Case IH FAA – Transmission Controller: Clutch A Solenoid Open Circuit Or Short To Ground

The transmission controller detects that the circuit for the Clutch A PWM solenoid is either broken (open circuit) or has shorted out to the chassis ground. Because of this fault, the controller will typically disable the affected clutch to prevent transmission damage.

• MXM
• MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Maxxum
• Puma

1. 1

   Inspect the wiring harness running from the Transmission Controller to the Clutch A solenoid for chafed wires, melted insulation, or pinched lines.

2. 2

   Disconnect the Clutch A solenoid and the transmission controller to check for corroded, backed-out, or loose pins.

3. 3

   Measure the resistance across the Clutch A solenoid pins using a multimeter to verify if the internal coil is open or shorted.

4. 4

   With the key ON, check the supply voltage and ground continuity at the solenoid connector to isolate whether the fault is in the wiring or the solenoid itself.

1. 1

   Resolve the Electrical Fault

   Repair any damaged wiring in the harness or replace the faulty Clutch A solenoid valve on the transmission valve block.

2. 2

   Prepare for Calibration

   If a PWM solenoid valve has been replaced, or if a mechanical repair was made, a Transmission/EDC Calibration is strictly required.

3. 3

   Warm Up

   Ensure the transmission oil is warmed up to operating temperature.

4. 4

   Enter Calibration Mode

   Start the engine and enter the diagnostic/calibration mode (H1 Clutch and Synchroniser Calibration).

5. 5

   Set Engine Speed

   Set the engine speed to 1200 ERPM (± 100 RPM).

6. 6

   Energize Clutch A

   Depress the clutch pedal and move the shuttle lever into forward. Release the clutch. The upper character on the display will show 'A', indicating that the Clutch 'A' solenoid is energized.

7. 7

   Verify Pressure

   Press and hold the downshift control switch and observe the pressure reading on a connected gauge. It should read 16–18 bar (for 120 to 155 models) or 20–22 bar (for 175 and 190 models).

8. 8

   Complete Calibration

   Follow the on-screen prompts to calibrate the clutch fill times. The display will show numbers increasing during the process, followed by "SOC", and finally "END" to signify completion.