Case IH 17903 (F-3510-03) - ECU – Engine Control Module (ECM / ECU): ECM 5 volt sensor supply 2 over voltage failure only

The Engine Control Module (ECM) has detected that the voltage on the #2 5-volt reference circuit is too high (exceeding the standard 5V baseline). This condition is typically caused by the 5-volt supply wire shorting to a higher voltage source (such as a 12V or 24V battery power wire) or an internal failure within the ECM itself.

• VESTRUM CVX
• Austoft 9000 Series
• Austoft 9900
• Austoft 9990

1. 1

   Identify Circuit Components: Consult the specific machine's wiring schematic to identify every engine sensor that shares the '5 Volt Sensor Supply 2' circuit (commonly pressure or position sensors).

2. 2

   Sensor Isolation Test: Turn the key to the ON position (engine OFF). Back-probe a sensor connector on this circuit and monitor the voltage. Unplug the sensors on this circuit one at a time. If the voltage drops back down to a normal 5.0V after unplugging a specific sensor, that sensor is internally shorted and is the culprit.

3. 3

   Harness Inspection: If all sensors are unplugged and the voltage remains high, inspect the engine wiring harness for chafing, melting, or pinch points where the 5V reference wire might be touching a 12V/24V battery supply wire.

4. 4

   ECM Output Test: Disconnect the engine wiring harness completely from the ECM. Turn the key ON and measure the voltage directly at the ECM pin for Sensor Supply 2. If the ECM outputs exactly 5.0V, the wiring harness has a short-to-power and needs repair. If the ECM outputs more than 5.5V with nothing connected, the ECM has suffered an internal hardware failure.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery terminal before repairing wiring or replacing modules.

2. 2

   Repair/Replace the Faulty Component

   If a sensor is shorted: Replace the specific sensor identified during the isolation test. Clear the code and verify the 5V reference returns to normal. If the harness is shorted: Locate the damaged section of the engine harness. Splice and heat-shrink the damaged 5V wire and the offending power wire, or replace the entire engine wiring harness if the damage is extensive. If the ECM is faulty: Remove the mounting bolts and harness connectors from the ECM. Install a replacement ECM.

3. 3

   Reprogramming

   If the ECM is replaced, the new module must be flashed/programmed with the correct engine dataset using the Case IH Electronic Service Tool (EST) to restore self-learning parameters and immobilizer/security handshakes.

4. 4

   Verification

   Reconnect the battery, turn the key ON, and use the diagnostic tool to clear the inactive 17903 (F-3510-03) code. Run the engine to ensure the code does not return.