94 M6 Service Engine Soon Light On
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Joined: Jun 2009
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94 M6 Service Engine Soon Light On
My dealer is telling me this is an EGR problem. They cleared the code, came back on next day. Only comes on when the car goes into closed loop. If you shut if off then restart, light goes out and stays off until it goes through another warm up cycle. Driveability is fine, good idle and no bucking or any other issues. Anyone else run into this? Thanks!
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Joined: Mar 1999
Posts: 2,067
From: Kernersville, NC
I had an SES light for an EGR code several years ago. It would come on during 6th gear cruising at light throttle. Had to have the EGR valve replaced.
Did they give you the specific code number for it?
Did they give you the specific code number for it?
Last edited by ACE1252; Jun 13, 2009 at 11:11 AM.
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From: Hell was full so they sent me to NJ
There are 2 different EGR codes for the 94 - one for the vacuum solenoid electrical circuit, and the other based on the PCM cycling the EGR valve and looking for a change in MAP to confirm the valve is working. The PCM can only run the MAP-based diagnostic under very steady-state conditions, like a constant RPM cruise. So that's why the code goes away when you reset it, and then reappears when the engine is operated under the very narrow set of conditions that permit the diagnostic to run.
If you have the code for low flow, could be the valve is not opening when it is supposed to. Check the vacuum lines from the intake manifold to the EGR vacuum solenoid, and from the solenoid to the EGR valve. Apply a ground to the solenoid to make sure it is opening. If the vacuum lines and solenoid are OK, apply a vacuum directly to the EGR valve with the engine idling. If the vacuum opens the valve and causes the engine to stumble badly, it will verify EGR flow when the valve opens. If not, you have a faulty EGR valve or the pintle on the valve or the hole in the intake manifold is plugged with carbon.
If you have the code for low flow, could be the valve is not opening when it is supposed to. Check the vacuum lines from the intake manifold to the EGR vacuum solenoid, and from the solenoid to the EGR valve. Apply a ground to the solenoid to make sure it is opening. If the vacuum lines and solenoid are OK, apply a vacuum directly to the EGR valve with the engine idling. If the vacuum opens the valve and causes the engine to stumble badly, it will verify EGR flow when the valve opens. If not, you have a faulty EGR valve or the pintle on the valve or the hole in the intake manifold is plugged with carbon.
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Joined: Jun 2002
Posts: 798
From: San Jose, CA
A view for the EGR can be found on ShoeBox's site here: http://shbox.com/1/egr1.jpg
And testing is here:
http://shbox.com/1/4th_gen_EGR.html
Hal
And testing is here:
http://shbox.com/1/4th_gen_EGR.html
Hal
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