Engine Control System - 3.6l (ly7) - DTC p0008 to p0128 Cadillac SRX I

Description

The engine control module (ECM) tests for a misalignment between both camshafts on one bank of the engine and the crankshaft. The misalignment would be at an idler sprocket for bank 1 or at the crankshaft. Once the ECM learns the position of both camshafts on one bank of the engine, the ECM compares the learned values to a reference value. If the ECM detects both learned values for one bank of the engine is exceeding a calibrated threshold in the same direction, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0008 Engine Position System Performance Bank 1

Conditions for Running the DTC

1. DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 are not set.
2. The engine is operating.
3. The ECM has learned the camshaft positions.
4. DTC P0008 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that both camshafts on bank 1 of the engine are mis-aligned with the crankshaft for more than 4 seconds.

Action Taken When the DTC Sets

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.

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. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed secondary timing chain can cause this DTC to set.
2. A single failed camshaft actuator or actuator solenoid will not cause this DTC to set. This diagnostic algorithm is designed to detect an alignment condition between a primary intermediate sprocket and the secondary timing chain, or the alignment between a primary intermediate sprocket and the crankshaft. Either condition would cause the camshaft timing for both cams on one bank to be off an equal number of degrees.
3. The presence of DTCs P0008 and P0009 along with P0016, P0017, P0018, and P0019 indicates a possible condition with the primary timing chain and the alignment between both intermediate sprockets and the crankshaft. Or, the crankshaft reluctor wheel has moved and is no longer referenced to top dead center (TDC).
4. Observing the desired and actual camshaft angle parameters, with a scan tool before a DTC sets, may help to isolate whether a condition is specific to one camshaft, one bank, or caused by a condition with the primary crankshaft timing.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

Test Description

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

1. 5: Inspect the crankshaft for a crankshaft position (CKP) reluctor wheel that has moved in its relationship to TDC on the crankshaft gear.

DTC P0008

The engine control module (ECM) tests for a misalignment between both camshafts on one bank of the engine and the crankshaft. The misalignment would be at an idler sprocket for bank 2 or at the crankshaft. Once the ECM learns the position of both camshafts on one bank of the engine, the ECM compares the learned values to a reference value. If the ECM detects both learned values for one bank of the engine is exceeding a calibrated threshold in the same direction, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0009 Engine Position System Performance Bank 2

1. DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 are not set.
2. The engine is operating.
3. The ECM has learned the camshaft positions.
4. DTC P0009 runs continuously once the above conditions are met.

The ECM detects that both camshafts on bank 2 of the engine are mis-aligned with the crankshaft for more than 4 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. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed secondary timing chain can cause this DTC to set.
2. A single failed camshaft actuator or actuator solenoid will not cause this DTC to set. This diagnostic algorithm is designed to detect an alignment condition between a primary intermediate sprocket and the secondary timing chain, or the alignment between a primary intermediate sprocket and the crankshaft. Either condition would cause the camshaft timing for both cams on one bank to be off an equal number of degrees.
3. The presence of DTCs P0008 and P0009 along with P0016, P0017, P0018, and P0019 indicates a possible condition with the primary timing chain and the alignment between both intermediate sprockets and the crankshaft. Or, the crankshaft reluctor wheel has moved and is no longer referenced to top dead center (TDC).
4. Observing the desired and actual camshaft angle parameters, with a scan tool before a DTC sets, may help to isolate whether a condition is specific to one camshaft, one bank, or caused by a condition with the primary crankshaft timing.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 5: Inspect the crankshaft for a crankshaft position (CKP) reluctor wheel that has moved in its relationship to TDC on the crankshaft gear.

DTC P0009

Circuit Description

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

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 within a predetermined range when the circuit is commanded OFF, this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0010 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 1
2. DTC P0013 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 1
3. DTC P0020 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Bank 2
4. DTC P0023 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit 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. DTCs P0010, P0013, P0020, and P0023 runs continuously once the above conditions are met for more than 1 second.

1. The ECM detects an open in the CMP actuator solenoid circuits when the solenoid is commanded OFF.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
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 ODM information is in the output driver module (ODM) data list.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-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.
3. 7: This step determines if there is an internal condition with the ECM. The CMP actuator control circuit is pulled-up to a voltage within the ECM. The ECM uses this voltage as a feedback circuit. 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 voltage is not within the specified range, there is a condition with the ECM.

DTC P0010, P0013, P0020, or P0023

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

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. If the ECM detects the desired camshaft position and the actual camshaft position angles are not within a calibrated value, this DTC sets.

This diagnostic procedure supports the following DTCs

1. DTC P0011 Intake Camshaft Position (CMP) System Performance Bank 1
2. DTC P0014 Exhaust Camshaft Position (CMP) System Performance Bank 1
3. DTC P0021 Intake Camshaft Position (CMP) System Performance Bank 2
4. DTC P0024 Exhaust Camshaft Position (CMP) System Performance Bank 2

1. Before the ECM can report DTC P0011, P0014, P0021, or P0024 failed, DTCs P0010, P0013, P0020, P0023, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
2. DTCs P0016, P0017, P0018, P0019, P0335, P0336, and P0338 are not set.
3. The engine speed is more than 500 RPM.
4. The engine must accelerate such that the CMP actuator system is commanded from the park position to the phased position. This is considered a cam control cycle. There must be a total of 4-10 cam control cycles for at least 2.5 seconds each in the phased position.
5. The engine is operating for approximately 1.8 seconds.
6. DTCs P0011, P0014, P0021, and P0024 run continuously once the above conditions are met for more than 1.0 second.

1. The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 5.0 degrees. OR
2. The ECM detects the difference between the actual camshaft angle and the locked position angle is more than 1.0 degree.
3. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. The engine oil condition has a major impact on the camshaft actuator system.
4. A low oil level condition may set this DTC. The engine may require an oil change. Inquire with the customer when the last oil change was performed. You may also monitor the Engine Oil Life parameter with a scan tool. Advise the customer an oil change may be required.
5. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft, camshaft actuator, or timing chain can cause this DTC to set.
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step determines if there is a condition with the CMP actuator system.
2. 6: This step is testing the ignition 1 voltage circuit of the CMP actuator solenoid for high resistance. If the voltage at the test lamp probe is not B+, there is a high resistance condition with the circuit.
3. 7: This step is testing the control circuit of the CMP actuator solenoid for high resistance. If the voltage at the test lamp probe is not less than the specified voltage, there is a high resistance condition with the circuit.
4. 11: This step isolates the condition. If the condition follows the CMP actuator solenoid, there is a condition with the solenoid.

DTC P0011, P0014, P0021, or P0024

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

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 ECM compares the camshaft position or the camshaft angle, to the position of the crankshaft. If the ECM detects a deviation between the camshaft position target and the crankshaft position, this DTC sets.

This diagnostic procedure supports the following DTCs

1. DTC P0016 Crankshaft Position (CKP) - Intake Camshaft Position (CMP) Correlation Bank 1
2. DTC P0017 Crankshaft Position (CKP) - Exhaust Camshaft Position (CMP) Correlation Bank 1
3. DTC P0018 Crankshaft Position (CKP) - Intake Camshaft Position (CMP) Correlation Bank 2
4. DTC P0019 Crankshaft Position (CKP) - Exhaust Camshaft Position (CMP) Correlation Bank 2

1. Before the ECM can report DTC P0016, P0017, P0018, or P0019 failed, DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, and P2095 must run and pass.
2. The engine is operating for more than 5 seconds.
3. The engine coolant temperature is between 0-95°C (32-203°F).
4. The calculated engine oil temperature is less than 120°C (248°F).
5. DTC P0016, P0017, P0018, and P0019 run continuously once the above conditions are met for approximately 10 minutes.

1. The ECM detects one of the following conditions: The ECM detects a deviation in the relationship between a camshaft and the crankshaft. A camshaft is too advanced in relationship to the crankshaft. A camshaft is too retarded in relationship to the crankshaft.
2. The condition exists for more than 4 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. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft, camshaft actuator, camshaft sensor, crankshaft sensor, or timing chain can cause this DTC to set.
3. An actuator that is in the full advance or retard position can cause this DTC to set.
4. The presence of DTCs P0008 and P0009 along with P0016, P0017, P0018, and P0019 indicates a possible condition with the primary timing chain and the alignment between both intermediate sprockets and the crankshaft. Or, the crankshaft reluctor wheel has moved and is no longer referenced to top dead center (TDC).
5. Observing the desired and actual camshaft angle parameters, with a scan tool before a DTC sets, may help to isolate whether a condition is specific to one camshaft, one bank, or caused by a condition with the primary crankshaft timing.
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step determines if there is a condition present.
2. 4: The listed DTCs may cause this DTC to set.
3. 5: Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft or timing chain can cause this DTC to set.

DTC P0016, P0017, P0018, or P0019

The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensors rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground, to maintain a desired temperature.

The ECM controls the heater 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 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 DTCs

1. DTC P0030 HO2S Heater Control Circuit Bank 1 Sensor 1
2. DTC P0036 HO2S Heater Control Circuit Bank 1 Sensor 2
3. DTC P0050 HO2S Heater Control Circuit Bank 2 Sensor 1
4. DTC P0056 HO2S Heater Control Circuit Bank 2 Sensor 2

1. The ignition 1 voltage is between 10.5-18 volts.
2. The engine speed is more than 80 RPM.
3. DTC P0030, P0036, P0050, and P0056 runs continuously once the above conditions are met for less than 1 second.

1. The ECM detects an open in the heater circuits of the HO2S when the heater is commanded OFF.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
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 ODM information is in the output driver module (ODM) data list.
4. An open fuse in the HO2S heater circuit may be caused by the heater element in one of the sensors. The condition may not be present until the sensor operates for a period of time. If no fault is present in the heater circuit, monitor the amperage of each heater using the DMM to determine if one of the heater elements is the cause of the open fuse.
5. Inspect the sensor pigtail or the harness for contacting the exhaust system.
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 4: If both DTCs are set for either the front sensors or the rear sensors, the ignition voltage circuit to the heaters may be open. The front sensors are fused separately from the rear sensors.
2. 5: The engine must be running for the ECM to operate the control circuit.
3. 6: The heater control circuit is equipped with a feedback circuit internal to the ECM. This feedback circuit allows the ECM to determine if the heater control circuit is open, shorted to ground, or shorted to a voltage. If the voltage is not within the specified range, there is a condition with the control circuit.

DTC P0030, DTC P0036, DTC P0050, or DTC P0056 - HO2S Heater Control Circuit (Open)

The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensors rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground, to maintain a desired temperature.

The ECM controls the heater 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 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 DTCs

1. DTC P0031 HO2S Heater Control Circuit Low Voltage Bank 1 Sensor 1
2. DTC P0037 HO2S Heater Control Circuit Low Voltage Bank 1 Sensor 2
3. DTC P0051 HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 1
4. DTC P0057 HO2S Heater Control Circuit Low Voltage Bank 2 Sensor 2

1. The ignition 1 voltage is between 10.5-18 volts.
2. The engine speed is more than 80 RPM.
3. DTCs P0031, P0037, P0051, and P0057 run continuously once the above conditions are met for less than 1 second.

1. The ECM detects a ground in the heater circuits of the HO2S when the heater is commanded OFF.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
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 ODM information is in the output driver module (ODM) data list.
4. Inspect the sensor pigtail or the harness for contacting the exhaust system.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 4: If both DTCs are set for either the front sensors or the rear sensors, the ignition voltage circuit to the heaters may be open. The front sensors are fused separately from the rear sensors.
2. 5: The heater control circuit is equipped with a feedback voltage. This feedback voltage allows the ECM to determine if the heater control circuit is open, shorted to ground, or shorted to a voltage. If the feedback voltage on the control circuit is not within the specified range, there is a condition internal to the ECM.

DTC P0031, DTC P0037, DTC P0051, or DTC P0057 - HO2S Heater Control Circuit Low Voltage

The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensors rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground, to maintain a desired temperature.

The ECM controls the heater 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 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 P0032 HO2S Heater Control Circuit High Voltage Bank 1 Sensor 1
2. DTC P0038 HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2
3. DTC P0052 HO2S Heater Control Circuit High Voltage Bank 2 Sensor 1
4. DTC P0058 HO2S Heater Control Circuit High Voltage Bank 2 Sensor 2

1. The ignition 1 voltage is between 10.5-18 volts.
2. The engine speed is more than 80 RPM.
3. DTC P0032, P0038, P0052, and P0058 run continuously once the above conditions are met for less than 1 second.

1. The ECM detects a short to voltage in the heater circuits of the HO2S when the heater is commanded ON.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
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 ODM information is in the output driver module (ODM) data list.
4. Inspect the sensor pigtail or the harness for contacting the exhaust system.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 4: The engine must be running for the ECM to operate the control circuit.
2. 6: Inspect the HO2S connector for water intrusion, corrosion, and bent or damaged terminals.
3. 7: Inspect the HO2S connector for water intrusion, corrosion, and bent or damaged terminals.

DTC P0032, DTC P0038, DTC P0052, or DTC P0058 - HO2S Heater Control Circuit High Voltage

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 HO2S, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0053 HO2S Internal Heater Resistance Bank 1 Sensor 1

1. Before the ECM can report DTC P0053 failed, DTCs P0030, P0031, P0032, P0101, P0121, P0122, P0123, P0131, P0132, P0133, P0221, P0222, P0223, P0335, P0336, P0338, P2237, P2243, and P2626 must run and pass.
2. The engine is operating.
3. The ignition 1 voltage is between 10.5-18 volts.
4. DTC P0053 runs continuously once the above conditions are met for 40 seconds.

1. There is an internal ECM condition with the integrated circuits for the HO2S bank 1 sensor 1.
2. The condition exists for more than 4 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 P0053

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 HO2S, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0059 HO2S Internal Heater Resistance Bank 2 Sensor 1

1. Before the ECM can report DTC P0059 failed, DTCs P0050, P0051, P0052, P0101, P0121, P0122, P0123, P0151, P0152, P0153, P0221, P0222, P0223, P0335, P0336, P0338, P2240, P2247, and P2629 must run and pass.
2. The engine is operating.
3. The ignition 1 voltage is between 10.5-18 volts.
4. DTC P0059 runs continuously once the above conditions are met for 40 seconds.

1. There is an internal ECM condition with the integrated circuits for HO2S bank 2 sensor 1.
2. The condition exists for more than 4 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 P0059

The mass air flow (MAF) sensor is located in the air intake duct. The MAF sensor is an airflow meter that measures the amount of air that enters the engine. The MAF sensor uses a hot film that is cooled by air flowing past the sensing film as air enters the engine. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required in order to maintain the hot film at a constant temperature. The engine control module (ECM) uses the MAF sensor in order to provide the correct fuel delivery for all operating conditions. The MAF sensor uses the following circuits in order to operate

1. An ignition 1 voltage circuit
2. A 5-volt reference circuit
3. A low reference circuit
4. A signal circuit

The ECM monitors the following inputs in order to calculate a predicted MAF sensor value

1. The throttle position (TP)
2. The engine speed

The ECM monitors the MAF sensor signal for being stuck in range, for being too low, or for being too high for a given operating condition. If the ECM detects the actual MAF sensor signal is not within a predetermined range of the calculated MAF sensor value, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0101 Mass Air Flow (MAF) Sensor Performance

1. Before the ECM can report DTC P0101 failed, DTCs P0102, P0103, P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, and P0338 must run and pass.
2. DTC P2176 is not set.
3. The engine speed is more than 320 RPM.
4. The MAF sensor signal is more than 11 grams per second.
5. The ignition 1 voltage is more than 10.5 volts.
6. The ECM detects more than 150 revolutions of the crankshaft.
7. DTC P0101 runs continuously once the above conditions are met for more than 2 seconds.

1. The ECM detects that the MAF sensor signal is not within a predetermined range of the calculated MAF value.
2. The condition exists for 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. Any un-metered air that enters the engine may cause this DTC to set.
4. Inspect the throttle plate for sticking, or for deposits on the throttle plate, or in the throttle bore.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 3: A circuit failure may cause this DTC to set. If DTC P0102 or P0103 are set, diagnose DTC P0102 or P0103 first.
2. 6: This step tests for high resistance in the ignition 1 voltage circuit of the MAF sensor. If the DMM does not display near battery voltage there is high resistance in the circuit.
3. 8: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the MAF sensor. If the amperage on the 5-volt reference circuit is less than 80 mA, test the 5-volt reference circuit for an open or a high resistance.
4. 9: This step tests for high resistance in the signal circuit of the MAF sensor.
5. 10: This step tests for high resistance in the low reference circuit of the MAF/intake air temperature (IAT) sensor. The MAF sensor and the IAT sensor share the low reference circuit. If there is a condition with the low reference circuit, a MAF and IAT sensor DTC may set. 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.
6. 15: Inspect the MAF/IAT sensor connector for water intrusion, corrosion, and bent or damaged terminals.
7. 16: Inspect the ECM connectors for water intrusion, corrosion, and bent or damaged terminals.

DTC P0101

The mass air flow (MAF) sensor is located in the air intake duct. The MAF sensor is an airflow meter that measures the amount of air that enters the engine. The MAF sensor uses a hot film that is cooled by air flowing past the sensing film as air enters the engine. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required in order to maintain the hot film at a constant temperature. The engine control module (ECM) uses the MAF sensor in order to provide the correct fuel delivery for all operating conditions. The MAF sensor uses the following circuits in order to operate

1. An ignition 1 voltage circuit
2. A 5-volt reference circuit
3. A low reference circuit
4. A signal circuit

The ECM monitors the MAF sensor signal for being stuck in range, for being too low, or for being too high for a given operating condition. If the ECM detects a MAF sensor signal voltage that is too low, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Voltage

1. Before the ECM can report DTC P0102 failed, DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0336, and P0338 must run and pass.
2. The engine is operating.
3. The ignition 1 voltage is more than 7.5 volts.
4. DTC P0102 runs continuously once the above conditions are met for less than 1 second.

1. The ECM detects that the MAF sensor signal is less than -11.7 grams per second.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 4: This step tests the ignition 1 voltage circuit. Repair the open or short to ground in the ignition 1 voltage circuit, if the test lamp does not illuminate.
2. 5: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the MAF sensor. If the amperage on the 5-volt reference circuit is less than 80 mA, test the 5-volt reference circuit for a short to ground, an open, or a high resistance.
3. 6: This step tests the signal circuit of the MAF sensor.

DTC P0102

The mass air flow (MAF) sensor is located in the air intake duct. The MAF sensor is an airflow meter that measures the amount of air that enters the engine. The MAF sensor uses a hot film that is cooled by air flowing past the sensing film as air enters the engine. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required in order to maintain the hot film at a constant temperature. The engine control module (ECM) uses the MAF sensor in order to provide the correct fuel delivery for all operating conditions. The MAF sensor uses the following circuits in order to operate

1. An ignition 1 voltage circuit
2. A 5-volt reference circuit
3. A low reference circuit
4. A signal circuit

The ECM monitors the following inputs in order to calculate a predicted MAF sensor value

1. The intake air temperature (IAT)
2. The engine coolant temperature (ECT)
3. The throttle position (TP)
4. The engine speed

The ECM monitors the MAF sensor signal for being stuck in range, for being too low, or for being too high for a given operating condition. If the ECM detects a MAF sensor signal voltage that is too high, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Voltage

1. Before the ECM can report DTC P0103 failed, DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0336, and P0338 must run and pass.
2. The engine is operating.
3. The engine speed is more than 320 RPM.
4. The ignition 1 voltage is more than 7.5 volts.
5. The above conditions exists for 1 second.
6. DTC P0103 runs continuously once the above conditions are met.

1. The ECM detects that the MAF sensor signal is more than 294 grams per second.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. Inspect for mis-routed harnesses. Inspect the MAF sensor harness for routing that is too close to the following components: Ignition coils Solenoids Relays Motors
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 4: This step tests the signal circuit of the MAF sensor for a short to voltage.
2. 5: This step tests for high resistance in the low reference circuit of the MAF/IAT sensor. The MAF sensor and the IAT sensor share the low reference circuit. If there is a condition with the low reference circuit, a MAF and IAT sensor DTC may set. 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.
3. 6: This step tests the low reference circuit for a short to voltage. The control module or the sensor may be damaged if the circuit is shorted to battery voltage. Ensure that a short to voltage is repaired before replacing any components.
4. 9: Inspect the MAF/IAT sensor connector for water intrusion, corrosion, and bent or damaged terminals.
5. 10: Inspect the ECM connectors for water intrusion, corrosion, and bent or damaged terminals.

DTC P0103

Diagnostic Fault Information

DTC P0111

Typical Scan Tool Data

IAT Sensor

The intake air temperature (IAT) sensor is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the IAT sensor within its typical operating range. If the ECM does not detect a predetermined change in the IAT during calibrated driving conditions, this DTC sets.

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

DTC P0111

Idle Test

1. Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass.
2. DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set.
3. The engine coolant temperature (ECT) at engine start is less than 48°C (118°F).
4. The ECT is more than 65°C (149°F).
5. The vehicle speed is less than 10 km/h (6.3 mph).
6. DTC P0111 runs continuously once the above conditions are met for more than 2 seconds.

Cruise Test

1. Before the ECM can report DTC P0111 failed, DTC P0101 must run and pass.
2. DTCs P0112, P0113, P0116, P0117, P0118, P0119, P0125, and P0128 are not set.
3. The ECT at engine start is less than 65°C (149°F).
4. The vehicle speed is more than 60 km/h (37 mph).
5. The MAF is between 11-42 g/s.
6. Decel fuel cut-off (DFCO) is not active.
7. DTC P0111 runs continuously once the above conditions are met for more than 2 seconds.

Idle Test

1. The ECM detects that the IAT increased less than 2°C (4°F).
2. The condition exists for a total of 16 seconds or 4 events of more than 4 seconds each.

Cruise Test

1. The ECM detects that the IAT decreased less than 2°C (4°F).
2. The condition exists for more than 1 minute or 16 events of more than 4 seconds each.

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. If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
2. High resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit could set a DTC.
3. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
4. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module (ECM) Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-control-module-ecm-connector-end)
2. «Engine Controls Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-controls-connector-end-views)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-output-controls)

Circuit/System Verification

1. Verify that the following DTCs are not set: P0101, P0112, P0113, P0116, P0117, P0118, P0119, P0125, P0128. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) .
2. 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. DTC P0111 should not set.

Circuit/System Testing

1. Ignition OFF, disconnect the MAF/IAT sensor.
2. Ignition ON, verify that the IAT sensor parameter is at -40°C (-40°F). If greater than -40°C (-40°F), test the signal circuit of the IAT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
3. Ignition OFF, remove the ECM/TCM fuse from the underhood fuse block.
4. Test for less than 5 ohms between the low reference circuit and the ECM housing. If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM.
5. Ignition OFF, install the ECM/TCM fuse to the underhood fuse block.
6. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the IAT sensor and verify the IAT sensor parameter is greater than 132°C (270°F). If less than 132°C (270°F), test the signal circuit of the IAT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
7. If all circuits/connections test normal, test or replace the MAF/IAT sensor.

Component Testing

1. Ignition OFF, disconnect the harness connector of the IAT sensor.
2. Test the IAT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature vs Resistance - Intake Air Temperature (IAT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-intake-air) table and verify that the resistance is within 5 percent of the specification. If the resistance vs temperature is not within 5 percent, replace the IAT sensor.

Repair Procedures

1. «Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2)
2. «Control Module References»(/cadillac/srx/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for engine control module replacement, setup, and programming

The intake air temperature (IAT) sensor is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit. If the ECM detects a low IAT signal voltage, which is a high temperature indication, this DTC sets.

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

DTC P0112

This diagnostic procedure supports the following DTC

DTC P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage

1. The engine run time is more than 3 minutes.
2. The engine is idling for more than 10 seconds.
3. DTC P0112 runs continuously once the above conditions are met.

The ECM detects that the intake air temperature is more than 132°C (270°F) for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. Use the Temperature vs Resistance table in order to test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the intake air temperature and the engine coolant temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to «Temperature vs Resistance - Intake Air Temperature (IAT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-intake-air) .
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step determines that a condition exists. If the temperature is more than the specified value, test for a condition in the circuits of the IAT sensor.
2. 4: This step isolates the condition. If the temperature is less than the specified value, the ECM and the signal circuit of the IAT sensor are OK.

DTC P0112

The intake air temperature (IAT) sensor is an integral part of the mass air flow (MAF) sensor. The IAT sensor is a variable resistor that measures the temperature of the intake air. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and supplies a ground to the low reference circuit. If the ECM detects a high IAT signal voltage, which is a low temperature indication, this DTC sets.

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

DTC P0113

This diagnostic procedure supports the following DTC

DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage

1. The engine run time is more than 3 minutes.
2. The engine is idling for more than 10 seconds.
3. DTC P0113 runs continuously once the above conditions are met.

1. The ECM detects that the intake air temperature is less than -42°C (-43.6°F) and remains steady within 3°C (5°F) during an air flow increase of more than 999 grams. The scan tool is limited to -40°C (-40°F), so the diagnostic procedure uses -39°C (-38°F) to determine if there is an IAT condition.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. Use the Temperature vs Resistance table in order to test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the intake air temperature and the engine coolant temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to «Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-engine-coolant) .
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step determines that a condition exists. If the temperature is less than the specified value, test for a condition in the circuits of the IAT sensor.
2. 5: This step tests for high resistance in the low reference circuit of the MAF/IAT sensor. The MAF sensor and the IAT sensor share the low reference circuit. If there is a condition with the low reference circuit, a MAF and IAT sensor DTC may set. 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.
3. 6: This step tests the low reference circuit for a short to voltage. The control module or the sensor may be damaged if the circuit is shorted to battery voltage. Ensure that a short to voltage is repaired before replacing any components.
4. 11: Inspect the MAF/IAT sensor connector for water intrusion, corrosion, and bent or damaged terminals.
5. 12: Inspect the ECM connectors for water intrusion, corrosion, and bent or damaged terminals.

DTC P0113

DTC P0116

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the mutual performance of the ECT and the intake air temperature (IAT) signals. The ECM monitors the warm up and cool down behavior of the sensors, after a vehicle driven at operating temperature is shut down. If the ECM detects that the ECT is not with in a predetermined range of IAT after a long soak, or the ECT and IAT are not within a range of each other, as compared to a previous cold start, this DTC sets.

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

DTC P0116

Condition 1

1. Before the ECM can report DTC P0116 failed, DTC P0101 must run and pass.
2. DTCs P0117, P0118, and P0119 are not set.
3. The engine run time of the previous ignition cycle was more than 10 minutes.
4. The accumulated air mass of the previous ignition cycle was more than 4000 grams
5. The minimum IAT during the previous ignition cycle is between -30 to +2°C (-22 to +36°F).
6. The IAT at ignition ON is between -30 to +2°C (-22 to +36°F).
7. DTC P0116 runs once an ignition cycle when the above conditions are met.

Condition 2

1. Before the ECM can report DTC P0116 failed, DTC P0101 must run and pass.
2. DTCs P0117, P0118, and P0119 are not set.
3. The ECT at the previous engine shut down is more than 85°C (185°F).
4. The ECM detects a predicted rise in the intake air temperature at ECM power down of the previous ignition cycle. The hood being open or a strong wind may prevent a rise in the IAT from occurring.
5. The block heater is not detected.
6. DTC P0116 runs once an ignition cycle when the above conditions are met.

1. The ECM determines the difference between the ECT and IAT at ignition ON is not within 10°C (18°F) of the difference recorded during a previous ignition cycle, when the enable conditions were met. OR
2. The ECM determines the IAT at ignition ON is within a calibrated range of the ECT and IAT recorded during a previous ignition cycle, but the ECT is not within 10°C (18°F) of the calibrated range.
3. Either condition exists for more than 4 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. Test the ECT and the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to «Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-engine-coolant) and «Temperature vs Resistance - Intake Air Temperature (IAT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-intake-air) .
2. If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
3. After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
4. High resistance in the circuits of either the ECT or IAT sensor could set a DTC.
5. A short to ground or voltage through a conductive material or fluid could set this DTC. Inspect the ECT sensor for evidence of coolant leaking into the connector body.
6. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
7. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals.

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module (ECM) Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-control-module-ecm-connector-end)
2. «Engine Controls Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-controls-connector-end-views)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-output-controls)

1. Verify that the following DTCs are not set: P0101, P0117, P0118, P0119. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/srx/i-2003-2009/remont/oem-general-information/#vehicle-dtc-information__diagnostic-trouble-code-dtc-list) .
2. Inspect the engine coolant level. Verify that the cooling system is operating correctly. If you suspect a condition with the engine cooling system, refer to «Symptoms - Engine Cooling»(/cadillac/srx/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__symptoms-engine-cooling) .
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. DTC P0116 should not set.

1. Ignition OFF, disconnect the ECT sensor.
2. Ignition ON, verify that the ECT sensor parameter is at -40°C (-40°F). If greater than -40°C (-40°F), test the signal circuit of the ECT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
3. Ignition OFF, remove the ECM/TCM fuse from the underhood fuse block.
4. Test for less than 5 ohms between the low reference circuit and the ECM housing. If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM.
5. Ignition OFF, install the ECM/TCM fuse to the underhood fuse block.
6. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor and verify the ECT sensor parameter is greater than 142°C (288°F). If less than 143°C (289°F), test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
7. If all circuits/connections test normal, test or replace the ECT sensor.

1. Ignition OFF, disconnect the harness connector of the ECT sensor.
2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature vs Resistance - Intake Air Temperature (IAT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-intake-air) table and verify that the resistance is within 5 percent of the specification. If the resistance vs temperature is not within 5 percent, replace the ECT sensor.

1. «Engine Coolant Temperature (ECT) Sensor Replacement»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2)
2. «Control Module References»(/cadillac/srx/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for engine control module replacement, setup, and programming

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects a low ECT signal voltage, which is a high temperature indication, this DTC sets.

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

DTC P0117

This diagnostic procedure supports the following DTC

DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage

1. The engine is operating.
2. The start up intake air temperature (IAT) is less than 72°C (161°F). OR
3. The engine is operating.
4. The start up intake air temperature (IAT) is more than 72°C (161°F).
5. The engine run time is more than 59 seconds.
6. DTC P0117 runs continuously once the above condition is met.

The ECM detects that the ECT is more than 140°C (284°F) for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. An overheating condition may cause this DTC to set.
4. After starting the engine, the ECT should rise steadily to about 90°C (194°F) then stabilize when the thermostat opens.
5. Use the Temperature vs Resistance table in order to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the engine coolant temperature and the intake air temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to «Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-engine-coolant) .
6. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step determines that a condition exists. If the temperature is more than the specified value, test for a condition in the circuits of the ECT sensor.
2. 4: This step isolates the condition. If the temperature is less than the specified value, the ECM and the signal circuit of the ECT sensor are OK.

DTC P0117

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects a high ECT signal voltage, which is a low temperature indication, this DTC sets.

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

DTC P0118

This diagnostic procedure supports the following DTC

DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage

1. The ignition is ON or the engine is operating.
2. DTC P0118 runs continuously once the above condition is met.

The ECM detects that the ECT is less than -42°C (-43.6°F) for more than 4 seconds. The scan tool is limited to -40°C (-40°F), so the diagnostic procedure uses -39°C (-38°F) to determine if there is an ECT condition.

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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. Use the Temperature vs Resistance table in order to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in a driveability condition. If the engine has sat overnight, the engine coolant temperature and the intake air temperature values should display within a few degrees. If the temperatures are not within 3°C (5°F), refer to «Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-engine-coolant) .
4. After starting the engine, the ECT should rise steadily to about 90°C (194°F) then stabilize when the thermostat opens.
5. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 6: This step is testing the low reference circuit for a short to voltage or for a low reference circuit that is open. If the low reference circuit within the ECM is open or if the low reference circuit is open between the ECM and the splice, a voltage of 3-5 volts will be measured on the DMM.
2. 7: This step isolates if there is a circuit that is shorted to voltage or if the low reference circuit is open internally or externally of the ECM. If there is no voltage on the low reference circuit after disconnecting all the sensors, the low reference circuit is open.

DTC P0118

DTC P0119

ECT Sensor

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

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

DTC P0119

1. DTCs P0117, P0118, P0125, and P0128 are not set.
2. The ignition is ON or the engine is operating.
3. DTC P0119 runs continuously once the above conditions are met.

1. The ECM detects that the ECT changed more than an expected value during a calibrated amount of time.
2. The condition exists for more than 4 seconds or an accumulation of 50 seconds over time.

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. Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to «Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-engine-coolant) .
2. If the vehicle has sat overnight, the intake air temperature (IAT) sensor and the ECT sensor values should display within 3°C (5°F).
3. After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
4. High resistance on either the ECT sensor signal circuit or the ECT sensor low reference circuit could set a DTC.
5. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
6. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire harness connector terminals.

Engine Controls Schematics

Connector End View Reference

1. «Engine Control Module (ECM) Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-control-module-ecm-connector-end)
2. «Engine Controls Connector End Views»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__engine-controls-connector-end-views)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__circuit-testing)
2. «Connector Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/srx/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__wiring-repairs)

Scan Tool Reference

1. «Scan Tool Data List»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-list)
2. «Scan Tool Data Definitions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-data-definitions)
3. «Scan Tool Output Controls»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-1-of-2__scan-tool-output-controls)

1. Observe the engine coolant temperature (ECT) sensor parameter with a scan tool while moving the ECT sensor connector and the engine control module (ECM) connector. The ECT sensor parameter should not fluctuate while moving the related harnesses and connectors. Repair the suspected harness or connection if the ECT parameter fluctuates more than 3°C (5°F) while moving the related harnesses and connectors.
2. Inspect the engine coolant level. Verify that the cooling system is operating correctly. If you suspect a condition with the engine cooling system, refer to «Symptoms - Engine Cooling»(/cadillac/srx/i-2003-2009/remont/cooling-system-mechanical/#engine-cooling-system__symptoms-engine-cooling) .
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. DTC P0119 should not set.

1. Ignition OFF, disconnect the ECT sensor.
2. Ignition ON, verify that the ECT sensor parameter is at -40°C (-40°F). If greater than -40°C (-40°F), test the signal circuit of the ECT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
3. Ignition OFF, remove the ECM/TCM fuse from the underhood fuse block.
4. Test for less than 5 ohms between the low reference circuit and the ECM housing. If greater than 5 ohms, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit/connections test normal, replace the ECM.
5. Ignition OFF, install the ECM/TCM fuse to the underhood fuse block.
6. Ignition ON, install a 3-amp fused jumper wire between the signal circuit and the low reference circuit of the ECT sensor and verify the ECT sensor parameter is greater than 142°C (288°F). If less than 143°C (289°F), test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.
7. If all circuits/connections test normal, test or replace the ECT sensor.

1. Ignition OFF, disconnect the harness connector of the IAT sensor.
2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature vs Resistance - Intake Air Temperature (IAT) Sensor»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2__temperature-vs-resistance-intake-air) table and verify that the resistance is within 5 percent of the specification. If the resistance vs temperature is not within 5 percent, replace the ECT sensor.

1. «Engine Coolant Temperature (ECT) Sensor Replacement»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2)
2. «Control Module References»(/cadillac/srx/i-2003-2009/remont/communication-devices/#computerintegrating-systems__control-module-references) for engine control module replacement, setup, and programming

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality. TP sensor 1 signal voltage increases from below 1 volt at idle to above 4 volts at wide open throttle (WOT). TP sensor 2 signal voltage decreases from above 4 volts at idle to below 1 volt at WOT.

The ECM compares the signal of the TP sensor 1 and TP sensor 2 through the entire range. If the ECM detects a predetermined difference between sensor 1 and sensor 2, or a predetermined difference from the predicted range, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0121 Throttle Position (TP) Sensor 1 Performance

1. The ignition 1 voltage is more than 7 volts.
2. The TP sensor 1 voltage is between 0.17-4.6 volts.
3. DTC P0121 runs continuously once the above conditions are met.

1. The TP sensor 1 disagrees more than 9 percent from TP sensor 2.
2. The TP sensor 1 disagrees more than 9 percent from the predicted value.
3. The above conditions are met for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. If there is a condition with the TP sensors the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step verifies that a condition exists. If there is a condition with a TP sensor circuit, the scan tool will display Disagree.
2. 5: This step tests for high resistance in the 5-volt reference circuit of the TP sensors. If the DMM does not display more than the specified voltage there is high resistance in the circuit.
3. 8: This step tests for high resistance in the low reference circuit of the TP sensor. 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 P0121

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality. TP sensor 1 signal voltage increases from below 1 volt at idle to above 4 volts at wide open throttle (WOT). TP sensor 2 signal voltage decreases from above 4 volts at idle to below 1 volt at WOT.

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

This diagnostic procedure supports the following DTC

DTC P0122 Throttle Position (TP) Sensor 1 Circuit Low Voltage

1. The ignition is ON, with the engine OFF, or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P0122 runs continuously once the above conditions are met.

The ECM detects the TP sensor 1 signal voltage is less than 0.18 volts for more than 4 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. If there is a condition with the TP sensors, the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step verifies that a condition exists.
2. 4: The TP sensors share a 5-volt reference circuit. If both DTCs P0122 and P0222 set, test for a condition in the 5-volt reference circuit.
3. 5: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the TP sensors. If the amperage on the 5-volt reference circuit is less than 50 mA, test the 5-volt reference circuit for an open or a high resistance.
4. 6: This step tests the signal 1 circuit of the TP sensor. If the TP sensor 1 voltage parameter is not 4.8-5.2 volts, test for a condition in the signal 1 circuit.

DTC P0122

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality. The TP sensor 1 signal voltage increases from below 1 volt at idle to above 4 volts at wide open throttle (WOT). The TP sensor 2 signal voltage decreases from above 4 volts at idle to below 1 volt at WOT.

If the ECM detects TP sensor 1 signal voltage is too high, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0123 Throttle Position (TP) Sensor 1 Circuit High Voltage

1. The ignition is ON, with the engine OFF or the engine is operating.
2. The ignition 1 voltage is more than 7 volts.
3. DTC P0123 runs continuously once the above conditions are met.

The ECM detects the TP sensor 1 signal voltage is more than 4.6 volts for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. If there is a condition with the TP sensors the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 2: This step verifies that a condition exists.
2. 5: This step tests the signal circuit for a short to voltage. If the scan tool displays a voltage after the TP sensor is disconnected, the circuit is shorted to a voltage.
3. 7: This step tests for high resistance in the low reference circuit of the TP sensor. 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.
4. 8: This step tests the low reference circuit for a short to voltage.

DTC P0123

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of air flow into an engine is proportional to the amount of heat an engine generates. The ECM monitors the amount of air flow into the engine to calculate engine coolant temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the closed loop temperature. If the coolant temperature does not increase normally or does not reach the closed loop temperature, diagnostics that use the ECT as enabling criteria, may not run when expected. If the engine coolant temperature fails to reach the closed loop temperature, before a predetermined amount of air flow enters the engine, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0125 Engine Coolant Temperature (ECT) Insufficient for Closed Loop Fuel Control

1. DTCs P0112, P0113, P0117, P0118, P0480, P0481, P0691, P0692, P0693, and P0694 are not set.
2. The engine is operating.

The actual ECT is not within 10°C (18°F) of the calculated ECT after 2-5 minutes, which depends on the amount of air flow into the engine after start-up.

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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 5: This step tests for excessive resistance in the ECT circuit.
2. 6: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.

DTC P0125

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of air flow into an engine is proportional to the amount of heat an engine generates. The ECM monitors the amount of air flow into the engine to calculate engine coolant temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach regulating temperature of the thermostat, diagnostics that use the ECT as enabling criteria, may not run when expected. If the engine coolant temperature fails to reach the thermostat regulating temperature, before a predetermined amount of air flow enters the engine, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0128 Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature

1. Before the ECM can report DTC P0128 failed, DTC P0117 must run and pass.
2. DTCs P0101, P0102, P0103, P0112, P0113, P0118, P0722, or P0723 are not set.
3. The engine speed is more than 960 RPM.
4. The ECT is less than 71°C (160°F) at start up.
5. The calculated ambient air temperature is more than -11°C (-12°F) and less than 45°C (113°F).
6. The vehicle speed is more than 15 km/h (9 mph).
7. The air flow coming into the engine has accumulated to more than 2,000 grams.
8. DTC P0128 runs continuously once the above conditions have been met for approximately 15 minutes.

1. The ECM detects that the actual coolant temperature is 10°C (18°F) less than the calculated coolant temperature.
2. The condition exists for more than 4 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. 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/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-introduction-2-of-2) .
3. An engine that soaks for about 8 hours will help diagnosis the condition. After the cold soak, operate the vehicle at highway speeds for 20 minutes while monitoring the Calculated ECT - Thermostat parameter with a scan tool. If there is a condition, the calculated temperature will be 10°C (18°F) more then the actual engine coolant temperature.
4. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/srx/i-2003-2009/remont/testing-diagnostics/#engine-control-system-36l-ly7-troubleshooting__intermittent-conditions) .

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

1. 7: This step tests for excessive resistance in the ECT circuit.
2. 8: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.

DTC P0128

See also:
• Intermittent Conditions
• Diagnostic System Check - Vehicle
• Camshaft Timing Drive Chain Alignment Diagram (W/Primary Inverted Tooth (IT) Chain)
• Camshaft Timing Drive Components Cleaning and Inspection
• Diagnostic Trouble Code (DTC) List - Vehicle
• Engine Controls Component Views
• Engine Control Module (ECM) Connector End Views
• Engine Controls Connector End Views
• Circuit Testing
• Wiring Repairs
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Control Module References
• Fluid and Lubricant Recommendations
• Oil Pressure Diagnosis and Testing
• Special Tools
• Measuring Voltage Drop
• Camshaft Position (CMP) Actuator Replacement - Bank 1 (Right) Intake
• Scan Tool Data List
• Scan Tool Data Definitions
• Scan Tool Output Controls
• Temperature vs Resistance - Intake Air Temperature (IAT) Sensor
• Diagnostic Repair Verification
• Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor
• Symptoms - Engine Cooling
• Disengaging Connectors Notice
• Loss of Coolant
• Thermostat Diagnosis
• Road Test Caution
• DTC P0102