'92 3300 Quad Module - What & Where?

[maxman]

'92 Grand Am; 3300 V6; 190,000 miles.
Running very rough. Service engine light intermittent. Took to Advance Auto and received error code report. Error Code (26) Quad Driver Module and Error Code (27) 2nd Gear Switch. Looking at the error codes listed in this forum, both codes (26) and (27) are related to the Quad Driver Module.

What is the Quad Module?
What does it do?
Where is it?
Will this cause the running rough?

Need some quick help, please. This is for a nice young neighbor gal needs to drive back to school 350 miles.

[xeroinfinity]

Just because you have a Quad driver code doesn’t mean the Quad driver is bad. All a Quad driver code means is that an expected value is not present when it’s suppose to be.

Also a Quad driver is a techy name for 4way on-off switch arranged in a group, hence the name Quad driver.
The computer watches the voltage values on each switch and knows that if the switch is on, a voltage value will be seen. When the switch is off the opposite voltage value will be seen.

So what can set a quad driver code?

How about a bad bulb? How about a bad fuse? The answer is yes to both questions. Yes, a bad bulb or failed fuse can set a Quad driver code. Start with checking your fuses.

There can be up to 3 fuses that supply power to circuits controlled by the Quad drivers. If the fuses are good the next check would be of all or some of the following, depending on how your vehicle is equipped: Up shift light bulb, coolant hot bulb, shift to drive bulb, A/C relay, coolant fan relay, EGR solenoid, Canister Purge solenoid, even a speedometer output signal goes to one of the switches on the Quad driver. The Quad Drvers is in the ECM.

It is unlikely you have a computer problem. It’s more likely that the Quad driver code is present because the computer is not seeing the information that it expects to see at one of the switches.

Sometimes this can be difficult to track downbut not impossible. Hope this helps.

[maxman]

Yeah, I read more into this after I posted and totally understand what you are saying. Thanks for the feedback!

[mazzy]

Did you fix the problem ? My 92 is doing the same thingy's ? I changed 1 fuse , does an automatic have a lighted up-shift light ? Mine was scanned & all 3 26 27 &28 codes came up ! I gotta figure this out soon !
Thanks for any info , Lori .