Case IH t13 – Engine Control Module (ECM) / Engine Control Unit (ECU): Test Shut Off Paths, Data Valid But Above Normal Range

During a normal shutdown, the engine control module runs a self-test on the shut-off paths. This code is triggered if the operator turns the key switch to the OFF position while the engine speed is not between 500 and 1000 RPM, or if the vehicle speed is not at 0 mph.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM115
• TM190
• Maxxum
• Puma

1. 1

   Verify operator habits: ensure the key is not turned off while the tractor is rolling or engine is above 1000 RPM

2. 2

   Check engine idle speed to ensure it drops below 1000 RPM when throttles are released

3. 3

   Inspect foot and hand throttle linkages for binding, sticking, or debris preventing return to base idle

4. 4

   Monitor live data for throttle potentiometers and transmission output speed sensor using a diagnostic tool (speed should be 0 mph when stationary)

1. 1

   Correct Shutdown Procedure

   If the diagnostic checks reveal no mechanical or electrical faults, instruct the operator to bring the tractor to a complete stop (0 mph) and let the engine return to low idle (500–1000 RPM) before turning the key switch OFF.

2. 2

   Adjust/Repair Linkages

   If the engine idle speed remains above 1000 RPM, clean, lubricate, and adjust the foot and hand throttle linkages so they fully return to the idle stop.

3. 3

   Test Potentiometers

   If the linkages are free but the ECM still reads high RPM at idle, use a multimeter to test the resistance/voltage of the foot and hand throttle potentiometers. If either sensor has a dead spot or fails to return to base voltage, replace the faulty potentiometer.

4. 4

   Replace Speed Sensor

   If the transmission output speed sensor is registering movement (>0 mph) while the tractor is parked, inspect the sensor wiring harness for shorts. If the wiring is intact, replace the transmission output speed sensor.

5. 5

   Clear Codes

   Once the repair is complete, use the service tool to clear the t13 error code. Test the system by running the tractor and performing a correct shutdown to ensure the code does not return.