New Holland TRANS 118 – Transmission Controller (TRANS module): C5-6 clutch solenoid coil or its wiring is shorted to power

The control module is detecting an unexpected +12V voltage on the circuit for the C5-6 transmission clutch solenoid, even when the driver/switch is commanded off. This condition prevents the proper engagement or disengagement of the C5-6 clutch pack.

• TG210
• TG230
• TG255
• TG285
• T8030
• T8040
• T9000 Series
• MX Series
• Magnum 235-340
• Magnum 275

1. 1

   Visually and physically check the transmission wiring harness for any bare wires, chafing, or loose connections that could be bridging the solenoid circuit to a 12V power source.

2. 2

   Perform a controller swap test with a similar tractor (if available) to determine if the short is physical (stays with the tractor's wiring/solenoid) or internal to the module (follows the controller).

3. 3

   Verify the software version on the Transmission Controller, as erratic voltage codes can sometimes be resolved with a simple software update from the dealer.

1. 1

   Disconnect the Battery

   Always disconnect the battery before performing electrical repairs to prevent further shorts.

2. 2

   Isolate the Circuit

   Disconnect the wiring harness connector directly at the C5-6 clutch solenoid on the transmission valve body.

3. 3

   Test the Wiring

   Using a multimeter, check for continuity between the solenoid signal wire in the harness and a known 12V power source. If continuity exists while the key is on (and the controller is disconnected), the wiring harness is shorted and must be traced and repaired.

4. 4

   Test the Solenoid Coil

   Measure the resistance across the pins of the C5-6 clutch solenoid coil itself. If the resistance is out of specification (reading as a dead short), the coil has failed internally.

5. 5

   Replace the Faulty Component

   If the harness is damaged, repair the bare wires and secure the harness away from pinch points. If the solenoid coil is shorted, remove the retaining nut/clip on the transmission valve body, slide the old coil off the valve cartridge, and install the new coil.

6. 6

   Reassemble and Clear Codes

   Reconnect all harnesses, reconnect the battery, and cycle the key to verify if the TRANS 118 code clears or changes to an 'open circuit' code (which would indicate a successful removal of the short).