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anti-lock light stays on

cedriccools
Posts: 26
Joined: Tue Sep 12, 2017 9:22 pm

anti-lock light stays on

Postby cedriccools » Mon Nov 06, 2017 10:26 pm

My anti-lock light is burning when I start the car, it doesn't go out after a while or so, it stays burningn :-)

now, I checked the forum and that could be a sign that the overvoltage relay has a broken fuse inside.

now, for some reason I can't find the overvoltage relay on my car (xj40 4.0 sovereign 1989.

I read it should be in the boot around the fuelfill area, or in the front mounted on the aircon blower.

i checked all the relays in the front, but couldnt get any wiser from it. the only one i thought it could be is this one.

Image


Image


I opened it but can't see a fuse.. is there anyone who has a picutre of the inside/outside from this overvoltage relay?

naki_k
Super Moderator
Posts: 28672
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: anti-lock light stays on

Postby naki_k » Tue Nov 07, 2017 12:10 pm

The over voltage relay is only on the 3.6/ 2.9 Digital Dash Models.

You need to check all your ABS sensors with a multimeter. Plus do a visual check for any wiring damage.

Do the brakes still work as normal?
Are the brake discs corroded, (from a long time standing).

Also check the plug pins on the ABS ecu, for any damp/ corrosion. (In the boot, behind the Right side carpet).

That relay in the picture is an aftermarket addition. Perhaps for an aftermarket alarm? Or often a bodge for something, rather than a proper fix. Follow where the wires go, to lead you.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6 x2
93 6.0 XJ81 XJ12
94 4.0 XJR
94 4.0 Daimler
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

nlcrane
Spain Rep
Posts: 7587
Joined: Sun Feb 07, 2010 7:36 pm
Location: Spain

Re: anti-lock light stays on

Postby nlcrane » Tue Nov 07, 2017 12:21 pm

naki_k wrote:The over voltage relay is only on the 3.6/ 2.9 Digital Dash Models.

You need to check all your ABS sensors with a multimeter. Plus do a visual check for any wiring damage.

Do the brakes still work as normal?
Are the brake discs corroded, (from a long time standing).

Also check the plug pins on the ABS ecu, for any damp/ corrosion. (In the boot, behind the Right side carpet).

That relay in the picture is an aftermarket addition. Perhaps for an aftermarket alarm? Or often a bodge for something, rather than a proper fix. Follow where the wires go, to lead you.


My sentiments exactly, that relay doesn’t look like a Jaguar installation, too recent for that and Jaguar didn’t mount relays without a plug in relay base. According to the schematics, the over voltage relay is mounted in the trunk (boot) on the left side under the trunk trim panel. It contains a relay, a zener diode (overvoltage detection) and a fuse (overvoltage protection). There is also a shrink insulated quench diode, external to the relay, but connected to it (to quench the reverse emf generated by a collapsing magnetic field).
ImageImageImage
1994 Sovereign Gold 4.0

Area rep. SPAIN
espana.xj40@googlemail.com

nlcrane
Spain Rep
Posts: 7587
Joined: Sun Feb 07, 2010 7:36 pm
Location: Spain

Re: anti-lock light stays on

Postby nlcrane » Tue Nov 07, 2017 12:33 pm

This may help a wee bit as well.

viewtopic.php?t=997927#p175733
ImageImageImage
1994 Sovereign Gold 4.0

Area rep. SPAIN
espana.xj40@googlemail.com

katar83
Posts: 2765
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: anti-lock light stays on

Postby katar83 » Tue Nov 07, 2017 1:38 pm

Isnt there a procedure to test the ABS system on a 40? You basically put a pin in the boot plug, then turn the ignition key to position X and wait and see how many times display flashes. You get the code from this and know straight away whats broken.

I'm pretty certain I did this with mine but that was years ago so I might be making this up, or this might only work with later cars?
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

cedriccools
Posts: 26
Joined: Tue Sep 12, 2017 9:22 pm

Re: anti-lock light stays on

Postby cedriccools » Wed Jan 03, 2018 8:44 am

Problem is solved. the left front ABS sensor was completely stuck and broken :-)

naki_k
Super Moderator
Posts: 28672
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: anti-lock light stays on

Postby naki_k » Wed Jan 03, 2018 8:57 pm

cedriccools wrote:Problem is solved. the left front ABS sensor was completely stuck and broken :-)


There you go. Saves time to check the basics first.
I have a spare if needed.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6 x2
93 6.0 XJ81 XJ12
94 4.0 XJR
94 4.0 Daimler
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300