V70 2001 Cruise control issue

[stuart bowes]

Hi all, new to the forum but not new to Volvos, I used to have a lovely little 360GLS which I did a bunch of stuff to and was a great little car if not the best looking (subjectively..) totally regret scrapping that thing..

anyway I now have a V70 (2001) at 55k and in quite nice condition. had a couple of minor things done (oil change / service / timing belt and water pump replacement)

I'm putting speakers in the boot because I'm from Essex, so that's basically law.. installed double din touchscreen. lovely car perfect for carting the kids about

only one problem.. randomly the cruise control seems to have stopped working
(I've searched and apologies if i didnt find the thread that already covers this.. there are hundreds and I'm quite busy lol sorry)

known facts:
========
'cruise' indicator lights up when I press the cruise button
does not engage or increase speed when pressing +
It did work until 3 days ago
I have changed the front discs and pads
I have been messing around in the boot a bit it's possible i disturbed something unwittingly?
brake lights come on when pressing brake pedal (very slight tap only rqd)
The stereo volume etc buttons work fine

it did work just once this morning, then i couldn't make it do it again.. so i'm suspecting possibly a loose connection or maybe the steering wheel button is dodgy?

is there a relay or fuse or something daft I should check first?

any other suggestions?

cheers

[cheshired5]

Best to ask a local member to plug it into Vida to begin with.
It will tell you if the button presses are being registered and that information alone will save you a lot of time.

[stuart bowes]

thanks for coming back to me, tbh I wouldnt mind buying that myself as it would be useful in the future

can I just check this is the unit that will do what you are talking about (plus other fault finding / clearing faults / etc)

thanks

https://www.cartool.co.uk/wholesale/...QaAkIHEALw_wcB

[ilmiont]

Those symptoms suggest may be clutch position sensor (exactly same symptoms as mine and many others).

Brake fluid seeps from the cylinder onto the clutch position sensor (CPS). Result is bad CPS readings so cruise won't engage.

I'm told it's an easy DIY fix if you put your head in the footwell, others will know the details more than me. If it's only just started, your CPS may be salvageable by cleaning it and reinstalling it.

When the CPS is reinstalled, either new or cleaned old, wrap it in plastic or similar to ensure that any further seepage doesn't cause the problem to resurface.

When I asked about this, I was told the seepage is nothing to worry about and somewhat expected with age.

I bought my car with exactly the same cruise issues as yours; a new CPS and a plastic bag later (done by local Volvo specialist) and my cruise works flawlessly.

(note: all the above assumes yours is a manual gearbox)

[cheshired5]

Originally Posted by stuart bowes

I wouldnt mind buying that myself as it would be useful in the future

can I just check this is the unit that will do what you are talking about (plus other fault finding / clearing faults / etc)

Yes.
I sell them too, fully tested, guaranteed working and decent software installation instructions to get you up and running.
£100 delivered to the UK mainland.

[stuart bowes]

Thanks for all the replies everyone

should have added, this is an auto (the mrs only has an Auto license and i dont want her sherking the driving duties ) but thanks for the info anyway

thanks for confirming re: fault reader I'll probably get myself one of those at some point because it's also showing up 'alarm fault' every now and then which im not quite so concerned about...

anyway.. back on topic..
===========

Im not sure if i've worked this out or this is a total coincidence... I read somewhere that the car is picky about 'unstable conditions' and I thought what else could be causing instability.. then i remembered the drivers side rear looked a bit low. pumped it up (15psi oops) and now every time I try the cruise control it works without fail.

it made me think.. decreased wheel diameter / slight difference in wheel speed relative to other wheels which had good pressure.. ?

strangely it actually started working more later in the day before pumping it up (and previously worked early in the morning) but still a bit intermittant, which made me wonder about temperatures and air pressure, etc. it's been very hot the last few days

is that likely or total b*ll"k£ lol

[BlueRubber]

I doubt tyre pressure is related to the issue, but maybe someone will correct me.

I had a similarish cruise control fault symptoms with my '02 v70 auto and it was fixed by replacing the brake pedal position sensor and is fairly easy to do.
Paid £122.68 for the parts from a Volvo Dealer.

I used Vida to scan the car before replacing the fault part and there were no error codes related to this issue.
However would still strongly recommend buying VIDA, it's an incredible bit of kit and cheshired5 is a trusted source of these.

My threads on this issue:
https://www.volvoforums.org.uk/showthread.php?t=293093
https://www.volvoforums.org.uk/showthread.php?t=297756

[stuart bowes]

thanks for the reply, I'm not sure the faults are so identical though mainly because you say your 'cruise' indicator was not coming up on the dash intermittently and mine was coming up every time, so it wasnt having trouble switching on as such, it just wasn't allowing me to set a speed

I'm still convinced at this point it was to do with the wheel speed sensor variations, correct me if wrong but there are sensors on every wheel? (or at least, the driver side rear definitely has one..)
Anyway, it is still working, I'm checking it every 2 mins just to make sure even when I wouldn't usually be using it

I'll update if that changes..

I definitely will get a VIDA but that's most likely going to be beginning of next year now unless something major goes wrong with it

[stuart bowes]

Still working 100%

might be an idea for an Admin to change the heading to "Cruise control failure, check tyre pressures?" and I'll come back to it if evidence suggests that's incorrect

thanks again to everyone

[stuart bowes]

well.. I spoke to soon lol

it was all going so well and then it cut out again during a long-ish journey. worked fine all week, then all the way there.. about halfway back it cut out on me doing **mph on the way back.. bugger

tyre pressure was again a bit low (20psi, need to get that sorted. probably corrosion round the rim, the tyre itself is good but that's a seperate issue)

pumped up again and put a footpump in the boot for now . but this time still no cruise.

so back to square one, im assuming previous diagnosis of dodgy brake position sensor is most likely until proven otherwise.. for £130 im not too fussed about just buying it and taking a punt

what else will a faulty brake position sensor affect?

one thing did come to mind, last time i booted it coming out of a turn and that's when it started working again.. i dont suppose it could be a simple case of cleaning the throttle body, could it?