Circuit Description
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal assembly. The sensor is actually 3 individual APP sensors within one housing. Three separate signal, low reference and 5-volt reference circuits connect the APP sensor assembly and the throttle actuator control (TAC) module. Each sensor has a unique functionality. The APP sensor 1 signal increases as the accelerator pedal is depressed, from below 1 volt at 0 percent pedal travel, with the pedal at rest, to above 2 volts at 100 percent pedal travel, with the pedal fully depressed. The APP sensor 2 signal decreases from above 4 volts at 0 percent pedal travel, to below 2.9 volts at 100 percent pedal travel. The APP sensor 3 signal decreases from around 3.8 volts at 0 percent pedal travel, to below 3.1 volts at 100 percent pedal travel. Notice that the signal circuits for APP sensor 2 and APP sensor 3 pull up to 5 volts and the APP sensor 1 signal circuit is referenced to low reference within the TAC module.
Conditions for Running the DTC
| • | DTCs P0606, P1517, and P1518 are not set. |
| • | The ignition is in the crank or run position. |
| • | The ignition voltage is greater than 5.23 volts. |
Conditions for Setting the DTC
| • | The APP sensor 3 voltage is less than 01.63 volts, or greater than 4.28 volts. |
| • | All above conditions are 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
| • | Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs could be set with no circuit or component conditions found during diagnostic testing. |
| • | When the TAC module detects throttle movement with a DTC P1285 set, a DTC P1286 also sets. |
| • | 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. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, 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 | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Important: If DTC P1518 or P1220 is also set, refer to Diagnostic Trouble Code (DTC) List for further diagnosis.
Does the scan tool indicate APP sensor 3 voltage within the specified values? | 3.29-4.28 V | Go to Step 3 | Go to Step 6 |
3 | Fully depress the accelerator pedal to the wide open throttle (WOT) position. Does the scan tool indicate APP sensor 3 voltage within the specified values? | 1.63-3.1 V | Go to Step 4 | Go to Step 6 |
4 |
Did this DTC fail this ignition during the above test? | -- | Go to Step 20 | Go to Step 5 |
5 | Slowly depress the accelerator pedal to WOT and then slowly return the pedal to the released position. Did this DTC fail this ignition during the above test? | -- | Go to Step 21 | Go to Diagnostic Aids |
6 |
Does the DMM indicate APP sensor 3 signal voltage within the specified values? | 3.94-6.06 V | Go to Step 11 | Go to Step 7 |
7 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 8 |
8 | Use a DMM in order to test the APP sensor 3 signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 9 |
9 | Use a DMM in order to test the APP sensor 3 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 10 |
10 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 23 |
11 | Use a DMM in order to test the APP sensor 3, 5-volt reference circuit for voltage. Does the DMM indicate voltage within the specified values? | 3.94-6.06 V | Go to Step 16 | Go to Step 12 |
12 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 13 |
13 | Use a DMM in order to test the APP sensor 3, 5-volt reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 14 |
14 | Use a DMM in order to test the APP sensor 3, 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 15 |
15 | Use a DMM in order to test for a short between the APP sensor 3, 5-volt reference circuit and all other TAC module circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 23 |
16 | With a DMM connected between the APP sensor 3 low reference circuit and the APP sensor 1 low reference circuit, measure the resistance. Does the DMM indicate resistance within the specified values? | 0-5 ohms | Go to Step 18 | Go to Step 17 |
17 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 23 |
18 |
Does the scan tool indicate APP sensor 3 voltage at the specified value? | 0 V | Go to Step 19 | Go to Step 24 |
19 |
Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 21 |
20 | Repair the intermittent connection as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 25 | -- |
21 | Inspect for poor connections at the harness connector of the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 22 |
22 | Replace the APP sensor assembly. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 25 | -- |
23 | Inspect for poor connections at the harness connector of the TAC module . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 25 | Go to Step 24 |
24 | Replace the TAC module. Refer to Electronic Throttle Actuator Control Module Replacement . Did you complete the replacement? | -- | Go to Step 25 | -- |
25 |
Does the DTC run and pass? | -- | Go to Step 26 | Go to Step 2 |
With a scan tool, observe the stored information, Capture info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | ||
