▶ Using a GDS, perform "VIN WRITING" procedure. Refer to the latest Reference manual for GDS and go to "Verification of Vehicle Repair" procedure.

▶ Using a GDS, read VIN information.

If there is no proper VIN information, perform "VIN WRITING" procedure.

If VIN information exists, substitute with a known-good ECM/PCM and check for proper operation. If the problem is corrected, replace ECM/PCM.

And go to "Verification of Vehicle Repair" procedure.