Code 42 problem
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
Code 42 problem
Computer thowing off a code 42, EST error. Only thing I can find anywhere is it indicates an open ground but generally gives instructions on how to test the ignition module. I have a new ignition module, new distributor wiring harnesses on the new module, new ecm just installed, new tps, new map sensor. Still get the code. So how do I find the open ground. Wouldn't something be having a problem if it was not grounded properly. Have not changed the coolant temperature sensor. Fan sensor driven by temperature, so eliminating that. Knock sensor? IAC's and fuel injectors relatively new. What else. Desparately seeking solution (not Susan 
).
).
Race Director
Joined: May 2006
Posts: 18,606
Likes: 2,542
have you read something like this for possibilities
http://wiki.answers.com/Q/GM_Scanner..._do_you_fix_it
http://wiki.answers.com/Q/GM_Scanner..._do_you_fix_it
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
have you read something like this for possibilities
http://wiki.answers.com/Q/GM_Scanner..._do_you_fix_it
http://wiki.answers.com/Q/GM_Scanner..._do_you_fix_it
Yes. Seen this or something very similar on other sites and have checked everything. Still stumped.
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
You know, I re-read everything about the est error code and it made reference to the est harness. My est wire was and has been connected, but the car is 32 years old, 235K miles on it. So last night, once again, I took the connector apart, sprayed contact cleaner on both ends, applied dielectric grease, and reconnected. CEL is gone! I can't believe it. Even though connector was tight, I guess corrosion was just enough to interrupt the signal. I can't believe it was so easy and I have spent so much time and $ chasing down this problem. Light stayed off for a 20 mile drive to work today. Let's hope it stays off! But, I can be happy that I now have new ignition module and all related distributor wiring harnesses, tps, map, ecm.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
You eliminated most problem areas so you should be good. As far as your bad connection.... Sometimes it's just better to cut the wire and install a new connector! I had an AC compressor plug that use to loose contact. I would fix it and never fails, the hottest days it would act up again.... So now I just replace before it happens again.
Knock on wood, I really haven't had any sensors go on mine with about 120k on it but my time will come.
Knock on wood, I really haven't had any sensors go on mine with about 120k on it but my time will come.
Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
You eliminated most problem areas so you should be good. As far as your bad connection.... Sometimes it's just better to cut the wire and install a new connector! I had an AC compressor plug that use to loose contact. I would fix it and never fails, the hottest days it would act up again.... So now I just replace before it happens again.
Knock on wood, I really haven't had any sensors go on mine with about 120k on it but my time will come.
Knock on wood, I really haven't had any sensors go on mine with about 120k on it but my time will come.
Went out at lunch and started the car and NO CEL! Just maybe....
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
DTC 42 is PIA to deal with. It can be caused by wires of 4 wire connector being routed too close to plug wires, the ignition module, ground wire connections on intake, ECM and connections. Fortunately no real drivability problems. Myself I would check the grounds, connector and routing. If I had access to know good modules might substitute one to see if it goes away. I really would worry to much with it unless you have a drivability concern. 42 is a code that many techs will tell you need both modules, because of the lack of clear cause.
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Thread Starter
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
Did change out module twice with no difference. Did re-route wires away from the 4 wire connector with no difference. New tps, no difference. New map, no difference. Ground on manifold checked, no difference. New ecm, no difference. New distributor cap and rotor, no difference. Made sure est wire connected tightly, no difference. Unconnected est wire, cleaned, di-electric grease, reconnected, problem solved. Been chasing this for 2 years! Simple step to clean and reseat EST connector and its fixed. Talk about frustrated.
