Anyone in the Midlands to fix ABS intermittent fault light

Clark · Mar 18th, 2023, 13:35

Hi All,

A week after the car comes back from being fixed with a clean MOT (before I sell)...my blimmin ABS light starts flickering again after playing good for 2.5 years. In the past the unit has been sent away many times only to come back with NFF as it has a lifetime warranty. I am convinced it's the usual connection issue.

Is there anyone in the Midlands that has experience of opening up the unit to solder and put back? I'd really appreciate it. Happy to drive over and pay (with money or beer or indian food!). Luckily the MOT was done the week before the fault popped up. The ABS system is working fine.

If not I plan to sell as it is. It's a common fault with many threads on how to solder and fix. The buyer has plenty of time before the next MOT

I can't find the thread anymore but there was a very good thread on the step by step process (with pictures) on how to fix? I could share it with my mechanic to help him.

Bob Meadows · Mar 19th, 2023, 14:01

https://www.volvoforums.org.uk/showthread.php?t=72655

The above link should take you to one of many forum advice topics on the ABS Module.
I also posted one some time back to include easier ways of removing the cover without butchering the thing.
(Worth a search for more info)

Most definitely a DIY fix and not complicated- easier on the wallet as well!
Good Luck.
Bob.

Clark · Mar 20th, 2023, 10:38

Thanks Bob.

Upon further reflection:
- if the unit was brand new in 2018 and sent back to the supplier a few times (as part of the lifetime warranty) already, coming back with NFF...it's relatively new unit and should be fine. Cracking it open probably isn't wise especially as it would make the lifetime warranty void.
- it may be worth me risking changing the ABS pump instead of assuming it's a connection issue inside the unit. I've heard they also cause similar faults but I have never changed/fixed mine

SteveSarre · Mar 20th, 2023, 19:53

Hi Clark

Is this on an 850R? (I don't know about 850s).

If the ABS control module has been back several times and NFF, then definitely worth not opening it up unnecessarily.

Before you dive in to replacing the ABS pump, have you thoroughly tested the front and rear reluctor rings and wheel speed sensors (and wiring)?

I think one or more of the reluctor rings or wheel speed sensors is more likely to be the cause, and I would guess that the correct ABS pump is hard to find.

Steve

Clark · Mar 20th, 2023, 20:35

Quote:

Originally Posted by SteveSarre

Hi Clark

Is this on an 850R? (I don't know about 850s).

If the ABS control module has been back several times and NFF, then definitely worth not opening it up unnecessarily.

Before you dive in to replacing the ABS pump, have you thoroughly tested the front and rear reluctor rings and wheel speed sensors (and wiring)?

I think one or more of the reluctor rings or wheel speed sensors is more likely to be the cause, and I would guess that the correct ABS pump is hard to find.

Steve

Hi Steve,

Yes it's an 850R. The ABS module was back a few times in 2018 so this fault MIGHT be different. Worth sending back to the manufacturer anyway to assess just to iron out whether it's 'something else'. As it's only 5 years old I would be surprised the unit is at fault. I'll keep the reluctor ring and wheel speed sensors in mind and investigate.

To be honest I am really starting to consider selling the car as it is with the flickering light. Luckily I got the MOT done before it started so the new owner has plenty of time to resolve. For someone good with their hands it's a cheap issue to fix to keep the beast on the road.

Luxobarge · Mar 20th, 2023, 21:27

Agree with Steve about checking/replacing the sensors and reluctors before diving in with a pump change. Better still, do you have access to a way of reading the codes? That's where I'd be heading, that way you'll probably get a good steer on where the fault actually lies, rather than guessing. The re-solder thing is so common, I guess we sometimes forget that occasionally you can get an actual genuine ABS fault!

Clark · Mar 21st, 2023, 10:25

Eyup,

Yeah you're right about the codes. I'll be sending the car back to the garage next week and asking for the codes before anything is done. I've been told when they connected it last week it said internal failure of the unit.

Just for my knowledge how would I be able to tell the reluctor rings need replacing - is there anything visual I would see?

It looks like the reluctor rings are all the same in design no matter which wheel they are for - around the £5/ring mark off ebay. The wheels speed sensors also look cheap around £10/wheel mark. £60 all in (excluding the potential wiring). Good (cheap) step 1.

Bob Meadows · Mar 21st, 2023, 10:44

Is the cable connector into the unit ok:~

A basic check but worth looking at, the one on my car 97' V70 has a flip over lid that needs to have a positive "click" that also close the loom connections.
Good Luck.
Bob.

SteveSarre · Mar 21st, 2023, 13:09

Hi Clark

For V70s ...

The reluctor rings can suffer physical damage to the teeth, very heavy corrosion or can split.
For the front, get under there and have a look.
The front sensors can get damaged if a stone lodges between the reluctor ring and the sensor. Also wiring can get damaged - again have a look.

I think it is more difficult to see the rear reluctor rings but I don't remember. May have to take the rear drum off. Reluctor rings for the rear may not be the same as for the front.

Front reluctor rings are easy to change once you have the front wheel spindle off. They live on the outer CV joint outer surface. Heat and chisel, off, clean up the CV joint outer surface and then heat the new ring and slip on.

Failure of the reluctor rings may not trigger a code. The ECU may simply think that the wheel(s) are not turning.

I once watched a mechanic test the front ABS rings and sensors by connecting an oscilloscope and looking for a pulsed waverform as you spin the wheel. Then compared to the other side to see how strong the pulses were. It may be possible to get a more technical specification of what to expect.

Hope that helps,
Steve

SteveSarre · Mar 21st, 2023, 14:05

PS

Some good reading in case it helps

https://www.volvoclub.org.uk/tech/se...ionControl.pdf

https://www.matthewsvolvosite.com/fo...ic.php?t=57050
https://www.matthewsvolvosite.com/fo...ic.php?t=41538
https://www.volvoforums.org.uk/showthread.php?t=256207

Mar 18th, 2023, 13:35	#1
Clark 850R+240GLT = Happiness Last Online: Oct 5th, 2023 15:29 Join Date: Feb 2010 Location: Birmingham	Anyone in the Midlands to fix ABS intermittent fault light Hi All, A week after the car comes back from being fixed with a clean MOT (before I sell)...my blimmin ABS light starts flickering again after playing good for 2.5 years. In the past the unit has been sent away many times only to come back with NFF as it has a lifetime warranty. I am convinced it's the usual connection issue. Is there anyone in the Midlands that has experience of opening up the unit to solder and put back? I'd really appreciate it. Happy to drive over and pay (with money or beer or indian food!). Luckily the MOT was done the week before the fault popped up. The ABS system is working fine. If not I plan to sell as it is. It's a common fault with many threads on how to solder and fix. The buyer has plenty of time before the next MOT I can't find the thread anymore but there was a very good thread on the step by step process (with pictures) on how to fix? I could share it with my mechanic to help him. Last edited by Clark; Mar 18th, 2023 at 13:37.

Mar 20th, 2023, 19:53	#4
SteveSarre Premier Member Last Online: Yesterday 22:08 Join Date: Oct 2004 Location: London/West Country	Hi Clark Is this on an 850R? (I don't know about 850s). If the ABS control module has been back several times and NFF, then definitely worth not opening it up unnecessarily. Before you dive in to replacing the ABS pump, have you thoroughly tested the front and rear reluctor rings and wheel speed sensors (and wiring)? I think one or more of the reluctor rings or wheel speed sensors is more likely to be the cause, and I would guess that the correct ABS pump is hard to find. Steve __________________ V70 2.5 Turbo AWD Man. 1999 Red V70 2.5 10V Auto 1998 Green C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)

Mar 20th, 2023, 21:27	#6
Luxobarge Premier Member Last Online: Yesterday 09:37 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Agree with Steve about checking/replacing the sensors and reluctors before diving in with a pump change. Better still, do you have access to a way of reading the codes? That's where I'd be heading, that way you'll probably get a good steer on where the fault actually lies, rather than guessing. The re-solder thing is so common, I guess we sometimes forget that occasionally you can get an actual genuine ABS fault! __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

Mar 21st, 2023, 13:09	#9
SteveSarre Premier Member Last Online: Yesterday 22:08 Join Date: Oct 2004 Location: London/West Country	Hi Clark For V70s ... The reluctor rings can suffer physical damage to the teeth, very heavy corrosion or can split. For the front, get under there and have a look. The front sensors can get damaged if a stone lodges between the reluctor ring and the sensor. Also wiring can get damaged - again have a look. I think it is more difficult to see the rear reluctor rings but I don't remember. May have to take the rear drum off. Reluctor rings for the rear may not be the same as for the front. Front reluctor rings are easy to change once you have the front wheel spindle off. They live on the outer CV joint outer surface. Heat and chisel, off, clean up the CV joint outer surface and then heat the new ring and slip on. Failure of the reluctor rings may not trigger a code. The ECU may simply think that the wheel(s) are not turning. I once watched a mechanic test the front ABS rings and sensors by connecting an oscilloscope and looking for a pulsed waverform as you spin the wheel. Then compared to the other side to see how strong the pulses were. It may be possible to get a more technical specification of what to expect. Hope that helps, Steve __________________ V70 2.5 Turbo AWD Man. 1999 Red V70 2.5 10V Auto 1998 Green C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)

Mar 21st, 2023, 14:05	#10
SteveSarre Premier Member Last Online: Yesterday 22:08 Join Date: Oct 2004 Location: London/West Country	PS Some good reading in case it helps https://www.volvoclub.org.uk/tech/se...ionControl.pdf https://www.matthewsvolvosite.com/fo...ic.php?t=57050 https://www.matthewsvolvosite.com/fo...ic.php?t=41538 https://www.volvoforums.org.uk/showthread.php?t=256207 __________________ V70 2.5 Turbo AWD Man. 1999 Red V70 2.5 10V Auto 1998 Green C70 T 20V Auto Conv. 2001 Blue, C70 T5 Auto Conv. 2000 Blue V70 2.5 Turbo AWD Auto 1998 Green, V70 2.5 10V Auto BiFuel 1999 Red (scrapped) V70 20v Auto 1999 Green (scrapped)

Mar 19th, 2023, 14:01	#2
Bob Meadows Premier Member Last Online: Today 10:05 Join Date: Sep 2017 Location: STANDISH LANCASHIRE	https://www.volvoforums.org.uk/showthread.php?t=72655 The above link should take you to one of many forum advice topics on the ABS Module. I also posted one some time back to include easier ways of removing the cover without butchering the thing. (Worth a search for more info) Most definitely a DIY fix and not complicated- easier on the wallet as well! Good Luck. Bob.

Mar 20th, 2023, 10:38	#3
Clark 850R+240GLT = Happiness Last Online: Oct 5th, 2023 15:29 Join Date: Feb 2010 Location: Birmingham	Thanks Bob. Upon further reflection: - if the unit was brand new in 2018 and sent back to the supplier a few times (as part of the lifetime warranty) already, coming back with NFF...it's relatively new unit and should be fine. Cracking it open probably isn't wise especially as it would make the lifetime warranty void. - it may be worth me risking changing the ABS pump instead of assuming it's a connection issue inside the unit. I've heard they also cause similar faults but I have never changed/fixed mine

Mar 21st, 2023, 10:25	#7
Clark 850R+240GLT = Happiness Last Online: Oct 5th, 2023 15:29 Join Date: Feb 2010 Location: Birmingham	Eyup, Yeah you're right about the codes. I'll be sending the car back to the garage next week and asking for the codes before anything is done. I've been told when they connected it last week it said internal failure of the unit. Just for my knowledge how would I be able to tell the reluctor rings need replacing - is there anything visual I would see? It looks like the reluctor rings are all the same in design no matter which wheel they are for - around the £5/ring mark off ebay. The wheels speed sensors also look cheap around £10/wheel mark. £60 all in (excluding the potential wiring). Good (cheap) step 1.

Mar 21st, 2023, 10:44	#8
Bob Meadows Premier Member Last Online: Today 10:05 Join Date: Sep 2017 Location: STANDISH LANCASHIRE	Is the cable connector into the unit ok:~ A basic check but worth looking at, the one on my car 97' V70 has a flip over lid that needs to have a positive "click" that also close the loom connections. Good Luck. Bob.

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