Case IH P24 – Electronic Management Unit (EMU) - Transmission / EDC Controller: 4WD Driver Over Temperature

The driver circuit responsible for operating the Front Wheel Drive (FWD / 4WD) solenoid is overheating. This condition is typically caused by excessive current draw, which is the result of either a short circuit in the wiring harness or an internal failure (low resistance) within the FWD solenoid coil itself.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• MX / TG Series
• CVX 170
• Puma 140
• Magnum 7200 Series

1. 1

   Test Solenoid Resistance: Disconnect the FWD solenoid connector (C034) and measure the coil resistance (should be 5–11 Ω at 20°C).

2. 2

   Check for Shorts to Ground: Check for a short circuit between the controller harness (pin C105–14) and earth ground.

3. 3

   Check for Cross-Shorts: Check for a short circuit between pin C105–14 and the other pins in the harness.

1. 1

   Power Down

   Turn off the key switch and disconnect the tractor's battery to protect the Electronic Management Unit from further electrical spikes.

2. 2

   Inspect and Replace Solenoid

   Locate the FWD solenoid valve on the transmission block. If the diagnostic checks in the previous step revealed resistance outside the 5–11 Ω range, remove and replace the FWD solenoid coil.

3. 3

   Repair Wiring

   If the solenoid tests fine, physically trace the wiring harness from connector C034 back to the EMU (specifically wire C105-14). Repair any chafed wires, melted insulation, or shorts to ground.

4. 4

   Reassemble and Power Up

   Reconnect the solenoid and the battery.

5. 5

   Clear Memory

   Access the controller's H-Menu and reset the non-volatile memory (H8) to clear the stored fault codes.

6. 6

   Perform Calibration

   The service manual explicitly states that a Transmission/EDC Calibration is required whenever error code P24 is present, or whenever a PWM solenoid valve has been replaced or an electrical repair has been effected. Follow your specific model's dash/touch-pad sequence to run the transmission calibration.