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640 quad driver code - 1995 Buick Riviera

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Quad driver module code 26 and 28

A quad driver is a transistor in the engine control module ! GM OBD Trouble Code 26 GM OBD Trouble Code 28

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Quad 4 drive error code is always on

The quad driver is a component inside the engine computer that controls 4 different sensors. The code usually means the computer is failing.

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Codes trouble olds engine troublecodes

quad driver A fault
ECM module have input and ouput, quad driver are there to activate a solenoid or relay
quad driver A drive a few of those output
example quad driver A control canister purge solenoid and the solenoid is defect . the quad driver will kick off until you change the solenoid
there is two kind of driver 1984 to will reset if trouble is repair
the other one is the ecm module itself have to be change after is repair .....(quad driver act has a driver or big fuse)

Oct 18, 2013 | 1992 Oldsmobile Cutlass Ciera

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Well code 640 is usually found on diesel engines for a problem with the intake air heater circuit.
There is a code 1640 for some GM cars which is for a problem with one of the quad drivers inside the computer.
You may want to get a second opinion on the code to make sure it really is 640.

Apr 06, 2013 | Oldsmobile Achieva Cars & Trucks

1 Answer

Quad driver module computer circuit #2 fault ?

I will start by pinout check current + to ECM and - ground there is many .
A Quad driver work like a big fuse d?pends some are resettable and other not reset(ECM defect) if it is so then you have to check all solenoid not short to ground before replacing ECM it will burn without checking the solenoid
hope it help

Feb 08, 2012 | 1988 Oldsmobile Delta 88

1 Answer

Pulling code p0650 qdm2 fault

Fix the Quad drivers codes first. I had a 95 LeSlober. Codes indicated a
quad driver fault, an EGR fault, and a problem similar to yours {limp
home mode in trans). Dealer said replace the computer($200.00), replace
the EGR valve ($150.00), plus another 150 in labor. I told them
nevermind, and pulled out the schematics, and found that a fuse that fed
one of the quad drivers was EGR, and one fed the trans solenoids. I just
couldn't find the fuse. Finally found it behind the passenger side kick
panel. Replaced the fuse and all worked well. Dealer would have charged
me 500 for this. Quad drivers supply power (or grounds) to systems that
have a medium current requirement . The quad driver fault could cause
the solenoid failure. Hope this helps, James Booth

May 18, 2011 | Buick Park Avenue Cars & Trucks

1 Answer

I have a 1995 buick la sabra i got an error code po676 quad driver module failure i replaced the E C M and i am still getting the same code

The quad driver in the ecm operates the higher amp draw for certain relays and solenoids one of them is faulty or there is a short to ground in the wiring.You will have to locate a wiring diag. and figure out which quad driver is the bad one and see what it controls.There should be at least 2 quad drivers maybe more and they would be numbered in the diag.

Mar 21, 2010 | 1995 Buick LeSabre

1 Answer

Have 95 saturn sl with code 26 and 27 quad driver

well the quad driver may not be at fualt and most likely is not.

there is a fualt line that the computer uses to monitor for fualts but the thing is one line monitors four different things and the code is to get you in the general area but not to the exact fualt. so from here you need to test for failed components. that code and the quad driver monitors the a/c , evap solniod , egr solenoid and coolant fan relay. the fan relay and egr are the most common i see all the time. and with you having an isssue with that coolant light i want to say check the fan circuit.

let me know if you have more question thank you and good luck

Nov 26, 2009 | 1995 Saturn Sl

4 Answers


There's a lot of information regarding your problem here:

My suggestion would be to contact a local dealer and have them run the diagnostic (usually under $100), then if the part is easily replaceable, do it yourself. If it's more involved, then bargain with the dealer on a good price to have the problem fixed.

I truly hope that the Quad Driver itself isn't what's causing the code.

Nov 02, 2009 | 1993 Saturn SL2

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