GM vehicles OBD1 with code 42
For some of you, who own a GM pre 1995 vehicle and getting the check engine light in your dash, please read carefully below. (For GM vehicles made before 1995 that has a distributor type ignition and has code 42-EST circuit failure and has the following symptoms:
Stalling at stop signs
No start but if you wait up to 2 hours, it will start again
TESTS:
1.) Please confirm the code first by resetting the code and see if the code will show up again a second time. If it does, it means this code is really a hard code that must be fixed. During no start, confirm the presence of ignition problem by checking the presence of spark using an especial tool ST125(cost under $5) and available in any local parts store.
2.)Make sure there is 12 volts supply going to your distributor when you turn the key on engine off.
FIX:
Remove the distributor assembly and replace the following:
Pick up coil
Ignition module
Once the above parts are replaced, reset the code and go for a quick road test to confirm. If your engine does not have a distributor, replace the crank sensor instead of the pick up coil. But check also for input voltage to the crank sensor circuit. If you need assistance, contact ATS.
