My scantool tells me quad driver 1 is bad ONLY if the brake pedal is depressed. WTF? What the hell does the brake switch have to do with the QDM?

Are you sure it is telling you that it is "bad"?

The Quad Driver "A" Fault sets if the brake is not applied (It is connected to the brake) and there is improper voltage detection at the

1. Canister Purge Solenoid
2. Temperature Lamp
3. Low Speed Fan Relay
4. TCC Apply

The Quad Driver circuit switch for the brake detection sets when you press the brake, but it shouldn't set a Code 26.

Not setting a code. Just reading bad on the data stream every time I hit the brake.

Try your tool on another Bonneville. Possibly the "bad" indicator in your software is incorrect.

You must have an Actron scan tool. I know this because I have one also and on all GM cars that ore ODB1 I see this. I see it on my 93 Bonne, my 94 Grand Am 3.1, my Buick Century 3.8. This is a software problem in the Actron Scan tool, they are reading the wrong bits in the stream. I have contacted them and they are aware of the probelm but since they arent making the product anymore have no intention of fixing it.

Cool. Software. Must be Microsoft.

I'm getting a code 26 and a service engine soon light. The light goes off when I press on the brake for a few seconds and then comes back on after I release for a few seconds. Any ideas?

This thread is very old. Your best bet is to start a new thread about this. Also post in the correct area and post information such as year of car and trim level. Thanks.

Hi Dan,

I'm new here. Can you tell me how to post a new thread? Thanks, Mike.

From the main page of the forum section you would like to post into, press the new thread button. It can seem hidden when reading and looking at other things. Holler if we can help further.