Case IH P87 – Transmission Controller / EDC (Electronic Draft Control) Controller: Solenoid Valve Power Stage, Data Valid But Above Normal Range

The controller has detected an electrical anomaly on the power stage circuit of a transmission proportional (PWM) solenoid valve. Specifically, the voltage or current is reading higher than the normal operating parameters. This is typically caused by a short to power in the wiring harness, a failed solenoid coil (internal short), or a fault within the controller's output driver.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190

1. 1

   Check for Accompanying Codes: Look for codes F24, E24, or 24, which indicate that the transmission memory has been reset or a calibration is required.

2. 2

   Harness Inspection: Inspect the transmission wiring harness routing down to the transmission control valves. Look for rubbed wires that may be shorting to a 12V power source.

3. 3

   Solenoid Resistance Test: Disconnect the affected transmission PWM solenoid valve and measure the resistance across its pins. Compare it to OEM specs to determine if the coil has shorted internally.

4. 4

   Controller Output Test: With the solenoid disconnected, turn the key ON and check the voltage at the harness connector to verify if the controller is constantly supplying excessive voltage.

1. 1

   Repair or Replace

   If the wiring harness is shorted to power, repair the damaged section. If the solenoid valve fails the resistance test, replace the transmission PWM solenoid valve.

2. 2

   Prepare for Calibration

   Anytime a PWM solenoid valve is replaced or a mechanical transmission repair is effected, you must perform a Transmission/EDC Calibration.

3. 3

   Calibration Setup

   Park the tractor on level ground, place all shift levers in neutral, and block the front and rear wheels. Apply the parking brake. Turn off the A/C and all electrical/hydraulic services. Ensure the transmission oil temperature is between 20°C and 50°C.

4. 4

   Execute Calibration

   Press and hold the High and Low range buttons, then start the engine. When 'CAL' appears on the transmission display, release the buttons. Set the engine speed to exactly 1200 RPM (± 100 RPM). Follow the on-screen prompts (holding the High/Low buttons as required for each clutch pack) until the display reads 'END', signifying the calibration is complete.