Case IH 191-18 - DEC – Engine Control Module (ECM): Transmission Output Shaft Speed - Data Valid But Below Normal Operating Range - Moderately Severe Level

Triggered when the Engine Control Module (ECM) detects that the frequency input signal from the transmission output shaft speed sensor (or auxiliary speed/pressure pickup) is below a calibrated threshold.

• MAGNUM AFS Connect
• Magnum 215
• Magnum 235
• Magnum 255
• Magnum 305
• Magnum 335
• Magnum 380
• MX210
• MX230
• MX255
• MX305

1. 1

   Inspect the transmission output shaft speed sensor and its wiring harness for any signs of physical damage, contamination, or corrosion.

2. 2

   Check the wiring harness for damage, corrosion, or loose connections.

3. 3

   Using a multimeter, perform continuity tests on the wiring from the sensor to the ECM to ensure proper electrical flow.

4. 4

   Verify the sensor's power supply and ground circuits, checking for a stable 5-volt reference where applicable.

5. 5

   Use an electronic service tool (such as Cummins INSITE or Case IH EST) to verify ECM data and check if the fault is active or inactive.

1. 1

   Turn the keyswitch to the OFF position.

2. 2

   Disconnect the engine harness from the ECM and the transmission output shaft speed sensor.

3. 3

   Check for short circuits from pin to pin on the harness.

   If the harness is damaged or fails resistance checks, repair or replace the engine harness.

4. 4

   Replace the transmission output shaft speed sensor.

   Perform this step if the wiring is intact but the sensor is failing to send the correct frequency signal.

5. 5

   Reconnect all components and turn the keyswitch to the ON position.

6. 6

   Start the engine and let it idle for 1 minute to validate the repair.

   The fault code status should change to INACTIVE, and the amber CHECK ENGINE lamp should turn off.

7. 7

   Use the electronic service tool to clear the inactive fault codes.

   Use the "Reset All Faults" command.