Hey Guys,

My 95 SSEi Keeps throwing the QDM-1 Failure code. After research I have learned that QDM-1 controls the high temp light (low speed fans), TCC apply, EVAP Canister Purge, and Boost Bypass valve.

My symptoms are as follows. My ECC light flashes indicating a problem as it pours out heat regardless of it being on or off. If I let the car shift into Overdrive it will stall, or in other words when the TCC solenoid tries to activate. My Boost Bypass valve is open at all times. Lastly, I do not believe my low speed fans are working, only my high speed.

So, since almost all of the functions of the QDM-1 are not working this leads me to believe it'* a problem with the Quad Driver Module rather than the individual sensors and solenoids. My question is where is the QDM-1 located? I recently (a day ago) installed a new PCM from AutoZone because the engine was misfiring (fixed the misfire.) The EEPROM from the old PCM was installed into the new PCM, is there any possibility that this chip (I do not know if it is OEM or not) is causing my QDM-1 failure?

One thread suggested that a vacuum problem may be to blame although I am unsure of the proper way to test for a vacuum leak and remain rather skeptical as this seems to be an electrical problem. Also, the 3 gauges on the right side of my cluster no longer function (Boost, Oil Pressure, and Temp.) They move back and forth independent of relaity.

Any Ideas would come much appreciated. I am unsure as to how to go about tackling these problems (Gauge Cluster, and QDM-1 Failure.) Thanks for your help.

Jondo welcome to the QDM club. The club no one wants to be in. The QDM does not exist in a physical location. It essentially is a fairytale land within the PCM.

Most likely you have (Randy'* terms) something feeding bad voltage or voltage/ground present where it isn't supposed to be. This is causing the computer to act funny and give you all kinds of problems.

Simple definition: something went bad under the hood and the puzzle is to figure out which item is bad.

Have you pulled the codes and gotten the numbers for actual QDM'* that it'* complaining about? Almost sounds like one of them is the one I have/had giving me a hard time. It had to do with the canister evap solenoid, TCC solenoid... You pretty much need to start figuring out what is and what isn't bad piece by piece.

On the cluster. Did this happen at the same time or was it a seperate instance? Mine was crazy like that when I got it. I've been able to get them working and stable...but the temp is very inaccuarate...I know that 200 is really 180 and 245 is really 215 so I use it as reference only. If seperate instance...get your hands on a good cluster... pull it apart like techinfo says and swap the little circuit board for those three gauges only. Magic.

I used a board from a 93 cluster and it works good...

More specifically, the QDM is the part if the PCM that provides a LO (ground) output to such items as indicator lights, relays and solenoids. The PCM monitors these outputs and throws a SES light when the voltage is not what is expected. This could be caused be a frayed wire shorting to ground, faulty relay or solenoid, or bad PCM. Unfortunately, the PCM will not tell you what specific circuit running off of that QDM is at fault. I'm taking a guess to say that if one item is causing a QDM failure, it potentially can affect the output of the PCM to the other circuits on the same QDM.

I'm interested in the boost solenoid. That'* probably where I'd start (from here cause you already tried a different PCM).

The ECC blinking os a seperate problem and sounds like the ever-so-popular air mix actuator. You can inspect the movement of the actuator through the glove box opening. There is a recent thread with pics and instructions but I'll have to find it.

Thanks for the quick response guys. Yes Randman the Boost Bypass Valve is closed (or just maybe 1 cm off the screw on the top of the manifold) at all times during idle, acceleration, ect. I currently have to drive the car so I have the vacuum line that opens the Bypass Valve off. This opens the Bypass Valve so no Boost is ever created. And to answer your future questions, yes the computer will still throw the code and malfunction if I stick the vacuum line back on (I drove it that way for a while too.) I just don't like the idea of my noisy supercharger to be under 100% Duty Cycle at all times.

On the Cluster..It'* been that way since I bought the car a couple weeks ago. Right now the car goes to Best Buy to have an aftermarket headunit to be put in. I'm going to see if they can't check the connections behind the cluster while they have the dash apart. My guess is that they are heavily oxidized and need to be cleaned or replaced with a new Cluster.

I'll Post back when I get back from Best Buy tonight on the QDM-1. I believe the code was P1640 by the way.

I had the same problem......Every once in a while I still do. But I never did anything about it....I just kept ignoring it and it just fixed itself and went away. Being a voltage based driver.....How'* your charging system doing for voltage?

You know, that'* a really good question. Here'* another clue. When I turn the key to the "run" position, my Drivers Information Center will display a "check gauges" along with the Check Engine Light and the Volt Light. However when I am driving the Volt Light is not on, and it takes probably 10-60 seconds for the Check Engine Light to come on.

The car stalled on me twice on the way home from Best Buy. First time in a while. I'm beginning to think maybe heat soak has something to do with it. What is the best way for me to tackle this? Should I just start throwing parts at it such as the Boost Bypass Valve Solenoid, TCC Solenoid, and so forth? Should I test the volts at the battery with the car running (should be about 14 volts right?)

The QDM-1 Failure Club sucks.

Everything you describe on start up is normal...except usually my SES light will stay on.....but I got a clusterfuck of problems with mine....different story different day.

Anyways, yes, check the voltage at the batterry with the car running.....should be something like 14 volts...maybe a lil more or lil less.

Hey 95SSEI,

What does the FSM say about my QDM-1 Failure code and how to go about fixing it? Also, where did you get the 95 SSEi FSM from??

Prolly from ebay. It doesn't say to fix anything...because of the number of systems that control it. My best advice would be check ouyt the evap canister and solenoid on top....and the other stuff and hope to hell it'* not the TCC solenoid.

Have you tried popping the battery out for a 1/2 hr to clear the PCM?

What was your voltage at also? Cars can do some pretty wicked things when they're low on power.

I second the QDM club suckage...check engine light came on again...ugh They should call it the FQDM

I got the FSM from Helm...they are the makers of the GM factory manuals. It says tons of stuff about testing for QDM'*. Gotta go get it and start checking it out....brb