Case IH 3259 (DTC 7822) - ECU – Engine Control Unit (ECU): Starter relay high side driver circuit short to ground failure

The Electronic Control Unit (ECU) controls the voltage to the starter control relay (often designated as K-062), which in turn controls the voltage to the main starter relay (K-005). The ECU actively monitors the high side control circuit of this relay. If the ECU detects a short to ground condition in this circuit, it logs this fault code. In some machines, this will trigger an emergency re-start mode or limit engine operation.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Puma Series Tractors
• Skid Steer Loaders (SSL) and Compact Track Loaders (CTL) (SR175)
• Machines equipped with FPT F5C / F5H engines

1. 1

   External Power Check: Check if an external power supply (such as a jump box or external charger) is connected to the tractor battery. If so, disconnect it and test the system for normal operation, as external voltage spikes can trigger this code.

2. 2

   Active vs. Inactive: Use the Electronic Service Tool (EST) to verify if the fault code is currently active. If it is inactive, the fault may be intermittent.

3. 3

   Relay Inspection: Test the starter control relay (K-062) and the starter relay (K-005) coils for internal shorts.

4. 4

   Harness Inspection: Visually inspect the wiring harness between the ECU and the starter relays for chafing, bare wires, or pinched sections causing a short to ground.

1. 1

   Disconnect External Power

   Remove any external power supplies or jump starters.

2. 2

   Trace the Circuit

   Using a multimeter, check the continuity of the high side driver circuit from the ECU (A-095) harness connector to the starter control relay (K-062). Check for continuity to ground.

3. 3

   Repair Wiring

   If a short circuit or short to ground is found in the wiring, repair or replace the affected wire harness section.

4. 4

   Software Update

   If the wire harness and relays test okay, connect the Electronic Service Tool (EST) and download/flash the correct (latest) level of software to the ECU.

5. 5

   Clear and Retest

   Clear the fault codes and cycle the key to see if the fault recurs.

6. 6

   Replace ECU

   If the fault persists after verifying the wiring is intact and the software is updated, the ECU's internal high side driver has failed. Remove and replace the ECU (A-095).