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DTC P1646: ID Code Incorrectness: Troubleshooting

WARNING: This page is about a different car, the 2011 Suzuki SX4. However, it is still accessible from the selected car via links, so may be relevant.
P1646: TROUBLESHOOTING CHART

Step Action YES NO
1  Is vehicle equipped with Immobilizer control system?  Go to Step 3. Go to Step 2.
2  CAN communication circuit check 
  1. Disconnect connectors of all control modules communicating by means of CAN.
  2. Check CAN communication circuit between control modules for open, short and high resistance.

Is each CAN communication circuit in good condition? 		 Substitute a known-good ECM and recheck. Repair circuit.
3  Was "Immobilizer Control System Check" performed?  Go to Step 4. Go to IMMOBILIZER CONTROL SYSTEM CHECK .
4  Registration of ignition key with ECM 
  1. Register the ignition key with ECM referring to REGISTRATION OF THE IGNITION KEY .

Was registration of ignition key completed? 		 Recheck DTC. Go to Step 5.
5  CAN communication circuit check 
  1. Disconnect connectors of all control modules communicating by means of CAN.
  2. Check CAN communication circuit between control modules for open, short and high resistance.

Is each CAN communication circuit in good condition? 		 Replace ID controller with new one. If DTC P1646 is still detected, substitute a known-good ECM and recheck. Repair circuit.
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