Case IH 3155 – Engine Control Unit (ECU) A-095: Intake air heater actuator is shorted to ground

The control circuit for the intake air heater relay (also known as the grid heater relay) has a short to ground condition.

• Steiger T4B
• Puma Series Tractors
• Magnum Series Tractors (MX210, MX230, MX255, MX285)
• 240 Series Axial-Flow Combines
• Farmall 40-45-50 Tractors

1. 1

   Verify that the tractor battery power supply has not been connected to an external power supply (like a jump box or external charger). If connected, disconnect it and test for normal operation.

2. 2

   Ensure the alternator and charging system are functioning correctly and not causing voltage irregularities.

3. 3

   Visually inspect for a faulty solenoid, faulty wire harness, or a faulty Central Control Unit (CCU) / Universal Control Module (UCM).

1. 1

   Inspect Harnesses and Connectors

   Visually inspect the relevant wiring harnesses and connectors between the ECU A-095 and the intake air heater relay K-023. Look for damage, bent or dislocated pins, corroded terminals, or broken wires.

2. 2

   Verify Connections

   Ensure that all connectors are fully seated and installed.

3. 3

   Flex Test

   Flex the involved harnesses while monitoring the circuit to reveal any intermittent breaks or shorts in the wiring.

4. 4

   Test for Short to Ground

   Using a multimeter, test the intake air heater relay K-023 control circuit for continuity to ground. If a short is found, locate and repair the shorted conductor in the harness.

5. 5

   ECU Software Check

   If there is no short to ground found in the wiring harness or the relay itself, check the ECU A-095 for the appropriate software version and re-flash the ECU if necessary.