Description:

This diagnostic trouble code (DTC) UIC 000091.02 is triggered when the control unit detects a mismatch between the output signals of the accelerator pedal potentiometer (B79). The voltage at channel 1 (lead 6066) must be double the voltage of channel 2 (lead 6045). If the voltages are not in this correct ratio, the system identifies a potential issue with the accelerator pedal sensor.

Reaction:

When this error occurs, the control unit may limit the engine performance to prevent unsafe operation. This might result in reduced acceleration or a “limp mode” to ensure the vehicle remains controllable.

Recommendations:

Inspect Accelerator Pedal Potentiometer:

• Check the wiring connections at the accelerator pedal potentiometer for any loose or damaged connectors.
• Measure the output voltages at channel 1 (lead 6066) and channel 2 (lead 6045) to confirm the discrepancy.
• Replace the accelerator pedal potentiometer (B79) if it is found to be faulty.

Verify Voltage Ratios:

• Ensure that the voltage at channel 1 is exactly double the voltage at channel 2. If the ratio is incorrect, recheck the wiring and sensor.

Check Control Unit:

• Inspect the control unit for any signs of damage or malfunction. Reset the control unit and clear the error code to see if it reoccurs.

Consult Technical Support:

• If the issue persists after the above checks, consult John Deere technical support for further assistance and potential software updates.

 

Note:

• In some cases, the mismatch in voltage ratios could be due to intermittent faults in the wiring or connectors. Ensure thorough inspection to avoid repeat occurrences.
• Keeping a log of the error code occurrences and the conditions under which they happen can help in diagnosing intermittent issues.