New Holland UCM 5502 – UCM (Universal Control Module): Boom Raise/Lower: Sensor Short to Power

The signal voltage from the spool position sensor on the loader arm (boom) control valve is abnormally high. The system has detected a short to a power source, which can be caused by a damaged wiring harness or an internal failure within the sensor itself.

• L213
• L215
• L218
• L220
• L223
• L225
• L230
• C227
• C232
• C238
• SR130
• SR150
• SR175
• SV185
• SR200
• SR220
• SR250
• SV250
• SV300
• TR270
• TR320

1. 1

   Inspect the wiring harness leading to the main hydraulic control valve, specifically looking at the X-21 connector and the sensor pigtail for rubbed, pinched, or exposed wires shorting to a 12V power source.

2. 2

   Using a multimeter, check the sensor signal wire (e.g., wire 0061) for continuity and verify if there is voltage present when the sensor is unplugged (which confirms a harness short).

3. 3

   Disconnect the Loader Arm Spool Sensor to isolate the fault. If the active fault code changes from 5502 (Short to Power) to 5501 (Short to Ground / Open Circuit), the wiring harness is likely intact, and the short is internal to the sensor.

1. 1

   Lower the boom to the ground, turn off the machine, and relieve hydraulic pressure.

2. 2

   Disconnect the battery using the quick disconnect switch, or manually disconnect the negative battery cable to prevent electrical spikes during repair.

3. 3

   Locate the main hydraulic control valve block. Identify the Loader Arm (Boom Raise/Lower) Spool Position Sensor.

4. 4

   If the diagnostic checks pointed to a harness issue, repair the damaged section of the wire or replace the affected harness segment.

5. 5

   If the sensor is internally shorted, unplug the electrical connector from the faulty spool position sensor.

6. 6

   Unthread and remove the faulty sensor from the control valve.

7. 7

   Install the new spool position sensor and tighten it to OEM specifications. Reconnect the electrical harness.

8. 8

   Reconnect the battery.

9. 9

   Power on the machine. The code should go inactive. If required, use the Electronic Service Tool (EST) to clear the stored fault codes from the UCM.