Case IH 116 – Transmission Controller (TCU): 1M Clutch Solenoid Short to +12V

The transmission controller has detected that the 1M clutch solenoid coil is turned on and the voltage on the low side of the coil is higher than expected, or that current is being sensed while the driver circuit is commanded off. This indicates a short circuit to a +12 Volt power source, either internal to the solenoid coil or within the wiring harness.

• MX Magnum
• STX Steiger
• STX Steiger 325
• STX Steiger 350
• STX Steiger 400
• STX Steiger 450
• STX Steiger 500
• STX Steiger 550
• STX Steiger 600
• Steiger Quadtrac
• Steiger Rowtrac
• Magnum
• Puma
• MX
• MXU

1. 1

   Identify the trigger: Verify if the fault code is recorded when shifting into forward gears 2, 7, 8, or 14, which utilize the 1M clutch.

2. 2

   Visually inspect the transmission controller (underneath the fuse/relay panel in the cab) and the transmission valve block wiring for obvious signs of wire chafing or harness damage.

3. 3

   Inspect connector ends at the 1M clutch solenoid and the TCU for damage, moisture, corrosion, bent pins, or dislocated pins.

4. 4

   Measure the resistance of the 1M clutch solenoid coil to check for an internal short.

5. 5

   Probe the wire between the 1M clutch solenoid and the transmission controller to check for continuity and ensure it is not shorted to a +12V power source.

1. 1

   Prepare the tractor for service

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate the 1M clutch solenoid

   Locate the transmission control valve block on the transmission housing where the 1M clutch solenoid is mounted.

3. 3

   Disconnect the solenoid

   Disconnect the electrical connector to the 1M clutch solenoid.

4. 4

   Test the solenoid coil resistance

   Using a multimeter, test the solenoid coil's resistance. If the coil is shorted internally (resistance is out of spec/too low), the solenoid must be replaced.

5. 5

   Test the wiring harness

   If the solenoid tests good, leave it disconnected and test the wiring harness from the solenoid connector back to the Transmission Controller for a short to power (+12V). Repair or replace the wiring harness if a short is found.

6. 6

   Replace the Transmission Controller (TCU)

   If both the solenoid and the wiring harness test perfectly fine, the Transmission Controller (TCU) itself has likely failed internally and will need to be replaced and recalibrated.

7. 7

   Clear fault codes

   After replacing the faulty component (solenoid, harness, or TCU), clear the fault codes.

8. 8

   Test drive the tractor

   Test drive the tractor, specifically shifting through forward gears 2, 7, 8, and 14 to verify the 1M clutch engages smoothly and the fault code does not return.