Case IH 3441 – Engine Control Unit (ECU) A-095: Auxiliary power relay low side driver circuit short to battery failure.

This fault occurs when the Engine Control Unit (ECU) monitors the auxiliary power relay (designated as K-064) and detects a short to a high source (battery voltage) condition on the low side of the control circuit.

• Steiger T4B
• Case IH 240 Series Axial-Flow® Combines
• Case IH Puma Series Tractors

1. 1

   Verify if an external power supply (such as a jump starter or external charger) is connected to the machine's battery. If connected, disconnect it and test the system for normal operation.

2. 2

   Ensure the machine's charging system (alternator/regulator) is not faulty and overcharging the circuit.

3. 3

   Check if the fault is active. If you also have code 3440 (DTC 8322) - Auxiliary power relay low side ECU driver circuit over temperature failure, address 3441 first.

4. 4

   Remove the K-064 auxiliary power relay and use a multimeter to check the coil for an internal failure.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to ensure safety while testing the electrical system.

2. 2

   Test/Replace the Relay

   Locate the K-064 auxiliary power relay. Remove it and test the coil resistance with a multimeter. If the relay coil is shorted or out of specification, replace the relay.

3. 3

   Inspect the Wiring Harness

   Trace the wiring harness between the ECU A-095 and the K-064 relay. Look for rubbed, melted, or pinched wires that could cause the low side driver circuit to short to battery voltage. Repair or replace the harness if damage is found.

4. 4

   Test the ECU/CCU

   If the relay and the wiring harness are both in good working condition, the fault may lie within the Engine Control Unit (ECU A-095) or the Central Control Unit (CCU). A dealer-level diagnostic tool (such as CNH EST) may be required to verify if the ECU's internal driver has failed.