quickcat

Can anyone explain to me what a Quad Driver code is?

Tom Piper

The Quad Drivers are part of the ECM in a '92.
They are not serviced separately from the ECM.

These drivers are essentially electronic amplifiers designed to be able to drive certain loads.

Tom Piper

OldCorvetteFan

Here's a link to some general information about quad drivers ...

http://www.onsemi.com/pub/Collateral/NCV7601-D.PDF

Steven

VenkmanP

The "quad" just means there are four in one IC.

quickcat

If I am getting a Quad Driver code would that indicate an ECM failure or is there a way to repair it.

quickcat

That's what I needed. I am going to have to crack her open and take a look.

VenkmanP

See what the shop manual says. My guess would be yes it means you need to replace the ECM.

ittlfly

There are several quad drivers in a 92 ECM with separate default codes. Each one is responsible for sensing several functions ie: canister purge etc. If a problem appears in one of its sensed items, it will throw a code. You need to read and follow your FSM for flow chart for the code that the ECM is throwing. There is a strong possibility that there is a problem with one of the items that the quad driver is sensing rather than a bad ECM. Hope that makes sense.

Randy93

My 93 got a code 28, then a 26, quad driver 3 & 1. You have to replace the ECM and trace down which sensor is sending a bad signal or is shorted. They are called quad drivers, because each one monitors 4 sensors. I had bad wiring to 2 sensors, hence the 2 codes.

VR'92

Getting a Quad Driver code does not mean the ECM is failing. I could just be the system that the QDM controls is failing. Most likley it is not an ECM failure. You need to get a service manual and look up the code.

quickcat

I am expecting my service manual to arrive today. I just got the car Friday.

ittlfly

What code is being thrown?

RacerX70CC

QDM (quad driver module) faults are typically the result of one of the controlled circuits failing, which in a lot of cases does smoke the QDM in the ECM. Typical failures include solenoids shorting out, or a short to ground on the solonoid's circuit, which of course will kill the QDM. The best way to fix this is to have a factory service manual, with the appropriate high-impedence DVOM (digital volt/ohm meter) to properly diagnose the circuit in question before destroying a new ECM. This isn't a case of "throw an ECM at it" to fix it.

YMMV

quickcat

28 Quad Driver 3

ittlfly

That driver supplies the ground for both fan relays and the A/C clutch control relay. Check to see that these items are working.

quickcat

They seem to be working fine, but I will do a more accurate test this afternoon.

93 ragtop

I installed 2 switches to turn on my fans. If they are set to on, I get a quad driver fault when scanning. Turn it off and the fault goes away.

VR'92

Have you removed any EGR/AIR equipment? This code will set with the removal of some of these items. Ask me how I know this?

mstock

Tell us how you know this

orenkrief

how do you know this????? i have the same code no egr valve and car dies after a 10 min drive