| Table 1: | APP Sensor Position Table |
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 one housing.
The APP sensor 1, 2 and APP sensor 3 are potentiometer type sensors, each with the following circuits:
| • | A 5-volt reference circuit |
| • | A low reference circuit |
| • | A signal circuit |
The engine control module (ECM) provides the APP sensors a 5-volt reference circuit and a low reference circuit. The APP sensors then provide the ECM 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 high at rest and decreases as the pedal is depressed. The APP sensor 3 signal voltage is high at rest and decreases as the pedal is depressed. If the ECM detects two or more APP open, this DTC will set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1125 Accelerator Pedal Position (APP) System
Conditions for Running the DTC
| • | The ignition switch is ON. |
| • | The ignition voltage is between 7-16 volts. |
Conditions for Setting the DTC
Two or three sensor signals contain an open circuit.
Action Taken When the DTC Sets
| • | The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | The ECM inhibits cruise control. |
| • | The ECM inhibits power take-off (PTO) control. |
Conditions for Clearing the DTC
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
If an intermittent condition is suspected, the following may cause an intermittent:
| • | Poor connections |
| • | Misrouted harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
Inspect for the following conditions:
| • | Poor connection at ECM--Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the DTC P1125 display on the scan tool while moving connectors and wiring harness related to the sensor. A change in the display will indicate the location of the fault. |
APP Sensor | Actual Pedal Position | % Depressed as Observed on a Scan Tool | Voltage as Observed on a Scan Tool |
|---|---|---|---|
1 | Pedal at rest | 0 | 0.52-0.80 |
1 | Pedal at full travel | 100 | 2.38-2.66 |
2 | Pedal at rest | 0 | 4.20-4.48 |
2 | Pedal at full travel | 100 | 2.34-2.62 |
3 | Pedal at rest | 0 | 3.92-4.09 |
3 | Pedal at full travel | 100 | 2.79-2.96 |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | Is DTC P0641 or P0651 also set? | Go to Step 3 | |
3 | Are any other accelerator pedal position (APP) sensor DTCs set? | -- |
