A quick check of the required fuses for the ABS circuit on the 2004's.

My wife's car suddenly decided to throw off and ABS warning that stayed lit. First check is the fuses and I found that the fuse in the main fuse box in the trunk hade a 15 amp in the slot that the owners manual said should be a 5 amp fuse.

Which is correct, as a too powerful fuse would end up possibly causing something to burn out before the fuse kicked to protect it and a too weak fuse might blow unnecessarily?

Originally it also lit the DSC light but after a couple of ignition cycles that went out. That can't be right though as without the ABS I don't see how the DSC could function properly anyway.

 

RD,

Do you have SDD or another means of retrieving flagged codes? The relevant codes will probably be C (Chassis), B (Body) and/or U (Network) DTCs, so you need a scanner capable of reading those. Common triggers for the ABS and DSC warning lamps are problems with a wheel speed sensor or its wiring harness. Sometimes a sensor just needs to be cleaned of accumulated metallic particles from brake dust and other gunk.

Knowing the code or codes that have been flagged will speed up the diagnosis.

The fact that the ABS light is on but the DSC light has extinguished is curious, and probably a clue.

To determine the correct value of that fuse, you can check the Electrical Guide, which you can download here:

2004 X350 Electrical Guide

Cheers,

Don

 

This from my electronic copy of owners' manual. Reference JJM 18 02 21/40

Front box

F20 30A ABS pump

F22 30A ABS module

Cabin

F17 5A ABS module


Trunk

No ABS fuse


??????????????

 

As part of the trouble shooting for ABS problems it's necessary to make sure that the 'brake light switch" is receiving power. Even if the brake bulb it self is burned out the ABS will still work but if the brake light switch itself loses power the ABS fault light comes on to signal.

That switch is fused, in the 2004 XJ8's at least, in the trunk fuse box at #44. The owners manual calls for a 5amp but my wife's car has a 15 amp fuse. Since the brake light works fine that circuit is at the moment O.K. and since it's been in there at least as long as we've owned the car I don't expect that it's the cause of the ABS light staying on permanently.


What I was asking is which is correct...a 5 amp fuse or a 15 amp fuse since obviously a 15amp could lead to a fried circuit if there was a short and the fuse didn't blow to protect it.

 

My SDD (JLR v1.30) is of course acting up at the moment and I haven't had the time to T/S it yet.


The Teves ABS literature calls out F44 in the rear fuse box as being a 5 AMP protecting the rear brake light switch but the Jag electrical manual says it's a fuse for the rear cigarette lighter and should be a 15 AMP so I'm guessing the TEVE's literature is either wrong or not relating to a 2004

 

As it turns out the TEVE's literature that goes into the codes relative to their system was evidently referring to either a different system or a different year and model of Jag. On checking the Jag electrical schematics of the entire car that F44 fuse is supposed to be for a rear cigarette lighter...of all things.

Geez....I'm 70 and have had to learn so damn many different cars and their bits and pieces since my very first../.which was dead simple 1960 Valiant and the electrical manual for the Jag is longer than the whole damn svc. manual for the Valiant.

They call that progress???<G><G>