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GM 3100 Check Engine Light P0401 - EGR problem


RYS

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I have a 1996 Regal with the 3100 V6 that has a check engine light. The code is P0401. I have replaced the EGR with a working one from a low mileage car. The light is still on. What should I check next? How can I be sure the new EGR works or my old one is bad? From what I can see on this engine the only parts of the EGR system is the valve itself and the pipe that goes from the intake to the exhaust manifold.

 

My next step is to soak the bottom of the EGR valve in carb cleaner and spray it down that tube as well.

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Follow the steps to that video. A few cautions:

 

-You will definitely need a new throttle body gasket, chances are your old one will disintegrate when you remove the throttle body.

-Make sure you install the new gasket properly. I installed mine apparently backwards, and it caused a massive leak after the throttle body which caused the engine to rev straight up to the rev limiter as soon as it was started. Readjusting the gasket solved this.

-There is a coolant pipe that runs right in front of the lower throttle body bolt. It is a pain in the ass to remove, but it can be done with regular tools, some time, and some swearing.

-You will need LOTS AND LOTS of carburetor cleaner and shop rags.

-Compressed air also helps for cleaning the top of the EGR passage.

-The video recommends using a cut piece of speedometer cable for cleaning the port. I used a leftover piece of brake cable from when my dad fixed the parking brake on our van. It worked just as well.

-The video also shows installing the cable in the drill and plunging it down through the EGR port into the intake plenum. I found it was easier to do the opposite, force the piece of cable through the port from the plenum side into the EGR passage. It is easier to get to and went straight through, the port is pretty difficult to see from the EGR passage.

-A piece of wire coat hanger is your friend.\

 

Also the EGR test cycle on your car is around 45-50 mph or more, in D, when the engine is not under a load. You will hear a puttering then the light should come on for the EGR. I'm not 100% sure if this is the same on your OBD2 car as mine has OBD1.5. But a sure fire way to turn my SES light on before I cleaned the port was to drive on the highway.

Edited by WhatTheFehl
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If you have a scantool, hook it up and clear the codes. Or take it to PepBoys and they will scan your codes and clear them for free. You could also try disconnecting the negative battery terminal for a few minutes and then hooking it back up. That usually cleared codes for mine, but once again, I have OBD1.5 and you have OBD2 so I'm not sure if this will work for you. By the way, when you first start it after hooking everything back up (battery, TPS, IAC, etc) it may stall immediately. That's just the TPS and/or the IAC resetting itself.

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It started right up and didn't stall. My local Autozone won't clear the code for me, just read it. They tell me "im not supposed to". I can't drive as far as pep boys the car is not registered and I have enough money into it I don't want to pay impound fees. I will try disconnecting the battery. I had it disconnected during the cleaning but I started the car with the EGR unplugged. :roll: Back outside.

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I also have a loose wire, can't find a place for it. Can someone identify it for me, thanks.

 

I have a feeling it may have been for the Dynaride which I think has been removed?

 

dscf2137.jpg

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Then you got something else going on.

 

The only code that came up yesterday was for the EGR. I'm pretty sure there is nothing else at fault for this light. Unless the EGR is no good. Unfortunately I don't have a 9v battery and wires to test it.

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