Engine Controls - 4.6l (lh2) - DTC p0010 to p0153 Cadillac XLR I

Circuit Description

The camshaft position (CMP) actuator system is comprised of 4 CMP actuator solenoids, 4 oil control valves, and 4 CMP actuators. The engine control module (ECM) sends an electrical signal through the control circuits to the CMP actuator solenoids when a cam timing change is desired. The ground circuits of the CMP actuator solenoids are used as a return. If the ECM detects an open on one of these circuits, DTC P0010, P0013, P0020, P0023 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

Conditions for Running the DTC

1. DTC P0010, P0013, P0020, P0023, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The engine is running.
3. The CMP actuator has been commanded for more than 1 second.
4. The ignition voltage is between 11-26 volts.
5. This diagnostic runs continuously.

Conditions for Setting the DTC

1. The ECM detects an open on a CMP actuator solenoid control or ground circuit.
2. The above condition is met for more than 1.6 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.

The CMP actuator system will be disabled until the end of the ignition cycle.

Conditions for Clearing the MIL/DTC

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0010, P0013, P0020, or P0023

The camshaft position (CMP) actuator system is comprised of 4 CMP actuator solenoids, 4 oil control valves, and 4 CMP actuators. The engine control module (ECM) sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The ground circuits of the CMP actuator solenoids are used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator, in turn, changes the CMP relative to the crankshaft position (CKP).

CMP Actuator Authority

If the desired CMP does not match the actual CMP for a calibrated amount of time, DTC P0011, P0014, P0021 or P0024 will set.

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. DTCs P0010, P0011, P0013, P0014, P0016, P0017, P0018, P0019, P0020, P0021, P0023, P0024, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The CMP actuators are commanded.
3. The engine oil pressure (EOP) is between 100-696.4 kPa (14.5-101 psi).
4. The engine speed is at an RPM between 1,000-6,500 RPM, that will allow for steady activation of the cam actuators based on calculated engine oil temperature (EOT).
5. The calculated EOT is between -10°C to +150°C (+14°F to +302°F).
6. The ignition voltage is between 11-16 volts.
7. DTC P0011, P0014, P0021, or P0024 runs continuously once the above conditions are met.

The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 6 degrees for more than 1.6 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.

The CMP actuator system will be disabled until the end of the ignition cycle.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

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 ECM sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The low reference circuit is used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator changes the camshaft position relative to the crankshaft position. If the ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees, DTC P0016, P0017, P0018, or P0019 will set.

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. DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
2. The engine is running.
3. The calculated oil temperature is between -10°C to +150°C (+14°F to +302°F).
4. The oil pressure is greater than 105 kPa (15 psi).
5. The Low Oil Switch parameter is 0.
6. The battery voltage is between 11-16 volts.
7. The CMP actuator is commanded to the park position or to its full travel.
8. DTC P0016, P0017, P0018, or P0019 runs continuously once the above conditions are met.

The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees for more than 3.6 seconds.

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

The CMP Actuator System will be disabled until the end of the ignition cycle.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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 camshaft, camshaft actuator, or timing chain can cause this DTC to set.
2. Inspect for a slow returning camshaft position actuator. A stuck or slow returning camshaft position actuator can cause this DTC to set.
3. If the condition is intermittent, refer to «Intermittent Conditions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-46l-lh2-troubleshooting__intermittent-conditions) .

Test Description

1. 2: This step determines if the condition is present.
2. 4: An incorrectly installed camshaft or timing chain can cause these DTCs to set.

DTC P0016, P0017, P0018, or P0019

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature and provide an accurate voltage signal. A low side driver within the engine control module (ECM) is pulse width controlled to provide current to the heater elements. The ECM will not allow continuous HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The ECM continuously monitors the HO2S operating state by briefly turning OFF the heater low side driver at regular intervals. A small reference voltage of approximately 4.5 volts is present at the heater low control circuit. When the low side driver is commanded ON the reference voltage is low, and when the low side driver is commanded ON the reference voltage is high, close to battery voltage. If the ECM detects that the HO2S heater low control circuit voltage is between 2.6-4.6 volts when the heater is commanded ON, the following DTCs will set

1. DTC P0030 for HO2S bank 1 sensor 1
2. DTC P0036 for HO2S bank 1 sensor 2
3. DTC P0050 for HO2S bank 2 sensor 1
4. DTC P0056 for HO2S bank 2 sensor 2

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 engine is running.
2. Battery voltage is more than 10 volts.
3. DTC P0030, P0036, P0050, or P0056 runs continuously once the above conditions are met.

The ECM detects that the HO2S heater low control circuit voltage is between 2.6-4.6 volts when the heater is commanded ON, indicating an open HO2S heater circuit.

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 3 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.

DTC P0030, P0036, P0050, or P0056

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature and provide an accurate voltage signal. A low side driver within the engine control module (ECM) is pulse width controlled to provide current to the heater elements. The ECM will not allow continuous HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The ECM continuously monitors the HO2S heater operating state by briefly turning OFF the heater low side driver at regular intervals. A small reference voltage of approximately 4.5 volts is present at the heater low control circuit. When the low side driver is commanded ON, the reference voltage is low, when the low side driver is commanded OFF the reference voltage is high, close to battery voltage. If the ECM detects that the HO2S heater low control circuit voltage is lower than 2.6 volts when the heater is commanded OFF, the following DTCs will set

1. DTC P0031 for HO2S bank 1 sensor 1
2. DTC P0037 for HO2S bank 1 sensor 2
3. DTC P0051 for HO2S bank 2 sensor 1
4. DTC P0057 for HO2S bank 2 sensor 2

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 engine is running.
2. Battery voltage is more than 10 volts.
3. DTC P0031, P0037, P0051, or P0057 runs continuously once the above conditions are met.

The ECM detects that the HO2S heater low control circuit voltage is below 2.6 volts when the heater is commanded OFF, indicating an HO2S heater circuit shorted to ground.

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 3 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.

DTC P0031, P0037, P0051, or P0057

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature and provide an accurate voltage signal. A low side driver within the engine control module (ECM) is pulse width controlled to provide current to the heater elements. The ECM will not allow continuous HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The ECM continuously monitors the HO2S heater current draw and operating state by briefly turning OFF the heater low side driver at regular intervals. A small reference voltage of approximately 4.5 volts is present at the heater low control circuit. When the low side driver is commanded ON the reference voltage is low, when the low side driver is commanded OFF the reference voltage is high, close to battery voltage. If the ECM detects that the HO2S heater low control circuit voltage is higher than 4.6 volts when the heater is commanded ON, the following DTCs will set

1. DTC P0032 for HO2S bank 1 sensor 1
2. DTC P0038 for HO2S bank 1 sensor 2
3. DTC P0052 for HO2S bank 2 sensor 1
4. DTC P0058 for HO2S bank 2 sensor 2

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 engine is running.
2. Battery voltage is more than 10 volts.
3. DTC P0032, P0038, P0052, or P0058 runs continuously once the above conditions are met.

The ECM detects that the HO2S heater low control circuit voltage is above 4.6 volts when the heater is commanded ON, indicating an HO2S heater circuit shorted to voltage.

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 3 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.

DTC P0032, P0038, P0052, or P0058

The throttle position (TP) is compared to an expected throttle position based on engine load. The engine control module (ECM) determines engine load based on inputs from the mass air flow (MAF) and the manifold absolute pressure (MAP) sensors. If the ECM detects that the current load and throttle position are not consistent with the expected load and throttle position, DTC P0068 is set.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0068 Throttle Body Airflow Performance

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0121, P0122, P0123, P0221, P0222, P0223 are not set.
2. The engine speed is more than 600 RPM and less than 6,300 RPM.
3. DTC P0068 runs continuously once the above conditions are met.

The ECM detects that the throttle position and indicated engine load do not correspond with the expected load and throttle position for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0068

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The MAF sensor used on this engine is a hot film meter (HFM) type. The engine control module (ECM) applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,500 Hz at idle to near 10,000 Hz at maximum engine load. The MAF sensor frequency signal is a function of the current required to keep the air flow sensing element at a fixed temperature above ambient. The air flowing through the sensor cools the sensing element. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required to maintain the hot film at a constant temperature. The ECM uses the MAF sensor signal to provide the correct fuel delivery for a wide range of engine speeds and loads. The MAF sensor uses the following circuits to operate

1. A 12-volt reference circuit
2. A low reference circuit that is shared with the intake air temperature (IAT) sensor
3. A signal circuit

The 12-volt reference circuit of the MAF sensor is also supplied to additional sensors and they are connected within the ECM. The 12-volt reference is shared by the following sensors

1. The MAF sensor
2. The crankshaft position (CKP) sensor
3. The camshaft position (CMP) sensor bank 1 intake
4. The CMP sensor bank 1 exhaust
5. The CMP sensor bank 2 intake
6. The CMP sensor bank 2 exhaust

The ECM uses the following sensor inputs to calculate a MAF value that is based on an intake manifold model

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

The ECM compares the actual MAF sensor frequency signal to the calculated MAF model. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. If the ECM detects the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF model DTC P0101 sets.

This diagnostic procedure supports the following DTC

DTC P0101 Mass Air Flow (MAF) System Performance

1. The engine is running.
2. This DTC runs continuously in a 12.5 ms loop.

The ECM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated and modeled MAF value for more than 400 ms.

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

1. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 4-10 g/s at idle to 210 g/s or more at the time of the 1-2 shift.
2. A high resistance of 15 ohms or more on the 12-volt reference voltage circuit will cause this DTC to set. A high resistance will cause a driveability concern before this DTC sets.
3. If the condition is intermittent, refer to «Inducing Intermittent Fault Conditions»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) and «Intermittent Conditions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-46l-lh2-troubleshooting__intermittent-conditions) .

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

1. 3: This step will determine if any mechanical faults have caused this DTC to set.
2. 6: This voltage drop test will determine if high resistance has caused this DTC to set.
3. 8: This step verifies the voltage signal from the ECM to the MAF sensor connector.
4. 9: This step will determine if the ECM can accurately process the frequency signal that it receives from the MAF sensor.
5. 10: This step will determine if an abnormal resistance of less than 1,150 ohms has skewed the MAF sensor frequency signal.

DTC P0101

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The MAF sensor used on this engine is a hot film meter (HFM) type. The engine control module (ECM) applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,500 Hz at idle to near 10,000 Hz at maximum engine load. The MAF sensor frequency signal is a function of the current required to keep the air flow sensing element at a fixed temperature above ambient. The air flowing through the sensor cools the sensing element. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required to maintain the hot film at a constant temperature. The ECM uses the MAF sensor signal to provide the correct fuel delivery for a wide range of engine speeds and loads. The MAF sensor uses the following circuits to operate

1. A 12-volt reference circuit
2. A low reference circuit that is shared with the intake air temperature (IAT) sensor
3. A signal circuit

The 12-volt reference circuit of the MAF sensor is also supplied to additional sensors and they are connected within the ECM. The 12-volt reference is shared by the following sensors

1. The MAF sensor
2. The crankshaft position (CKP) sensor
3. The camshaft position (CMP) sensor bank 1 intake
4. The CMP sensor bank 1 exhaust
5. The CMP sensor bank 2 intake
6. The CMP sensor bank 2 exhaust

If the ECM detects the frequency signal is less than the possible range of a correctly operating MAF sensor DTC P0102 sets.

This diagnostic procedure supports the following DTC

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

1. The engine is running.
2. The Engine Speed parameter is more than 544 RPM.
3. This DTC runs continuously in a 12.5 ms loop.

The ECM detects that the MAF sensor frequency signal is less than 200 Hz for more than 200 ms.

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

1. A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 4-10 g/s at idle to 210 g/s or more at the time of the 1-2 shift.
2. A high resistance of 15 ohms or more on the 12-volt reference circuit may cause this DTC to set. A high resistance will cause a driveability concern before this DTC sets.
3. A high resistance of 10 ohms or more on the ground circuit may cause this DTC to set. A high resistance will cause a driveability concern before this DTC sets.
4. A short between the MAF sensor 12-volt reference circuit and the IAT signal circuit will produce a stalling condition that becomes a Crank/No Start condition.
5. If the condition is intermittent, refer to «Inducing Intermittent Fault Conditions»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) in Wiring Systems and «Intermittent Conditions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-46l-lh2-troubleshooting__intermittent-conditions) .

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

1. 4: This step will determine if a shorted component has caused this DTC to set.
2. 5: This step will determine if a shorted component has caused this DTC to set.
3. 6: This step will determine if any mechanical faults have caused this DTC to set.
4. 7: This voltage drop test will determine if high resistance has caused this DTC to set.
5. 9: This step verifies the voltage signal from the ECM to the MAF sensor connector.
6. 11: This step will determine if the ECM can accurately process the frequency signal that it receives from the MAF sensor.
7. 12: This step will determine if an abnormal resistance of less than 1,150 ohms has skewed the MAF sensor frequency signal.

DTC P0102

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The MAF sensor used on this engine is a hot film meter (HFM) type. The engine control module (ECM) applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,500 Hz at idle to near 10,000 Hz at maximum engine load. The MAF sensor frequency signal is a function of the current required to keep the air flow sensing element at a fixed temperature above ambient. The air flowing through the sensor cools the sensing element. The amount of cooling is proportional to the amount of the air flow. As the air flow increases, more current is required to maintain the hot film at a constant temperature. The ECM uses the MAF sensor signal to provide the correct fuel delivery for a wide range of engine speeds and loads. The MAF sensor uses the following circuits to operate

1. A 12-volt reference circuit
2. A low reference circuit that is shared with the intake air temperature (IAT) sensor
3. A signal circuit

The 12-volt reference circuit of the MAF sensor is also supplied to additional sensors and they are connected within the ECM. The 12-volt reference is shared by the following sensors

1. The MAF sensor
2. The crankshaft position (CKP) sensor
3. The camshaft position (CMP) sensor bank 1 intake
4. The CMP sensor bank 1 exhaust
5. The CMP sensor bank 2 intake
6. The CMP sensor bank 2 exhaust

If the ECM detects the frequency signal is more than the possible range of a correctly operating MAF sensor DTC P0103 sets.

This diagnostic procedure supports the following DTC

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

1. The engine is running.
2. The Engine Speed parameter is more than 544 RPM.
3. DTC P0103 runs continuously once the above conditions are met in a 12.5-millisecond loop.

The ECM detects that the MAF sensor frequency signal is more than 12,425 Hz for more than 200 milliseconds.

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 3 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 air induction system for any water intrusion. The water rapidly cools the hot sensing elements in the sensor causing a false indication of excessive air flow. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
2. A steady or intermittent high resistance in the 12-volt reference circuit of the MAF sensor will skew the MAF sensor frequency high and may cause this DTC to set.
3. If the condition is intermittent, refer to «Inducing Intermittent Fault Conditions»(/cadillac/xlr/i-2003-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) in Wiring Systems and «Intermittent Conditions»(/cadillac/xlr/i-2003-2009/remont/testing-diagnostics/#engine-controls-46l-lh2-troubleshooting__intermittent-conditions) .

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

1. 3: This step tests for electromagnetic interference (EMI) on the signal circuit of the MAF sensor. A frequency reading with the MAF sensor disconnected may indicate an EMI related fault or a poor connection at the ECM. Disconnecting the MAF sensor may set additional related DTCs.
2. 4: This step will determine if incorrect harness routing has caused this DTC to set.
3. 5: This step will determine if water intrusion has caused this DTC to set.
4. 6: This step will determine if a steady or intermittent high resistance at any point in the 12-volt reference circuit of the MAF sensor has caused this DTC to set.

DTC P0103

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature, and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.

Within the ECM, the diagnostic has the ability to determine an inaccurate input from the MAP sensor. Calibrated within the diagnostics are estimates for MAP based on throttle position and engine speed. the diagnostic compares the estimated value to the actual sensor input. If the ECM detects that the MAP sensor input is not within a calibrated limit of the estimated value, DTC P0106 sets.

This diagnostic procedure supports the following DTC

DTC P0106 Barometric Pressure (BARO) Sensor Performance

1. DTC P0068, P0101, P0102, P0103, P0107, P0108, P0122, P0123, P0222, P0223, P0506, P0507, P2101, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2138, or P2176 are not set.
2. The engine speed is between 600-6,300 RPM.
3. DTC P0106 runs on a 25 ms loop.
4. DTC P0106 runs continuously once the above conditions are met.

The ECM detects that the MAP sensor pressure is not within a calibrated limit of the estimated value for more than 3 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 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 5: This step tests the ability of the MAP sensor to correctly indicate BARO.

1. 14: The measurement noted in this step will be used in subsequent steps if the measurement does not exceed the specified value.

1. 17: This step calculates the resistance in the 5-volt reference circuit.

1. 18: This step calculates the resistance in the low reference circuit.

DTC P0106

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.

The ECM monitors the MAP sensor signal for pressure outside of the normal range. If the ECM detects that the MAP sensor pressure is excessively low, DTC P0107 sets.

This diagnostic procedure supports the following DTC

DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage

1. The ignition is ON.
2. DTC P0107 runs continuously once the above conditions are met.

The ECM detects that the MAP sensor pressure is less than 20 kPa for more than one 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 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 6: The measurement noted in this step will be used in subsequent steps if the measurement is not less than the specified value.
2. 7: This step calculates the resistance in the 5-volt reference circuit.

DTC P0107

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, air temperature and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on the 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor in order to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 19 kPa when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO.

The ECM monitors the MAP sensor signal for pressure outside of the normal range. If the ECM detects that the MAP sensor pressure is excessively high, DTC P0108 sets.

This diagnostic procedure supports the following DTC

DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit

1. The engine is running.
2. The throttle is steady.
3. DTC P0108 runs continuously once the above conditions are met.

The ECM detects that the MAP sensor pressure is more than 102 kPa for more than one 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 3 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.

DTC P0108

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit. If the ECM detects an excessively low IAT signal voltage, indicating a high temperature, DTC P0112 sets.

This diagnostic procedure supports the following DTC

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

1. The ignition is ON. OR
2. The engine is running for more than 2 minutes.
3. DTC P0112 runs continuously once the above conditions are met.

The IAT Sensor parameter is more than 128°C (262°F), for more than one 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 3 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.

DTC P0112

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The engine control module (ECM) supplies 5 volts to the IAT signal circuit, and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the IAT signal circuit. If the ECM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.

This diagnostic procedure supports the following DTC

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

1. The ignition is ON. OR
2. The engine is running for more than 2 minutes.
3. DTC P0113 runs continuously once the above conditions are met.

The IAT Sensor parameter is less than -39°C (-38°F) for more than 1 second.

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

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

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

1. 7: This step tests for the proper operation of the circuit in the low voltage range.

DTC P0113

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the engine control module (ECM) for engine control and as an enabling criteria for other diagnostics.

The purpose of this ECT sensor performance diagnostic is to detect an ECT sensor that is stuck in range. This diagnostic will detect a fixed ECT signal throughout the complete range of the sensor.

Using this diagnostic, the ECM calculates the following

1. The delta or change in the actual ECT from start-up ECT
2. The delta or change in the modeled ECT from start-up ECT

When the delta of the modeled ECT reaches a calibratable value it is compared to the delta of the actual ECT.

If the ECM detects that the actual change in the measured ECT is less than the change in the modeled ECT, DTC P0116 sets.

This diagnostic procedure supports the following DTC

DTC P0116 Engine Coolant Temperature (ECT) Sensor Performance

1. DTCs P0101, P0102, P0103, P0112, P0113, P0117, P0118 are not set.
2. The engine is running.
3. Engine metal over-temperature protection (EMOP) is not active
4. This diagnostic will run once and complete during all driving conditions.

If the ECM detects that the actual change in the measured ECT is less than the change in the modeled ECT, DTC P0116 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0116

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 a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the ECT signal circuit. If the ECM detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P0117 sets.

This diagnostic procedure supports the following DTC

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

1. The ignition is ON.
2. DTC P0117 runs continuously once the above condition is met.

The ECM detects that the ECT Sensor parameter is more than 138°C (280°F) for less than 1 second.

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

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0117

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The ECT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the ECT signal circuit. If the ECM detects an excessively high ECT signal voltage, which is a low temperature indication, DTC P0118 sets.

This diagnostic procedure supports the following DTC

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

1. The ignition is ON.
2. The intake air temperature (IAT) is more than -7°C (+19.4°C).
3. The engine has been running for more than 2 minutes.
4. DTC P0118 runs continuously once the above conditions are met.

The ECT sensor parameter is less than -39°C (-38°F) for less than 1 second.

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

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

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

1. 7: This step tests for the proper operation of the circuit in the low voltage range.

DTC P0118

The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-volt reference circuit and a common low reference circuit. The 5-volt reference circuit is also shared with accelerator pedal position (APP) sensor 2. The 5-volt reference voltage is supplied on 2 separate engine control module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to the throttle plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. If the ECM detects the TP sensor 1 signal voltage is less than 0.98 volts, DTC P0122 sets.

This diagnostic procedure supports the following DTC

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

1. The battery voltage is more than 10 volts.
2. The ignition is ON.
3. DTC P0122 runs continuously once the above conditions are met.

The TP sensor 1 voltage is less than 0.98 volts for more than 60 milliseconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

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

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

1. 4: The ECM performs a comparison of the signals from both TP sensors during the entire range of operation. If the DTC does not set with the key ON and the accelerator pedal released, actuating the throttle may cause the DTC to set.
2. 7: The 5-volt reference for the TP sensors and the APP sensor 2 are connected inside the ECM. This step is to determine if the APP sensor is affecting the 5-volt reference circuit of the TP sensors.

DTC P0122

The throttle position (TP) sensors 1 and 2 are located within the throttle body assembly. The TP sensors share a common 5-volt reference circuit and a common low reference circuit. The 5-volt reference circuit is also shared with accelerator pedal position (APP) sensor 2. The 5-volt reference voltage is supplied on 2 separate engine control module (ECM) terminals, but the terminals are connected internally to the same voltage supply. Each TP sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to the throttle plate movement. When the throttle plate is in the closed position, the TP sensor 1 signal voltage is near the low reference and increases as the throttle plate is opened. TP sensor 2 signal voltage at closed throttle is near the 5-volt reference and decreases as the throttle plate is opened. If the ECM detects the TP sensor 1 signal voltage is more than 4.89 volts, DTC P0123 sets.

This diagnostic procedure supports the following DTC

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

1. The battery voltage is more than 10 volts.
2. The ignition is ON.
3. DTC P0123 runs continuously once the above conditions are met.

The TP sensor 1 voltage is more than 4.89 volts for more than 60 milliseconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0123

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the engine control module (ECM) for engine control and as an enabling criteria for other diagnostics. This input also determines if the ECT is insufficient for Closed Loop fuel control.

This time to Closed Loop fuel control diagnostic is designed to detect a system that is not reaching optimum fuel control in a reasonable amount of time. When the engine is started, the ECM uses a timer and a modeled ECT table that is based on ECT at start-up to determine a calibrated threshold. When this threshold is met, the modeled ECT is compared to the actual measured ECT.

If the ECM detects that the measured ECT is not within a calibrated range of the modeled ECT, DTC P0125 sets.

This diagnostic procedure supports the following DTC

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

1. DTCs P0068, P0101, P0102, P0103, P0112, P0113, P0117, P0118 are not set.
2. The engine is running for more than 30 seconds.
3. The Intake Air Temperature Sensor parameter is more than -8.25°C (+17°F).
4. The engine idle time is less than 50 percent.
5. The fuel cut off time is less than 50 percent.
6. The engine metal overtemperature protection (EMOP) is not active.
7. DTC P0125 will run once and complete in a drive cycle.

If the ECM detects that the measured ECT is not within a calibrated range of the modeled ECT, DTC P0125 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0125

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the engine control module (ECM) for engine control and as an enabling criteria for other diagnostics. This input also determines if the ECT is insufficient for thermostat regulating of the coolant.

This engine coolant thermostat monitoring diagnostic is designed to detect a stuck open thermostat. When the engine is started the ECM uses a timer and a modeled ECT table that is based on engine coolant temperature at start-up, intake air temperature (IAT), engine speed (RPM) and engine load to determine when the calibrated threshold of 90°C (194°F) has been met. When this threshold is met, the modeled ECT is compared to the actual measured ECT.

If the ECM detects that the modeled ECT has met the threshold of 90°C (194°F) and the measured ECT has not met the minimum calibrated thermostat regulating temperature of 72°C (161°F) for more than 10 seconds, DTC P0128 sets.

This diagnostic procedure supports the following DTC

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

1. DTCs P0068, P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0125, P1101, P1258 are not set.
2. The start-up ECT Sensor parameter is less than 42°C (107°F)
3. The Intake Air Temperature Sensor parameter is more than -10°C (14°F).
4. The engine idle time is less than 95 percent.
5. The fuel cut off time is less than 50 percent.
6. The engine metal overtemperature protection (EMOP) is not active.
7. This diagnostic will run once in a 500 ms loop, under normal driving conditions within the enabling conditions.

If the ECM detects that the modeled ECT has met the threshold of 90°C (194°F) and the measured ECT has not met the minimum calibrated thermostat regulating temperature of 72°C (161°F) for more than 10 seconds, or the ECT remains below 62°C (143°F), DTC P0128 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 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.

DTC P0128

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust stream more quickly and accurately 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 signal 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 signal voltage. The ECM monitors the voltage variation on the signal circuit and attempts to keep the voltage constant by increasing or decreasing the amount of current flow or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal 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 system is lean, the oxygen level will be high and the lambda value will be high, or more than 1. When the system is rich, the oxygen level is low and the lambda value will be low, or less than 1. The ECM uses this information to maintain the proper air/fuel ratio. If the ECM detects an HO2S circuit that is shorted to ground, DTC P0131 will set for bank 1 sensor 1, or DTC P0151 will set for bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1
2. DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1

1. DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0132, P0133, P0135, P0137, P0138, P0139, P0140, P0141, P0152, P0153, P0155, P0157, P0158, P0159, P0160, P0161, P1137, P1138, P1157, P1158, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2626, P2629, P167A, P167B are not set.
2. The engine is running.
3. DTC P0131 or P0151 runs continuously once the above conditions are met.

The ECM detects a short to ground in one of the following HO2S circuits for more than 1 second

1. The input pump current circuit
2. The output pump current circuit
3. The reference voltage circuit
4. The low reference circuit

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 3 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.

DTC P0131 or P0151

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust stream more quickly and accurately 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 signal 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 signal voltage. The ECM monitors the voltage variation on the signal circuit, and attempts to keep the voltage constant by increasing or decreasing the amount of current flow or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal 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 system is lean, the oxygen level will be high and the lambda value will be high, or more than 1. When the system is rich, the oxygen level is low and the lambda value will be low, or less than 1. The ECM uses this information to maintain the proper air/fuel ratio. If the ECM detects an HO2S circuit that is shorted to voltage, DTC P0132 will set for bank 1 sensor 1, or DTC P0152 will set for bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0132 HO2S Circuit High Voltage Bank 1 Sensor 1
2. DTC P0152 HO2S Circuit High Voltage Bank 2 Sensor 1

1. DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0132, P0133, P0135, P0137, P0138, P0139, P0140, P0141, P0152, P0153, P0155, P0157, P0158, P0159, P0160, P0161, P1137, P1138, P1157, P1158, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2626, P2629, P167A, P167B are not set.
2. The engine is running.
3. DTC P0132 or P0152 runs continuously once the above conditions are met.

The ECM detects that one of the following HO2S circuits is shorted to voltage for more than 1 second

1. The input pump current circuit
2. The output pump current circuit
3. The reference voltage circuit
4. The low reference circuit

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 3 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.

DTC P0132 or P0152

The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust stream more quickly and accurately 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 signal 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 signal voltage. The ECM monitors the voltage variation on the signal circuit and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal 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 system is lean, the oxygen level will be high and the lambda value will be high, or more than 1. When the system is rich, the oxygen level is low and the lambda value will be low, or less than 1. The ECM uses this information to maintain the proper air/fuel ratio. The ECM uses the forced lean or the forced rich condition of the catalyst diagnostic to simultaneously test the response time of the HO2S. If the ECM detects that the amplitude of the HO2S signal does not match an expected value, DTC P0133 will set for bank 1 sensor 1 or DTC P0153 will set for bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0133 HO2S Slow Response Bank 1 Sensor 1
2. DTC P0153 HO2S Slow Response Bank 2 Sensor 1

1. DTCs P0021, P0024, P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0135, P0137, P0138, P0139, P0140, P0141, P0151, P0152, P0155, P0157, P0158, P0159, P0160, P0161, P0201-0208, P0221, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0279, P0280, P0282, P0283, P0300, P0301-0308, P0335, P0336, P0340, P0341, P0345, P0346, P0351-0358, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449, P0453, P0454, P0455, P0458, P0459, P0496, P2231, P2234, P2237, P2240, P2243, P2247, P2251, P2254, P2626, P2629, P167A, P167B are not set.
2. The HO2S Loop Status parameter is Closed.
3. The BARO parameter is more than 74 kPa.
4. The Engine Speed parameter is between 1,216-3,000 RPM.
5. The MAF Sensor parameter is between 13-83 g/s.
6. The catalyst diagnostic is running.
7. DTC P0133 or P0153 runs continuously once the above conditions are met.

The ECM detects that the amplitude of the HO2S signal does not match an expected value during the forced rich or forced lean portion of the catalyst diagnostic test for more than 2 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 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 10: This step will use the behavior of the HO2S input pump current circuit to determine if the HO2S output pump current circuit is shorted to ground.

DTC P0133 or P0153

See also:
• Engine Controls Schematics
• Diagnostic System Check - Vehicle
• Intermittent Conditions
• Wiring Repairs
• Circuit Testing
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Control Module References
• Diagnostic Trouble Code (DTC) List - Vehicle
• Ground Distribution Schematics
• Oil Pressure Diagnosis and Testing
• Oil Pump Outlet Tube Cleaning and Inspection
• Camshaft Timing Drive Chain Alignment Diagram
• Restricted Exhaust
• Checking Aftermarket Accessories
• Altitude Versus Barometric Pressure
• Measuring Voltage Drop
• Probing Electrical Connectors
• Testing for Short to Ground
• DTC P2089, P2091, P2093, or P2095
• Special Tools
• Engine Compression Test
• DTC P0641
• Using Connector Test Adapters
• Cooling System Draining and Filling (Static Fill)
• Cooling System Draining and Filling (GE 47716)
• Thermostat Diagnosis
• Temperature Versus Resistance
• Accelerator Pedal Position Sensor Replacement
• DTC P2251 or P2254
• Scan Tool Data List
• Exhaust Leakage
• Fuel System Diagnosis
• DTC P0135 or P0155
• DTC P0106