John Deere 000168.02 – PTI: Erratic IVT Module Supply Voltage

The Power Train Control Unit (PTI) is receiving an unstable, fluctuating, or implausible voltage supply. SPN 168 indicates a problem related to the electrical system's battery potential or voltage, and FMI 2 signifies the data is erratic, intermittent, or incorrect. This unstable voltage can cause random error codes and intermittent failures of various systems, specifically affecting the proper operation of the IVT (Infinitely Variable Transmission) or AutoPowr transmission.

• 6R Series
• 6125R
• 7R Series
• 8R Series
• 7210R
• 7930
• 8430
• 7x20 Series
• 7x30 Series
• 7920
• 7830
• 7630
• 7720
• 8130
• 8530

1. 1

   Perform a visual inspection of the battery, alternator, and related wiring for loose or corroded terminals, frayed wires, rodent damage, or loose ground connections

2. 2

   Test battery health using a multimeter (should read at least 12.6 volts) and perform a load test to ensure the batteries can hold a charge under load

3. 3

   Inspect fuses related to the cab, transmission, and engine controllers for poor connections that could cause intermittent voltage drops

4. 4

   Test alternator output voltage with the engine running (should provide a steady charging voltage between 13.5 and 14.5 volts)

5. 5

   Perform a voltage drop test on both the positive and negative circuits between the battery and the PTI/ACU controllers to check for high-resistance cables or connections

6. 6

   Inspect the wiring harness and connectors leading to the Power Train Control Unit (PTI) and Armrest Control Unit (ACU) for corrosion, pushed-out pins, or damage. Back-probe the ACU connector to verify a stable 12.7-volt supply

1. 1

   Address connection issues

   If any loose or corroded connections are found on the battery terminals, ground straps, or controller connectors, disconnect them, clean all contact surfaces thoroughly, and re-torque to the proper specification.

2. 2

   Replace faulty power components

   Replace the battery if it fails a load test or cannot maintain a proper charge. Replace the alternator or its voltage regulator if the output is erratic or outside the 13.5-14.5V range. Replace any blown fuses after investigating the cause of the overcurrent.

3. 3

   Repair wiring

   If a voltage drop test reveals high resistance in a cable, or if a visual inspection shows damage to a wiring harness, repair or replace the affected section of the harness.

4. 4

   Replace control unit

   If all electrical supply to the controller is verified to be stable but the fault code persists, the issue may be internal to the Power Train Control Unit (PTI). Replace the controller.