Case IH 13001 – Universal Control Module (UCM): Reference voltage 5VREF1 – voltage too low

This code indicates that the 5-volt reference circuit 1 (5VREF1), which supplies power to various sensors on the machine, has dropped below its acceptable operating range. This is typically caused by a short to ground in the wiring harness, an internally shorted sensor pulling the circuit voltage down, or a failure within the control module itself.

• MAXXUM T4E
• Puma
• Magnum
• Maxxum
• Steiger
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Telehandlers (Farmlift series)
• T7
• T8
• CVT
• Profi

1. 1

   Using a multimeter, measure the voltage output at the 5VREF1 pin directly at the UCM connector. If it is below 5V, proceed to isolate the circuit.

2. 2

   Disconnect the sensors powered by the 5VREF1 circuit one at a time. Monitor the voltage at the UCM or watch the active fault codes to see if voltage returns to 5V (indicating an internally shorted sensor).

3. 3

   Inspect the wiring harness between the UCM and the sensors for chafing, pinched wires, or a direct short to ground.

4. 4

   Inspect the UCM and sensor connectors for pushed-out pins, corrosion, or moisture ingress.

1. 1

   Power Down

   Turn off the machine and disconnect the battery before performing any electrical repairs.

2. 2

   Repair Wiring / Replace Sensor

   If a sensor was found to be shorted during diagnostics, replace the faulty sensor. If a short to ground was found in the harness, repair the damaged section of wire or replace that segment of the harness.

3. 3

   Replace UCM (If Necessary)

   If the wiring harness tests perfectly (no shorts to ground) and all sensors are unplugged, but the UCM still fails to output 5 volts on the 5VREF1 circuit, the UCM has failed internally and must be replaced.

4. 4

   Reassemble and Clear Codes

   Reconnect all sensors and the battery. Use the Electronic Service Tool (EST) or the machine's diagnostic display menu to clear the stored error codes.

5. 5

   Verify Repair

   Cycle the key and operate the machine to ensure the 13001 code does not return.