P2138
DTC P2138
CIRCUIT DESCRIPTION
The accelerator pedal position (APP) sensor 1 and APP sensor 2 are potentiometer type sensors, each with the following circuits:
- A 5-volt reference circuit
- A low reference circuit
- 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 and the APP sensor 2 signal voltages are both low at rest and increase as the pedal is depressed. When the control module detects that the APP sensor 1 and the APP sensor 2 signal circuits are out of correlation, DTC P2138 sets.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation
CONDITIONS FOR RUNNING THE DTC
- DTC P2107 is not set.
- The ignition is in the crank or run position.
- The Ignition 1 Signal parameter is more than 5.23 volts.
- The communication between the TAC module and the powertrain control module (PCM) must be valid.
CONDITIONS FOR SETTING THE DTC
The accelerator pedal position indicated by APP sensor 1 disagrees with the accelerator pedal position indicated by APP sensor 2 by more than 0.269 volts for longer than 135 milliseconds. This test occurs continuously.
OR
The PCM learned minimum accelerator pedal position of APP sensor 1 disagrees with the learned minimum accelerator pedal position of APP sensor 2. This test occurs once per ignition cycle at power-up.
OR
The PCM detects that the APP sensor 1 signal circuit is shorted to the APP sensor 2 signal circuit, to voltage, or to ground for longer than 100 milliseconds. This test occurs continuously.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- 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.
- The control module commands the TAC system to operate in the Reduced Engine Power mode.
- A message center or an indicator displays Reduced Engine Power.
- Under certain conditions the control module commands the engine OFF.
CONDITIONS FOR CLEARING THE DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.
TEST
