Case IH 3258 (DTC 6722) - ECU – Electronic Control Unit (ECU) A-095: Starter relay high side driver circuit short to battery failure

The Electronic Control Unit (ECU) A-095 provides voltage to the starter control relay (K-062), which controls voltage to the main starter relay (K-005). The ECU actively monitors the K-062 control circuit and logs this fault if it detects that the high side of the K-062 control circuit is shorted to a battery voltage source.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Puma Series Tractors

1. 1

   Verify if an external power supply (such as a jump box or booster battery) is currently connected, as this can artificially trigger the short-to-battery logic

2. 2

   Use the Case IH Electronic Service Tool (EST) to check if the fault is currently active or an inactive/intermittent historical code

3. 3

   Test the machine's charging system for overvoltage conditions

4. 4

   Inspect the wiring harness between the ECU A-095 and the K-062 starter control relay for chafing, melted insulation, or wires shorting to a 12V power source

5. 5

   Test the K-062 control relay, K-005 starter relay, and the starter solenoid for internal shorts

1. 1

   Verify the Code

   Connect the EST to the diagnostic port. If the fault is inactive, clear the code and operate the machine to see if it returns. If active, proceed to step 2.

2. 2

   Isolate the Circuit

   Disconnect the K-062 starter control relay. Use a multimeter to measure the voltage on the high-side control wire coming from the ECU A-095. If battery voltage is present when the circuit should be unpowered, there is a short to battery in the harness.

3. 3

   Repair Wiring

   If a short is found in the harness, locate the damaged section of the wire and repair or replace the harness.

4. 4

   Test the Relay

   If the wiring is intact, test the K-062 relay coil. An internally shorted relay can cause feedback to the ECU. Replace the relay if it fails resistance testing.

5. 5

   Software/ECU Replacement

   If the wiring and relays are perfectly fine, the fault is likely internal to the ECU A-095. The service manual recommends first attempting to reinstall or flash the ECU A-095 software. If the software flash fails or the code persists, the ECU A-095 must be replaced.