Case IH 38 – Transmission Control Module (ECM / TCU): CLUTCH PACK (B) PULSE WIDTH MODULATED SOLENOID OR ECM DRIVER SHORT CIRCUIT TO 12 VOLTS

While the tractor is being operated, the Clutch Pack (B) Pulse Width Modulated (PWM) Solenoid becomes unexpectedly energized due to a short circuit to 12 volts. This uncommanded energization prevents the transmission from safely allowing a shuttle shift from forward to reverse.

• MX Magnum
• STX Steiger
• Case IH MX Series (MX210, MX230, MX255, MX285 Magnum)
• Case IH Puma Series
• TN Series Tractors

1. 1

   Turn the starter key to the OFF position

2. 2

   Test for a circuit shorted to 12 volts between ECM connector 1, pin 11 and the solenoid coil terminal

3. 3

   Test for a short circuit across the solenoid coil terminals themselves

4. 4

   Test for a short circuit between ECM connector 1, pin 5 and the solenoid coil terminal

1. 1

   Power Down

   Ensure the tractor is off and the key is removed to prevent active voltage on the ECM pins.

2. 2

   Access the ECM

   Locate the Transmission ECM and disconnect Connector 1.

3. 3

   Harness Repair

   If the multimeter tests in the diagnostic phase reveal a short to 12V on the wiring harness between pins 5/11 and the Clutch Pack B solenoid, locate the chafed wire in the loom and repair/splice the connection.

4. 4

   Solenoid Replacement

   If the wiring harness tests good, the short is internal to the solenoid coil. Remove the transmission side cover/valve block access to reach the Clutch Pack B PWM Solenoid and replace it.

5. 5

   ECM Replacement

   If both the wiring and the solenoid are intact, the ECM driver itself is internally shorted to 12 volts, requiring a replacement of the Transmission ECM.