Case IH 17906 (F-3511-06) - ECU – Engine Control Module (ECM): ECM 5 volt sensor supply 3 high side output driver over temperature failure

The internal transistor/driver inside the ECM that supplies the 5-volt power for Sensor Supply 3 is overheating. This overheating is almost always caused by excessive current draw, which typically points to a direct short circuit to ground in the engine wiring harness or an internally shorted sensor on that specific 5V circuit.

• VESTRUM CVX
• Magnum
• Puma
• Steiger
• Maxxum
• harvesters

1. 1

   Identify which sensors are powered by 5 Volt Sensor Supply 3 on your specific engine model (commonly engine speed, camshaft position, or pressure sensors).

2. 2

   Perform a sensor isolation test: turn key OFF, disconnect sensors on the circuit one at a time, turn key ON, and check if the fault code changes from FMI 06 to FMI 04 (indicating the disconnected sensor is shorted).

3. 3

   Inspect the engine wiring harness between the ECM and the sensors for chafing, rubbing, or pinched wires causing a short to ground.

4. 4

   Inspect the ECM connectors and sensor connectors for moisture, corrosion, or bent pins.

5. 5

   Perform a resistance test: with battery disconnected and ECM unplugged, measure the resistance of the 5V supply wire to ground (should be an open circuit with no continuity).

1. 1

   Turn off the machine and disconnect the battery before performing any electrical repairs.

2. 2

   Replace the specific sensor identified during the isolation test.

   If a sensor is shorted.

3. 3

   Locate the damaged section of the engine wiring harness. Repair the chafed/pinched wires using proper soldering and heat-shrink tubing, or replace the affected harness section entirely.

   If the wiring is shorted.

4. 4

   Reconnect all sensors, the ECM, and the battery.

5. 5

   Turn the key ON and use the AFS Pro display or a diagnostic service tool to clear the inactive fault codes.

6. 6

   Replace the ECM and reprogram with the correct engine dataset using the appropriate service tool.

   If the ECM is damaged: If the wiring harness and all sensors test perfectly fine, but the ECM still fails to output 5V on Supply 3 and logs the over-temperature code, the ECM's internal driver is permanently damaged.