Case IH 519043-06 - DEC – DEC: DEC Reverse battery relay - current above normal or shorted to ground

The control module has detected an electrical draw on the reverse battery relay circuit that exceeds the normal operating threshold, or the circuit has shorted directly to a ground source.

• MAGNUM AFS Connect
• Magnum 180 AFS Connect
• Magnum 200 AFS Connect
• Magnum 240 AFS Connect
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Verify Battery History: Confirm if the batteries were recently replaced, jump-started, or if a reverse polarity event occurred, as this is the primary trigger for the reverse battery protection circuit.

2. 2

   Relay Inspection: Locate the reverse battery relay in the main fuse/relay power distribution box. Inspect the relay housing and socket for signs of thermal damage, melting, or corrosion.

3. 3

   Circuit Testing: Using a multimeter, test the wiring harness between the DEC module and the relay socket. Check for continuity to ground on the power supply wire to confirm if a short-to-ground is present in the harness.

4. 4

   Relay Bench Test: Remove the relay and test it for internal shorts across the coil pins.

1. 1

   Power down the tractor, remove the key, and disconnect the negative battery cable to prevent further electrical damage.

   Power down the tractor, remove the key, and disconnect the negative battery cable to prevent further electrical damage.

2. 2

   Access the engine/transmission fuse and relay box (location varies slightly depending on the specific Magnum AFS Connect cab configuration).

   Access the engine/transmission fuse and relay box (location varies slightly depending on the specific Magnum AFS Connect cab configuration).

3. 3

   Remove the suspect reverse battery relay.

   Remove the suspect reverse battery relay.

4. 4

   If the harness tested positive for a short to ground during diagnostics, trace the wiring harness from the relay block back to the DEC module. Repair any chafed, pinched, or exposed wires and re-loom the harness.

   If the harness tested positive for a short to ground during diagnostics, trace the wiring harness from the relay block back to the DEC module. Repair any chafed, pinched, or exposed wires and re-loom the harness.

5. 5

   If the harness is intact but the relay is internally shorted, replace the relay with a new OEM unit.

   If the harness is intact but the relay is internally shorted, replace the relay with a new OEM unit.

6. 6

   Reconnect the negative battery cable.

   Reconnect the negative battery cable.

7. 7

   Turn the ignition on and use the Case IH Electronic Service Tool (EST) laptop or the AFS Pro monitor to verify the code has changed from "Active" to "Inactive." Clear the inactive fault codes.

   Turn the ignition on and use the Case IH Electronic Service Tool (EST) laptop or the AFS Pro monitor to verify the code has changed from "Active" to "Inactive." Clear the inactive fault codes.