John Deere 91.04 – OIC: Accelerator Pedal Signal Voltage Low

The control unit has detected that the voltage at the signal input of the accelerator pedal potentiometer (often designated as sensor B79) has dropped below the minimum acceptable threshold (typically below 0.3 to 0.5 volts). This low-voltage condition usually indicates a short to ground in the sensor circuit, a disconnected/damaged wiring harness, or an internally failed potentiometer.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6020
• 6030
• 7030
• 6J
• 6D
• 6E
• 5M
• 5R
• 5E
• 8130-8530
• 8230T-8430T
• 9470RT
• 9520RT
• 9570RT
• 210L EP

1. 1

   Inspect Wiring for Shorts to Ground: Trace the wiring harness from the accelerator pedal potentiometer (B79) to the OIC/Cab module. Look for rubbed-through insulation, pinched wires, or exposed copper shorting against the chassis.

2. 2

   Verify Connections: Disconnect the plug at the foot throttle sensor. Inspect the pins and terminals for corrosion, moisture ingress, or loose fitment. Clean and reseat the connector.

3. 3

   Test Potentiometer Supply Voltage: Using a multimeter, verify that the sensor is receiving the correct 5V reference supply voltage from the control module. If the supply voltage is missing, the issue is in the harness or the module.

4. 4

   Test Potentiometer Functionality: Measure the signal return voltage while slowly sweeping the pedal from the rest position to full throttle. The voltage should scale smoothly. If it drops out or reads near 0V constantly, the sensor has failed.

1. 1

   Power Down

   Turn off the ignition and disconnect the battery ground cable to prevent electrical spikes.

2. 2

   Access the Sensor

   Locate the accelerator pedal assembly on the cab floor. The potentiometer is mounted directly to the side of the pedal pivot mechanism.

3. 3

   Remove the Faulty Sensor

   Disconnect the electrical harness connector from the sensor. Remove the mounting screws/bolts holding the rotary position sensor to the pedal bracket.

4. 4

   Install the New Sensor

   Mount the replacement potentiometer in the exact same orientation. Tighten the mounting hardware to OEM spec (do not overtighten, as the plastic housing can crack).

5. 5

   Reconnect and Reassemble

   Plug the electrical connector back in, ensuring the locking tab clicks into place.

6. 6

   Clear Codes and Calibrate

   Reconnect the battery. Turn the key to the ON position. You may need to use a John Deere Service ADVISOR tool to clear the inactive 000091.04 code and perform an accelerator pedal calibration (EOL calibration) so the OIC learns the new 0% and 100% voltage values.

7. 7

   Test

   Verify that the foot throttle responds correctly and the code does not return.