Case IH 49 – Transmission Controller (TRANS) or Electronic Draft Control (EDC) / Hydraulic Systems controller: Wheel speed sensor open or short circuit

The control module is either not receiving a signal from the wheel speed sensor due to a break in the wiring (open circuit) or the sensor's wiring is improperly making contact with ground or a power source, such as a short to +5V or +12V.

• JXC
• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• JX Series
• JX1070C
• TM Series
• TS Series

1. 1

   Observe the dash to see if the instrument panel displays the correct tractor speed while moving

2. 2

   Check the relevant fuses, such as Fuse 9 or Fuse 16 (often a 15-amp fuse tied to Trailer Brakes and Hydraulic Regulations)

3. 3

   Inspect the wiring harness and connectors between the wheel speed sensor and the controller for melted wires, pinched harnesses, or corroded pins

4. 4

   Use a multimeter to check for an open circuit or a short circuit, and test for the presence of the reference voltage (+12V or +5V) at the sensor connector

1. 1

   Locate and Isolate

   Locate the wheel speed sensor (sometimes integrated as a radar assembly) and disconnect its wiring harness.

2. 2

   Test the Harness

   Probe the harness pins (e.g., testing between the signal pin and ground) to check for an open circuit or a short.

3. 3

   Repair Wiring

   If the multimeter indicates an open circuit or a short in the wiring, repair the damaged section of the harness or replace the harness entirely.

4. 4

   Replace Blown Fuses

   If a short circuit caused a fuse to blow during operation, replace the fuse (e.g., 15-amp) only after the wiring short has been repaired.

5. 5

   Replace the Sensor

   If the wiring harness tests perfectly fine (no shorts, no opens, and proper voltage is supplied to the connector), the internal circuitry of the sensor has failed. Remove and replace the wheel speed sensor / radar assembly.

6. 6

   Verify Repair

   Reconnect all components, clear the fault codes from the controller, and operate the tractor to ensure the speedometer works and Code 49 does not return.