The ECM threw code 21 for ignition system malfunction. There are no drivability problems except that fuel mileage may be lower. I haven't calculation it yet, I am just going by the mileage and previous gauge position. The power transistor fails the continuity test. Power and ground look ok to the ignition module. The manual calls for a logic tester to test the ignition signal to the ECM, which I don't have. Is this possible to have a bad ignition power transistor without any drivability problems or can there be another cause for the code 21?
- posted
15 years ago