P2128
P2128-ACCELERATOR PEDAL POSITION SENSOR 2 CIRCUIT HIGH
For a complete wiring diagram refer to Diagrams/Electrical.
- When Monitored:
With the ignition on and no other APPS No.2 DTCs present.
- Set Condition:
When APP Sensor No.2 voltage is too high. Idle is additionally forced any time the brake is applied or failed. Acceleration rate and Engine output are limited. One trip fault and the code will set within 5 seconds. ETC light is flashing.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. ACTIVE DTC
Start the engine and allow it to reach normal operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.
NOTE: If you are viewing data recorder information or Freeze Frame data the APP Sensor No. 2 is pulled low by the PCM as part of its system testing. This test happens every 320 milliseconds and may not show up on the scan tool but may show up on a data recorder or lab scope. It is acceptable to see the voltage close to zero with a normal sensor when using a data recorder/lab scope.
With the scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go To 2
No
- Go To 8
2. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE
Turn the ignition off.
Disconnect the PCM harness connectors.
Disconnect the APP Sensor harness connector.
Ignition on, engine not running.
Measure the voltage on the (K29) APP Signal 2 circuit in the APP Sensor harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (K29) APP Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 3
3. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO THE (K857) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Measure the resistance between the (K29) APP Signal 2 circuit and the (K857) 5-volt Supply circuit in the APP Sensor harness connector.
Is the resistance below 10 ohms?
Yes
- Repair the short between the (K29) APP Signal 2 circuit and the (K857) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 4
4. (K29) APP SIGNAL 2 CIRCUIT SHORTED TO THE (K855) 5-VOLT SUPPLY CIRCUIT
Measure the resistance between the (K29) APP Signal 2 circuit and the (K855) 5-volt Supply circuit in the APP Sensor harness connector.
Is the resistance below 10 ohms?
Yes
- Repair the short between the (K29) APP Signal 2 circuit and the (K855) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 5
5. (K400) APP RETURN 2 CIRCUIT OPEN
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (K400) APP Return 2 circuit from the APP Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 6
No
- Repair the open in the (K400) APP Return 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
6. ACCELERATOR PEDAL POSITION SENSOR
Connect the PCM harness connectors.
Ignition on, engine not running.
With a scan tool, monitor the Accelerator Pedal Position Sensor voltage.
Is the voltage above 0 volts?
Yes
- Go To 7
No
- Replace the APP Sensor Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function to relearn the APPS values.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
7. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
8. APP SENSOR NO.2 SWEEP
Ignition on, engine not running.
With a scan tool, monitor the Accelerator Pedal Position Sensor voltage.
Slowly press the Accelerator Pedal down.
Does voltage start at approximately 0.22 of a volt and go above 2.31 volts with a smooth transition?
Yes
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
No
- Replace the APP Sensor Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function to relearn the APPS values.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test