Case IH 735-05 - DEC – Transmission Control Unit (TCU): Transmission C2 clutch solenoid valve current is low

The control module is detecting insufficient electrical current flowing through the C2 clutch solenoid circuit, which typically points to a broken wire, a disconnected plug, a blown fuse, or an internally failed (open) solenoid coil.

• MAGNUM AFS Connect
• Farmlift Telescopic Handlers (Stage IV models: 632, 635, 735, 742, 935)
• Maxxum series (5120, 5130, 5140, 5150)
• Magnum series tractors
• Steiger series tractors

1. 1

   Park the machine on firm ground, apply the parking brake, shut down the engine, and use tire chocks before testing.

2. 2

   Measure with a multimeter to confirm that the parts are not electrically charged before handling.

3. 3

   Inspect the transmission control fuses, specifically Fuse 12, as a blown fuse can cause an open circuit reading for the C2 clutch solenoid.

4. 4

   Check the transmission wiring harness for breaks or chafing.

5. 5

   Inspect the C2 Clutch Solenoid electrical connector (X-169) for corrosion, backed-out pins, or damage.

6. 6

   Unplug the C2 clutch solenoid and measure the resistance (ohms) across the solenoid pins. An infinite reading (OL) confirms the solenoid coil is internally open.

1. 1

   Ensure the machine is powered off and secured.

2. 2

   Locate the transmission valve body / manifold where the C2 clutch solenoid is mounted.

3. 3

   Disconnect the electrical connector (X-169) from the C2 clutch solenoid.

4. 4

   If the diagnostic checks revealed a wiring issue, repair the open circuit in the harness or splice in a new replacement connector.

5. 5

   If the solenoid itself failed the resistance test, remove the retaining hardware securing the C2 solenoid valve to the transmission manifold.

6. 6

   Remove the faulty solenoid and clean the mounting surface.

7. 7

   Install the new C2 clutch solenoid valve.

   Lubricate any O-rings with clean transmission fluid prior to installation.

8. 8

   Reconnect the electrical connector.

9. 9

   Clear the fault codes using a diagnostic tool or by cycling the battery power, then test drive the machine to ensure the transmission shifts correctly and the code does not return.