Case IH 23 – Transmission ECM: Clutch Pack (B) Pulse Width Modulated (PWM) Solenoid Coil Short Circuit

The Clutch Pack (B) PWM Solenoid experiences a short circuit while the tractor is being driven in Reverse or Forward. The Transmission Status Lamp will flash, Clutch Pack (B) becomes inoperable, and the transmission is disabled.

• JXC
• MXM
• TN55
• TN65
• TN70
• TN75
• TN60A
• TN70A
• TN75A
• TN85A
• TN95A
• TN Series
• TNA Series
• TND Series
• TNS Series
• TNDA Series
• TNSA Series

1. 1

   Inspect the wiring harness for a short between ECM connector 1, pin 11 and ECM connector 1, pin 5 wires

2. 2

   Test for a direct short across the two terminals of the Clutch Pack (B) PWM solenoid coil

3. 3

   Perform a current draw test using an Electronic Service Tool (EST) or multimeter (fault triggers if the Clutch Pack (B) current value is lower than 230 mA or higher than 480 mA)

4. 4

   Verify if the EST H9, Channel 7 value is reading below 200 counts

5. 5

   Test the reverse solenoid hydraulic pressure circuit to rule out mechanical binding causing electrical overload

1. 1

   Safety First

   Park the tractor on a level surface, engage the parking brake, turn off the engine, and disconnect the battery power before servicing the electrical system.

2. 2

   Locate Components

   Locate the Transmission ECM and trace the wiring harness down to the transmission control valve assembly where the Clutch Pack (B) PWM Solenoid is mounted.

3. 3

   Inspect and Repair Wiring

   Carefully inspect the wiring harness between ECM connector 1 (pins 11 and 5) and the solenoid. Look for melted insulation, pinched wires, or chafing against the transmission housing. Repair or replace the harness if a short to ground or short to voltage is found.

4. 4

   Test the Solenoid

   Disconnect the harness from the Clutch Pack (B) PWM Solenoid. Measure the internal resistance of the coil. If the coil is internally shorted (reading out of spec or showing continuity across the terminals where it shouldn't), the solenoid must be replaced.

5. 5

   Replace the Solenoid

   Remove the retaining hardware for the faulty PWM solenoid valve assembly. Coat the new valve components with clean transmission oil (e.g., Case IH Akcela Nexplore Fluid) prior to assembly. Install the new solenoid and tighten the retaining bolts to the specified torque (typically 27 Nm / 20 ft. lbs).

6. 6

   ECM Verification

   If both the wiring harness and the solenoid test perfectly fine, the Transmission ECM itself is likely faulty and will need to be replaced and reprogrammed.

7. 7

   Reassembly and Calibration

   Reconnect the battery. Use the Electronic Service Tool (EST) to clear the fault codes and perform a clutch calibration routine to ensure the new solenoid engages smoothly.