ABS Wiring fault - how to fix?

[mark123]

I haven't read your whole thread, but I wondered if the earth from the engine loom to the gearbox could be loose. Easily missed after a clutch change.

 

[dann2707]

I had a look at that matey and it's all on and perfect. I have an update though i'll copy and paste from my project thread. Thanks for the reply though @mark123 :smile:

Went over to @bashracing's last night to see if the speed sensor problem is still there, it is!!

I've changed the reluctor ring along with the ABS sensor itself and it's still signalling intermittently. The other 3 wheel speeds are constant but the nearside front is always under hence the annoying revving problem( the nearside sensor is used as the speed sensor). We're now under the impression it's a wiring fault so guess what i'll be doing tonight after work :smiley:

I said to Dave last night that I reckon it's pulled on the loom when I did a three point turn the day after I lowered it as when I did that turn all the 3 lights came on (ABS SERV and something else) this was when @optical or @incy-spider noticed that my ABS wiring holder arms whatever they're called, the ones that are attached to the coilover struts to keep the wiring in place weren't attached so my thoughts are that it's snagged the wire and it's rubbing on something/pulled something out of place.

I will get to the bottom of this. I must have burned SO much fuel going to work and back sat in traffic and it's revving the tits off it after every creep forward. No wonder i'm always skint oh wait that's due to buying car parts lol

I've just found this thread though and it' looking more and more promising that the wiring is to blame. Definitely having a look at this tonight!


http://www.cliosport.net/threads/abs-causes-idle-to-wander.294024/

 

[Rubicon_]

I had the same after rebuilding my car. Took the gearbox earth strap off and cleaned the ends and body then done the same with the loom to gearbox earth and it works perfect now.

 

[dann2707]

I've checked the earths mate, showing no resistance on the multimeter

I'll hopefully be able to show what I've found this evening x

 

[Briv6]

I just hope you find this gremlin .. Isn't it worth a drive to a specialist like Fred or mick at this stage ?

 

[dann2707]

I just hope you find this gremlin .. Isn't it worth a drive to a specialist like Fred or mick at this stage ?

Thanks mate, me too! It's becoming tiresome. I think it might be worth going to a specialist but that = $$$$ and me being a yorkshire man doesn't really comply when it could be something so simple.

Tonight I tested the wiring from the nearside ABS sensor where it connects to the actual ABS sensor loom to the hub. It read 4.6 volts so I tested the other side and that read exactly the same.

I also traced the wiring from the abs sensor to the loom it connects to and it all looks absolutely perfect, no splits or cracks, it just goes nicely back into the main loom.

The problem i'm seeing now is that the sensors are both getting the correct/ equally the same 4.6 volts which to me indicates that the wiring may not be at fault past the abs sensor. Could it potentially be the reluctor ring and sensor gap? I've taken pictures (albeit s**t ones) of the nearside (one that is displaying as being faulty):

DSCN2880 by dann2707, on Flickr

DSCN2882 by dann2707, on Flickr

DSCN2883 by dann2707, on Flickr


And the offside (working properly):

DSCN2876 by dann2707, on Flickr

DSCN2878 by dann2707, on Flickr

DSCN2877 by dann2707, on Flickr



Do you think the air gap looks larger on the new reluctor ring and sensor as opposed to the other side? Also the nearside ring looks like its too far on the hub when i've put it on, maybe these are messing up the signals or are these things absolutely and completely negligible? Getting desperate lol

@bashracing @mick

 

[bashracing]

air gap should be 1mm ideally, the 5v reference down is only part of the battle dan you also need the signal back to modulator valve/abs ecu,
Does any one on here have the wiring diagram for the abs loom so we can test the continuity of the wire back to the ecu?
who's the resident sparky guru?

 

[flebay]

Hi,
I had this fault, disconnect the power steering pressure switch connector plug and see if it goes away.
Mine was getting stuck when the weather was cold causing the revs to rise because the ecu thought the steering was on full lock.
£21.00 part number 497610324r

 

[bloke]

air gap should be 1mm ideally, the 5v reference down is only part of the battle dan you also need the signal back to modulator valve/abs ecu,
Does any one on here have the wiring diagram for the abs loom so we can test the continuity of the wire back to the ecu?
who's the resident sparky guru?

just do a live data read of the road speeds they see, should pretty much tell you if everything is ok. this thread does have a clutching at straws sort of theme to it though, car needs plugging in and a proper look at and take it from there.

 

[dann2707]

just do a live data read of the road speeds they see, should pretty much tell you if everything is ok. this thread does have a clutching at straws sort of theme to it though, car needs plugging in and a proper look at and take it from there.

We have done buddy.

The other night all three wheels apart from the nearside front sensor read 4 km/hr and the latter reading 1 km/hr. That's the problem here

 

[bloke]

must of missed that sorry. sensor problem would kick of the traction control but that shouldn't make revs rise, not sure though if tc has kicked in if it cuts when the clutch switch is activated? disconnect the clutch switch and see if the revs still pick up when the clutch is pressed.

 

[dann2707]

must of missed that sorry. sensor problem would kick of the traction control but that shouldn't make revs rise, not sure though if tc has kicked in if it cuts when the clutch switch is activated? disconnect the clutch switch and see if the revs still pick up when the clutch is pressed.

The nearside front sensor acts as a speed sensor so it's telling the ecu it's going at a lower speed than what I am so apparently it's telling the car to rev as an anti stall measure

I'll ask for a wiring diagram now.

 

[bloke]

they are all wheel speed sensors used for the abs, never even thought about what one the car takes it's speed from though? didn't think the car is advanced enough to have anything like an anti stall?

 

[dann2707]

they are all wheel speed sensors used for the abs, never even thought about what one the car takes it's speed from though? didn't think the car is advanced enough to have anything like an anti stall?

I can't find the thread now but I was under the impression the front nearside sensor acted as the speed sensor reading. Either way this sensor is giving a bad reading when looking at the live data and it's giving the symptoms of a faulty speed sensor (revving between changing gears, hesitating, revving by itself) 😧

It's just so weird that no one has seen this issue before, or at least those reading this thread. Ideally I need to tag a load of specialists Anyone know their usernames on here please?

 

[bloke]

if it is that one that gives the speed reading then logically your speedo will be under reading. try reading them at around 15mph and see how they are to each other. or as a quick one just un plug the sensor and see how it drives, will bring on abs etc lights but be a quick way to see if it does anything to the initial problem?

 

[dann2707]

I was thinking that, or surely making it fluctuate like mad as per the signal it's receiving.

Good shout on the disconnecting, i'll give that a go tomorrow and report back! Could I remove the fuse for it individually in the passenger side fusebox do you know? Saves me getting the wheel off etc

 

[bloke]

pulling the fuse will just kill the abs/tc but not sure what the score would be with the car still seeing the wheel speed sensor? would be tempted to unplug. take it you've got traction control? if so could just turn it off and see if that makes a difference?

 

[MicKPM]

Ideally you need to graph the wheel speed sensor signals to spot errors as numerical values change so fast you struggle to see fluctuations (unless they're cometely fekked).

If one wheel has an obvious fault then start by counting the teeth on the target to make sure they're the same, paying close attention to the condition of the target ring itself (not covered in copper grease, not damaged/cracked.

Air gap will make a difference but a genuine sensor will self gap when fitted correctly to the hub. Normally 1mm is fine but again, check your target rings as aftermarket items are common now and consistency isn't always common in this area.

 

[MicKPM]

Oh and the ABS module takes all four speed signals and create an average which it outputs to the INSTRUMENTS via the ECU.

 

[dann2707]

Ideally you need to graph the wheel speed sensor signals to spot errors as numerical values change so fast you struggle to see fluctuations (unless they're cometely fekked).

If one wheel has an obvious fault then start by counting the teeth on the target to make sure they're the same, paying close attention to the condition of the target ring itself (not covered in copper grease, not damaged/cracked.

Air gap will make a difference but a genuine sensor will self gap when fitted correctly to the hub. Normally 1mm is fine but again, check your target rings as aftermarket items are common now and consistency isn't always common in this area.

Thanks for the reply mate, appreciate it

The ring is an aftermarket piece but only changed last week way after the problem started. I'll double check tonight how many teeth are on the other side.

We graphed it before and instead of the signal mirroring the other wheel at some points it was reading 0 so the line on the graph dipped straight to the base of the chart, then shot up to somewhere below the other speed of the other wheel. It never fully copied the other wheel at any point.

 

[MicKPM]

Possibly a sensor fault thenBut check the target first.

 

[dann2707]

Possibly a sensor fault thenBut check the target first.

I changed the reluctor ring due to the original problems

Is there some kind of test I can do with a multimeter on the contacts to see if the ring is passing the sensor and giving the correct signals when the magnet is excited etc. If so, what values should I be looking for when the ring passes the sensor? Thanks Mick!

I should have the ABS loom diagram today.

 

[MicKPM]

The "Sensor" and the "Target" aren't the same thing Dan. You've switched targets but this may not be the fault. You really need to scope the channel for that wheel and look at the waveform it generates as a DMM will be no good unless it can graph the numerical output or you are some kind of machine that can see mV fluctuations in mS. Then, move to another wheel channel (I'd advise a comparable rear) and repeat the test which will then give you something to compare it to.

Mick

 

[dann2707]

The "Sensor" and the "Target" aren't the same thing Dan. You've switched targets but this may not be the fault. You really need to scope the channel for that wheel and look at the waveform it generates as a DMM will be no good unless it can graph the numerical output or you are some kind of machine that can see mV fluctuations in mS. Then, move to another wheel channel (I'd advise a comparable rear) and repeat the test which will then give you something to compare it to.

Mick

I'm with you Mick, thanks I've changed the sensor too by the way.

I wonder if it would be worth a trip down to you as you're not a million miles away for you to diagnose. Can you pm me a price on how much you'd charge to sort it out please as in labour per hour etc. Thanks.

 

[MicKPM]

Hard to say for sure i'm afraid as I don't know what's wrong with it but i'd say no more than 2hrs labour, so £80+VAT

If you wanted to book in though, drop me a line via our website and i'll get you in fella - www.diamondmotors.co.uk

Mick

 

[dann2707]

Hard to say for sure i'm afraid as I don't know what's wrong with it but i'd say no more than 2hrs labour, so £80+VAT

If you wanted to book in though, drop me a line via our website and i'll get you in fella - www.diamondmotors.co.uk

Mick

This problem is really frustrating now haha going to give you a ring today if that's cool to get me booked in.

 

[MicKPM]

Drop me an email via the website if you wouldn't mind please Dan. I'm up to my balls in broken Renaults today and to make it even worse, the wife is going in to be induced later this afternoon #panic

http://www.diamondmotors.net - I'm sure you can find the "Contact us" link and fill a form in from there :wink:

Mick

 

[dann2707]

Drop me an email via the website if you wouldn't mind please Dan. I'm up to my balls in broken Renaults today and to make it even worse, the wife is going in to be induced later this afternoon #panic

http://www.diamondmotors.net - I'm sure you can find the "Contact us" link and fill a form in from there :wink:

Mick

What a lame excuse :wink:

Just kidding, congratulations to you and the wife mate! Hope all is well

 

[dann2707]

I've just been trawling the net and found this thread and it's absolutely spot on with everything that's wrong with mine.

Cruise control doesn't work, revs dip, feels like it's going to stall especially in reverse, gear changes are dodgy.

He also got a diagnostic done and the speed sensor fault came up! same as mine


http://www.bba-reman.com/forums/Topic118723.aspx

Sent you an email btw mick, know you'll be busy though

 

[MicKPM]

I know, I replied to

 

[dann2707]

I know, I replied to

My apologies, it went straight into my junk mail. I will reply asap