Overview
| CODE | REASON | EFFECT |
| Fault Code: 131 PID: P91 SPN: 91 FMI: 3/3 LAMP: Red SRT: |
High voltage detected at accelerator pedal position number 1 circuit.
|
The engine will operate in Limp Home mode. |
Circuit Description
The accelerator position sensor is a Hall effect sensor attached to the accelerator pedal. The accelerator position sensor varies the signal voltage to the engine control module (ECM) as the accelerator pedal is depressed and released. Low signal voltage is received by the ECM when the accelerator pedal is at 0 percent. A high signal voltage is received by the ECM when the accelerator pedal is at 100 percent. The accelerator pedal position circuit contains an accelerator pedal position 5 volt supply, accelerator pedal position return, and accelerator pedal position signal.
The accelerator pedal contains two position sensors. Both position sensors receive a 5 volt supply from the ECM. The signal voltage from accelerator pedal position sensor 1 is twice as much as the signal voltage from the accelerator pedal position sensor 2.
Component Location
The accelerator pedal or lever position sensor is mounted to the accelerator pedal assembly. Refer to the OEM service manual.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.
Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the accelerator pedal signal voltage was out of range high.
Action Taken When the Fault Code is Active
- The ECM illuminates the red STOP ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
Conditions for Clearing the Fault Code
- To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
- The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
- The ECM will turn off the red STOP ENGINE lamp immediately after the diagnostic runs and passes.
- For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
- The “Reset All Faults” command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.
Shop Talk
Newer engines use two throttle position sensors to determine the throttle position. Older throttle pedals used a single throttle position sensor and an idle validation switch. If Fault Codes 132 and 1241 are active when the accelerator pedal is in the idle position, and Fault Code 132 goes inactive, and Fault Code 1239 goes active when the throttle is depressed, the incorrect throttle pedal has been installed in the vehicle. A throttle pedal with two acceleration position sensors must be installed.
If troubleshooting an intermittent accelerator problem:
The accelerator pedal or lever position sensor signal voltage can be monitored with the recommended Cummins® electronic service tool or equivalent, while flexing the harness to locate the intermittent connection. Intermittent connections will show up as abrupt changes in signal voltage displayed by the recommended Cummins® electronic service tool or equivalent.
Possible causes of this fault code include:
- Accelerator pedal or lever position signal circuit shorted to battery or (+) 5 volt supply
- Open accelerator pedal return circuit in the harness or connections
- Accelerator supply shorted to battery
- Malfunctioning accelerator pedal or lever position sensor.
NOTE: The three wires in the accelerator position sensor circuit must be twisted together.
- Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.
Troubleshooting Summary
Solution: S00000045
Verification
Conditions
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
Before troubleshooting this fault code, troubleshoot any fault code that is active or has more than one inactive count within the last 25 engine operating hours from the following list:
- Sensor supply 4: 2185, 2186
Linked Solutions
- None
Repair
- Perform a search on the appropriate fault codes.
Validation
- None
Solution: S00000444
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the accelerator pedal position sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Measure the voltage between the accelerator pedal position 1 sensor SUPPLY pin to the accelerator pedal position 1 sensor RETURN pin at the sensor connector of the OEM wiring harness.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- Proceed to the Linked Solutions section if voltage is not within the following specification: 4.75 – 5.25 VDC
Repair
- No additional action is required for this solution.
Validation
- None
Solution: S00000549
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the OEM wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the accelerator pedal position sensor SUPPLY pin at the accelerator pedal position sensor OEM wiring harness connector and the accelerator pedal position sensor SUPPLY pin at the OEM wiring harness ECM connector.
- Measure the resistance between the accelerator pedal position sensor RETURN pin at the accelerator pedal position sensor OEM wiring harness connector and the accelerator pedal position sensor RETURN pin at the OEM wiring harness ECM connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning OEM wiring harness has been detected if the resistance is greater than the following specification: 10 Ω
Linked Solutions
- None
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000368
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the accelerator pedal position sensor from the OEM wiring harness.
Action
- Inspect the pins and connectors for damage.
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
- Wait 30 seconds before checking the circuit response.
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
Specification
- A malfunctioning accelerator pedal position sensor has been detected if the following fault code became active with the sensor disconnected: 132
Linked Solutions
- None
Repair
- Replace the accelerator pedal position sensor.
Refer to OEM Service Manual
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000467
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the accelerator pedal position sensor from the OEM wiring harness.
- Disconnect the OEM wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the accelerator pedal position sensor SIGNAL pin at the accelerator pedal position sensor OEM wiring harness connector and the accelerator pedal position sensor SIGNAL pin at the OEM wiring harness ECM connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning OEM wiring harness has been detected if the resistance is greater than the following specification: 10 Ω
Linked Solutions
- None
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000468
Verification
Conditions
- Turn keyswitch OFF.
- Disconnect the accelerator pedal or lever from the OEM wiring harness.
- Disconnect the OEM wiring harness connector from the ECM.
Action
- Inspect the pins and connectors for damage.
- Measure the resistance between the accelerator pedal position sensor SIGNAL pin at the OEM wiring harness ECM connector and all other pins in that connector.
- Refer to the circuit diagram or wiring diagram for connector pin identification.
Specification
- A malfunctioning OEM wiring harness has been detected if the resistance is less than the following specification: 100k Ω
Linked Solutions
- None
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
Solution: S00000443
Verification
Conditions
- Connect all components.
- Turn keyswitch ON.
- Connect the recommended Cummins® electronic service tool or equivalent.
Action
- Use the recommended Cummins® electronic service tool or equivalent to read the fault codes.
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revision listed in the ECM calibration revision history for applicable changes.
Specification
- If a calibration update for this fault code is available, the ECM calibration revision must be that revision or higher.
Linked Solutions
- None
Repair
- Prior to downloading the ECM calibration, check to see that all job images and all other troubleshooting has been documented as downloading an ECM calibration will remove the fault codes on the ECM.
- Download the updated ECM calibration code.
Validation
- Connect all components
- Connect the recommended Cummins® electronic service tool or equivalent.
- Disable the fault code.
- Operate the engine within the “Conditions for Clearing the Fault Code” found in the Overview section of the troubleshooting procedure.
- Verify that the fault code is no longer active.
- Check ECM Calibration Revision History
- Use the recommended Cummins® electronic service tool or equivalent to find the current ECM code and revision number in the ECM.
- Compare the ECM code and revision number in the ECM to the calibration revisions listed in the ECM Calibration Revision History Database for applicable changes related to this fault code.
- Refer to ECM Calibration Revision History Database.
If all steps have been completed and no root cause has been identified, then follow the technical escalation process.