Good morning folks...

Cherry is coming along. I'm pleased...

I have a few questions about an ABS light that's ALWAYS been on. Is there a "hard reset" for the 1990 XJS? Performing one can work wonders on my XK8/R.

Front and rear breaks seem to work fine and are responsive. Jacked rear of car running in gear, pushed brakes lightly, rears stopped. "New" wear on R discs since craddle drop and new calipers. Fronts,,, spun them by hand, had a friend push break, wheels locked... Discs show usual wear from breaking.

Yesterday I undid the upper ball joints (will be replacing soon) which was an experience in learning to get to the front sensors. The LH was caked in grease and grime (BAD INNER SEAL?). Cleaned and refit. The RH not so much but did the same, refit. I also tightened up the upper control arm bolts, the arms were flopping around - this made a noticable change. Good!

Rears removed and cleaned. They were clean.

Tapped 12v on all ABS solenoids in the "BLOCK" all clicked with vigor. Did this maybe 20times in each. Just (carefully) tapping the voltage to loosen them up...?

Umm,,, took a ohms reading on each front sensor... The readings were steady and nearly identical. Sorry, I don't remember the number. I'll take ohms readings on the sensor and block pins today and report back. What should I be looking for?

Took the car for a spin. Light remained...
30amp fuses are good.

I'll go into the boot today to get at the ECU...

Ok - tell me what I need to be DOING, lol
I'm at a loss.

Will, does a hard reset work? Touching the NEG to the POS post on the battery to drain capacitors in the ECU? How does one reset this light?




WHO the HECK thought this type of bolt head made sense, lol??? What size is it? 9/16ths???

 

That slimmed down bolt head is used in the outer bolt of the two that secure the top front wishbones to the ball joint. It has to be so because if it was the normal size the disc brake would foul the bolt head on full lock. If you insert that bolt the wrong way round, you will find out for yourself!

Sorry i cannot help with the ABS, I do not have it, thank goodness!
Cheers
Greg

 

Hi Greg!

​​​​Haha.. Yeah, I took pictures and put it back right way round... It was just tough to get a tool on... I have to say, I love the set up with the upper and ball joint. Seems like it's going to make replacement not so tough...

My brakes work fine. I don't know how crazy I'll go chasing that light. Hmm... I'm getting voltage at the ECU, just checked and about 1.1 k steady ohms at each sensor. Don't know if that's right or wrong. New sensors cost a hella lot. And at the abs block between 3 something and 5-6 something ohms at the solenoids - which I think AIN'T good...

She's running and driving right nice tho... I'll be going back to the exhaust downpipes thread to update later. I think the placing of the O2 sensors made a difference.

Hope others will chime in on some ABS guidance.

 

Hi Jay

How long does the Brake Pump run, after you turn the ignition on before the Brake Pump cuts out and how many times can you Pump the Brakes before the Brake Pump cuts back in again, as it 'could' be a problem with the Accumulator Black Ball not holding pressure

In any event don't unscrew it, or your whole Car could get covered in Brake Fluid

Ask me how I know or rather don't!

 

JJJ,

I'd suggest that you do a formal electronic assessment of the problem. Go through the 32 ABS diagnostic tests as defined in the Workshop Manual.

Good luck

Paul

 

Thanks Paul. I don't have the formal assessment info.... I'll take a look, tho.

OB... The accumulator runs for about 15 seconds or so, usually on start up. If I have had her running sometimes shorter, sometimes not at all... I HOPE it's not that... A pretty penny...

 

Hi Jay

Paul (ptjs) is the real expert on these, so it could be a lot cheaper to follow his advice but those Wheel Speed Sensors do look a bit of a mess, so have a go at cleaning them up first and see if that makes any difference

 

Good Morning and Good Afternoon, Good People

Just to report back,,, I haven't had much luck with the ABS system, yet... I do feel I will get it though, down the road...

This is a separate but related-ish question...

When looking at the rear hub carrier,,, taking off the ABS sensor, the hole that is left,,, where is that in relationship to the inner and outer bearings? Is the reluctor wheel for the sensor exciter/signal in the cavity BETWEEN the inner and outer bearings, races and seals - on an ABS car?

 

JJJ,

If you look at the diagram on Jaguar's parts website, it certainly seems to be set up that way.

Paul

 

Hey, thanks Paul...
Web sites and diagrams are great and I've been using them - but there's nothing like the confidence that comes from goooood ol fashioned experience... That's why I love the help I get on this site...

 

Also,,, I've seen lots of photos (lots of the xj6 set up) but not a lot picturing the hub and carrier, with ABS and inboard braking on the XJS... In that, does that reluctor sit inside of the shell of the aluminum bell,,, in the cylinder on the XJS with abs and inboard or,,, is it just against the inner seal outside of the carrier. If you have or have found a diagram of that, I'd love to take a gander...

I'm trying to do my homework before the weekend - my only time to work on the car....

If I'm seeing what I'm seeing correctly, according to this photo, the reluctor/sensor wheel is well within the cavity/cylinder in the carrier in that space between the bearings, seals and races... #14

 

JJJ,

Although there are very occasionally errors, I'd always trust Jaguar's own parts website before relying on any independent vendor diagrams.

https://parts.jaguarlandroverclassic.../brand/jaguar/

Can you not verify from the sensor location in the top of the hub carrier to determine the exact position of the reluctor ring?

Paul

 

That seals it! Thanks Paul... Same image, basically.

I cannot look and see at the moment because I'm at work... The sensor on my carrier is on the side, not in the top. I have so little time that I like to be somewhat prepared for the task before the day of. So here I am...

Thanks for the heads up

 

Hi Jay

You could be in luck! (or maybe not depending) but when I removed the IRS Cage on my V12 XJS 'The same year as yours' I took loads of Photo's of the Cage Removal Process, including a, what some might say is a Stunning Image! or the Reluctor Wheel in the Hub Carrier, where the Wheel Speed Sensor goes in the Side

Though I'm not sure that this is your problem with the ABS light coming on, as I had a Similar thing and had to replace the Accumulator Ball, as the Pump kept cutting in and running, which can be difficult to hear when you've got 'Bon Jovi' blasting out of the ICE

Are you absolutely sure that you Bled the Low Pressure side of the System, especially up near the Brake Pump as if you didn't do that then you'll be wasting your time, as 'Paul' ptjs Finally managed to convince me to do some years ago, as removing that Plastic Elbow is not for the Feint Hearted

Although you could try 'Warrjon's' method of using a Pressure Bleeder but if you do then use the minimum pressure or else it could blow the pressure bleeder off the Top of the Reservoir and then send Brake Fluid flying everywhere! (which as I'm sure you know) with Strip the Paintwork in a Blink!

Not my favourite method but if you decide to go that way, then cover the whole thing with a Cloth while you're doing it 'just in case' and also have a bucket of Soapy Water handy to wash off any Brake Fluid in case the worst should happen but do use the lowest pressure that you need to do the job (or you will be Crying for ever!)

See Link Below: The Photo of the Reluctor Wheel, is about 1/3 of the way down page 106

Photo of the Relutor Wheel for the Wheel Speed Sensor plus what's involved in removing the IRS Cage on an XJS V12 with Loads of Step by Step Photos that wasn't half as difficult to do as some might think

 

I know nothing about ABS, but having had my hubs apart recently, and looking at OB's pic in the thread he linked to, I am 100% sure that the reluctor wheel is in between the two bearing in the hub. Apart from cleaning it up through the hole, I cannot see what could be amiss with it. The pickup, who knows, but I should have thought that the wheel itself is very unlikely to be the trouble, unless dirty somehow.