John Deere 91.02 – OIC, UIC, TIA, or EPC: Accelerator Pedal Potentiometer, Voltages at Channel 1 and Channel 2 Not in the Correct Ratio

The control unit has detected a mismatch between the dual output signals of the accelerator pedal potentiometer (Sensor B79). The voltage at Channel 1 (lead 6066) must be exactly double the voltage of Channel 2 (lead 6045). When this ratio is incorrect, the system limits or completely disables the function of the foot accelerator pedal to prevent unsafe, unintended acceleration.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 6090MC
• 6100MC
• 6110RC

1. 1

   Inspect the wiring harness at the accelerator pedal potentiometer (B79) for loose pins, corrosion, or damaged insulation

2. 2

   Measure the output voltages at Channel 1 (lead 6066) and Channel 2 (lead 6045) while slowly depressing the pedal to confirm Channel 1 is exactly double Channel 2

3. 3

   Test the circuit for shorts to ground or open circuits in the wiring leading back to the OIC/Cab module

4. 4

   Clear the code via the display, cycle the ignition key off and back on, and check if the code returns to rule out a momentary glitch

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical spikes while working with cab modules.

2. 2

   Access the Pedal

   Lift or remove the rubber floor mat up and over the foot throttle assembly.

3. 3

   Remove Assembly

   Remove the mounting cap screws holding the foot throttle assembly to the cab floor.

4. 4

   Disconnect Sensor

   Unplug the electrical harness connector from the foot throttle sensor (B79).

5. 5

   Swap Component

   Remove the cover from the back side of the foot throttle to access the rotary potentiometer. Remove the faulty sensor and install the new one. (Note: On some IVT models, the entire pedal assembly is replaced as a single sealed unit).

6. 6

   Reinstall

   Bolt the pedal assembly back to the floor, reconnect the wiring harness, and lay the floor mat flat.

7. 7

   Relearn/Calibrate

   Reconnect the battery. Turn the key to the ON position without starting the engine. The tractor's ECU may require a few minutes to relearn the new sensor's base voltage parameters. Clear any stored OIC 000091.02 codes.