Engine Controls - 3.6l - Diagnosis (DTC p1551 - p2189) Cadillac CTS I

Circuit 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. If the ECM detects that the throttle position is NOT within a predetermined range when commanded to the rest position, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC.

DTC P1551 Throttle Valve Rest Position Not Reached During Learn

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 5-60°C (41-140°F).
4. The intake air temperature (IAT) is 5-60°C (41-140°F).
5. The ignition 1 voltage is more than 10 volts.
6. The accelerator pedal position (APP) is less than 15 percent.
7. DTC P1551 runs when the throttle actuator control motor is deactivated.

Conditions for Setting the DTC

The ECM detects the TP sensor angle is less than 1.8 percent or more than 13.0 percent when the throttle actuator control motor is deactivated.

Action Taken When the DTC Sets

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. Operating the throttle valve with the Throttle Position control function of the scan tool may cause additional DTCs to set. DO NOT attempt to diagnose DTCs set during this function.
3. 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.
4. Inspect for a condition in which the throttle valve may have been held open.
5. Inspect for conditions in which ice may have formed in the throttle bore.
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

Test Description

The number below refers to the step number on the diagnostic table.

1. 5: The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 3-5 percent. This is referred to as the rest position. The throttle valve should not be completely closed, nor should they be open any more than the specified 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. Replace the throttle body if any of these conditions are found. The throttle valve is spring loaded in a slightly open position and should move in either direction without binding. The throttle valve should always be under spring pressure.

DTC P1551 Throttle Valve Rest Position Not Reached During Learn

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio. If there is an internal ECM condition with the integrated circuits for the heated oxygen sensor, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P167A Control Module HO2S Bank 1 Sensor 1 System Performance

1. The engine is operating.
2. The ignition 1 voltage is between 10.7-18 volts.
3. DTC P167A runs continuously once the above conditions are met.

There is an internal ECM condition with the integrated circuits for HO2S bank 1 sensor 1 for more than 10 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

DTC P167A

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio. If there is an internal ECM condition with the integrated circuits for the heated oxygen sensor, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P167B Control Module HO2S Bank 2 Sensor 1 System Performance

1. The engine is operating.
2. The ignition 1 voltage is between 10.7-18 volts.
3. DTC P167B runs continuously once the above conditions are met.

There is an internal ECM condition with the integrated circuits for HO2S bank 2 sensor 1 for more than 10 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

DTC P167B

This diagnostic trouble code (DTC) may set if there is an engine torque limitation caused by requested torque higher than the maximum allowable torque.

This diagnostic procedure supports the following DTC

DTC P1845 Torque Limit Management

The engine speed is more than 40 RPM.

The engine torque output exceeds a maximum allowable torque for 10 minutes.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

The number below refers to the step number on the diagnostic table.

1. 4: A mechanical condition can cause this DTC to set. Inspect accessory drive components for a condition that could cause excessive drag on the engine.

DTC P1845 Torque Limit Management

An intake manifold runner control (IMRC) valve is used to change the intake manifold plenum configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum. When the IMRC valve is closed, the intake manifold is configured to 2 smaller plenums. The IMRC valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied directly to the IMRC solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is within a predetermined range when the circuit is commanded OFF, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2008 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit

1. The engine speed is more than 80 RPM.
2. The ignition 1 voltage is between 10-18 volts.
3. The ECM has commanded the IMRC solenoid ON and OFF at least once during the ignition cycle.
4. DTC P2008 runs continuously once the above conditions are met.

1. The ECM detects the control circuit voltage for the IMRC solenoid is between 2.6-4.6 volts when the driver is commanded OFF.
2. The condition exists for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The output driver module (ODM) information is in the ODM data list.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen for an audible click when the IMRC solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 4: This step tests the ignition 1 voltage circuit to the IMRC solenoid.
3. 5: This step tests the control modules ability to supply a ground to the IMRC solenoid.
4. 6: This step tests the feedback voltage from the ECM. If a voltage is not available, this indicates an internal ECM condition.

DTC P2008 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit

An intake manifold runner control (IMRC) valve is used to change the intake manifold plenum configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum. When the IMRC valve is closed, the intake manifold is configured to 2 smaller plenums. The IMRC valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied directly to the IMRC solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is less than a predetermined value when the circuit is commanded OFF, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2009 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit Low Voltage

1. The engine speed is more than 80 RPM.
2. The ignition 1 voltage is between 10-18 volts.
3. The ECM has commanded the IMRC solenoid ON and OFF at least once during the ignition cycle.
4. DTC P2009 runs continuously once the above conditions are met.

1. The ECM detects the control circuit voltage for the IMRC solenoid is less than 2.6 volts when the driver is commanded OFF.
2. The condition exists for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The output driver module (ODM) information is in the ODM data list.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen for an audible click when the IMRC solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 5: This step tests the feedback voltage from the ECM. If a voltage is not available, this indicates an internal ECM condition.
3. 6: This step tests the ignition 1 voltage circuit to the EVAP canister purge valve.

DTC P2009 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit Low Voltage

An intake manifold runner control (IMRC) valve is used to change the intake manifold plenum configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum. When the IMRC valve is closed, the intake manifold is configured to 2 smaller plenums. The IMRC valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied directly to the IMRC solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is more than a predetermined value when the circuit is commanded ON, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2010 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit High Voltage

1. The engine speed is more than 80 RPM.
2. The ignition 1 voltage is between 10-18 volts.
3. The ECM has commanded the IMRC solenoid ON and OFF at least once during the ignition cycle.
4. DTC P2010 runs continuously once the above conditions are met.

1. The ECM detects the control circuit voltage for the IMRC solenoid is more than 4.6 volts when the driver is commanded ON.
2. The condition exists for less than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The output driver module (ODM) information is in the ODM data list.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen for an audible click when the IMRC solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 4: This step tests for voltage at the IMRC solenoid.

DTC P2010 Intake Manifold Runner Control (IMRC) Solenoid Control Circuit High Voltage

The camshaft position (CMP) actuator solenoid is pulse width modulated (PWM). The engine control module (ECM) controls the CMP actuator solenoid duty cycle by controlling the amount of solenoid ON time.

Ignition voltage is supplied directly to the CMP actuator solenoid. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is less than a predetermined value when the circuit is commanded OFF, this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P2088 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 1
2. DTC P2090 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 1
3. DTC P2092 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 2
4. DTC P2094 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 2

1. The engine speed is more than 80 RPM.
2. The ignition 1 voltage is between 10-18 volts.
3. The ECM has commanded the CMP actuator solenoid ON and OFF at least once during the ignition cycle.
4. DTC P2088, P2090, P2092, and P2094 runs continuously once the above conditions are met for more than 1 second.

1. The ECM detects a short to ground in the CMP actuator solenoid circuits.
2. The condition exists for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The output driver module (ODM) information is in the ODM data list.
4. If the ignition 1 voltage circuit is shorted to ground, other component DTCs will set.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if the condition exists. The engine speed must be increased to enable the CMP actuator solenoids. The DTC will not set unless the solenoid is commanded ON and OFF at least once during the ignition cycle.
2. 5: This step verifies that the ECM is providing a ground to the CMP actuator solenoid.

DTC P2088, P2090, P2092, or P2094

The camshaft position (CMP) actuator solenoid is pulse width modulated (PWM). The engine control module (ECM) controls the CMP actuator solenoid duty cycle by controlling the amount of solenoid ON time.

Ignition voltage is supplied directly to the CMP actuator solenoid. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is more than a predetermined value when the circuit is commanded ON, this DTC sets.

This diagnostic procedure supports the following DTCs

1. DTC P2089 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage Bank 1
2. DTC P2091 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage Bank 1
3. DTC P2093 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage Bank 2
4. DTC P2095 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage Bank 2

1. The engine speed is more than 80 RPM.
2. The ignition 1 voltage is between 10-18 volts.
3. DTC P2089, P2091, P2093, and P2095 runs continuously once the above conditions are met for more than 1 second.

1. The ECM detects a short to voltage in the CMP actuator solenoid circuits.
2. The condition exists for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The output driver module (ODM) information is in the ODM data list.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if the condition exists.
2. 4: This step verifies that the ECM is providing a ground to the CMP actuator solenoid.

DTC P2089, P2091, P2093, or P2095

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.

Fuel Trim Biasing is used by the ECM to keep the post catalyst HO2S voltage within a range of 580-665 mV as possible. 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. If the ECM detects that the fuel trim bias is commanded lean for more than a calibrated amount, DTC P2096 or P2098 set.

This diagnostic procedure supports the following DTCs

1. DTC P2096 Post Catalyst Fuel Trim System Low Limit Bank 1
2. DTC P2098 Post Catalyst Fuel Trim System Low Limit Bank 2

1. Before the ECM can report DTC P2096 or P2098 failed, DTCs P0030, P0031, P0032, P0041, P0050, P0051, P0052, P0101, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0160, P0161, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2273, P2626, and P2629 must run and pass.
2. The engine is operating.
3. The post catalyst fuel trim control is enabled.
4. The front and rear HO2S are in closed loop.
5. DTC P2096 and P2098 run continuously once the above conditions are met for more than 50 seconds.

The post catalyst fuel trim correction factor is biased lean by more than 3 percent of the HO2S lambda value.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if a condition exists.
2. 5: This step is testing for a rear HO2S sensor circuit condition. A circuit condition sets this DTC.
3. 8: This step inspects for the rear sensors being connected to the correct bank of the engine. This condition causes this DTC to set.
4. 9: This step is testing for an intermittent circuit condition. Thoroughly inspect the HO2S circuits for an intermittent circuit condition.
5. 10: This step is testing for an intermittent circuit condition. Thoroughly inspect the HO2S circuits for an intermittent circuit condition.

P2096 or P2098 Post Catalyst Fuel Trim System Low Limit Bank 1 or 2

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.

Fuel Trim Biasing is used by the ECM to keep the post catalyst HO2S voltage within a range of 580-665 mV as possible. 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. If the ECM detects that the fuel trim bias is commanded rich for more than a calibrated amount, DTC P2097 or P2099 set.

This diagnostic procedure supports the following DTCs

1. DTC P2097 Post Catalyst Fuel Trim System High Limit Bank 1
2. DTC P2099 Post Catalyst Fuel Trim System High Limit Bank 2

1. Before the ECM can report DTC P2097 or P2099 failed, DTCs P0030, P0031, P0032, P0041, P0050, P0051, P0052, P0101, P0131, P0132, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0160, P0161, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2273, P2626, and P2629 must run and pass.
2. The engine is operating.
3. The post catalyst fuel trim control is enabled.
4. The front and rear HO2S are in closed loop.
5. DTC P2097 and P2099 run continuously once the above conditions are met for more than 50 seconds.

The post catalyst fuel trim correction factor is biased rich by more than -3 percent of the HO2S lambda value.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if a condition exists.
2. 5: This step is testing for a rear HO2S sensor circuit condition. A circuit condition sets this DTC.
3. 8: This step inspects for the rear sensors being connected to the correct bank of the engine. This condition causes this DTC to set.
4. 9: This step is testing for an intermittent circuit condition. Thoroughly inspect the HO2S circuits for an intermittent circuit condition.
5. 10: This step is testing for an intermittent circuit condition. Thoroughly inspect the HO2S circuits for an intermittent circuit condition.

P2097 or P2099 Post Catalyst Fuel Trim System High Limit Bank 1 or 2

The engine control module (ECM) opens the throttle valve by applying a pulse width modulated voltage to the throttle actuator control motor. The ECM reverses the polarity on the throttle actuator control motor control circuits in order to close the throttle valve. The ECM increases the pulse width as necessary to open the throttle valve. The ECM monitors throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position. If the ECM detects that the output driver for the throttle actuator control (TAC) motor does not deactivate when commanded OFF, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2100 Throttle Actuator Control (TAC) Motor Control Circuit

1. Before the ECM can report DTC P2100 failed, DTC P2101 must run and pass.
2. The ignition is ON or the engine is operating.
3. DTC P2100 runs continuously once the above conditions are met for more than 1 second.

The ECM detects the output driver for the TAC motor does not deactivate when commanded OFF.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. 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. Observe the Freeze Frame/Failure Records.
4. The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 3-5 percent. This is referred to as the rest position.
5. The throttle valve should not be completely closed or open any more than a specified amount.
6. The throttle valve should move open and to the closed position without binding under the normal spring pressure.
7. The throttle should NOT be free to move open or closed WITHOUT spring pressure.
8. The scan tool has the ability to operate the throttle control system using the TP function located in the TAC System menu. This function operates the throttle valve through the entire range in order to determine if the TAC system operates correctly.
9. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if the condition exists. A TP sensor DTC may cause this DTC to set.
2. 3: Depending on the condition, DTC P0638, P2100, P2101, and/or P2119 may set individually or together.
3. 8: When the ignition is turn ON, the ECM operates the TAC motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.

P2100 Throttle Actuator Control (TAC) Motor Control Circuit

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the throttle actuator control motor. The ECM monitors the actual throttle valve position using throttle position (TP) sensors 1 and 2. The ECM compares this actual position to the commanded throttle position. If the difference between the actual position and the commanded position is more than a predetermined value, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2101 Control Module Throttle Actuator Position Performance

1. The ignition is ON.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P2101 runs continuously once the above conditions are met for more than 1 second.

The ECM detects that the difference between the commanded and the actual throttle plate position is more than 10 percent.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. 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. Observe the Freeze Frame/Failure Records.
4. The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 3-5 percent. This is referred to as the rest position.
5. The throttle valve should not be completely closed or open any more than a specified amount.
6. The throttle valve should move open and to the closed position without binding under the normal spring pressure.
7. The throttle should NOT be free to move open or closed WITHOUT spring pressure.
8. The scan tool has the ability to operate the throttle control system using the TP function located in the TAC System menu. This function operates the throttle valve through the entire range in order to determine if the throttle actuator control (TAC) system operates correctly.
9. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if the condition exists. A TP sensor DTC may cause this DTC to set.
2. 3: Depending on the condition, DTC P0638, P2100, P2101, and/or P2119 may set individually or together.
3. 7: An incorrect idle learned position may cause this DTC to set. If the throttle value was restricted the ECM could learn the incorrect position. For example, ice may form in the throttle body causing the throttle valve restriction. Observe the freeze frame/failure records to determine when the condition occurred.
4. 9: When the ignition is turn ON, the ECM operates the throttle actuator control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.

P2101 Control Module Throttle Actuator Position Performance

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. If the ECM detects the incorrect voltage level at the ignition 1 voltage supply circuits, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2105 Throttle Actuator Control (TAC) System - Forced Engine Shut down

1. The ECM power down process in the last drive cycle completely finished.
2. DTC P2105 runs continuously once the above condition is met.

The ECM detects the incorrect voltage level at the ignition 1 voltage supply circuits.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

The numbers below refer to the step numbers on the diagnostic table.

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

DTC P2105

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 (TP) sensor 1 and 2. The ECM amplifies the TP sensor 1 signal in order to obtain a more accurate signal. The ECM monitors the TP sensor 1 amplification output whenever the ignition is ON and a closed throttle test is performed. If the ECM detects the internal TP sensor 1 amplification output does not correlate with the TP sensor 1 signal voltage, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2107 Throttle Actuator Control (TAC) Module Internal Circuit

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 5-60°C (41-140°F).
4. The intake air temperature (IAT) is 5-60°C (41-140°F).
5. The ignition 1 voltage is more than 10 volts.
6. The accelerator pedal position (APP) is less than 15 percent.
7. The ECM is performing the closed throttle test with the ignition ON and the engine OFF.
8. DTC P2107 runs once the above conditions are met during the TAC system initialization.

The ECM detects the internal TP sensor 1 amplification output does not correlate with the TP sensor 1 signal voltage.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

P2107 Throttle Actuator Control (TAC) Module Internal Circuit

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 (TP) sensor 1 and 2. If the ECM detects the throttle valve did not return to the rest position within a calibrated time, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2119 Throttle Closed Position Performance

1. The ignition is ON.
2. The vehicle speed is 0 km/h (0 mph).
3. The engine speed is less than 40 RPM.
4. The engine coolant temperature (ECT) is 5-60°C (41-140°F).
5. The intake air temperature (IAT) is 5-60°C (41-140°F).
6. The ignition 1 voltage is more than 10 volts.
7. The accelerator pedal position (APP) is less than 15 percent.
8. DTC P2119 runs once per ignition cycle when the above conditions are met for more than 1.0 second.

The ECM determines that the throttle valve did not return to the rest position within 720 milliseconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. 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. Observe the Freeze Frame/Failure Records.
4. The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 3-5 percent. This is referred to as the rest position.
5. The throttle valve should not be completely closed or open any more than a specified amount.
6. The throttle valve should move open and to the closed position without binding under the normal spring pressure.
7. The throttle should NOT be free to move open or closed WITHOUT spring pressure.
8. The scan tool has the ability to operate the throttle control system using the TP function located in the TAC System menu. This function operates the throttle valve through the entire range in order to determine if the TAC system operates correctly.
9. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if the condition exists. A TP sensor DTC may cause this DTC to set.
2. 3: Depending on the condition, DTC P0638, P2100, P2101, and/or P2119 may set individually or together.
3. 8: When the ignition is turned ON, the ECM operates the TAC motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.

P2119 Throttle Closed Position Performance

The accelerator pedal assembly contains 2 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.

If the ECM detects that the APP sensor 1 signal voltage is too low, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage

1. The ignition is ON or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P2122 runs continuously once the above conditions are met.

The APP sensor 1 voltage is less than 0.84 volts for more than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If DTCs P0700, P2122, P2128, and P2138 are set together in various combinations, inspect the APP sensor 1 and 2 signal circuits for being shorted together.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the internal circuits of the APP sensor 1 throughout its range of motion. If this DTC sets when slowly moving the pedal from the rest position to wide open throttle (WOT), replace the APP assembly for an internal fault.
2. 5: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the APP sensor 1. If the amperage on the 5-volt reference circuit is less than 80 mA, there is a condition with the 5-volt reference circuit or the ECM.
3. 7: This step tests for high resistance in the low reference circuit of the APP sensor 1. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

DTC P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage

The accelerator pedal assembly contains 2 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.

If the ECM detects that the APP 1 signal voltage is too high, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

1. The ignition is ON or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P2123 runs continuously once the above conditions are met.

The APP sensor 1 voltage is more than 4.82 volts for more than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the internal circuits of the APP sensor 1 throughout its range of motion. If this DTC sets when slowly moving the pedal from the rest position to wide open throttle (WOT), replace the APP assembly for an internal fault.
2. 7: This step tests for high resistance in the low reference circuit of the APP sensor 1. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

DTC P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

The accelerator pedal assembly contains 2 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.

If the ECM detects that the APP sensor 2 signal voltage is too low, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2127 Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage

1. The ignition is ON or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P2127 runs continuously once the above conditions are met.

The APP sensor 2 voltage is less than 0.66 volts for more than 1 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the internal circuits of the APP sensor 2 throughout its range of motion. If this DTC sets when slowly moving the pedal from the rest position to wide open throttle (WOT), replace the APP assembly for an internal fault.
2. 5: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the APP sensor 2. If the amperage on the 5-volt reference circuit is less than 50 mA, there is a condition with the 5-volt reference circuit or the ECM.
3. 7: This step tests for high resistance in the low reference circuit of the APP sensor 2. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

DTC P2127 Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage

The accelerator pedal assembly contains 2 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.

If the ECM detects that the APP sensor 2 signal voltage is too high, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage

1. The ignition is ON or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P2128 runs continuously once the above conditions are met.

The APP sensor 2 voltage is more than 4.82 volts for more than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If DTCs P0700, P2122, P2128, and P2138 are set together in various combinations, inspect the APP sensor 1 and 2 signal circuits for being shorted together.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 3: This step tests the internal circuits of the APP sensor 2 throughout its range of motion. If this DTC sets when slowly moving the pedal from the rest position to wide open throttle (WOT), replace the APP assembly for an internal fault.
2. 7: This step tests for high resistance in the low reference circuit of the APP sensor 2. The ECM must be completely powered down to obtain an accurate resistance reading. It may take up to 30 minutes for the ECM to power down after the ignition key is removed. Removal of the ECM/TCM fuse allows the ECM to power down completely.

P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage

The accelerator pedal assembly contains 2 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 volt at rest to above 4 volts when fully depressed. The APP sensor 2 signal voltage increases as the pedal is depressed, from approximately 0.5 volts at rest to more than 2 volts with the accelerator pedal fully depressed.

If the ECM detects that the difference between APP sensor 1 and 2 signal voltage is more than a predetermined value, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation

1. The battery voltage is more than 7 volts.
2. The ignition is ON or the engine is operating.
3. DTC P2138 run continuously once the above conditions are met for more than 1 second.

This DTC set when one of the following conditions occur

1. The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.21 volts.
2. The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 0.27 volts with a partially pressed pedal.
3. The ECM detects that the voltage difference between APP sensor 1 and 2 is more than 1.07 volts with a fully pressed pedal.
4. The ECM detects that the APP sensor 1 voltage is more then 1.17 when leaving the idle range and the voltage difference between APP sensor 1 and 2 is more than 0.04.
5. The above conditions are met for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. If DTCs P0700, P2122, P2128, and P2138 are set together in various combinations, inspect the APP sensor 1 and 2 signal circuits for being shorted together.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

DTC P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the throttle actuator control motor. The ECM monitors the actual throttle valve position using throttle position (TP) sensor 1 and 2. If the ECM detects that TP sensor 1 and 2 voltages are not within a specified range during the throttle learn procedure or the throttle learn procedure is not learned after an ECM replacement, this DTC sets.

This diagnostic procedure supports the following DTC.

DTC P2176 Minimum Throttle Position Not Learned

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 5-60°C (41-140°F).
4. The intake air temperature (IAT) is between 5-60°C (41-140°F).
5. The accelerator pedal position (APP) sensor angle is less than 14.9 percent.
6. The ignition 1 voltage is more than 10 volts.
7. DTC P2176 run continuously once the above conditions are met for more than 1 second.

The ECM detects that the TP sensor 1 voltage is not between 0.2-0.9 volts during the throttle learn procedure.

OR

The ECM detects that the TP sensor 2 voltage is not between 4.2-4.8 volts during the throttle learn procedure.

OR

The minimum throttle position is not learned after an ECM replacement.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
2. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to «Engine Controls Component Views»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-introduction) .
3. Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore.
4. The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 2-5 percent. This is referred to as the rest position. The throttle valve should not be completely closed, nor should the throttle valve be open any more than the specified amount. The throttle valve should move open and to the closed position without binding under normal spring pressure. The throttle should NOT be free to move open or closed WITHOUT spring pressure. Replace the throttle body if any of these conditions are found.
5. If the conditions for running the DTC are out of range, this DTC will not be able to be cleared until the ECM learns the throttle position.
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The number below refers to the step number on the diagnostic table.

1. 2: A TP sensor DTC may cause this DTC to set.

DTC P2176 Minimum Throttle Position Not Learned

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 oxygen sensors (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. If the ECM detects an excessively lean condition, this DTC sets.

This diagnostic procedure supports the following DTCs.

1. DTC P2177 Fuel Trim System Lean at Cruise or Accel Bank 1
2. DTC P2179 Fuel Trim System Lean at Cruise or Accel Bank 2

1. Before the ECM can report DTC P2177 or P2179 failed, DTCs P0101, P0121, P0122, P0123, P0133, P0153, P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068 must run and pass.
2. The fuel system is in closed loop.
3. The long fuel trim is active.
4. The engine coolant temperature (ECT) is more than 60°C (140°F).
5. The evaporative emission (EVAP) canister purge solenoid valve is not enabled.
6. The intake air temperature (IAT) is less than 60°C (140°F).
7. The fuel level is more than 11.6 percent.
8. The amount of air flow into the engine is more than 7,000 grams.
9. DTC P2177 and P2179 run continuously once the above conditions are met for at least 300 seconds.

1. The Total Fuel Trim Avg. is more than 23 percent.
2. The condition exists for 6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a lean condition.
2. Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if there is a current condition.
2. 4: If DTC P2177 and P2179 is set at the same time, this indicates that both banks of the engine are operating lean. Inspect for items that would cause both banks of the engine to operate lean.
3. 5: Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. 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. 6: A vacuum leak causes DTC P2177 and P2179 to set at the same time. Inspect all areas of the engine for a vacuum leak. Also inspect the PCV valve 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.

DTC P2177 or P2179

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 oxygen sensors (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. If the ECM detects an excessively rich condition, this DTC sets.

This diagnostic procedure supports the following DTCs.

1. DTC P2178 Fuel Trim System Rich at Cruise or Accel Bank 1
2. DTC P2180 Fuel Trim System Rich at Cruise or Accel Bank 2

1. Before the ECM can report DTC P2178 or P2180 failed, DTCs P0101, P0121, P0122, P0123, P0133, P0153, P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068 must run and pass.
2. The fuel system is in closed loop.
3. The long fuel trim is active.
4. The engine coolant temperature (ECT) is more than 60°C (140°F).
5. The evaporative emissions (EVAP) canister purge solenoid valve is not enabled.
6. The intake air temperature (IAT) is less than 60°C (140°F).
7. The fuel level is more than 11.6 percent.
8. The amount of air flow into the engine is more than 7,000 grams.
9. DTC P2178 and P2180 run continuously once the above conditions are met for at least 300 seconds.

1. The Total Fuel Trim Avg. is less than -22 percent.
2. The condition exists for 6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. A fuel delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich condition.
2. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines whether the fault is present.
2. 4: If DTC P2178 and DTC P2180 set at the same time, then both banks of the engine are operating rich. Inspect items that would cause both banks of the engine to operate rich.
3. 5: Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. 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.

DTC P2178 or P2180

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 oxygen sensors (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. If the ECM detects an excessively lean condition, this DTC sets.

This diagnostic procedure supports the following DTCs.

1. DTC P2187 Fuel Trim System Lean at Idle Bank 1
2. DTC P2189 Fuel Trim System Lean at Idle Bank 2

1. Before the ECM can report DTC P2187 or P2189 failed, DTCs P0101, P0121, P0122, P0123, P0133, P0153, P0221, P0222, P0223, P0336, P0338, P0443, P0458, P0459, P0461, P0462, P0463, P2066, P2067, and P2068 must run and pass.
2. The fuel system is in Closed Loop.
3. The long fuel trim is active.
4. The engine coolant temperature (ECT) is more than 60°C (140°F).
5. The evaporative emissions (EVAP) canister purge solenoid valve is not enabled.
6. The intake air temperature (IAT) is less than 60°C (140°F).
7. The fuel level is more than 11.6 percent.
8. The amount of air flow into the engine is more than 7,000 grams.
9. DTC P2187 and P2189 run continuously once the above conditions are met for at least 300 seconds.

1. The Total Fuel Trim Avg. is more than 40 percent.
2. The LT FT Idle/Decel is more than 7 percent.
3. The condition exists for 6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. A fuel delivery condition causes this DTC to set. Thoroughly inspect all items that cause a lean condition.
2. Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-36l-troubleshooting__intermittent-conditions) .

The numbers below refer to the step numbers on the diagnostic table.

1. 2: This step determines if there is a current condition.
2. 4: If DTC P2187 and P2189 is set at the same time, this indicates that both banks of the engine are operating lean. Inspect for items that would cause both banks of the engine to operate lean.
3. 5: Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. 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. 6: A vacuum leak causes DTC P2187 and P2189 to set at the same time. Inspect all areas of the engine for a vacuum leak. Also inspect the positive crankcase ventilation (PCV) valve 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.

DTC P2187 or P2189

See also:
• Intermittent Conditions
• Engine Controls Schematics
• Engine Control Module (ECM) Connector End Views
• Engine Controls Connector End Views
• Diagnostic System Check - Engine Controls
• Diagnostic Trouble Code (DTC) List
• Circuit Testing
• Wiring Repairs
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Symptoms - Engine Exhaust
• DTC P0121
• DTC P0221
• Disengaging Connectors Notice
• Idle Learn Procedure
• Accelerator Pedal Position (APP) Sensor Replacement
• Measuring Voltage Drop
• DTC P0638
• Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool)
• Symptoms - Engine Mechanical
• DTC P2101