Need Help - 88 Grand Am

[KillJoy]

As some may know, my Beater is an 88 Grand Am LE (2.3L Quad Four)

I am getting the following OBD-I Error Code:

26 Quad - Driver (QDM) Circuit

WFT is this, and what do I need to do to fix it?

KillJoy

PS - I DO NOT want to have to take this to the Stealership if I do not have to.

[ctrlraven]

Wow I had the same car for my very first car, lasted me a good while but always had to replace the coil packs every 4-5 months.

Here is some info I found on your code.

Quad-Driver Modules (QDM) are a kind of switch. It's like if you walk into a room and have someone turn on the light for you instead of doing it yourself and then that person tells you the light is on or off. Here is the technical description of the QDM circuits. CIRCUIT DESCRIPTION:
Quad-Driver Modules (QDM) are used to control certain components in some engine management systems. When the ECM is commanding a component "ON," the QDM closes the switch completing the circuit to ground. Each QDM output has a sense line. When a component is commanded "ON," the voltage potential on the sense line is low, and when the component is commanded "OFF" the voltage potential on the sense line is high. DTC 26 will set when the ECM is commanding a component "ON" and the voltage potential on a QDM "A" sense line is high, or if the component is commanded "OFF" and the voltage potential on a QDM "A" sensor line is low.
Either of these conditions will cause the QDM "A" fault line to display HIGH and set DTC 26. On all vehicles, the QDM "A" fault status on the scan tool will display HIGH with the brake applied or if the engine is not running. On vehicles with a 3T40 transmission, the QDM "A" fault status on the scan tool will read HIGH until the TCC in-line switch is closed. These conditions will not cause DTC 26 to set even though the fault line displays HIGH. To simulate driving in second gear and change the QDM status to low, disconnect TCC connector and connect a test light between harness terminals "A" and "D."
DTC 26 will set if:
The system is running in "CLOSED LOOP."
Brake switch is closed (brake not applied).
Transaxle in mid or high gear.
The ECM detects an improper voltage level on a QDM "A" controlled circuit for 10 seconds.Quad-driver sense voltage shows a low voltage for 5 seconds when battery voltage should be present or if the sense voltage shows battery voltage for 20 seconds when a low voltage should be present.


Do all your idiot lights come on? Check your battery cables and relays.

[KillJoy]

Do all your idiot lights come on? Check your battery cables and relays.


I think so...at Power On.

Also, the Brake Light comes on randomly. I just though the Sensor may be bad. Maybe I will look into getting that fixed :rolleyes:

KillJoy

[ctrlraven]

Good old Quad4 engine vehicles. I was told by mechanic that did some work on mine that he hated them because they had several different computers that oversee different things and was always a pain to try and narrow problems down. I bet the brake light coming on at random has something to do with it.