2000 XC70 Transmission being funny on freeway...[ faulty brake pedal switch 9128577]

[FlyingVolvo]

I talked to Chris at XeMODeX this morning, great guy! We talked about the issue and all the variables.

He said that it is likely one of two things. Since my MAF is new and the electrical system has been tested, he said it is likely the ETM or the Engine Management Relay. They are sending a replacement ETM to me anyway, but I will also be replacing that relay, since it supplies the power to the ETM and other various components.

I should be getting the replacement in a few days, I'll keep the thread updated with my adventures.

[FlyingVolvo]

FIXED!!!



It was the brake pedal switch. Not only did I have the replace the switch itself, but I also had to bend the metal piece that it's attached too. I bent it towards the brake pedal, so that it makes better contact with more pressure from the retracting pedal.

After I did this, the torque converter lockup up promptly and cruise control worked perfectly. I'm actually thinking that the old switch may have been okay, but that it still just wasn't making contact. That metal piece was tough to bend, but that's exactly what fixed it... so I wonder how it got bent back in the first place? Or maybe it was a combination of the two.

Either way, I'm happy to have lockup on the freeway again!

[jblackburn]

Hurray!

Silly Volvos.

[FlyingVolvo]

It really is the greatest feeling when you go for that first drive and realize everything's perfect!

[dcarlson12]

RE the brake pedal switch, are you saying that the switch was staying closed or open? i.e. I guess it was acting as though the brake was being applied. Would this have also caused your brake lights to have been lighted up?

[jblackburn]

There are two sets of contacts in the switch. One set (one on the left, one right) controls the brake lights. The rest controls everything else - on a 1998 model, the shiftlock - on a 1999/2000 model, apparently the cruise control kick-out and transmission lockup as well. That one is a bit less sensitive to pedal application than the brake lights themselves, but if the metal bracket was bent out far enough, it's possible the brake lights wouldn't work unless the pedal was pressed down significantly too.

[FlyingVolvo]

RE the brake pedal switch, are you saying that the switch was staying closed or open? i.e. I guess it was acting as though the brake was being applied. Would this have also caused your brake lights to have been lighted up?

I'm actually a little curious about that too. I'm wondering if there were loads of confused people driving down the highway wondering why I was apparently hitting the brakes every second or two... or going up long hills with the brakes on.

The switch was not getting pushed in enough. When you release the brake pedal, the pressure of the pedal comes and pushes in a button, similar to a regular pen or something. When you release the brakes, the spring inside the switch pushes out, telling the car that the brakes are being applied.

[huzzsaba]

Is there any way of getting photos of what exactly you replaced and the bracket you had to bend?

Thanks

[FlyingVolvo]

Here is a picture of the switch:

Courtesy of FCP.

9128577.jpg (20.19 KiB) Viewed 1146 times

Remove the knee bolster by removing the single Torx screw in the middle. You also have to disconnect the courtesy light to get the thing out of there.

It's all pretty simple from there. Look at your brake pedal and follow it up. You'll see the switch from the picture position in a way that lets the pedal hit that raised part of the switch when it retracts. The metal bracket is pretty obvious, and I was able to bend it a couple of degrees by pushing with my thumb, and my other hand as support. It's tough and cramped, but it's even easier to do with the switch removed.

However, as someone mentioned in this thread earlier, if your switch is original, it's probably pretty brittle. I broke a couple of the clips on my old one when I took it out. I'm not sure how I would have done it if I had to re-use that switch. But I get the feeling that there would be some JB Weld involved!

Are you experiencing the same issues as I was?

[polskamafia mjl]

Glad you got her taken care of!