89 vette CODE 42 HELPPPPP!!!!!
Thread Starter
Racer
Joined: Aug 2004
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From: Audubon PA
89 vette CODE 42 HELPPPPP!!!!!
Can someone please help me with a code 42 diagnoses??? I was getting an intermittent then steady "Service Engine Light", I did the paperclip thing and got CODE 42. I looked it up and found that it's an ignition or timing problem so I replaced the ignition module, cap, rotor, wires, and plugs. The car ran great for about 400 to 500 mile, but the light is back code 42. The light is intermitent sometimes and other times it stays on. Where can I go from here. Please help me. Thanks, jzvette
The car still runs good??
The car still runs good??
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by jzvette
Where can I go from here. Please help me.
RACE ON!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
42 is no voltage on the bypass line. You disconnect this circuit to set base timing, which if you or someone recently did, check the wire. Otherwise, it's brown wire from the distributor near the battery and brake booster. It has a barrel plug or connector which can deterioate over time. Check this wire first.
Team Owner
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From: Summerland B.C. Canada
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
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From: Audubon PA
I will re-check that wire, but when the new cap was put on the brown wire was re-connected. I just recently replaced the ECM(as you Know) and the ignition module. According to Alldata diagnostic specs it says it will either be the Ignition module, ECM, or CKT 424 faulty connection, or CKT 423 shorted to ground, or CKT 424 shorted to ground, or an intermittent problem. I guess there is no easy fix to this, I've been getting this code alot recently but after the ignition module was replaced it went away then I installed new ECM and its back.
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
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From: Audubon PA
SunCr,
I was talking to a tech and I explained to him that the code 42 vanished when I replaced the ignition module, wires, plugs, cap and rotor. Then I explained to him that the code came back when I replaced ECM. He said that I could have a bad ECM or that the prom may not be seated properly. I purchased a NAPA ECM. Maybe I should check to make sure the prom is seated properly and roadtest. If it comes back maybe it's the ECM. What do you think??? jzvette
I was talking to a tech and I explained to him that the code 42 vanished when I replaced the ignition module, wires, plugs, cap and rotor. Then I explained to him that the code came back when I replaced ECM. He said that I could have a bad ECM or that the prom may not be seated properly. I purchased a NAPA ECM. Maybe I should check to make sure the prom is seated properly and roadtest. If it comes back maybe it's the ECM. What do you think??? jzvette
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by jzvette
What do you think??? jzvette
RACE ON!!!
Advanced
Joined: Dec 2001
Posts: 69
Likes: 0
From: Hannibal, Missouri
Originally Posted by SunCr
42 is no voltage on the bypass line. You disconnect this circuit to set base timing, which if you or someone recently did, check the wire. Otherwise, it's brown wire from the distributor near the battery and brake booster. It has a barrel plug or connector which can deterioate over time. Check this wire first.
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Thread Starter
Racer
Joined: Aug 2004
Posts: 417
Likes: 0
From: Audubon PA
SunCr,
I will check the brown wire as you instructed. This is the brown wire connector at the distributor cap on the brake booster side, right. I will unplug and replug and see if that does the trick. How can I tell if this plug is bad?? How can I test it??
Thanks, jzvette
I will check the brown wire as you instructed. This is the brown wire connector at the distributor cap on the brake booster side, right. I will unplug and replug and see if that does the trick. How can I tell if this plug is bad?? How can I test it??
Thanks, jzvette
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
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From: Audubon PA
SunCr,
I looked at the brown connector (barrel type brown connector at the Distrib Cap) and unpluged it, it looked clean and in good shape. i repluged it back in (It's next to another barrel plug on Distrib cap, right??). I drove car and about 2 minutes into the drive the Service engine light comes on, and again a code 42. Car seems to be running great, no change, maybe a slight stumble in idle right when the light came on but after that the car ran smooth. The barrel plug is brown but the wire is a lighter color, it seems to go into a wiring harness below the distributor toward the brake booster. I'm going to try and do the ohms test of the circuits tomorrow. I'm not very experienced with this electical diagnostics, but I'll try my best. jzvette
I looked at the brown connector (barrel type brown connector at the Distrib Cap) and unpluged it, it looked clean and in good shape. i repluged it back in (It's next to another barrel plug on Distrib cap, right??). I drove car and about 2 minutes into the drive the Service engine light comes on, and again a code 42. Car seems to be running great, no change, maybe a slight stumble in idle right when the light came on but after that the car ran smooth. The barrel plug is brown but the wire is a lighter color, it seems to go into a wiring harness below the distributor toward the brake booster. I'm going to try and do the ohms test of the circuits tomorrow. I'm not very experienced with this electical diagnostics, but I'll try my best. jzvette
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Since the brown wire and the connector look good, make sure the prom is fully seated. I'd pull the PROM out and reseat it to be sure. Clear the code by disconnecting the barrel plug on the red wire from the battery. If it comes back, use your old ECM (if you haven't returned it for a core) to rule out the new one as being the culprit. Assuming these things check out, you can follow the chart someone else posted or spring for a new module, though with the ECM being the last thing replaced, its probably more likely that it's the ECM connector or the PROM not being seated.
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
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From: Audubon PA
SunCr,
I spoke to a tech and I was looking at the wrong barrel plug. I know know what and where that brown wire is and I will check it tomorrow. I do think you may be right about the PROM not being seated, I will also check that and clear the code and see if it comes back. I can return the new ECM for another (no cost) I purchased it from a NAPA shop down the street. I will also use the flow chart test to rule out evreything. I will first start with checking that brown wire. Thanks again jzvette
I spoke to a tech and I was looking at the wrong barrel plug. I know know what and where that brown wire is and I will check it tomorrow. I do think you may be right about the PROM not being seated, I will also check that and clear the code and see if it comes back. I can return the new ECM for another (no cost) I purchased it from a NAPA shop down the street. I will also use the flow chart test to rule out evreything. I will first start with checking that brown wire. Thanks again jzvette
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
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From: Audubon PA
SunCr,
I tried to find the wire you instructed me to check, but I can't locate it. It should be a single barrel plug and the wire is tan with black stripe per flow chart info from alldata. Can you better tell me where it is exactly. I see the tan/black wire but it goes to a four wire(white, tan with black stipe, purple with white stripe, and black with red stipe) connector. The connector I'm looking for should be between the 4way connector and the ECM by the firewall behind the distributor, but I can't find it. The good news is that the light hasn't come back on yet. I'm going to post new thread looking for tan wire. jzvette
I tried to find the wire you instructed me to check, but I can't locate it. It should be a single barrel plug and the wire is tan with black stripe per flow chart info from alldata. Can you better tell me where it is exactly. I see the tan/black wire but it goes to a four wire(white, tan with black stipe, purple with white stripe, and black with red stipe) connector. The connector I'm looking for should be between the 4way connector and the ECM by the firewall behind the distributor, but I can't find it. The good news is that the light hasn't come back on yet. I'm going to post new thread looking for tan wire. jzvette
Thread Starter
Racer
Joined: Aug 2004
Posts: 417
Likes: 0
From: Audubon PA
SunCr,
I did find that tan wire with the black stripe and it was loose. I reconnected it and I will keep my fingers crossed and hope there won't be any more code 42's. Thanks again and I will keep you posted. Thanks jzvette
I did find that tan wire with the black stripe and it was loose. I reconnected it and I will keep my fingers crossed and hope there won't be any more code 42's. Thanks again and I will keep you posted. Thanks jzvette
