Engine Controls - 8.1l (DTC p0601 to p2a04) Chevrolet Cab & Chassis Silverado 3500

Circuit Description

This diagnostic applies to internal microprocessor integrity conditions within the powertrain control module (PCM). This diagnostic also addresses whether or not the PCM is not programmed.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0601 Control Module Read Only Memory (ROM)
2. DTC P0602 Control Module Not Programmed
3. DTC P0604 Control Module Random Access Memory (RAM)
4. DTC P0606 Control Module Internal Performance
5. DTC P2610 Control module Ignition Off Timer Performance

Conditions For Running The DTC

DTC P0601

1. The ignition switch is in the Run or Crank position.
2. DTC P0601 runs continuously when the above condition is met.

DTC P0602

1. The ignition switch is in the ON position.
2. DTC P0602 runs continuously when the above condition is met.

DTC P0604

1. The ignition switch is in the Run or Crank position.
2. DTC P0604 runs continuously when the above condition is met.

DTC P0606

1. The ignition switch is in the Run or Crank position, or the key is being turned OFF.
2. DTC P0606 runs continuously when the above condition is met.

DTC P2610

1. The PCM is powered down.
2. DTC P2610 runs once every time the key is turned OFF.

Conditions For Setting the DTC

The PCM detects an internal failure or incomplete programming for more than 5 seconds.

Action Taken When DTCs P0601, P0602, P0604, P0606 Set

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.

Action Taken When DTC P2610 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/DTCs P0601, P0602, P0604, P0606, P2610

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.

Test Description

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

1. 2: A DTC P0602 indicates the PCM is not programmed.

DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

The powertrain control module (PCM) provides 5 volts to the following sensors

1. The engine oil pressure (EOP) sensor
2. The manifold absolute pressure (MAP) sensor

These 5-volt reference circuits are independent of each other outside the PCM, but are bussed together inside the PCM. Therefore a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The PCM monitors the voltage on the 5-volt reference circuit. If the PCM detects that the voltage is out of tolerance, DTC P0641 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0641 5-Volt Reference 1 Circuit

1. The engine is running.
2. DTC P0641 runs continuously when the above condition is met.

The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit for more than 2 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 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. 9: A short to voltage on the signal circuit of the MAP sensor will backfeed through the sensor into the 5-volt reference circuit and set this DTC.

DTC P0641

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. For example, a failure condition exists if the control module detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.

This diagnostic procedure supports the following DTC

DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit

1. The engine speed is more than 400 RPM.
2. DTC P0650 runs continuously when the above condition is met.

The control module detects that the commanded state of the MIL driver and the actual state of the control circuit do not match for more than 5 seconds.

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. 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 emission related diagnostic.
3. Clear the MIL and the DTC with a scan tool.

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

1. 5: This step tests for a short to ground in the MIL control circuit. With the powertrain control module (PCM) disconnected and the ignition ON, the MIL should be OFF.
2. 6: This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be no voltage on the MIL control circuit.

DTC P0650

The powertrain control module (PCM) provides 5 volts to the following sensors

1. The air conditioning (A/C) pressure sensor.
2. The fuel tank pressure (FTP) sensor, if equipped.

These 5-volt reference circuits are independent of each other outside the PCM, but are bussed together inside the PCM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The PCM monitors the voltage on the 5-volt reference circuit. If the PCM detects that the voltage is out of tolerance, DTC P0651 sets.

This diagnostic procedure supports the following DTC

DTC P0651 5-Volt Reference 2 Circuit

1. The engine is running.
2. DTC P0651 runs continuously when the above condition is met.

The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit 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.

DTC P0651

The transmission control module (TCM) malfunction indicator lamp (MIL) request circuit signals the powertrain control module (PCM) that the TCM is requesting MIL illumination.

This diagnostic procedure supports the following DTC

DTC P0802 Transmission Control Module (TCM) MIL Request Circuit

1. The ignition is ON for less than 7 seconds.
2. The ignition voltage is more than 11 volts.
3. DTC P0802 runs continuously when the above conditions are met.

The PCM is detecting an incorrect voltage level on the TCM MIL request 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 P0802

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is intermittently high, DTC P1106 sets.

This diagnostic procedure supports the following DTC

DTC P1106 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent High Voltage

1. DTCs P0068, P0120, P0220, P2135 are not set.
2. The engine is running.
3. The throttle angle is less than 0.4 percent when the engine speed is less than 1,200 RPM. OR The throttle angle is less than 20 percent when the engine speed is more than 1,200 RPM.
4. DTC P1106 runs continuously when the above conditions are met.

The PCM detects that the MAP sensor voltage is intermittently more than 4.9 volts for a calibrated amount of time.

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.

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

1. 3: This step attempts to pinpoint the location of the intermittent fault.

DTC P1106

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is intermittently low, DTC P1107 sets.

This diagnostic procedure supports the following DTC

DTC P1107 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage

1. DTCs P0068, P0120, P0220, P0641, P0651, P2135 are not set.
2. The ignition is ON.
3. The throttle angle is more than 0 percent when the engine speed is less than 800 RPM. OR The throttle angle is more than 12.5 percent when the engine speed is more than 800 RPM.
4. DTC P1107 runs continuously when the above conditions are met.

The PCM detects that the MAP sensor voltage is intermittently less than 0.055 volt for a calibrated amount of time.

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.

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

1. 3: This step attempts to pinpoint the location of the intermittent fault.

DTC P1107

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 powertrain control module (PCM) 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 PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an intermittent high IAT signal voltage, indicating a low temperature, DTC P1111 sets.

This diagnostic procedure supports the following DTC

DTC P1111 Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

1. DTCs P0101, P0102, P0103, P0113 are not set.
2. The engine run time is more than 120 seconds.
3. The ECT Sensor parameter is more than 60°C (140°F).
4. The vehicle speed is less than 11 km/h (7 mph).
5. The mass air flow is less than 15 g/s.
6. DTC P1111 runs continuously when the above conditions are met.

The PCM detects that the IAT Sensor parameter is less than -38°C (-36°F) intermittently for a calibrated amount of time.

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.

Diagnostic Aids

1. An IAT sensor or PCM which is intermittently shorted, open, or skewed is possible, yet very unlikely.
2. A skewed sensor could result in poor driveability conditions.
3. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-81l-troubleshooting-diagnosis__intermittent-conditions) .

DTC P1111

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 powertrain control module (PCM) 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 PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an intermittent low IAT signal voltage, indicating a high temperature, DTC P1112 sets.

This diagnostic procedure supports the following DTC

DTC P1112 Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage

1. DTC P0112 is not set.
2. The engine run time is more than 45 seconds.
3. The vehicle speed is more than 40 km/h (25 mph).
4. The ECT Sensor parameter is less than 125°C (257°F).
5. DTC P1112 runs continuously when the above conditions are met.

The PCM detects that the IAT Sensor parameter is more than 128°C (262°F) intermittently for a calibrated amount of time.

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

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

1. An IAT sensor or PCM which is intermittently shorted, open, or skewed is possible, yet very unlikely.
2. A skewed sensor could result in poor driveability conditions.
3. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-81l-troubleshooting-diagnosis__intermittent-conditions) .

DTC P1112

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) 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 lowers. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P1114 sets.

This diagnostic procedure supports the following DTC

DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage

1. The engine run time is more than 10 seconds. OR The engine run time is less than 10 seconds when the intake air temperature (IAT) is less than 50°C (122°F)
2. DTC P1114 runs continuously when the above condition is met.

The PCM detects that the ECT Sensor parameter is more than 138°C (280°F) intermittently for a calibrated amount of time.

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

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

1. An ECT sensor or PCM which is intermittently shorted, open, or skewed is possible, but very unlikely
2. An intermittent short to ground in the ECT sensor signal circuit could result in a DTC P1114.
3. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-81l-troubleshooting-diagnosis__intermittent-conditions) .

DTC P1114

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) 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 lowers. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high signal voltage, which is a low temperature indication, DTC P1115 sets.

This diagnostic procedure supports the following DTC

DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

1. The engine run time is more than 60 seconds. OR The engine run time is less than 60 seconds when the intake air temperature is more than 0°C (32°F).
2. DTC P1115 runs continuously when the above condition is met.

The PCM detects that the ECT Sensor parameter is less than -38°C (-36°F) intermittently for a calibrated amount of time.

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

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

1. An ECT sensor or PCM which is intermittently shorted, open, or skewed is possible, but very unlikely
2. An intermittent open or a short to voltage in the ECT sensor signal circuit could result in DTC P1115 setting. Refer to «Intermittent Conditions»(/chevrolet/cab-chassis-silverado-3500/2004-2007/remont/testing-diagnostics/#engine-controls-81l-troubleshooting-diagnosis__intermittent-conditions) .

DTC P1115

The accelerator pedal position (APP) sensor is mounted on the accelerator pedal assembly. The sensor is actually two individual APP sensors within one housing. Two separate signal circuits are used to connect the accelerator pedal sensor assembly and the throttle actuator control (TAC) module.

If only one APP sensor DTC is set, the redundant APP systems allow the TAC system to continue operating normally. This DTC sets if the powertrain control module (PCM) detects a condition with more than one APP sensor. One APP sensor DTC will not cause the Reduced Engine Power message to be displayed. Two APP sensor DTCs for the same sensor also will not cause the Reduced Engine Power message to be displayed. However, if two or more DTCs are set involving more than one APP sensor, this DTC will set and the Reduced Engine Power message is displayed.

This diagnostic procedure supports the following DTC

DTC P1125 Accelerator Pedal Position (APP) System

1. DTCs P2108 or U0107 are not set.
2. The ignition switch is in the Crank or Run position.
3. The ignition voltage is greater than 5.23 volts.
4. DTC P1125 runs continuously when the above conditions are met.

1. Two or more APP sensors are out of range. OR
2. The APP sensors disagree.
3. The above condition is present 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.

1. Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. The APP sensor 1 and the throttle position (TP) sensor 1 5-volt reference circuits are internally connected within the TAC module.
3. The APP sensor 2 and the TP sensor 2 5-volt reference circuits are internally connected within the TAC module.
4. When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Remember this if you review the information stored in Captured Info.
5. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

DTC P1125

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. The PCM monitors the number of rich-to-lean and lean-to-rich transitions. If the PCM detects that the number of transitions were less than a specified value, DTC P1133 sets for HO2S bank 1 sensor 1, or DTC P1153 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P1133 HO2S Insufficient Switching Bank 1 Sensor 1
2. DTC P1153 HO2S Insufficient Switching Bank 2 Sensor 1

1. DTCs P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The EVAP Purge Solenoid Command parameter is more than 1 percent.
4. The MAF Sensor parameter is between 20-55 g/s.
5. The Engine Speed parameter is between 1,200-3,000 RPM.
6. The TP Indicated Angle parameter is 5 percent more than the value observed at idle.
7. The Loop Status parameter is closed.
8. The Ignition 1 Signal parameter is between 10-18 volts.
9. The Fuel Tank Level Remaining parameter is more than 10 percent.
10. The Engine Run Time parameter is more than 160 seconds.
11. This diagnostic runs one time per drive cycle once the above conditions are met.

The PCM detects that the affected HO2S lean-to-rich or rich-to-lean transitions are less than a calibrated value for a 100 second monitoring period.

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. 2: If the voltage is varying above and below the specified value, the condition is not present.

DTC P1133 or P1153

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. The PCM monitors the rich-to-lean and lean-to-rich transition time. A transition is defined as, the HO2S voltage changes from above 625 mV to below 250 mV or from below 250 mV to above 625 mV. If the PCM detects that the difference between the rich-to-lean average transition time and lean-to-rich average transition time is more than a specified value, DTC P1134 sets for HO2S bank 1 sensor 1, or DTC P1154 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P1134 HO2S Transition Time Ratio Bank 1 Sensor 1
2. DTC P1154 HO2S Transition Time Ratio Bank 2 Sensor 1

1. DTCs P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The EVAP Purge Solenoid Command parameter is more than 1 percent.
4. The MAF Sensor parameter is between 20-55 g/s.
5. The Engine Speed parameter is between 1,200-3,000 RPM.
6. The TP Indicated Angle parameter is 5 percent more than the value observed at idle.
7. The Loop Status parameter is closed.
8. The Ignition 1 Signal parameter is between 10-18 volts.
9. The Fuel Tank Level Remaining parameter is more than 10 percent.
10. The Engine Run Time parameter is more than 160 seconds.
11. This diagnostic runs one time per drive cycle once the above conditions are met.

The PCM detects that the difference between the HO2S rich-to-lean average transition time and the lean-to-rich average transition time is more than a calibrated value for a 100 second monitoring period.

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. 2: If the voltage is varying above and below the specified value, the condition is not present.

DTC P1134 or P1154

System Description

The powertrain control module (PCM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft speed. By monitoring the wheel speed sensors, the antilock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to effect misfire detection, a rough road signal is sent to the PCM on the serial data circuit. If DTC P0300 is set with the malfunction indicator lamp (MIL) illuminated, and the rough road information is not available due to an ABS malfunction, DTC P1380 will set.

This diagnostic procedure supports the following DTC

DTC P1380 Misfire Detected - Rough Road Data Not Available

1. The vehicle speed is more than 8 km/h (5 mph).
2. The engine load is less than 60 percent.
3. The engine misfire is detected and DTC P0300 is set with the MIL illuminated.
4. The engine speed is less than 7,000 RPM.
5. DTC P1380 runs continuously when the above conditions are met.

An ABS malfunction exists for more than 45 seconds, preventing the PCM from receiving rough road detection data.

1. The control module stores the DTC information into memory 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 Failure Records.
3. 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 P1380

The powertrain control module (PCM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft speed. By monitoring the wheel speed sensors, the antilock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to effect misfire detection, a rough road signal is sent to the PCM on the serial data circuit. If DTC P0300 is set with the malfunction indicator lamp (MIL) illuminated, and there is no communication with the brake control module, DTC P1381 will set.

This diagnostic procedure supports the following DTC

DTC P1381 Misfire Detected - No Communication with Brake Control Module

1. The vehicle speed is above 8 km/h (5 mph).
2. The engine speed is below 7,000 RPM.
3. The engine load is less than 60 percent.
4. Engine misfire is detected and DTC P0300 is set with the MIL illuminated.
5. DTC P1381 runs continuously when the above conditions are met.

The PCM cannot communicate with the brake control module for more than 45 seconds.

1. The control module stores the DTC information into memory 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 Failure Records.
3. 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 P1381

The predicted throttle position (TP) is compared to the actual throttle position. The two values should be within a calibrated range of each other. Both the powertrain control module (PCM) and the throttle actuator control (TAC) module redundantly monitor the predicted and actual throttle position. This DTC sets if the PCM detects an out of range condition between the predicted and actual throttle position.

This diagnostic procedure supports the following DTC

DTC P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

1. DTC U0107 is not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. The TAC System is not in the battery saver mode.
5. This diagnostic runs continuously when the above conditions are met.

1. The TAC module detects that the predicted and the actual throttle positions are not within a calibrated range of each other.
2. The PCM and the TAC cannot determine the throttle position.
3. Both of the TP sensors are invalid.
4. All of the above conditions are met for more than 1 second.

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

1. Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. Verify that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
3. When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing an individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
4. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 7: If the TP indicated angle does not follow the movement of the throttle blade and no TP sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
2. 18: Locating and repairing an individual condition may correct more than one DTC.

DTC P1516

The commanded throttle position (TP), based on accelerator pedal position (APP) and possibly other limiting factors, is compared to the actual TP. The 2 values should be within a calibrated range of each other. Both the powertrain control module (PCM) and the throttle actuator control (TAC) module redundantly monitor the commanded and actual TP. This DTC sets if the PCM detects an out-of-range condition between commanded and actual pedal position.

This diagnostic procedure supports the following DTC

DTC P2101 Control Module Throttle Actuator Position Performance

1. DTCs P0601, P0602, P0604, P0606, P1516, P2108, U0107 are not set.
2. DTCs P0120 and P0220 are not active at the same time.
3. The ignition switch is in the crank or run position.
4. The ignition voltage is more than 8.5 volts.
5. The TAC System is not in the battery saver mode.
6. This diagnostic runs continuously when the above conditions are met.

1. The PCM detects that the commanded and actual throttle positions are not within a calibrated range of each other.
2. The above condition is met for less than 1 second.

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

1. Inspect for mechanical concerns or binding that may be temperature related. Components may not move freely in extreme heat or cold due to the presence of contaminants or ice formation.
2. Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
3. When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing an individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
4. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 4: If the TP indicated angle does not follow the movement of the throttle blade, and no TP sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
2. 15: Locating and repairing an individual condition may correct more than one DTC.

DTC P2101

The throttle actuator control (TAC) module contains data which is essential for proper TAC System operation. The TAC module continuously tests the integrity of this data. When the TAC module is unable to write or read data to and from random access memory (RAM), or the TAC module is unable to correctly read data from the flash memory or an internal TAC module processor fault is detected, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2108 Throttle Actuator Control (TAC) Module Performance

1. DTC U0107 is not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is greater than 6 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. The TAC module determines that an internal data test did not pass.
2. The above condition is met for more than 1 second.

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

1. Verify that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
2. Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
3. When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing an individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.

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

1. 4: Locating and repairing an individual condition may correct more than 1 DTC.

DTC P2108

The accelerator pedal position (APP) sensor 1 is a potentiometer type sensor with the following three circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

The control module provides the APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensor then provides the control module a signal voltage proportional to pedal movement. The APP sensor 1 signal voltage is low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 1 signal or APP sensor 5-volt reference voltage is outside the predetermined range, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit

1. DTCs P0601, P0602, P0606, P2108, or U0107 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. The APP sensor 1 voltage is less than 0.24 volts or more than 4.49 volts. OR
2. The 5-volt reference is less than 4.54 volts or more than 5.21 volts.
3. One of the above conditions is present for more than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. OR The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

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

1. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
3. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 12: This test isolates whether the short is to another TAC System circuit in the harness or within the TAC module.
2. 26: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.

DTC P2120

The accelerator pedal position (APP) sensor 1 and APP sensor 2 are potentiometer type sensors, each with the following circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

The control module provides the APP sensors a 5-volt reference circuit and a low reference circuit. The APP sensors then provide the control module signal voltages proportional to pedal movement. The APP sensor 1 signal voltage is low at rest and increases as the pedal is depressed. The APP sensor 2 signal voltage is also low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 1 signal and the APP sensor 2 signal circuits are out of correlation, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2121 Accelerator Pedal Position (APP) Sensor 1 Performance

1. DTCs P0606, P2108, or U0107 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. APP sensor 1 disagrees with APP sensor 2 by more than 10.5 percent.
2. The above condition is present for more than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set for a single APP sensor, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

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

1. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
3. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 2: This step determines if a communication condition exists.
2. 5: This step isolates an internal APP sensor failure. The condition may only occur at a certain accelerator pedal position. Monitoring the APP angles for sensor 2 and sensor 3 is an accurate way of verifying the actual position of the pedal. The APP angles for all 3 sensors should be within a few percent of each other. If the pedal is at rest, the APP angle for all 3 sensors should be 0 percent. If the pedal is fully depressed, all APP angles should be 100 percent.
3. 6: The APP sensor 1 shares a common 5-volt reference circuit with the throttle position (TP) sensor 1. Monitoring the TP sensor 1 voltage aids in diagnosing the APP sensor 5-volt reference and low-reference circuits. If the scan tool displays near 0 volts, the circuits are OK.
4. 9: With the TAC module still connected, this test will help determine a short to the signal circuit either within the TAC module or wiring.
5. 10: This step determines whether the TAC module or a shorted circuit is causing the condition.
6. 19: When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.

DTC P2121

The accelerator pedal position (APP) sensor 2 is a potentiometer type sensor with the following circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

The control module provides the APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensor then provides the control module a signal voltage proportional to pedal movement. The APP sensor 1 signal voltage is low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 2 signal or the APP sensor 5-volt reference voltage is outside the predetermined range, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2125 Accelerator Pedal Position (APP) Sensor 2 Circuit

1. DTCs P0601, P0602, P0606, P2108, U0107 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. The APP sensor 2 voltage is less than 0.24 volt or more than 4.49 volts. OR
2. The 5-volt reference is less than 4.54 volts or more than 5.21 volts.
3. One of the above conditions is present for more than 1 second.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. If one or more APP sensor DTCs are set, the following occurs: The control module commands Reduced Engine Power mode. The APP indicated angle is limited to a predetermined value to limit the amount of throttle control. OR The APP indicated angle is limited to 0 percent. The control module only allows the engine to idle. The message center displays Reduced Engine Power.

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

1. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
3. For an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 2: The throttle position (TP) sensor 2 and the APP sensor 2 share a common 5-volt reference source. Diagnose DTC P0220 first if P0220 is also set.
2. 18: This test determines whether or not the TAC module can recognize a change in signal voltage.
3. 19: There are 2 separate 5-volt reference sources within the TAC module. The TP sensor 1 and the APP sensor 1 share one 5-volt reference source. The TP sensor 2 and the APP sensor 2 share another common 5-volt reference source. This test determines whether the signal circuit is shorted to any one of the 5-volt reference circuits. If a short exists, the corresponding sensor voltage will be pulled low.
4. 20: The previous step found the signal circuit and a 5-volt reference circuit shorted together. This test isolates whether the short is in the harness or within the TAC module.
5. 26: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.

DTC P2125

The throttle position (TP) sensors 1 and 2 are potentiometer type sensors each with three circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

The TP sensors are used to determine the throttle plate angle for various engine management systems. The control module provides each TP sensor a 5-volt reference circuit and a low reference circuit. The TP sensors then provide the control module with signal voltage proportional to throttle plate movement. Both TP sensor signal voltages are low at closed throttle and increase as the throttle opens. When the control module detects that TP sensor 1 signal and TP sensor 2 signals disagree or signal voltages are outside the predetermined range, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2135 Throttle Position (TP) Sensor 1-2 Correlation

1. DTCs P2108, or U0107 not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. The TP sensor 2 disagrees with the TP sensor 1 by more than 7.5 percent.
2. The above condition is present for more than 1 second.

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

1. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
3. If this DTC is determined to be intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-197325-S02683201702005101100000) .

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

1. 21: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.

DTC P2135

The secondary fuel pump is located in the rear fuel tank. The secondary fuel pump is powered by a secondary fuel pump relay. Fuel is transferred from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to the primary fuel pump. The secondary fuel pump relay supply voltage is received from the primary fuel pump relay when the primary fuel pump is energized. This DTC sets when the powertrain control module (PCM) commands the secondary fuel pump ON and a predetermined change in both the front and rear fuel level sensors does not occur.

This diagnostic procedure supports the following DTC

DTC P2636 Fuel Transfer Pump Flow Insufficient

1. DTCs P0461, P0462, P0463, P2066, P2067, P2068 are not set.
2. The vehicle speed is 0 km/h (0 mph).
3. The engine has been idling for more than 2 minutes and 20 seconds.
4. The primary fuel level is less than 60 L (15.8 gal).
5. The secondary fuel level is more than 3 L (2.6 gal).

The PCM does not detect a change of 4 L (1.06 gal), in both the primary and the secondary fuel level sensors, with the secondary pump commanded ON for 120 seconds.

1. The PCM stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The PCM records the operating conditions at the time the diagnostic fails. The PCM 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.

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

1. 2: This step tests the supply voltage circuit of the secondary fuel pump relay. The test lamp should illuminate as the primary fuel pump is commanded ON.
2. 4: This step verifies the secondary fuel pump operation. Listen for an audible sound as the secondary fuel pump relay harness connector is jumpered.
3. 5: This step verifies that there is adequate fuel in the rear fuel tank. The rear fuel tank sensor voltage must be above 1 volt in order to continue.
4. 7: This step tests the secondary fuel pumps ability to transfer fuel. The rear fuel level sensor voltage should decrease while the secondary fuel pump is ON.
5. 8: This step tests for a short to ground on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to ground is indicated.
6. 9: This step tests for a short to voltage on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to voltage is indicated.
7. 10: This step verifies the secondary fuel pump relay operation. An audible click should be heard as the secondary fuel pump relay control circuit is grounded. The secondary fuel pump should turn ON as the fuel pump relay control circuit is grounded.

DTC P2636

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream.

The HO2S bank 1 sensor 2 and HO2S bank 2 sensor 2 are used for catalyst monitoring. This diagnostic runs once per ignition cycle. This diagnostic consists of two tests, a passive test and an intrusive test. During the passive test, if the HO2S bank 1 sensor 2 or HO2S bank 2 sensor 2 voltage transitions below 349 mV and above 710 mV, the DTC will pass for this ignition cycle. If the DTC does not pass during the passive test, the intrusive test will begin. During the intrusive test, the control module will force the air-to-fuel ratio rich and/or lean. The control module then waits for a predicted response from the HO2S. If the HO2S voltage transitions below 349 mV and/or above 710 mV, the DTC will pass for this ignition cycle. If the control module does not receive the expected response from the HO2S, DTC P2A01 will set for HO2S bank 1 sensor 2 or DTC P2A04 will set for HO2S bank 2 sensor 2.

This diagnostic procedure supports the following DTCs

1. DTC P2A01 HO2S Circuit Bank 1 Sensor 2
2. DTC P2A04 HO2S Circuit Bank 2 Sensor 2

DTCs P0053, P0054, P0059, P0060, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0200, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1134, P1153, P1154 are not set.

Passive Test

1. The engine is running.
2. The Engine Run Time parameter is less than 13.5 minutes.
3. This diagnostic runs one time per drive cycle once the above conditions are met.

Intrusive Test

1. The Engine Run Time parameter is more than 13.5 minutes.
2. The Ignition 1 Signal parameter is between 10-18 volts.
3. The Engine Speed parameter is between 900-5,000 RPM.
4. The MAF Sensor parameter is between 5-100 g/s.
5. The Vehicle Speed parameter is between 24-131 km/h (15-82 mph).
6. The Short Term FT Bank 1 and Bank 2 parameter is between -10 and +10 percent.
7. The maximum number of intrusive attempts is less than 100.
8. This diagnostic runs one time per drive cycle once the above conditions are met.

1. This diagnostic concludes within 15.5 minutes.
2. The PCM detects that the HO2S bank 1 sensor 2 or HO2S bank 2 sensor 2 did not transition below 349 mV and above 710 mV during the passive test.
3. One of the following tests fail: Lean Intrusive Test The PCM detects that the HO2S bank 1 sensor 2 or HO2S bank 2 sensor 2 is more than 349 mV for 60 seconds. The HO2S bank 1 sensor 1 and HO2S bank 2 sensor 1 is less than 300 mV. OR Rich Intrusive Test The PCM detects that the HO2S bank 1 sensor 2 or HO2S bank 2 sensor 2 is less than 710 mV for 60 seconds. The HO2S bank 1 sensor 1 and HO2S bank 2 sensor 1 is more than 600 mV.

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. 2: If the voltage does not change more than the specified value, the condition is present.

DTC P2A01 or P2A04

See also:
• Service Programming System (SPS)
• Engine Controls Schematics
• Engine Controls Connector End Views
• Powertrain Control Module (PCM) Connector End Views
• Engine Oil Pressure Sensor and/or Switch Replacement
• Intermittent Conditions
• DTC P0113
• Scan Tool Data List
• Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)
• Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool)
• Oil Consumption Diagnosis
• Symptoms - Antilock Brake System
• DTC U0107
• DTC P2135