Case IH 17911 (F-3512-03) - ECU – Engine Control Module (ECM / ECU): ECM 5 volt sensor supply 4 over voltage failure

The ECM has detected that the voltage on the #4 5-volt sensor supply circuit is higher than the normal operating range (typically above 5.5V), caused by a short to a higher voltage source, an internally shorted sensor backfeeding voltage, or an internal ECM failure.

• VESTRUM CVX
• Magnum series tractors (180, 200, 240, 340, 380)
• Steiger series tractors (370, 420, 500, 620)
• MXM series tractors
• Wheel Loaders and Crawler Dozers (1021F, 1150K)
• Equipment utilizing the MTA CCM & APH Stage V MR on-board diagnostics systems

1. 1

   Sensor Isolation: Disconnect the sensors powered by the #4 5-volt supply circuit one at a time. Monitor the diagnostic display or use a multimeter to see if the voltage drops back to normal. If disconnecting a specific sensor clears the over-voltage condition, that sensor is internally shorted and backfeeding voltage.

2. 2

   Harness Inspection: Inspect the engine wiring harness for chafing, pinched wires, or melted insulation. Look specifically for areas where the 5V supply wire might be rubbing against a 12V power wire or battery source.

3. 3

   ECM Output Test: Disconnect the engine harness from the ECM. Turn the key on and measure the voltage output directly at the ECM pin for sensor supply #4. If the ECM is outputting battery voltage (12V) instead of 5V with the harness disconnected, the ECM has suffered an internal failure.

1. 1

   Disconnect battery

   Turn off the ignition and disconnect the machine's battery ground cable to prevent electrical spikes.

2. 2

   Replace faulty sensor

   If a sensor is faulty: Replace the internally shorted sensor identified during the diagnostic isolation test.

3. 3

   Repair or replace harness

   If the harness is shorted: Repair the damaged wires using approved splicing methods, or replace the affected engine wiring harness section to eliminate the short to battery voltage.

4. 4

   Replace ECM

   If the ECM is internally shorted: Unplug the main harness connectors from the ECM and unbolt it from the engine mounting bracket. Install a new or remanufactured ECM.

5. 5

   Clear fault codes

   Reconnect the battery, turn the key on, and use the diagnostic display or a service tool to clear the inactive fault codes.

6. 6

   Verify repair

   Start the engine and verify that the 5V sensor supply #4 voltage is within the normal range and that code 17911 (3512-03) does not return.