Case IH 13002 – UCM (Universal Control Module): Reference voltage 5VREF1 – voltage too high.

This code indicates that the 5-volt reference circuit 1 (5VREF1), which supplies power to various sensors, is reading a voltage that is out of range on the high side (typically greater than 5.2V). This usually means the 5V circuit is shorted to a 12V power source, a sensor has failed internally and is bleeding 12V into the 5V line, or the internal voltage regulator inside the control module has failed.

• MAXXUM T4E
• Puma 130
• Puma 145
• Puma 160
• Puma 210
• Magnum 210
• Magnum 255
• Magnum 380
• Maxxum 110
• Maxxum 120
• Maxxum 130
• Steiger
• SR220
• SV300
• TR
• TV380
• T7.170
• T7.220
• T7.270

1. 1

   Verify the fault by turning the ignition switch ON (Engine OFF) and checking if code 13002 is active.

2. 2

   Measure voltage at the 5VREF1 pin on the UCM connector or at one of the sensors on the circuit. The fault is active if voltage is greater than 5.2V.

3. 3

   Disconnect sensors sharing the 5VREF1 circuit one at a time. If the voltage drops back to ~5.0V (or the code goes inactive), the disconnected sensor is shorted internally.

4. 4

   Inspect the wiring harness between the UCM and the sensors. Look for chafing, pinched wires, or melted insulation where the 5VREF1 wire might be shorting to a 12V power wire.

5. 5

   Measure voltage directly at the 5VREF1 output pin on the UCM with all sensors unplugged and wiring verified. If the UCM is outputting battery voltage (12V) instead of 5V, the module's internal regulator has failed.

1. 1

   Turn the key ON, engine OFF.

2. 2

   Disconnect sensors on the 5VREF1 circuit one by one.

3. 3

   Replace the faulty sensor

   if disconnecting it resolves the over-voltage condition.

4. 4

   Repair the wiring harness

   if you locate a short-to-power (12V) in the 5VREF1 circuit. Splice and heat-shrink the damaged wires, ensuring they are routed away from pinch points.

5. 5

   Replace the UCM

   if the module itself is outputting the high voltage. (Note: A replacement UCM will need to be flashed/programmed by a dealer to match your specific machine's configuration).

6. 6

   Clear Codes

   After the repair is made, use the "HC" menu (Clear all stored fault codes) on the diagnostic display or an Electronic Service Tool (EST) to clear the code.

7. 7

   Verify Operation

   Cycle the key and verify the fault code does not return and that all hydraulic/electronic functions operate normally.