John Deere 970.31 – Engine Control Unit (ECU) / Engine Interface Control Unit (EIC): Immobilizer System: Key authentication or control unit authentication failed / Auxiliary Engine Shutdown Switch Active

The enable signal from the Engine Interface Control (EIC) to the Engine Control Unit (ECU) is missing, or the transponder chip inside the ignition key failed to authenticate with the immobilizer system. The ECU will allow the engine to start, but it will only run briefly before commanding an immediate engine shutoff. Subsequent attempts will result in the engine cranking but failing to start.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5M Series
• 6R Series
• 7R Series
• 8R Series
• 8RT Series
• 8RX Series
• 9570 STS
• 9670 STS
• 9770 STS
• PowerTech 4.5L
• PowerTech 6.8L
• PowerTech 8.1L
• PowerTech 9.0L
• 7260R
• 7280R

1. 1

   Verify the Key Type: Ensure the operator is using a programmed immobilizer key, which can be visually identified by a plastic head that is slightly thicker than standard non-chipped keys.

2. 2

   Check Key Assignment: Verify the key is specifically programmed to that exact machine. A standard key will fit the ignition and turn the engine over, but without the correct RFID chip, it will trigger this code.

3. 3

   Check Auxiliary Shutdown Circuit (if no immobilizer is equipped): Check the wiring harness and fuses supplying power to the ECU (specifically Pin A1 on some OEM engine applications) to ensure the ECU is reading an input voltage on the auxiliary engine shutdown input wire.

1. 1

   System Reset / Recovery Attempt

   Turn the ignition key to the OFF position. Insert a known valid, programmed immobilizer key into the ignition. Turn the key to the ON position, but DO NOT START the engine. Wait at least 3 seconds to allow the immobilizer system and the ECU to communicate and authenticate the key's transponder chip. Turn the key to start the engine and attempt vehicle system recovery.

2. 2

   Inspect Wiring

   If the code persists with a known good key, inspect the wiring harness between the ignition switch, the EIC, and the ECU for breaks, corrosion, or blown fuses.

3. 3

   Dealer Reprogramming

   If all keys are lost, or if the immobilizer ring/ECU is replaced, you must contact an authorized John Deere dealer to order new keys and have the immobilizer system reprogrammed to recognize them.