John Deere 521192.31 – ECU or EIC: Immobilizer Control Device Fault

The system failed to recognize the ignition key or the immobilizer control unit. This is often caused by a loss of power/communication to the immobilizer module, a blown fuse, or the use of an unprogrammed/non-chipped key.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 8310RT
• 8335RT
• 8360RT
• 9470RT
• 9520RT
• 9570RT
• 5045E
• 5055E
• 5065E
• 5075E
• 5085E
• 5095E
• 5100E
• 5075M
• 5085M
• 5100M
• 5115M
• 6115M
• 5065M
• 5090M
• 5090R

1. 1

   Verify the operator is using the correct, chipped immobilizer key (a conventional, non-chipped key will turn the ignition but trigger this fault).

2. 2

   Reset the system: if the wrong key was inserted, remove it, insert the correct valid key, turn on the ignition (DO NOT START), and wait at least 3 seconds before attempting to crank.

3. 3

   Inspect the fuse panel for blown fuses related to the Immobilizer Control Unit, EIC, and Engine ECU.

4. 4

   Check the wiring harness, ground connections, and power supply lines going to the immobilizer control unit and the ignition key antenna ring.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal before servicing electronic components.

2. 2

   Replace Blown Fuses

   If a fuse was found blown during diagnostics, replace it with one of the exact same amperage.

3. 3

   Repair Wiring

   If the harness between the immobilizer controller, the ignition switch antenna, or the ECU/EIC is damaged, repair or replace the affected wiring loom.

4. 4

   Replace the Immobilizer Controller

   If power and ground are verified but the module fails to communicate or authenticate valid keys, locate the immobilizer control unit (often located under the dash/cowl area) and replace it.

5. 5

   Dealer Programming

   If the immobilizer control unit is replaced, or if new keys are required, a John Deere dealer must use Service ADVISOR to program the new module and pair the transponder keys to the tractor.