John Deere 91.08 – Cab Module (OIC) / Engine Control Unit (ECU): Accelerator Pedal Signal Voltage Out Of Range

The Engine Control Module (ECM) or Cab Control Unit (CAB) has detected an abnormal frequency or update rate from the accelerator pedal position sensor. Although the code name implies a voltage issue, it actually indicates the signal is erratic, dropping out, or not updating as frequently as expected. This is often caused by intermittent harness connections, poor grounds, electromagnetic interference (EMI), or fretting corrosion. When this fault occurs, the system may default the throttle position to zero, limiting the engine to a low idle speed as a safety measure.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5M
• 6M
• 7030 series
• 330G
• 331G
• 332G
• 333G
• 644H
• 640
• 648G-III
• 460D
• PowerTech 8.1L
• PowerTech 10.5L
• PowerTech 12.5L

1. 1

   Inspect the wiring harness and connectors leading to the accelerator pedal potentiometer for physical damage, loose pins, or corrosion.

2. 2

   Check for environmental interference such as moisture intrusion or extreme temperatures; ensure the sensor housing is dry and intact.

3. 3

   Test the voltage at the signal input of the accelerator pedal potentiometer (a reading of less than 0.5 volts indicates a problem with the signal lead or the 5V reference supply voltage coming from the OIC/ECU).

4. 4

   Sweep the pedal slowly while monitoring the signal voltage or PWM frequency with a multimeter or diagnostic tool to see if the signal drops out or spikes out of range.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery ground to prevent electrical shorts.

2. 2

   Access the Pedal Assembly

   Remove the lower cab trim or floor matting as necessary to access the accelerator pedal mounting hardware and wiring harness.

3. 3

   Disconnect the Harness

   Unplug the electrical connector from the accelerator pedal potentiometer.

4. 4

   Replace the Component

   If diagnostics point to a failed sensor, remove the retaining hardware holding the pedal assembly or potentiometer in place. Install the new potentiometer or complete pedal assembly.

5. 5

   Reassemble and Reconnect

   Plug the wiring harness back in, ensuring the connector clicks and locks securely. Reconnect the battery.

6. 6

   Clear Codes and Test

   Use a diagnostic tool to clear the 000091.08 fault code from the OIC/ECU. Start the machine and monitor the accelerator response to ensure the error does not recur.