1996 Volvo 850 Turbo Multiple Part Failures - Need Help!

medford volvo · Post by **medford volvo** » 06 Jan 2009, 18:14

Hi,

I need some advice on how to troubleshoot the issue with my 850 Turbo. Went out and my car would not start. Dug into it and found that my fuel pump had failed. Replaced the fuel pump. When I started the car I notcied my cold idle was not working properly and my cooling fan was not working. (THe car has been previously working with no issues). So I replaced the Idle speed control and the fan motor assembly and the car seemed to run fine.

I drove it to the store and back and parked it. (No more then one mile) The next time I tried to start it, I had no luck. I troubleshot this and found the cam shaft postion sensor had failed. I replaced this and now the car starts, but I now have the ABS light and the traction control off light on the dash that I can not get to clear.

My guess on the ABS is the sensor. I have no clue what the traction control light could be.

I keep feeling like I have some larger issue happening with this car, but I can not figure out what could link all these things together. I love my volvo, but I can' afford to continue to replace every sensor in the car as they blow one by one.

Any idea what the common link here could be? Electrical? But none of these things are in the same circuit. Any ideas how to troubleshoot this any further? Any advice on what I should do? Is it time to send this horse out to pasture?

Thanks in advance for the help, it is greatly appreciated.

chuckcintron · Post by **chuckcintron** » 06 Jan 2009, 18:56

ABS and traction are the same unit: the ABS controller underneath the brake cylinder/distribution bank. This is a common failure on these cars.

As long as you are getting 12VDC when off and approx 14VDC when running (measured anywhere) your charging system is ok. You could have ground issues, but I'd expect more of a global loss of power rather than piece parts failing as you describe.

A bad ECU could certainly make all of this stuff look like points of failure, but you mentioned that you troubleshot these parts and found they actually did fail, right?

-Chuck

wolfspiritky · Post by **wolfspiritky** » 06 Jan 2009, 20:01

Parts get old and wear out but, this seems to be unusual for so much at once.

The ABS/TRACTION control units are infamous for going out on the 850. Your "Tracs" is controlled by your ABS. In layman's terms, the unit senses one wheel at higher RPM so it signals breaking to that wheel to stabilize and equalize traction.....hence "Traction Control". I just had mine (97 R) refurbed. Lights were out for a week then boom...on again. I just haven't swapped out my sensors.

medford volvo · Post by **medford volvo** » 06 Jan 2009, 20:51

Thanks for the help. Understanding the traction control and the ABS are the same system, certainly helps. Now I only have 5 individual failures I can not relate, rather then 6.

Unless I have multiple shorts, in multiple harnesses, I thought I could rule out the grounding as an issue.

As for troubleshooting these, I did the best I could, and replacing the part clearly resolved the issue. I still have the Cam shaft position sensor, is there any way I can test this outside of the car to ensure it is broken? Any suggestions on how to nail down if if I have an issue with the ECU, or just some really bad luck?

chuckcintron · Post by **chuckcintron** » 07 Jan 2009, 07:48

I haven't had a chance to look into a diag on the cps -- but it's a hall effect device so if the resistance curve can be found it ought to be easy to troubleshoot. The only way I can think of without that is to compare the resistance range to a known good sensor.

I'd worry about the ECU last. I can count the number of people I've heard about who have had that issue on the fingers of one hand.

-Chuck

bobsnow100 · Post by **bobsnow100** » 07 Jan 2009, 08:47

I don't think you can test the cam position sensor off the car. It can also be intermitent problem with it. When mine was bad, the car wouldn't start and other times it would be ok for a few weeks and then out of no where it would not start again. Then the nexy day it would start. Once I replaced it ,I haven't had the problem with that issue again.

wolfspiritky · Post by **wolfspiritky** » 07 Jan 2009, 10:19

bobsnow100 wrote:I don't think you can test the cam position sensor off the car. It can also be intermitent problem with it. When mine was bad, the car wouldn't start and other times it would be ok for a few weeks and then out of no where it would not start again. Then the nexy day it would start. Once I replaced it ,I haven't had the problem with that issue again.

Mine would be fine then, sometimes when I hit a bump in the road the car would die! Did diagnostics with the box under the hood (never remember what it's called) flashed the code for the cam sensor and, luckily, I deal a lot with one particular yard, bought a used one for $5. Changed it out and had no problems.

It is electronic!!!! Intermittent is the norm.

Post by **MadeInJapan** » 07 Jan 2009, 20:09

The cam position sensor tends to give misfire codes (if you can get the car up and running)...did anyone in this post get any of those codes when the CPS was going out- just curious.

wolfspiritky · Post by **wolfspiritky** » 07 Jan 2009, 21:50

MadeInJapan wrote:The cam position sensor tends to give misfire codes (if you can get the car up and running)...did anyone in this post get any of those codes when the CPS was going out- just curious.

No Dave, it's been a year since then for me.

Post by **MadeInJapan** » 08 Jan 2009, 04:41

Sorry 'bout that.
How about the original poster, has he checked that?