| 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. Three separate signal, low reference, and 5-volt reference circuits are used to interface the APP sensor with the engine control module (ECM). Each sensor has a unique functionality to determine pedal position as shown in the table below. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle via fuel injector control. If the ECM detects a condition with more than 1 sensor within the APP sensor, DTC P1125 sets.
APP Sensor | Actual Pedal Position | % Depressed as Observed on a Scan Tool | Voltage as Observed on a Scan Tool |
|---|---|---|---|
1 | Pedal at rest | 0 | .52 - .80 |
1 | Pedal at full travel | 100 | 2.12 - 2.78 |
2 | Pedal at rest | 0 | 4.25 - 4.53 |
2 | Pedal at full travel | 100 | 2.24 - 2.93 |
3 | Pedal at rest | 0 | 3.95 - 4.13 |
3 | Pedal at full travel | 100 | 2.69 - 3.16 |
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 in the Crank or Run position. |
| • | The ignition voltage is between 7-16 volts. |
Conditions for Setting the DTC
| • | The ECM detects a condition with more than one APP sensor. |
| • | 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. |
Diagnostic Aids
| • | The APP sensor 2, 5-volt reference circuit is shared with the barometric pressure (BARO) sensor and the turbo boost solenoid, and they are internally connected within the ECM. |
| • | For an intermittent, refer to Intermittent Conditions . |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |
2 | Is DTC P0642, P0643, P0652, P0653, P0698, or P0699 also set? | Go to Step 3 | |
3 | Are any other APP sensor DTCs set? | -- |
