P2123
DTC P2123
CIRCUIT DESCRIPTION
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within 1 housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the APP sensor with the engine control module (ECM). Each sensor has a unique functionality to determine the pedal position as shown in the table. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle via the fuel injector control. If the ECM determines high voltage in the APP sensor 1 circuit, DTC P2123 sets.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
CONDITIONS FOR RUNNING THE DTC
- DTCs P0642 or P0643 are not set.
- The ignition switch is in the Crank or Run position.
- The ignition voltage is between 7-16 volts.
- DTC P2123 runs continuously.
CONDITIONS FOR SETTING THE DTC
- The APP sensor 1 voltage is more than 4.75 volts.
- The above condition is present for less than 1 second.
ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- If one or more APP sensor DTCs are set for a single APP sensor, the following occurs:
- The control module will not command Reduced Engine Power mode.
- The control module will use the remaining two APP sensors to calculate throttle response.
- If certain multiple APP sensor DTCs are set for more than one 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 message center displays Reduced Engine Power.
- If all three APP sensors are out of range, the following occurs:
- The control module commands Reduced Engine Power mode.
- 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.
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
