I'm chasing down a ABS/TRAC fault on my 2000 XK8 using Gus' super-informative check sheet.

(Yes, I cleaned the sensors, replaced the bad LF sensor-to-harness connector, refreshed the battery, replaced the brake switch, checked fuses and all that... The error code is immediate with Key On)

My question is about the resistance reading values. Mine are as follow:

LF = 1.107
RF = 1.089

LR = 1.094
RR = 1.103

The readings are steady.

Gus notes that acceptable values are 2.00 - 2.20 with a nominal reading of 2.014 for his 1999 XK8.

Is it possible that the spec. values are different for a 2000 model year? I think the chance of me having 4 bad cables - one being brand new - is rather slim.

Also, if I remove the ABS module for repair, can I still drive the car? With brakes, I mean.

Thanks!

 

Seems there must have been an MY change.

I've measured a few cars, all 2001 MY or later I think, and all good sensors have measured ~ 1 k ohms.

Pretty sure a car can be dirven w/o the ABS module ... just non-ABS braking in that case. Somebody better confirm that though; not sure.

 

Thanks Dennis.

The ABS has been a trail of issues and a lot of work chasing them all down. At this point I think I have the gremlin cornered in the ABS Module which I'll send out to be repaired.

 

Spurlee: After cleaning my ABS Sensors, I thought the same thing when I did the simple solder job. Now it says a "wrong part installed" on my speedometer, and threw up ABS/check engine lights. My speedometer's also not working now.

I bought a ABS module with the ABS motor online for $70, however they sent me a 5 hole part from an XJ8. My XK8 has 6 tubes. It was returned, and another ABS module purchased for $120--until a thunderstorm flooded a creek and salvage XK8 before they could pull the part. How's that for luck.

My XK8 was running okay until I tried to start it the other day. It starts for a second or two, but won't rev at all. I suspect the fuel pump went out. I'll have to solve that problem before getting back on the ABS issue.

Good luck, and let us know how you're doing with your problem!

 

You have to disconnect each brake line to remove the module, so I don't think you can drive the car with the module removed. But just do it in a day; remove the module, open it up, solder the joint, RTV the case, seal it up, and reinstall it. I don't see the need to let the RTV dry before reinstalling it. It's going to dry whether it's in the car or on the workshop bench. And there's no pressure in the module to blow out the RTV. From what I've seen this job should just take a few hours at the most.

 

Using a procedure posted on Roadfly a few years ago by a long-suffering XK8 owner named Jeff Cline, I was able to remove the module without disconnecting brake lines. This is Jeff's description ...

Removal Instructions I think I may have driven the car with the module out, but not sure anymore. (This is often the case with things that happened more than 15 minutes ago.)


[edit] Spurlee, you mentioned the ohm readings were stable. Did you turn the steering lock to lock while watching this? A blip seen while doing this is a dead give-away of trouble. Best seen with an analog meter. Good luck ...

 

Well, you gave me several things to think about.

Bamaman had some bad luck with internet parts for sure. The more I look into it the more I think it's a risky proposition, but sometimes you just have to do it. I learned that with Jaguar part numbers you must match exactly the 3 letter prefix but you can often move up the alphabet on the suffix letters - they indicate software editions and later versions support earlier ones.

I had intended to so the solder repair myself and it would be a 1 day process as Rev says. However, I've since decided that a quality rebuilder (ModuleMaster rebuilds ABS modules for as low as $100, 2 day average turn-around, 5 Year Guarantee) probably does some repairs beyond what I would or could do and it might be worth the $100. Plus the warranty is potentially valuable and my soldering skills are C-.

Instructions for ABS removal for other vehicles (I'm doing a Mustang for a friend) indicate that you can drive without it - with the lines connected. Of course, that doesn't mean that you can drive my particular car in that condition... I'll check and report back.

Since I'm going to replace the brake lines with S/S ones I'll be replacing the fluid anyway so opening the lines to pull the ABS unit isn't a real problem. I'd just like to drive the car while waiting for the module to return. If the brakes are soft or it doesn't work entirely I'll just park it for a week.

Thanks for the advice!

 

Piece of cake.

Removed the negative battery terminal and the 2 connections to the ABS CPU.

I removed the 4 10mm bolts that hold the ABS unit in place and the ABS unit would move quite a bit, but not nearly enough to make clearance, so I removed the 4 brake line fittings. No fluid leaked out.

4 Torx head bolts and the ABS CPU wiggles right out.

I refitted the 4 bolts for the carrier. Then I did the the brake lines and tightened them down. Warning! These are fine thread brass fittings going into an aluminum block - be careful! A little anti-sieze helps a lot.

Here's what I found out:

Yes, you can drive the car. But, you'll be looking at a lot of flashing lights while you do it. Here's the messages, lights and codes I received:

Low Brake Fluid
ASC Not Avaliable
Incorrect Part Fitted

The Red Brake warning illuminates
The Yellow ABS warning illuminates
The TRAC Off dash button is illuminated
Cruise is disabled
The Check Engine Light is illuminated

Codes are:

Current - P1637 Powertrain failure, P1638 Powertrain failure

Pending - P1111 General Fault, P1637 Powertrain Failure

All this seems perfectly normal.

 

On the way out today, after a couple of accumulated miles some additional things came on:

Failsafe Mode

Transmission Fault

The coolant gauge stopped working

The tach stopped working

I returned home and when I restarted it, all of this last set of messages went away and the gauges were working. There were no new codes.

Rather than risk a cascading list of "problems" I returned and parked it for the week.

 

That poor guy. Too bad he finally sold her. He had just about every problem that you can think of and did most of the repairs himself and was a very valuable source of info.

 

Hi Spurlee,
I had almost the same resistance numbers on my XK8 2002. I had several issues with my car. I bought an used ABS module but that turned out to be bad. 1 wheel sensor showing 3 miles difference from the other three wheels. And one bad OEM replacement ABS harness. If you keep having the problems. Troubleshoot one at time and invest or find someone who has the autoenginuity, car computer.

 

I an really impressed with Module Master. My rebuilt module will be back to me in 5 days including shipping. $120 total with insurance. And a 5 year warranty.

Hopefully this is the end of the trail on this issue.

 

Scott,

Have you sent that module out yet?? You seem like a rather resourceful guy that isn't afraid of much. I don't see any reason you couldn't repair it yourself; especially since it's already in your hand.

Jump on it!

 

XJRGuy,

Thanks for the vote of confidence! I have no doubt I could resolder the connection points, I've done similar, more delicate, things on the Corvette. In fact, I'd encourage people to do the repair, it is a satisfying DIY project.

Module Master did a great job, just as advertised. It came back in an electrostatic bag with smelled to have been solvent cleaned along the way, perfectly sealed and looked like new. I received an itimized invoice indicating that they did the following:

1. Repaired the signal amplifier
2. Repaired the power circuit
3. Bench test

Their charge was $100 plus $20 for return shipping and insurance. 5 year warranty.

ModuleMaster

I installed it, disconnected the battery, and made the connections. The old codes remained in memory and I cleared them out. A short trip brought up no codes, nor the ABS/Trac message. The car ran like a champ. No apparent need to bleed the brakes either.

I would really recommend that at the onset of problems people follow Gus' ABS Hard Fault worksheet, it's very useful and gets right to the heart of the matter.

Right now I'll call this issue closed.

 

Spurlee

Hi Scott, How did you know that your ABS system was bad. I have great brake pedal before engine start, but I have a very soft brake pedal after I start my 2001 XK8. Could I have a bad ABS and need a replacement? I have NO codes..... Ron

 

ABS faults will send a message NO ABS or NO ABS/NO TRAC (if equipped) when it is experiencing problems. ABS is a bolt on addition to the primary braking system (a gross simplification, but generally true), thus even when it is not working you have 100% operating brakes.

I believe you are experiencing a minor problem with the primary brake system, not the ABS. You have a hard brake pedal before the engine starts because the power brake booster isn't powered up yet and, essentially, the brake sysem isn't active. Once you start the car the system is operative, your problem occurs - soft pedal.

First things first. Check to see that you have sufficient brake fluid in the resovior. It is under the vanity cover on the driver's side. There are hard-to-see indexing marks on the little plastic tank. If low, top it off with new fluid - DOT 3 - from a sealed container available most anywhere for less than $3.

Beyond that, take it to a brake place (there's nothing particualarly special about Jaguar XK8 brakes - they are everyday Ford components) and they will diagnose it. They will likely tell you it is time for new brake pads or that your rubber brake lines have gone soft or that you have a small vaccum leak among the hoses in the booster system. They might sense that the booster itself is going bad but that is unusual, have it checked elsewhere to be sure.

Good luck!

 

I know this is an old post, but new people will probably run into the same problem. In my 2002 XK8 I was able to use a Dremel with a flexible shaft and cut-off wheel to open a window in the correct location on the brake module. You need to cut it a little tall to allow clearance for the soldering gun. Re-soldered the two commonly offending terminals and viola, problem solved. I then carved out a rubber grommet to seal up the window.

Lazy Mark