| Table 1: | APP Sensor Position Table |
Circuit Description
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal assembly. The sensor is actually 3 individual APP sensors within 1 housing. Three separate signal, low-reference and 5-volt reference circuits connect the APP sensor assembly to the throttle actuator control (TAC) module. Each sensor has a unique functionality.
TP sensor 1 and APP sensor 1 share a 5-volt reference circuit that are connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that are connected within the TAC module. If only 1 APP sensor DTC is set, the redundant APP systems allow the TAC system to continue operating normally. 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. If an out of range condition is detected with this APP sensor, this DTC will be set.
The table below shows the percentage and voltage readings of the scan tool based on the position of the APP.
APP Sensor | Actual Pedal Position | % Depressed as Observed on the Scan Tool | Voltage as Observed on the Scan Tool |
|---|---|---|---|
1 | Pedal at rest | 0 | Below 1.0 |
1 | Pedal at full travel | 100 | Above 2.0 |
2 | Pedal at rest | 0 | Above 4.0 |
2 | Pedal at full travel | 100 | Below 2.9 |
3 | Pedal at rest | 0 | Above 3.8 |
3 | Pedal at full travel | 100 | Below 3.1 |
Conditions for Running the DTC
| • | DTCs P1517 and P1518 are not set. |
| • | The ignition switch is in the crank or run position. |
| • | The ignition voltage is greater than 5.23 volts. |
Conditions for Setting the DTC
| • | Two or more APP sensors are out of range, or all 3 APP sensors disagree, or 1 APP sensor is out of range and the other 2 APP sensors disagree. |
| • | All of the above conditions exist for less than 1 second. |
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 MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | 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 emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Inspect the TAC module connectors for signs of water intrusion. When this condition occurs, multiple DTCs could be set without circuit or component conditions found during diagnostic testing. |
| • | The APP sensor 1 and the TP sensor 1, 5-volt reference circuits are internally connected within the TAC module. |
| • | The APP sensor 2 and the TP sensor 2, 5-volt reference circuits are internally connected within the TAC module. |
| • | 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. Be aware of this if you review the stored information in Capture Info. |
| • | For an intermittent, refer to Intermittent Conditions . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
This DTC indicates that two or more APP sensor DTCs are also set. Go to the APP sensor DTCs that are set and perform those diagnostic tests. Are any APP sensor DTCs set? | -- |
