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Discussion Starter #1
Been getting the "SES" light on my 94 for a couple of years.Runs fine,just annoying.
Getting trouble codes #75,76,& 77 saying all 3 EGR solenoids are bad. I installed a new EGR valve when it first started but still comes on every time I drive it.Usually as I let off the pedal to come to a stop.
Also got soft codes saying:
Quad driver 1--bad
Quad driver 2--bad
Quad driver 3--ok
Quad driver 4--bad

Don't have a clue what this is. Like I said, it runs great.I'd just light to stop the light.
Don't wanna just pull the bulb!!
Any ideas?
Thanks
 

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Less than 8 cylinder Moderator
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3.4 car?
 

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Discussion Starter #3
Yep. 3.4 with auto trans.I've been researching while waiting a reply.I'm wondering if the quad drivers are causing the EGR solenoid malfunction?
 

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Could be. Is it the electronic EGR or is it a trditional vacuum style? Haven't dealt with many 3.4 F bodies.
 

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Discussion Starter #5
Electronic.No vacuum.I replaced it a year or two ago when the problem first started. I can erase the trouble codes but after a day or two it returns.
 

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Think I have my service manual for my 94 GP yet. Can't gaurantee I can find an answer in there but it should be close
 

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I had the same problem on a 1994 grand prix se which had the 3.1 in it. I know its a different engine, but same problem it sounds like. Kept kicking out egr codes whenever I cleared them. I actually pruchased a couple egr solenoids trying to fix the problem. I knew someone at a local shop & had them check it out for me. It turned out to be the egr passageways were clogged up in the manifold. Cleared them out..problem never came back.
 

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I'd clean the passages out and see what happens
 

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quad driver codes are bad news.

if a quad driver has fails, it's possible you had a dead short in a relay or solenoid that damaged the ECM

(a quad driver is like a minature switch bank in the ECM itself)
 
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