1999 S70 T5 140,000mi - ABS/TRACS/Brake/Speedo/Odo

bigmuse85 · Post by **bigmuse85** » 16 Mar 2009, 11:21

My 1999 S70 T5 has started randomly having the STC ABS and BRAKE lights coming on. The speedometer and odometer also will occasionally cease to function, with the speedometer going down to zero while in motion and the odometer reading as dashes all the way across. Also, the Up arrow on the dash will blink occasionally and affect drive-ability as if the car was in winter mode. All these problems arose around the same time and will occasionally go away completely for a few days and then suddenly come back for a few days. Could this be a speed sensor? What's my first step of diagnosis? Thanks.

Post by **MadeInJapan** » 16 Mar 2009, 11:49

Welcome to MVS.
What you describe are classic signs of the ABS unit doing out- they go out slowly and then finally become nonfunctional. If you'll look in our repair database, there are instructions on how to rebuild this unit yourself or you can take it out and ship it off for a rebuild- Victor Rocha is probably the best at this and his information is under the parts tab at the top of this screen.

C@lvin · Post by **C@lvin** » 16 Mar 2009, 11:52

Exremely familiar symptoms!

The easy answer is to have Victor Rocha rebuild your ABS controller for around $150 - don't know exactly the current going rate (google him and see). He's a great guy, very helpful and does good work. His web site also provides diagnosis and removal information.

The not so easy answer is that it actually could be something else. I'd take the time to check out the sensor wires for shorts, measure resistance, measure gaps, etc.

Have you gotten a CEL? Had the codes read?

My personal experience is that I've had three Volvo and Saab ABS failure situations in which I had the controller rebuilt and in two out of three times the problem was actually something else. (96 850 T5, 00 V70, Saab 9-5 4cyl wagon)

Once, it was a missing axle nut (S70) which caused the gap between the wheel sensor and the pulse wheel to go into and out of the required gap range causing intermittent ABS failure and false activiation. (Eventually I actually found two other message posters who experience the identical problem).

In my Saab, it ended up being a battery/battery cable problem.

There are huge amounts of posts on this topic here and all other Volvo discussion boards because it's a common problem, so I suggest you begin by spending some time reading up on it. Someone (I think it's Ozark Lee) has actually posted information on DIY rebuild of the controller. If I had a controller die on me at this point, I'd be very tempted to do that.

Keep us posted, and let us know if you have more questions after reviewing some of the history posted here or elsewhere.

bigmuse85 · Post by **bigmuse85** » 16 Mar 2009, 13:02

I do have a CEL on, but haven't gotten the codes read, as it's $75 at a local import shop and I've heard that the readers at Advance Auto or somewhere else where it's free to get it done won't read the codes for a Volvo. A bad ABS/Tracs module couldn't cause the speedometer to go out could it? Thanks again guys.

bigmuse85 · Post by **bigmuse85** » 16 Mar 2009, 13:03

is there a guide anywhere on how to inspect the wheel sensors? i don't even know what they look like

... also, if i'm going to spend $75 to get my codes read anyways, would it be worth it to buy a reader such as http://www.obdkey.com/obd_orders.asp that i could connect to my laptop and read the codes? will a reader such as this tell me all i need to know with a volvo?

Post by **Ozark Lee** » 16 Mar 2009, 13:30

A bad ABS/Tracs module couldn't cause the speedometer to go out could it?

Yes. The speedometer signal is generated in the ABS module based on information from the wheel sensors. The are basically 2 kinds of ABS modules from 1996 and on; those that have already broken and those that are going to break.

...Lee

C@lvin · Post by **C@lvin** » 16 Mar 2009, 14:22

The readers can read generic OBDII codes - get them read and post them here and others may be able to help.

Occasionally the generic codes aren't enough. Only Volvo or a larger independent can afford the Volvo code reader for Volvo specific codes.

Here is a place to see a diagram of the sensor and wheel unit. Put in you model information and go to the Front Brake and Rear Brake sections. Then inlarge the picture.
http://www.eeuroparts.com/

I'm not familiar with the reader that you mention. I picked up a $60 to $70 reader at Wal-Mart that has been quite useful to me. Most of them will, but make sure the one you get will also clear the codes.

For manuals, I don't think the Haynes covers anything after 1997, but much of the information for your 1999 will be similar if not the same. I picked up a VADIS (dealer shop manual on CD) on e-Bay for around $70 that has been extremely useful.

bigmuse85 · Post by **bigmuse85** » 16 Mar 2009, 16:26

Looks like I'm gonna be doing some soldering in my ABS module tomorrow if I have time. Thanks a lot guys. Codes from generic reader are:

P0722
P0442
P0455
P1618
P1633

Some of these may no longer be an issue as I fixed a cracked evap tube.

bigmuse85 · Post by **bigmuse85** » 18 Mar 2009, 21:40

Refurbished my ABS module today, so far so good... will update in the next few days.

C@lvin · Post by **C@lvin** » 19 Mar 2009, 07:11

Great news. Gives me confidence to try it myself if I have another failure.

Keep us posted.