code 42 help
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Instructor
Joined: Jun 2006
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From: tullahoma tn
code 42 help
1990 non ZR1 keeps giving me a code 42 have replaced the ECM and the Ignition Control Module. Checked the wires to the Module from the ECM the best i can tell everything seems to be ok. Can any one help me
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
42 for this Year means it's not switching over to the Module which is simply grounded by the ECM to control timing. There is a barrel disconnect on a tan wire that's close to the battery which you open to set base timing. Yours may have been left open, may have been opened during an emissions test to check base timing and the code wasn't cleared, or the connector may be broken.
Thread Starter
Instructor
Joined: Jun 2006
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From: tullahoma tn
Thread Starter
Instructor
Joined: Jun 2006
Posts: 164
Likes: 0
From: tullahoma tn
42 for this Year means it's not switching over to the Module which is simply grounded by the ECM to control timing. There is a barrel disconnect on a tan wire that's close to the battery which you open to set base timing. Yours may have been left open, may have been opened during an emissions test to check base timing and the code wasn't cleared, or the connector may be broken.
Intermediate
Joined: Jun 2009
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From: Headland AL
NCM Member '09
Don't know if this will help but try this webb site:
http://www.asashop.org/autoinc/may97/techtips.htm
DM
http://www.asashop.org/autoinc/may97/techtips.htm
DM
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Intermediate
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From: Headland AL
NCM Member '09
I was still getting an intermittent code 42 and 43 like you. I'd replaced the ECM, plugs, fuel filter, ect. and finally disconnected the negative battery terminal and disconnected every plug from the ECM forward. I made sure every connection was clean and tight. I also checked every ground connection. After I reconnected the battery, everything seems to run normal. Once in a while I get a momentary change in exhaust sound and the fuel mileage indicator on the dash shows some weird readings like 99 MPG and the service engine light will flicker, but as suddendly as it appeared, it goes away and the engine runs great. It won't set a code now, only that occassional flicker of the SES light. I'm going to connect a fuel pressure gauge to it next and tape it to the windshield so I can watch it while I drive. Guess we'll see where that leads us.
DM
DM
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Joined: Jun 2006
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From: tullahoma tn
I was still getting an intermittent code 42 and 43 like you. I'd replaced the ECM, plugs, fuel filter, ect. and finally disconnected the negative battery terminal and disconnected every plug from the ECM forward. I made sure every connection was clean and tight. I also checked every ground connection. After I reconnected the battery, everything seems to run normal. Once in a while I get a momentary change in exhaust sound and the fuel mileage indicator on the dash shows some weird readings like 99 MPG and the service engine light will flicker, but as suddendly as it appeared, it goes away and the engine runs great. It won't set a code now, only that occassional flicker of the SES light. I'm going to connect a fuel pressure gauge to it next and tape it to the windshield so I can watch it while I drive. Guess we'll see where that leads us.
DM
DM
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Then you need to check the wire from the Module to the ECM to make sure it's not open. Otherwise, the White wire from the ECM to the Module is essentially your timing control. Grounded by the Module, it's essentially and on/off thing. Make sure that wire is good - in fact, make sure the Module connector is secure.
Thread Starter
Instructor
Joined: Jun 2006
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From: tullahoma tn
Then you need to check the wire from the Module to the ECM to make sure it's not open. Otherwise, the White wire from the ECM to the Module is essentially your timing control. Grounded by the Module, it's essentially and on/off thing. Make sure that wire is good - in fact, make sure the Module connector is secure.
Last edited by hill; Aug 10, 2009 at 10:18 AM.
Intermediate
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From: Headland AL
NCM Member '09
Problem Solved
I finally took mine to a well know shop and they determined that the ECM had failed. This was the third ECM in 2,000 miles. The problem was a "Super Chip" installed in the ECM. They removed it and the car's running great. What was your outcome?
kycharlie
kycharlie
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From: tullahoma tn
