John Deere 91.03 – Main Control Module (OIC): Accelerator Pedal Signal Voltage High

The control unit measures a voltage in excess of the normal operating range (typically above 4.5 to 4.7 volts) at the signal input of the accelerator pedal potentiometer. This overvoltage situation indicates that the sensor circuit is either shorted to a power supply lead or has an open circuit, leading to erratic throttle behavior, unresponsive acceleration, or the engine RPM control being disabled.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8230T
• 8330T
• 8430T
• 9470RT
• 9520RT
• 9570RT
• 329E
• CT332
• 444J
• 544J
• 624J
• 770G
• 772G

1. 1

   Test Signal Voltage: Use a multimeter or diagnostic tool to check the signal voltage from the throttle position sensor (normal is 0.5V to 4.5V; above 4.7V indicates an active fault).

2. 2

   Inspect Wiring for Shorts: Check the wiring harness associated with the accelerator pedal potentiometer for damaged insulation, chafing, or exposed wires shorting to a power supply lead.

3. 3

   Check for Open Circuits: Use a multimeter to test for continuity between the sensor and the control module to ensure there are no broken wires.

4. 4

   Verify Connections: Inspect all connectors and terminals in the throttle circuit for loose pins, moisture, or corrosion.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Repair Wiring/Connectors

   If the diagnostic checks revealed chafed wires, open circuits, or corroded connectors, repair or replace the damaged wiring harness sections and clean/re-pin the connectors.

3. 3

   Replace the Sensor

   If the wiring and connections are intact but the sensor voltage remains out of range (internally shorted/failed), remove the faulty accelerator pedal potentiometer/foot throttle sensor and install a new OEM replacement.

4. 4

   Reassemble and Reconnect

   Reconnect the sensor harness and restore battery power.

5. 5

   Reset and Test

   Clear the fault codes using a diagnostic tool or the machine's service menu. Start the machine and test the accelerator pedal response through its full range of motion to ensure the voltage stays within the 0.5V–4.5V specification and the code does not return.