Test Description
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- If there is a problem with ECM that causes a "SCAN" tester to not read Serial Data, then ECM should flash Code 12. If Code 12 does flash, ensure "SCAN" tester is working properly by testing on another vehicle. If "SCAN" tester is functioning properly and circuit No. 461 is okay, the PROM, MEM-CAL, or ECM may be at fault for "NO ALDL" symptom.
- If light goes off when ECM connector is disconnected, then circuit No. 419 is not shorted to ground.
- This step checks for an open diagnostic circuit No. 451.