ABS light MOT failiure on my 940 - Page 3

CTCNetwork · May 20th, 2011, 16:43

Hi,

Have a look on the back of the ashtray you have removed to look at the fuses. it should have a diagram of the fuse panel and a what fuse does what description.

Des. . .

zardoz · May 20th, 2011, 18:20

Quote:

Originally Posted by CTCNetwork

Hi,

Have a look on the back of the ashtray you have removed to look at the fuses. it should have a diagram of the fuse panel and a what fuse does what description.

Des. . .

Going out now to do just that
cheers.!

zardoz · May 20th, 2011, 18:55

Right, i have just looked at that diagram on the back of the ashtray panel. It has no numbered fuse for the ABS. On the fuse diagram sticker there is a un numbered add on right at one end that says 'ABS' & additional fuses refer to owners manual'

The 1993 940 owners manual insists that the ABS fuse is "underneath the dashboard to the right of the steering wheel." [page 5.7]

CTCNetwork · May 20th, 2011, 20:03

Hi,

The ABS CPU is on the drivers side, against the side and right in the corner. Can't say I have seen a fuse there, but mine is a '96 model.

Des. . .

zardoz · May 20th, 2011, 20:09

Back outside to look for the damed illusive abs fuse, yet again. This thing is driving me insane

XCNick · Oct 23rd, 2011, 20:31

Hi, - not sure whether you're still battling with this problem, but I've just been around the loop myself, trying to find why the ABS light on my 940 wouldn't come on with the ignition, when all the simple checks proved negative. Plenty of advice for ABS lights which are allways on, none for ABS lights which won't come on.
I managed to find an american market electrical wiring daigram at http://www.matthewsvolvosite.com/volvo-wiring-diagrams, which shows the circuitry on the Instrument panel backplane, the ABS ECU and the relays on the ABS Control module.

Using this, it was relatively easy to find that the fault was a damaged track on the plastic film backplane for the instrument binnacle, not supplying 12 Volts to the ABS light, and so the ABS fault circuit. The plastic circuit sheet bends around the sides of the cluster, and I'm assuming the copper strip has cracked. Soldered the track, and ABS light came back, plus another for water temp which I hadn't noticed was missing.

Oh, the diagram does not seem to show the mythical ABS surge protector relay, which I also spent 4 hours looking for.

Best of Luck

kiloran · Aug 30th, 2023, 15:41

Apologies for the thread resurrection but it trends highly on Google search so it's useful to add some further information here. If your on board diagnostics (position 3) isn't reporting any faults (see https://www.volvoclub.org.uk/faq/Bra...cCodeRetrieval) and just flashing 1-1-1 it's worth checking the ABS control relay.

On RHD cars it's mounted on the side bulkhead under the dash to the right of the accelerator pedal. Look behind the bonnet pull and you'll see it. The Volvo part number is 897169. Take off the trim panel under the steering wheel to access it (three Torx head screws).

First thing to do is to check the 10A fuse which is in a red plastic holder on top of the relay. In my regular experience this fuse holder can easily wiggle loose, causing the fuse legs to lose contact with the relay, resulting in no power to the ABS system and therefore the ABS light coming on.

It's a particularly crappy design which is almost guaranteed to fail - the fuse holder has some tiny plastic legs which provide an interference/friction fit to the relay casing. The fuse sits flat on top of the relay with the plastic holder pushing the legs down on the contacts. The solution, as always, is to gaffa (or electrician's) tape the fuse holder securely down on the relay. That should get power back to the ABS unit and turn the light off. Bear in mind that following a long power down the ABS light might take a few seconds to go out and I've also seen behaviour where it only goes out once the car has gone over 30mph and you've used the brakes.

If it isn't that the next step is to replace/repair the relay. It clips on to the trim in similar way to the infamous radio supression relay does so just pull it gently upwards and disconnect the multiplug from the bottom. Remember, if you have OBD and the ABS position (position 3) is only flashing 1-1-1 it's either the relay, a wiring fault, or a failed ABS ECU. It's almost certainly the relay and it's cheap and easy fix.

J liddy · Aug 30th, 2023, 18:03

This post just drags on check fault finder code if you have one otherwise buy a new ABS sensor on ebay and disconnect the front sensor 1 at a time plug in the new Sensor if warning light goes off presto you found the problem they are about £22 on ebay at moment that's what I paid
OK

May 20th, 2011, 16:43	#21
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, Have a look on the back of the ashtray you have removed to look at the fuses. it should have a diagram of the fuse panel and a what fuse does what description. Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

May 20th, 2011, 18:55	#23
zardoz Junior Member Last Online: Jun 3rd, 2011 05:29 Join Date: May 2009 Location: chester View Photos By: zardoz	Right, i have just looked at that diagram on the back of the ashtray panel. It has no numbered fuse for the ABS. On the fuse diagram sticker there is a un numbered add on right at one end that says 'ABS' & additional fuses refer to owners manual' The 1993 940 owners manual insists that the ABS fuse is "underneath the dashboard to the right of the steering wheel." [page 5.7] Last edited by zardoz; May 20th, 2011 at 19:07.

May 20th, 2011, 20:03	#24
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, The ABS CPU is on the drivers side, against the side and right in the corner. Can't say I have seen a fuse there, but mine is a '96 model. Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to."

May 20th, 2011, 20:09	#25
zardoz Junior Member Last Online: Jun 3rd, 2011 05:29 Join Date: May 2009 Location: chester View Photos By: zardoz	Back outside to look for the damed illusive abs fuse, yet again. This thing is driving me insane Last edited by zardoz; May 20th, 2011 at 20:18.

Oct 23rd, 2011, 20:31	#26
XCNick New Member Last Online: Oct 5th, 2017 20:03 Join Date: Mar 2008 Location: Chepstow	ABS Light Not working Hi, - not sure whether you're still battling with this problem, but I've just been around the loop myself, trying to find why the ABS light on my 940 wouldn't come on with the ignition, when all the simple checks proved negative. Plenty of advice for ABS lights which are allways on, none for ABS lights which won't come on. I managed to find an american market electrical wiring daigram at http://www.matthewsvolvosite.com/volvo-wiring-diagrams, which shows the circuitry on the Instrument panel backplane, the ABS ECU and the relays on the ABS Control module. Using this, it was relatively easy to find that the fault was a damaged track on the plastic film backplane for the instrument binnacle, not supplying 12 Volts to the ABS light, and so the ABS fault circuit. The plastic circuit sheet bends around the sides of the cluster, and I'm assuming the copper strip has cracked. Soldered the track, and ABS light came back, plus another for water temp which I hadn't noticed was missing. Oh, the diagram does not seem to show the mythical ABS surge protector relay, which I also spent 4 hours looking for. Best of Luck

Aug 30th, 2023, 15:41	#27
kiloran Senior Member Last Online: Aug 30th, 2023 18:22 Join Date: May 2015 Location: Fordingbridge View Photos By: kiloran	Apologies for the thread resurrection but it trends highly on Google search so it's useful to add some further information here. If your on board diagnostics (position 3) isn't reporting any faults (see https://www.volvoclub.org.uk/faq/Bra...cCodeRetrieval) and just flashing 1-1-1 it's worth checking the ABS control relay. On RHD cars it's mounted on the side bulkhead under the dash to the right of the accelerator pedal. Look behind the bonnet pull and you'll see it. The Volvo part number is 897169. Take off the trim panel under the steering wheel to access it (three Torx head screws). First thing to do is to check the 10A fuse which is in a red plastic holder on top of the relay. In my regular experience this fuse holder can easily wiggle loose, causing the fuse legs to lose contact with the relay, resulting in no power to the ABS system and therefore the ABS light coming on. It's a particularly crappy design which is almost guaranteed to fail - the fuse holder has some tiny plastic legs which provide an interference/friction fit to the relay casing. The fuse sits flat on top of the relay with the plastic holder pushing the legs down on the contacts. The solution, as always, is to gaffa (or electrician's) tape the fuse holder securely down on the relay. That should get power back to the ABS unit and turn the light off. Bear in mind that following a long power down the ABS light might take a few seconds to go out and I've also seen behaviour where it only goes out once the car has gone over 30mph and you've used the brakes. If it isn't that the next step is to replace/repair the relay. It clips on to the trim in similar way to the infamous radio supression relay does so just pull it gently upwards and disconnect the multiplug from the bottom. Remember, if you have OBD and the ABS position (position 3) is only flashing 1-1-1 it's either the relay, a wiring fault, or a failed ABS ECU. It's almost certainly the relay and it's cheap and easy fix. __________________ '93MY Volvo 940SE 2l Petrol Manual non-a/c "Valhallarama"

Aug 30th, 2023, 18:03	#28
J liddy Senior Member Last Online: May 12th, 2024 19:20 Join Date: Jul 2019 Location: Stoke on trent	This post just drags on check fault finder code if you have one otherwise buy a new ABS sensor on ebay and disconnect the front sensor 1 at a time plug in the new Sensor if warning light goes off presto you found the problem they are about £22 on ebay at moment that's what I paid OK

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