need help with code 43
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 1
From: JACKSON MS
need help with code 43
Car; 1993 Corvette coupe auto. Put in lt4 hot cam kit. Car ran fine for about a week. Getting ready to go to track, gave it 1 more test run and the vette starts to run bad. I made it home, and now it only starts and goes dead. when it does run, it runs bad and goes dead when it goes to close loop. only consant code is 43. I ran test according to flow chart. It said I have bad knock sensors or ECM. The knock sensors are new. With the scan tool hooked to the system I can hit on the manifold and the scan tool picks up a knock singal. I have tried another Dist., module, coil, and computer. same results. I replaced the mem-cal and now when the car starts it runs fine for a few minutes and then it starts to shut down like its not getting any fire and the scan tool shows a code 41 est open circuit. When the car warms up it runs fine and shows no codes. I have replaced everything that I know to replace and still get the same result. Do you guys have any I dea what the problem might be?
Last edited by ICANTDR55; Sep 17, 2008 at 01:52 AM. Reason: miss print
Melting Slicks
Joined: Apr 1999
Posts: 2,521
Likes: 4
From: Windham, NH
To be honest with you, it sounds like the computer is the problem. I went thru a similar situation on my wife's 93. With NO warning it started to throw all kinds of codes and would die out if you tapped on the computer with your finger. Here is a link to my post on the subject.
http://forums.corvetteforum.com/show...178&highlight=
Good luck!!
http://forums.corvetteforum.com/show...178&highlight=
Good luck!!
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
It could be the ICM.Did you use the heat sink paste when you replaced it? Since you said it runs OK for a few minutes it may be either bad and/or heating up. I don't get the relationship between the memcal and the 43 though. I would use the trouble shooting tree in the FSM for the ICM first.It could be as simple as a bad connection.
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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You can remove your ICM and have it tested at most auto parts stores like AutoZone or NAPA.
Have you tested your spark module? It's located on the HVAC blower motor on the passenger side of the car. That can also throw a Code 43.
Since your knock sensors are new, if that doesn't fix it, I, too, am leaning toward your ECM. They're hard to find for 1992 and 1993 models, though.
You'll probably wind up getting a re-man or O.E.M. salvage yard unit. And don't forget to save your PROM chip as you'll need it for the replacement ECM.
Have you tested your spark module? It's located on the HVAC blower motor on the passenger side of the car. That can also throw a Code 43.
Since your knock sensors are new, if that doesn't fix it, I, too, am leaning toward your ECM. They're hard to find for 1992 and 1993 models, though.
You'll probably wind up getting a re-man or O.E.M. salvage yard unit. And don't forget to save your PROM chip as you'll need it for the replacement ECM.
Thread Starter
Racer
Joined: Aug 2001
Posts: 355
Likes: 1
From: JACKSON MS
It could be the ICM.Did you use the heat sink paste when you replaced it? Since you said it runs OK for a few minutes it may be either bad and/or heating up. I don't get the relationship between the memcal and the 43 though. I would use the trouble shooting tree in the FSM for the ICM first.It could be as simple as a bad connection.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
After doing some checking I found 43 to be KS and 41 to be ICM.
Last edited by Redeasysport; Sep 18, 2008 at 10:27 AM.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
This applies to my 1985... I'm not sure if the same logic fits on yours.
On my coupe, I was getting a constant code 43, but when I ran through the flow chart everything always checked out fine. In the mean time, I fixed an array of problems - one of which was an excessively noise cat converter (pieces were bouncing around inside), at which point my code 43 stopped appearing. I think in my case, the knock sensor was seeing constant detonation (which was actually the cat), and trying to retard the timing. After so many seconds of not being able to stop the knocking, the ECM thinks something must not be working, since the knock sensor is still transmitting data, and throws a code 43. Which was not related to the real problem on my coupe at all.
Is that relevant in your case? I do not know.
On my coupe, I was getting a constant code 43, but when I ran through the flow chart everything always checked out fine. In the mean time, I fixed an array of problems - one of which was an excessively noise cat converter (pieces were bouncing around inside), at which point my code 43 stopped appearing. I think in my case, the knock sensor was seeing constant detonation (which was actually the cat), and trying to retard the timing. After so many seconds of not being able to stop the knocking, the ECM thinks something must not be working, since the knock sensor is still transmitting data, and throws a code 43. Which was not related to the real problem on my coupe at all.
Is that relevant in your case? I do not know.
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