C70 jerking forward when coming off boost

[Plodmonkey]

My c70 is jerking forward like am slamming brakes on but it's only when abs light comes on car is smooth as hell when light is not on and now the cruise control has gone off

I really don't have a clue wot is going on

[Dave86]

I have the same problem when my abs lights on i just clear the codes and its fine again for a few weeks be interested in finding out why hopefully someone more knowledgeable be come along and enlighten us

[Plodmonkey]

So just clearing it sorts it for a while

[Dave86]

Yep works for me although once you've cleared it u need to need the car right off and then restart it sometimes the abs light stays on until you start move.

[Wobbly Dave]

Don't suppose you read what the codes were saying?

[Liddo]

Dont suppose its dry joints in the ABS module! That ole chesnut ;)

[Wobbly Dave]

I was going to suggest it but I was keen to find out what if any codes were showing.

[Dave86]

Only one i can remember is p1550 front abs wheel speed sensor faulty but then i clear it.and its perfect again :-)

[Wobbly Dave]

I'd look to change the fault wheel sensor & check the ring for missing teeth or cracks.

[Dave86]

Dunno what wheel it is and where would i find said ring

[Wobbly Dave]

It should say in the fault codes. There is a castlated reluctor ring on the outside of the CV joint -
http://www.reluctorrings.com/images/reluctorrings.jpg

that the sensor detects as the drive shaft rotates. The top of the castlations are closer than the bottom - which is how the car calculates the speed of the wheel. If the ring is damaged, rusted or split then the voltages will be spurious & your ABS warning light will come on. I have had to replace both front sides on mine.

The sensor is bolted into a hole in the suspension leg knuckle. They can go ary but this is less common. If it is more than 1 sensor at a time - then the ABS Unit needs repairing. I can help with this.

[Dave86]

Fault come just said 'wheel speed sensor faulty left or right front' so don't really help much. as for the picture you posted i don't even know what im looking at lol

ps. sorry punto60s don't mean to hijacking your thread.

[Plodmonkey]

Thats fine mate lol but y is it jerking when coming off boost that's wot am trying to figure out lol but it's only when abs light is on :s

[Wobbly Dave]

Fault come just said 'wheel speed sensor faulty left or right front' so don't really help much. as for the picture you posted i don't even know what im looking at lol

ps. sorry punto60s don't mean to hijacking your thread.
So you don't know where the drive shafts are?

Punto - we need the codes to help.

[Plodmonkey]

So you don't know where the drive shafts are?

Punto - we need the codes to help.

Haven't got 1 yet as cand find the bloody lead mate this is what happens when your girlfriend and mother start tidying your room can't find nout and I have drove from Sunderland to Glasgow and it didn't miss a beat no abs light no jerking or nothing so god nos probs doesn't like Sunderland

[Dave86]

Yeah i know where the driveshafts are :)

[Wobbly Dave]

well on the outer ends of the drive shafts are the outer CV joints. On the outside of the CV joints you will see the reluctor rings as per photo. Check to see they aren't cracked, split or missing teeth. I believe now you can buy them without replacing the CV joint. HTH.

[Dave86]

Right o ill have a look