into the engine is greater than 7,000 g.
  13. DTCs P2187 and P2189 run continuously when the above conditions are met.

The Total Fuel Trim Avg. is greater than 23 % for 4 s or for a cumulative of 30 s.

The Total Fuel Trim Avg. is greater than 40 %, or the long term fuel trim Idle/Decel is greater than 6 %. Either condition exists for 4 s or for a cumulative of 30 s.

DTCs P2177 and P2187 are Type B DTCs.

DTCs P2177 and P2187 are Type B DTCs.

  1. A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a lean condition. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  2. Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
  3. 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.
  4. 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.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 P2177 or P2187 should not be set. If there are other DTCs set besides DTC P2177 or P2187 refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) to diagnosis the applicable DTC.
  2. Ignition ON, observe the BARO pressure parameter and compare the reading on the scan tool to the barometric pressure table. Refer to «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) . If the BARO pressure is not within the range specified for your altitude, refer to «DTC P2227, P2228, or P2229 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p1516-to-dtc-p2433) .
  3. Engine at normal operating temperature, observe the Average Total Fuel Trim parameter with a scan tool. The Average Total Fuel Trim should be between -22 to +23 %. If not within the specified range, verify none of the following conditions exist: A mass air flow sensor signal that is skewed-If the Short Term Fuel Trim parameter changes greater than 20 % when the MAF sensor is disconnected, refer to «DTC P0101 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) or «DTC P0101 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) . The air intake system after the MAF sensor for vacuum leaks Fuel contamination - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) and «Fuel System Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-system-cleaning) . Splits, kinks, or improper connections at the vacuum hoses. The fuel system is operating lean. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Vacuum leaks at the intake manifold or throttle body Leaking crankcase ventilation system The engine control module grounds for being clean, tight, and in the correct locations A high engine oil level condition-A high engine oil level causes oil residue to form on the mass air flow sensor, causing a lean indication. The MAF sensor does not need to be replaced. Vacuum leaks that only affect one bank of the engine - For example, the intake manifold, the injector O-rings. Lean injectors - Refer to «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Missing, restricted, or leaking exhaust components - Refer to «Symptoms - Engine Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . The heated oxygen sensor (HO2S) is installed securely and the electrical connector is not contacting the exhaust system. An engine mechanical condition - Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) .
  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. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the HO2S inputs are added and used by the ECM to calculate short and long term fuel trim fuel delivery adjustments. If the HO2S indicate a lean condition, fuel trim values will be above 0 percent. If the O2S indicate a rich condition, fuel trim values will be below 0 percent. Short term fuel trim values change rapidly in response to the HO2S signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1.

P2178

  1. Before the ECM can report DTC P2178 failed, DTCs P0008, P0009, P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
  2. The engine speed is between 1,200-3,400 RPM.
  3. The mass air flow is between 7-83 grams/second.
  4. The throttle angle is less than 100 percent.
  5. The engine load is between 17-55 percent.
  6. The fuel system is in closed loop.
  7. The engine is not in decel fuel cut-off (DEFCO).
  8. The long term fuel trim is active.
  9. The engine coolant temperature (ECT) is greater than 60°C (140°F).
  10. The intake air temperature (IAT) is less than 61°C (142°F).
  11. The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
  12. The fuel level is greater than 12 percent.
  13. The amount of air flow into the engine is greater than 7,000 grams.
  14. DTC P2178 run continuously once the above conditions are met for at least 300 seconds.

P2188

  1. Before the ECM can report DTC P2188 failed, DTCs P0008, P0009, P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0101, P0121, P0122, P0123, P0133, P0201, P0202, P0203, P0204, P0205, P0206, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2068 P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
  2. The engine speed is between 480-1,001 RPM.
  3. The engine load is between 7-32 percent.
  4. The MAF is between 1-8 grams per second.
  5. The fuel system is in closed loop.
  6. The engine is not in decel fuel cut-off (DEFCO).
  7. The long term fuel trim is active.
  8. The engine coolant temperature (ECT) is greater than 60°C (140°F).
  9. The intake air temperature (IAT) is less than 61°C (142°F).
  10. The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
  11. The fuel level is greater than 12 percent.
  12. The amount of air flow into the engine is greater than 7,000 grams.
  13. DTC P2188 run continuously once the above conditions are met.

The Total Fuel Trim Avg. is less than -22 percent. The condition exists for 4 seconds or for a cumulative of 30 seconds.

The Total Fuel Trim Avg. is less than -40 percent. The LT FT Idle/Decel is less than -6 percent. The condition exists for 4 seconds or for a cumulative of 30 seconds.

DTCs P2178 and P2188 are Type B DTCs.

DTCs P2178 and P2188 are Type B DTCs.

  1. A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich condition. Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LAU Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  2. Review the Freeze Frame/Failure Records with a scan tool.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 P2178 or P2188 should not be set. If there are other DTCs set besides DTC P2178 or P2188, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) to diagnosis the applicable DTC.
  2. Ignition ON, observe the BARO pressure parameter and compare the reading on the scan tool to the barometric pressure table. Refer to «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) . If the BARO pressure is not within the range specified for your altitude, refer to «DTC P2227, P2228, or P2229 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p1516-to-dtc-p2433) .
  3. Engine at normal operating temperature, observe the Average Total Fuel Trim parameter with a scan tool. The Average Total Fuel Trim should be between -22 to +23 percent. If not within the specified range, inspect for the following conditions: A mass air flow sensor signal that is skewed. If the Short Term Fuel Trim parameter changes greater than 20 percent when the MAF sensor is disconnected, refer to «DTC P0101 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) or «DTC P0101 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) . A collapsed air intake duct A restricted air filter element - Refer to «Air Cleaner Element Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) or «Air Cleaner Element Replacement (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) . The MAF sensor for foreign objects. Excessive fuel in the crankcase - Change the oil as necessary. Fuel contamination - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) and «Fuel System Cleaning»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions__fuel-system-cleaning) . The engine control module grounds for being clean, tight, and in the correct locations Rich injectors - Refer to «Fuel Injector Solenoid Coil Test (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Restricted exhaust system - Refer to «Symptoms - Engine Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . An engine mechanical condition - Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) .
  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. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

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

  1. DTCs P0053, P0059, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0151, P0152, P0153, P0154, P0155, P0178, P0179, P0201-P0208, P0300, P0301-P0308, P0411, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0606, P1133, P1153, P1516, P2101, P2135, P2176, P2269, P2440, P2444, P2A00, P2A03 are not set.
  2. The device control is not active.
  3. The intrusive diagnostics are not active.
  4. The engine overspeed protection is not active.
  5. Reduced power mode, ETC DTC, is not active.
  6. The power take-off (PTO) is not active.
  7. The traction control is not active.
  8. The fuel control is in air-fuel Closed Loop.
  9. The system voltage is more than 10 V, or less than 18 V.
  10. The engine coolant temperature (ECT) is warmer than -20°C (-4°F).
  11. The engine speed is greater than 350 RPM, but less than 6,000 RPM.
  12. The mass air flow is greater than 11 g/s, but less than 510 g/s.
  13. Percent ethanol is less than 87 %.

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

DTCs P219A and P219B are Type B DTCs.

DTCs P219A and P219B are Type B DTCs.

  1. The air fuel imbalance diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may set a false DTC.
  2. Monitoring the misfire current counters, or misfire graph, may help to isolate the cylinder that is causing the condition.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Troubleshooting with a Test Lamp»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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. Read and record the Freeze Frame/Failure Records data taking note of the speed and load at which the DTC set.
  2. Diagnose any other DTCs that are set. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  3. With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 20-48 kPa (2.9-7.0 psi). If the MAP sensor parameter is not between 20-48 kPa (2.9-7.0 psi), refer to «DTC P0106 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) or «DTC P0107 or P0108 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) .
  4. Inspect the air induction system for modified, damaged, leaking, or restricted components.
  5. Inspect the crankcase ventilation system for improper operation.
  6. Inspect the vacuum hoses for splits, kinks, and improper connections.
  7. Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.
  8. Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to «Symptoms - Engine Exhaust»(/cadillac/srx/ii-2009-2012/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  9. Test the fuel injectors for improper operation. Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  10. Test for fuel contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  11. Test for excessive fuel in the crankcase due to leaking injectors.
  12. Test the ignition system for improper operation. Refer to «Electronic Ignition System Diagnosis»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) .
  13. Test the engine for any mechanical conditions such as sticking valves, lifters, etc., which could alter the flow into the combustion chamber. Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) .

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

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The barometric pressure (BARO) sensor responds to changes in altitude and atmospheric conditions. This gives the engine control module (ECM) an indication of barometric pressure. The ECM uses this information to calculate fuel delivery. The BARO sensor is located within the controller and is not serviced as a separate unit. The BARO sensor provides a voltage signal to the ECM relative to the atmospheric pressure changes. The ECM monitors the BARO sensor signal for a voltage outside of the normal range.

P2227

  1. Before the ECM can report DTC P2227 failed, DTCs P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0114, P0121, P0122, P0123, P0221, P0222, P0223, P0236, P0237, P0238, P2228, and P2229 must run and pass.
  2. The engine is operating.
  3. The engine speed is less than 1,120 RPM.
  4. The throttle position sensor parameter is less than 10 %.
  5. DTC P2227 runs whenever the above conditions are met.

P2228 or P2229

  1. The ignition is ON.
  2. The DTCs run continuously when the above condition is met for 0.2 s.
  1. The ECM detects that the BARO sensor signal plus a calibrated threshold is less than the boost pressure sensor signal plus a calibrated threshold for more than 9 s. OR
  2. The ECM detects that the BARO sensor signal plus a calibrated threshold greater than the boost pressure sensor signal plus a calibrated threshold for more than 9 s. OR
  3. The ECM detects that the BARO pressure changed greater than 5 kPa (0.7 psi) within 20 s. OR
  4. The ECM detects that the BARO pressure changed greater than 10 kPa (1.5 psi) since the last ignition cycle.

P2228

  1. The ECM detects that the BARO sensor voltage is less than 0.20 V for 0.5 s. OR
  2. The ECM detects that the BARO sensor signal is less than 45 kPa (6.5 psi) for 2 s

P2229

  1. The ECM detects that the BARO sensor voltage is greater than 4.8 V for 0.5 s. OR
  2. The ECM detects that the BARO sensor signal is greater than 115 kPa (16.7 psi) for 2 s.

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

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

Schematic Reference

Connector End View Reference

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Start the engine. Observe the DTC information with a scan tool. DTCs P2227, P2228, or P2229 should not set.
  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. Inspect the atmospheric vent on the K20 ECM case for one of the following conditions: Moisture in the vent inlet Debris in the vent inlet If a condition exists, attempt to clean or dry the atmospheric inlet.
  2. Start the engine. Observe the DTC information with a scan tool. DTCs P2227, P2228, or P2229 should not set. If DTC P2227, P2228, or P2229 sets, replace the K20 ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 ReferenceP0641, P2227, P2228P2228P0641, P2229P2227
SignalP2227, P2228P2227, P2228P2227, P2229P2227
Low ReferenceP2227, P2229P2227
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, Engine OFF Parameter Normal Range: 56-105 kPa (8.1-15.2 psi), varies with altitude
5 V Reference0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Signal0 kPa (0 psi)0 kPa (0 psi)127 kPa (18.4 psi)
Low Reference127 kPa (18.4 psi)

BARO

The barometric pressure (BARO) sensor is integral to the throttle inlet absolute pressure sensor and responds to changes in altitude and atmospheric conditions. This gives the ECM an indication of barometric pressure. The ECM uses this information to calculate fuel delivery. The BARO sensor provides a voltage signal to the ECM relative to the atmospheric pressure changes. The ECM monitors the BARO sensor signal for a voltage outside of the normal range.

  1. DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0222, P0223, P1516, P2135, P2228, or P2229 is not set.
  2. The engine is running. OR
  3. DTC P0106, P0107, P0108, P2228, P2229, or P2230 is not set and not pending.
  4. Ignition ON, engine OFF
  5. DTC P2227 runs continuously when the above conditions are met.
  1. The engine is running.
  2. The DTCs run continuously when the above condition is met.

P2230

  1. DTC P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0222, P0223, P1516, P2135, P2228, or P2229 is not set.
  2. The engine is running.
  3. DTC P2230 runs continuously when the above conditions are met.
  1. The engine is running.
  2. The ECM detects that the difference between the BARO signal and the calculated BARO is greater than 15 kPa (2.2 psi) if the vehicle has traveled at most 0.5 km (0.31 mi) since the last calculated BARO update, or the ECM detects that the difference between the BARO signal and the calculated BARO is greater than 25 kPa (3.6 psi) if the vehicle has traveled greater than 0.5 km (0.31 mi) since the last calculated BARO update. OR
  3. Ignition ON, engine OFF
  4. The ECM detects that the BARO pressure is less than 50 kPa (7.3 psi) or greater than 115 kPa (16.7 psi).

The ECM detects that the BARO sensor voltage is less than 1.95 V for greater than 4 s.

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

The ECM detects that the difference between the current BARO sensor reading and the previous BARO sensor reading is greater than 10 kPa (1.5 psi).

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

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

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

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0641 is not set. If a DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0455-to-dtc-p150cp1400) for further diagnosis.
  2. Ignition ON, observe the scan tool BARO parameter. Compare the parameter to the «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) table. The BARO parameter should be within the specified range indicated in the table.
  3. Engine running observe the DTC information with a scan tool. DTC P2227, P2228, P2229, or P2230 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the B17 BARO 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 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 BARO 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 BAROr 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, replace the B17 BARO sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Throttle Inlet Absolute Pressure Sensor Replacement (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions) for BARO sensor replacement
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. Or, to detect if the HO2S signal voltage switches at the same rate at which the ECM is commanding the heater ON and OFF.

  1. The engine is operating.
  2. The ignition voltage is greater than 10 volts.
  3. The calculated exhaust gas temperature is between 250-800°C (482-1,472°F) for greater than 90 seconds.
  4. The HO2S heater control is enabled for greater than 10 seconds.
  5. DTC P2232 runs continuously once the conditions above exist for greater than 10 seconds.
  1. The ECM detects that the HO2S 2 signal voltage increases greater than 2 volts within 0.04 second, in 4 out of 6 HO2S heater switch OFF samples.
  2. The condition exists for greater than 4 seconds, or for a cumulative of 30 seconds.

DTCs P2232 is a Type B DTC.

DTCs P2232 is a Type B DTC.

  1. The HO2S voltage should be between 350-550 mV with the ignition ON. If the voltage is greater than the specified value, there is a condition with the HO2S circuits. If the voltage does not change after disconnecting the HO2S, the condition is between the sensor and the ECM. If the voltage is between 350-550 mV after disconnecting the sensor, the condition is with the HO2S.
  2. Inspect the HO2S harness connector for water intrusion. Moisture in a connector may cause voltage to bleed to other circuits within the connector.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 HO2S 2 voltage parameter. The HO2S voltage parameter should be less than 1,050 mV.
  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 B52 HO2S 2.
  2. Ignition ON, verify that the HO2S parameter is between 350-500 mV. If greater than 500 mV, test the signal circuit terminal 4 of the HO2S sensor for a short to the heater control circuit terminal 2. If the circuit/connections test normal, replace the K20 ECM.
  3. If all circuits/connections test normal, replace the B52 HO2S 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Sensor 2 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The turbocharger incorporates a wastegate that is controlled by a pressure differential, that is determined by the engine control module (ECM) by means of a pulse width modulation (PWM) solenoid valve, in order to regulate the pressure ratio. A charge air bypass valve is integrated within the unit, and is also controlled by the ECM by utilizing a remotely mounted solenoid valve to prevent surging and damage from vibrations by opening during abrupt closed throttle conditions. When the bypass valve is commanded open during closed throttle deceleration conditions, the bypass valve allows the air to recirculate in the turbocharger and maintain speed. Within a calibrated range during the closed throttle event, or upon a wide open throttle command, the bypass valve will then close to optimize turbocharger response.

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

  1. The throttle position
  2. The engine speed
  3. Intake Air (Boost) Pressure and Temperature Sensor
  4. Barometric Pressure (BARO)
  1. DTC P0101, P0111, P0112, P0113, or P0114 is not set.
  2. The boost pressure versus BARO ratio is between 1.1-3.2.
  3. The charge air bypass valve has been commanded ON for greater than 1 s immediately after an abrupt closed throttle has occurred and the resulting pressure ratio across the turbo exceeds the calibrated pressure ratio limit.
  4. The engine is running.
  5. The ignition voltage is between 10-18 V.
  6. The ECM has commanded the bypass valve.
  7. The intake air temperature is greater than 15°C (59°F).
  8. The DTCs run continuously when the above conditions are met.

The ECM detects that the bypass valve is stuck in the closed position. The ECM by comparing the measured MAF to the modeled MAF has detected a series of pulsations in the induction system that exceed a calibrated threshold.

DTC P2261 is a Type B DTC.

DTC P2261 is a Type B DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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. DTCs P0033, P0034, or P0035 should not set. If any of the DTCs are set, refer to «DTC P0033-P0035»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p0008-to-dtc-p0118) for further diagnosis.
  2. Ignition ON, command the Turbocharger Bypass Solenoid Valve between Inactive and Active with a scan tool. An audible click should be heard.
  3. Engine running, command the Turbocharger Bypass Solenoid Valve between Inactive and Active with a scan tool while observing the following control circuit status parameters: Turbocharger Bypass Solenoid Valve Control Circuit High Voltage Test Status Turbocharger Bypass Solenoid Valve Control Circuit Open Test Status Turbocharger Bypass Solenoid Valve Control Circuit Low Voltage Test Status The parameters should alternate between OK and Not Run with each change in command.
  4. Engine idling, rapidly depress the accelerator pedal from the rest position to the wide open throttle (WOT) position and release pedal. A valve that is stuck shut will generate an unusual pulsating noise. Compare to similar vehicle. There should not be any unusual noise. If there is unusual noise, refer to «Turbocharger Cleaning and Inspection»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-1-of-5__turbocharger-cleaning-and-inspection) .
  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. Inspect for any damage, restrictions, improper routing or connecting of the vacuum hoses on the charge air bypass solenoid valve and the charge air bypass valve. If a condition is found, repair as necessary.
  2. Clear the DTC and operate the vehicle within the Conditions for Running the DTC. If the DTC cannot be cleared or continues to reset, replace the charge air bypass valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turbocharger Disassemble»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-repair-instructions-off-vehicle-1-of-5__turbocharger-disassemble)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range. The ECM test for the following conditions

  1. The ECM monitors the HO2S voltage to determine if the signal voltage goes above a predetermined threshold within a certain amount of time. If the ECM determines that the signal voltage remains below a threshold, the ECM will command the fuel system rich to determine if the HO2S signal voltage can be forced above the threshold within a certain amount of time.
  2. The ECM monitors the HO2S voltage during power enrichment to ensure that the signal voltage goes above a predetermined threshold during power enrichment.
  1. Before the ECM can report DTC P2270 failed, DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P0443, P0458, and P0459 must run and pass.
  2. DTC P0461, P0462, P0463, P2066, P2067, or P2068 is not set.
  3. The engine is operating.
  4. The ignition voltage is greater than 10 V.
  5. The rear HO2S are at operating temperature for greater than 10 s.
  6. The long term fuel control is enabled.
  7. The mass air flow sensor is greater than 10 g/s.
  8. The MAF sensor is between 6-33 g/s for greater than 3 s during the intrusive test.
  9. DTC P2270 runs continuously when the above conditions are met for approximately 10 min when the fuel level is greater than 12 %.
  10. DTC P2270 runs continuously when the above conditions are met for approximately 20 min when the fuel level is less 12 %.

The ECM detects that the rear HO2S voltage is less than 650 mV for greater than 100 s, then an intrusive test is performed. The ECM will enrich the fuel mixture up to 30 % and then wait for 10 s at 30 %. The ECM detects that the HO2S voltage is less than 650 mV during the intrusive test for greater than 4 s or for a cumulative of 30 s, the DTC sets.

DTC P2270 is a Type B DTC.

DTC P2270 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0137, P0138, or P0140 is not set. If any of the listed DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Operate the engine above 1,200 RPM for 30 s, observe the HO2S 2 voltage parameter. The reading should fluctuate above and below the range of 350-550 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. Engine operating, move the related HO2S harness between the B52 HO2S harness connector and the K20 engine control module (ECM) while monitoring the HO2S 2 voltage parameter. Verify that the HO2S 2 parameter does not change abruptly while moving the related harnesses. If the HO2S parameter does change abruptly while moving the related harnesses repair the circuit as necessary.
  2. Ignition OFF, disconnect the harness connector at the B52 HO2S 2.
  3. Ignition ON, verify that the HO2S 2 parameter is between 350-500 mV. If less than the specified range, test the signal circuit terminal 4 for a short to ground. If the circuit/connections test normal, replace the K20 ECM.
  4. Verify that none of the following conditions exist: Lean fuel injectors - Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Water intrusion in the HO2S harness connector Low fuel system pressure - Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . The vacuum hoses for splits, kinks, and proper connection The air intake system after the mass air flow sensor for vacuum leaks Exhaust system leaks Contaminated HO2S - Silicon An engine mechanical condition - Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . If you find any of the above conditions, repair as necessary.
  5. If all circuits/connections test normal, replace the B52 HO2S 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Sensor 2 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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, 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
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal0.00 VApproximately 1.27 VApproximately 1.27 V
HO2S Low Signal0.00 VApproximately 1.27 VApproximately 1.27 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 0-1,275 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.

  1. DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.
  2. The ignition voltage is between 10-32 V.
  3. The engine speed is between 1,225-2,100 RPM.
  4. The mass air flow (MAF) is between 4-13 g/s.
  5. The vehicle speed is between 64-125 km/h (40-78 mph).
  6. The fuel level is greater than 10 %.
  7. The fuel system is in Closed Loop.
  8. The predicted catalytic converter temperature is between 615-980°C (1,139-1,796°F).
  9. The HO2S is ON for more than 180 s.
  10. The DTCs run once per ignition cycle when the above conditions are met.

P2270

The ECM does not detect a HO2S voltage greater than 800 mV before accumulated mass air flow exceeds 62 grams.

P2272

The ECM does not detect a HO2S voltage greater than 800 mV before the accumulated mass air flow exceeds 62 grams.

DTCs P2270 and P2272 are Type B DTCs.

DTCs P2270 and P2272 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__heated-oxygen-sensor-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 B52 HO2S heater DTCs are set. If a B52 HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Engine running, observe the appropriate scan tool B52 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 1.27 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. If all circuits test normal, test or replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  3. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range. The ECM test for the following conditions

  1. The ECM monitors the HO2S voltage to determine if the signal voltage goes below a predetermined threshold within a certain amount of time. If the ECM determines that the signal voltage remains above the threshold, the ECM will command the fuel system lean to determine if the HO2S signal voltage can be forced below the threshold within a certain amount of time.
  2. The ECM monitors the HO2S voltage during fuel cut-off to determine if the signal voltage is greater than a predetermined threshold.
  1. Before the ECM can report DTC P2270 failed, DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P0443, P0458, and P0459 must run and pass.
  2. DTC P0461, P0462, P0463, P2066, P2067, or P2068 is not set.
  3. The engine is operating.
  4. The ignition voltage is greater than 10 V.
  5. The rear HO2S are at operating temperature for greater than 10 s.
  6. The fuel injectors are enabled.
  7. The long term fuel control is enabled.
  8. The mass air flow sensor is greater than 10 g/s.
  9. The MAF sensor is between 6-33 g/s for greater than 3 s during the intrusive test.
  10. The accumulated air flow into the engine is greater than 15 g during the fuel cut-off event.
  11. DTC P2271 runs continuously when the above conditions are met.

The ECM detects that the rear HO2S voltage is greater than 650 mV for greater than 100 s, then an intrusive test is performed. The ECM will lean the fuel mixture up to -7 % and then wait for 10 s at -7 %. If the ECM detects that the HO2S voltage is still greater than 650 mV, the ECM then tests the HO2S at the next decel fuel cut-off. If the ECM detects the HO2S voltage is greater than 200 mV after 4 s or for a cumulative of 30 s in decel fuel cut-off, the DTC sets.

DTC P2271 is a Type B DTC.

DTC P2271 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0137, P0138, or P0140 is not set. If any of the listed DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Operate the engine above 1,200 RPM for 30 s, observe the HO2S 2 voltage parameter. The reading should fluctuate above and below the range of 350-550 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. Engine operating, move the related HO2S harness between the B52 HO2S harness connector and the K20 ECM while monitoring the HO2S 2 voltage parameter. Verify that the HO2S 2 parameter does not change abruptly while moving the related harnesses. If the HO2S parameter does change abruptly while moving the related harnesses, repair the circuit as necessary.
  2. Ignition OFF, disconnect the harness connector at the B52 HO2S 2.
  3. Ignition ON, verify that the HO2S parameter is between 350-500 mV. If greater than 500 mV, test the signal circuit terminal 4 for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
  4. Verify that none of the following conditions exist: Rich fuel injectors - Refer to «Fuel Injector Solenoid Coil Test (LF1, LFW)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Water intrusion in the HO2S harness connector High fuel system pressure - Refer to «Fuel System Diagnosis (LF1 China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Fuel System Diagnosis (LF1 Except China)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated - Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-symptom-troubleshooting-and-diagnosis) . A collapsed air intake duct A restricted air filter element Exhaust system restrictions Excessive fuel in the crankcase An engine mechanical condition - Refer to «Symptoms - Engine Mechanical»(/cadillac/srx/ii-2009-2012/remont/mechanical/#engine-mechanical-28l-or-30l-diagnostic-information-and-procedures) . If you find any of the above conditions, repair as necessary.
  5. If all circuits/connections test normal, replace the B52 HO2S 2.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Control Module References»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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, 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
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal0.00 VApproximately 1.27 VApproximately 1.27 V
HO2S Low Signal0.00 VApproximately 1.27 VApproximately 1.27 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 0-1,275 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.

  1. Before the ECM can report DTC P2271, or P2273 failed, DTCs P013A, P013C, P013E, P014A, P2270, and P2272 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 1,225-2,100 RPM.
  5. The mass air flow (MAF) is between 4-13 g/s.
  6. The vehicle speed is between 64-125 km/h (40-78 mph).
  7. The fuel level is greater than 10 %.
  8. The fuel system is in Closed Loop.
  9. The predicted catalytic converter temperature is between 615-980°C (1,139-1,796°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.

P2271

The ECM does not detect an HO2S voltage less than 100 mV before accumulated mass air flow exceeds 36 grams.

P2273

The ECM does not detect an HO2S voltage less than 100 mV before the accumulated mass air flow exceeds 36 grams.

DTCs P2271 or P2273 are Type B DTCs.

DTCs P2271 or P2273 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__heated-oxygen-sensor-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 B52 HO2S heater DTCs are set. If a B52 HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. Engine running, observe the appropriate scan tool B52 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 1.27 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. If all circuits test normal, test or replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  3. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/srx/ii-2009-2012/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»(/cadillac/srx/ii-2009-2012/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 ReferenceP0237, P0452, P0522, P0642, P159F, P15A1, P2432P0522, P2432P0236, P0643, P15A0, P2433*P2431
Secondary Air Injection Pressure Sensor SignalP2432P2432P2433*P2431
Low ReferenceP2433P2431
*Internal ECM or sensor damage may occur if the circuit is shorted to B+.

The secondary air injection system aids in the reduction of hydrocarbon emissions during a cold start. The electric air pump forces fresh air into the exhaust stream in order to accelerate the catalyst operation. A secondary air injection pressure sensor is used to monitor the air flow from the secondary air injection pump. The engine control module (ECM) supplies voltage to the 5 V reference circuit and provides a ground for the low reference circuit. The sensor provides a signal voltage to the ECM relative to the pressure changes within the secondary air injection system.

P2431

  1. DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P050C, P2227, P2228, or P2229 is not set.
  2. The secondary air injection system has been commanded ON and OFF during the ignition cycle.
  3. Battery voltage is between 10-18 V.
  4. Engine speed is 680-3,500 RPM.
  5. Intake air temperature is between -12 to +80°C (10.4-176°F).
  6. Engine coolant temperature is between -10.5 to +69.8°C (13-158°F).
  7. Mass airflow is less than 100 g/s.
  8. Catalyst heating is active.
  9. Current altitude is less than 3,000 m (9,843 ft).
  10. The difference between intake air temp and engine coolant start temp is less than 15°C (59°F).
  11. The DTC runs once per ignition cycle when the above conditions exist.

P2432 or P2433

  1. The ignition is ON, or the engine is operating.
  2. The DTCs run continuously when the above condition exists for greater than 1 s.
  1. The ECM detects that the secondary air injection pressure sensor is 5 kPa (0.7 psi) less than the BARO sensor when the secondary air injection pump is commanded ON. OR
  2. The ECM detects that the secondary air injection pressure sensor is 5 kPa (0.7 psi) greater than the BARO sensor when the secondary air injection pump is commanded OFF.

P2432

The ECM detects that the secondary air injection pressure sensor signal is less than 0.5 V for greater than 1 s.

The ECM detects that the secondary air injection pressure sensor signal is greater than 4.5 V for greater than 1 s.

DTCs P2431, P2432 and P2433 are Type B DTCs.

DTCs P2431, P2432 and P2433 are Type B DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/cadillac/srx/ii-2009-2012/remont/body-electrical/#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 diagnostic trouble code (DTC) information with a scan tool. Verify that DTCs P0641, P0642, P0643, P2227, P2228, or P2229 are not set. If any of the above DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/ii-2009-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Observe the scan tool Secondary Air Injection Pressure Sensor voltage parameter. The reading should be between 1.0-4.0 V.
  3. Compare the scan tool BARO pressure parameter to the «Altitude Versus Barometric Pressure»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-specifications__altitude-versus-barometric-pressure) table. The BARO should be within the specified range displayed in the table for the specific altitude. If not within the specified range, refer to «DTC P2227, P2228, or P2229 (LAU)»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-dtc-p1516-to-dtc-p2433) for further diagnosis.
  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 B157 secondary air injection 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 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 Secondary Air Injection Pressure Sensor voltage parameter is less than 0.5 V. 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 Secondary Air Injection Pressure Sensor voltage parameter is greater than 4.8 V. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, test or replace the B157 secondary air injection pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Secondary Injection Shutoff Valve Pressure Sensor Replacement»(/cadillac/srx/ii-2009-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-28l-30l-repair-instructions)
  2. «Control Module References»(/cadillac/srx/ii-2009-2012/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics (LF1)
• Component Connector End Views
• Throttle Actuator Control (TAC) 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
• Throttle Body Assembly Replacement (LF1)
• Engine Control Module Description
• Power Distribution Schematics
• Electrical Center Identification Views
• Relay Replacement (Attached to Wire Harness)
• Fuel Injector Solenoid Coil Test (LAU)
• Road Test Warning
• Exhaust Leakage
• DTC P0641, P0651, P0697, or P06A3 (LF1)
• Altitude Versus Barometric Pressure
• DTC P0101 (LAU)
• Fuel System Cleaning
• Symptoms - Engine Exhaust
• Symptoms - Engine Mechanical
• Turbocharger System Description
• Turbocharger Cleaning and Inspection
• Turbocharger Disassemble
• Heated Oxygen Sensor Wiring Repairs
• Heated Oxygen Sensor Resistance Learn Reset Caution
• Secondary Air Injection System Description
• Diagnostic Aids

More articles — Engine Performance