Case IH 3261 (DTC 6B22) - ECU – Engine Control Unit (ECU / ECM): Starter relay low side driver circuit short to battery failure

The ECU controls the voltage to the starter control relay (K-062), which controls the main starter relay (K-005). The ECU continuously monitors the low side control circuit of the K-062 relay. If the ECU detects that this circuit is shorted to a high voltage source (battery voltage) or experiences an over-temperature/over-current condition, it will log this fault code.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• Puma Tractors
• Steiger Tractors
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Verify if the fault is currently active using the Electronic Service Tool (EST).

2. 2

   Check if the machine's battery is connected to an external power supply such as a jump box or charger, and disconnect it.

3. 3

   Ensure the alternator and charging system are functioning correctly and not overcharging.

4. 4

   Check for related codes, such as 3403 (DTC 8A22), and diagnose 3261 first if both are active.

1. 1

   Locate the Starter Control Relay

   Identify relay K-062 (Starter Control Relay) in the machine's fuse/relay panel.

2. 2

   Test the Relay Coil

   Remove the K-062 relay. Use a multimeter to measure the resistance across the relay coil pins to check for an internal short or failure. If the resistance is out of specification (shorted), replace the relay.

3. 3

   Inspect the Wiring Harness

   Trace the low side control circuit wiring between the K-062 relay socket and the ECU (A-095). Look for rubbed, melted, or pinched wires that could be shorting the circuit to a 12V power source (short to high source condition). Repair any damaged wiring.

4. 4

   Test the ECU

   If the relay tests good and the wiring harness shows no shorts to battery voltage, the fault may lie within the ECU itself. The ECU A-095 or Central Control Unit (CCU) may require a software flash or replacement.