2000 V70XC ABS wheel sensor ohms test

deviantwagon · Post by **deviantwagon** » 30 Nov 2011, 14:14

Hi all,

I have had the typical problems with my abs lights all seem to. The Module has been replaced with one of Matty's good oes about 6 months ago and has been great. I do clean the wheel sensors every so often as well. I have the lights back again (traction control and red brake light off and on, the ABS and CEL on all the time) so I did a clean, reset and after a few miles to calibrate they are back. I tested the connector for the passenger side wheel sensor (only one I could find easily) and with my meter on 2000K I read 1800 and some change ohms. Matty's site states they should be between 900-1380 ohms. Sooo being that close but out of range would you guys say that is the problem? I want to check the drivers side (need to find it) too. The rear seems to be two sensors connected to one harness-plug, I am unsure what kind of ohm reading I should get there... It seems that as soon as I get some snow they go...My mind is saying a little snow to add to already high resistance might be the issue

thoughts?

FCPEURO · Post by **FCPEURO** » 30 Nov 2011, 16:53

I would check the driver side before you go and replace the sensor on the passenger side. More then likely the passenger side on is bad but if the driver side one is around 1800K also, then it could be something with the meter.

Post by **kcodyjr** » 30 Nov 2011, 19:11

ABS light on constantly even when the TRACS light isn't, and sometimes the "red brake light" comes on?

The typical ABS module/sensor problems should turn on the ABS and TRACS lights together, and not the brake failure light.

Sounds like a hydraulic problem, actually. Is it losing fluid? Any gripes about braking feel?

If you're not sure what's up, it might be worth having it professionally looked at. You might find yourself in the middle of an unscheduled field test of your Volvo's crashworthiness. End of lecture.

Post by **jimmy57** » 30 Nov 2011, 20:32

99 and later except S40/V40 Nedcar platform have sensors for which an ohm test is not valid. They are sensors that the CM applies a milliamp current signal to and its conductivity is affected by the tooth proximity.
If you attach the ohmmeter to the pins on sensor leads and move wheel slowly the resistance value will fluctuate. If the wheel is stopped the resistance will stabilize.

deviantwagon · Post by **deviantwagon** » 01 Dec 2011, 07:57

kcodyjr wrote:ABS light on constantly even when the TRACS light isn't, and sometimes the "red brake light" comes on?

The typical ABS module/sensor problems should turn on the ABS and TRACS lights together, and not the brake failure light.

Sounds like a hydraulic problem, actually. Is it losing fluid? Any gripes about braking feel?

If you're not sure what's up, it might be worth having it professionally looked at. You might find yourself in the middle of an unscheduled field test of your Volvo's crashworthiness. End of lecture.

Always up for a good test experience! The fluid is so simple I haven't even looked there....went straight for the complicated, typical causes. Yes the abs and TRACS light up together...the red brake light is intermittent. The pedal is pretty good and have never hard an issue with fade. perhaps a good bleed and fluid check...that would be a nice easy fix!

Post by **kcodyjr** » 01 Dec 2011, 12:00

deviantwagon wrote:Always up for a good test experience!

In that case, if you do have a sacrificial Volvo, a suitable driving area with strong fixed obstacles such as trees, and of course permission from the landowner, then I do recommend trying it. A helmet and racing seat, maybe roll bars, would ordinarily be good advice, but in this case they kind of defeat the purpose. Do be sure you're adjusted into your seat by the book, though, and for God's sake use your head about what to hit and how fast.

We all talk about how safe these tanks are, but I've seen two totaled from the inside, a 242 doing 60 or so into the length of a New England style low rock wall, and an 850 doing about 25 into the panic-stop-raised tail of a Grand Marquis. I'll spare you the dramatic visceral impressions - you've got to see these things perform to really, truly, appreciate what they're made of.

deviantwagon · Post by **deviantwagon** » 20 Jan 2012, 10:12

Was the wheel sensor on the drivers side front...replaced and all good now. I will take a photo..it has a notch i the center of it ...almost looks like the gear on the wheel ground into it (couldn't really happen but .....)

No Sacrificial Volvo here....at least not yet!