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

Post by **jblackburn** » 13 May 2011, 21:30

From what I have read about the ETM issue, I would think so.

By the way, does your Taptatalk crash on you all the time? Mine has like 4 times tonight. Stupid iPhone.

Post by **FlyingVolvo** » 13 May 2011, 21:34

Nope, never have had an issue with it. Android for the win!

And yeah... I wish this crap was easier to figure out. I don't know what would cause this all of a sudden.

Posted from my Droid Incredible using Tapatalk.

Post by **FlyingVolvo** » 14 May 2011, 08:38

I installed stock airbox and reset the computer. It was all good for about 10 miles, entering lockup in 4th gear.... then I went for another drive and it's doing the same damn thing. Funny thing is that cruise control worked this time, and it was acting up while in cruise control.

huzzsaba · Post by **huzzsaba** » 14 May 2011, 11:07

I have the exact same problem wit my 99 v70 t5, except that the car runs perfectly when the cruise control is engaged. Once it is turned off, it will start doing what you described.

I flushed the transmission fluid and it still does the same thing. I also believe its something electrical and not the transmission itself since it has been doing this for the past 10,000 kilometres and. also this happens at speeds above 80 km/h which would be I guess anything above 45 miles per hour. Also it is very sensitive to position of the throttle pedal.

However, like I said, it works fine with the cruise control every time

Post by **FlyingVolvo** » 14 May 2011, 13:48

I'm determined to get to the bottom of it!

It's weird, I just did another 80 mile drive. It acts up a lot (RPM bouncing...lock/unlock) in the first few miles, then it "stabilizes" to where it just doesn't lock up at all. Cruise control is on/off, but mostly doesn't work.

It's gotta be the ETM or something... I just want it fixed because A. Losing gas mileage reving higher on freeway, B. I feel that the constant locking/unlocking is hard on the torque converter and heating up the tranny too much.

Posted from my Droid Incredible using Tapatalk.

Post by **EstVolvo** » 14 May 2011, 22:47

Have you fixed the ABS module or upgraded TCM software?
Mine jumps sometimes from 2000 RPMs to 2300 or so when I turn on the cruise control ...

Post by **FlyingVolvo** » 14 May 2011, 23:18

The ABS module was replaced once in 2009 with a remaned unit. I wonder... could I test this by pulling the ABS fuse (I assume there is one)?

I don't hear/feel anything in the brakes though.

Post by **kcodyjr** » 14 May 2011, 23:21

In addition to electrical, there are vacuum lines involved in the cruise control.

Have you hunted down and checked/replaced all of them, including the one under the battery tray that tends to rot?

Post by **jimmy57** » 15 May 2011, 00:20

The cars with electronic throttle do not have the vac pump and hoses. The throttle unit is commanded by ECM for cruise function.

Check for AC voltage with the engine running with various electrical loads on over several minutes. An alternator with failing diodes not fully rectifying all the AC current can cause odd problems with anything that is speed signal based (and other stuff not reliant on speed signals).

Post by **FlyingVolvo** » 15 May 2011, 10:31

I went to Autozone today and had the entire charging system tested. Luckily I had a very knowledgeable guy who helped me out and even knew a good amount about Volvos!

He said everything electrically checks out, and that it had some of the better numbers that he's seen.

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

Re: Transmission being funny on freeway...