I've been researching the common ASC/TRAC unavailable problem. Have tested circuits, cleaned sensors - all the suggested simple fixes. Everything is pointing to the module, which I want to send off for testing and a fix next week. In the midst of posting and searching I was questioned if I was getting the ABS warning light in addition to the warning message. I wasn't, but also realized I wasn't seeing it during the basis system check at start up either. I was told to change the bulb, but it appears to be an LED. I say appears as I I find in that location is a couple of pins soldered to the PC board (bulb portion is missing). Here's the strange part - occasionally when its been really humid and rainy, the waring fails to appear and the TRAC override on the dash works. Things dry up and the warning reappears. This has me thinking that the system is recognizing the failure of the bulb during the system check and identifying it as a complete system failure. But on those few occasions the humidity has fooled the system into thinking a bulb is there, it evaporates and it passes the test. I suppose the humidity could also be doing the same thing with the faulty solder points on the module, but before I send it off to find there's nothing wrong with it, I'd like to test the bulb theory. Anybody ever have a similar issue? Any advise on replacement bulbs or direction on getting the PC board off the back of the cluster would be appreciated.

 

What are the DTCs for the Module?????????????
Ask the module what it thinks is wrong!!!
C codes (chassis DTCs) can be read with PDU,WDS,IDS,AutoEnginuity etc.

bob gauff

 

Everything that's been done up to now points to a module fault - most likely the known faulty solder points on the power connector. I went ahead yesterday and repaired the faulty LED in the gauge cluster. In the process a buddy that's worked on his share of Jags got back to me and he was pretty sure the missing bulb wouldn't trigger the fault. I've got everything back in, and a nice ABS icon now when I turn the key to the on position, however, I've got the front pulled off the motor for a timing component swap so I can't start it up yet.

 

I for one would have loved to see pictures of you going about the led repair, what did you use, and was finding polarity difficult?

 

Hi Bluerdg
I have same problem on my 2000 xj8, ABS is on, TRAC/ASC not available, please keep posting, if you found the problem.

 

It wasn't as bad as I thought. You can lift the PC board up along the bottom edge to gain access to the LED's. I picked up a 2 pack of Bright White LED's from Radio Shack with operating range of 3.2-3.6v. If you look at the interior the PC board is laid out with a wiring diagram. ABS light is LED 10, as I recall. The diagram shows you the anode and diode layout. The schematic mark is also a circle with a flat side. The actual LED has a matching flat face. I grabbed the back side of the old LED leads with a pair of needle nose and heated the solder with an electronics soldering tip. They pulled out cleanly. Clipped the leads on the new LED a little over a 1/4" dipped in some paste flux and used the needle nose to put it in place. A slight bend on the protruding ends holds in in place. Melt a small bead of solder on electronics tip and touch to prefluxed leads and your done. I had it out and back in place with nicely glowing ABS light in less than an hour. My big question was the voltage - knew the wedge bulbs were in the 3.4v range so the 3.2-3.6v seemed the best option - also the anode and diode size as well as general bulb size matched up visually with those still in place.

 

Here's a recap of the info my buddy provided.

1. Missing or faulty bulb should not cause the fault.
2. There are a variety of clues that can be obtained by the warnings provided and when they are seen. In my searches I've even seen that you can get the unavailable warning from a bad connection on the TPS. My buddy says that if you get both the warning and ABS with ignition in on position and after starting, it's most likely a faulty module. If after starting you get BOTH on or off intermittently it's the module. One without the other can mean other issues, and the issue is dependent on which one you get.
3. You can have the ABS module tested if you can find a shop with the proper gear - I'm just in a location in the middle of nowhere with regard to Jag shops so I'm kind of on my own unless I'm up for a road trip. I've got the front of the motor pulled down right now for a timing chain job so I figured while she was down I'd deal with the ABS unit. Unfortunately, at the moment I can't start mine up, but I'm getting both with the ignition on so it's most likely the module. I found a shop in TN on E-bay that will test the module for all known issues, fix any evident issues as well as any they think might become one, and ship the unit back within a week, all with a lifetime guarantee. $55 + shipping to them so I sent mine out this morning. The unit is vehicle specific so this makes the most sense for me, otherwise I'd have to take the car into a shop and have a new unit programmed to the car. Problem is the car goes into restricted mode due to the other systems that run through the unit (trans, throttle, brakes - basically any system getting info off the wheel sensors). Good thing to keep in mind if you want to try the rebuild route.

 

I was kind of in a rush yesterday when I did the repair (didn't know if I was going to have to pull the ABS module or not) and I wasn't really set up for pics. However, based on how easy it was, and how cheap LED's are I might swap out the LED I used for something a bit lower key. I used a "Bright White" LED and that is exactly what I got - a brilliantly white ABS light. I sent my module off this morning and hopefully it comes back and solves my issue - if so I and my wife will only have to deal with the light during the system check which is fine, but if the module checks out and I still have the light I'll have to start looking at other potential issues. Since I replaced a non-existent bulb, I want to keep one but may need something a bit more subdued if I have to drive with it on until I find the problem. If I have to go back in, I'll have the timing done by then so I'll have a little more time to document the procedure properly.

 

Hi Bluerdg
Thank you very much for your posts, i will sit on my hands and wait for your next posts.

 

I had the same issue but have two xjrs so I switched modules and solved the problem. I had my module rebuilt with a ebay vendor. Works great.

 

Hi bluerdg
Did you get your module from repair shop?

 

Hi
I had the same problem about 2 weeks ago. ABS went on and ASM and Trac error messages keep appearing. I could not find a Code Scanner at a reasonable price that would be able to read our Jaguar ABS system sensors. I brought the car to Indy shop who has a scanner that does read the ABS codes but for some reason it had a problem connecting to any of the codes. After waiting 10 days I decided to try to solved the problem with cleaning the wheel speed sensors. After I cleaned the 2 front ones I took a test drive and the ABS warning light went out finally after I went about 200 ft. It been 2 days now without any warning lights or messages. I hope it is really fixed now.
This was not a hard job. I did not even have to take the wheels off. Removing the sensor from the harness was easy just push the tab up and away to make it pop off. Only getting each of the sensors loose proved to be a little bothersome. I had to twist it a little each way while trying to pull it out. They do come out though.
Jim Lombardi

 

Thanks for input Jim
I will try to do that tomorrow, hope it will fix my ABS problem too!

 

Hi Victorpalm
Before I started working on the sensors I printed out the DIY (has instructions and pictures) that is on this forum.

The DIY says that "You need to take off the wheels". I read some where in the forum that another member did it without removing the wheels. I may be lazy but these mounted tires are heavy and I get tired pretty easy.

For the front wheel sensors you only have to turn the front tires sharply to the left on drivers side and to the right on the other side. Then you can access the sensors from the front of the wheel opening.

I had to jack up the rear to do the driver side, then jack up the rear on the other side. For safety you might want to place vehicle stands per instructions in your Jaguar manual. The JTIS says "Place suitable vehicle stands in position at the front or rear vehicle jacking points. Lower the vehicle onto the vehicle stands." I added to words "or rear". In case you want to know I did not use the vehicle stands. I did not know if it was needed because I only jacked one side and completed the cleaning for that one side before I started on the other side.

Continuing on the rear wheels. You need to jack up it up high enough to get enough clearance to reach the rear sensors (go as high as you can but still have the tire make contact with the pavement. Then you can access the sensor from the rear of the wheel opening.
By the way this was the first time since I owned this car that the jack has been taken out of the trunk. It looks like brand new. Also I think it is a great design and easy to use with its racket handle.

Here is the hyperlink to the Cleaning the Wheel Speed Sensors:

https://www.jaguarforums.com/forum/x...e4/#post208422

Remember to thank Reverend Sam for the great job he did on this DIY. Use the Thanks button when you go to the DIY posting.
Jim Lombardi

 

HI Jim
I was planing to clean the sensors today, but some thing else came up, and i cant do it until Tuesday.
Thank you very much for detailed instructions, and I will check the weblink. I will update if any progress or not. Still hoping that will solve the ABS problem.
Victor

 

My Vanden Plas has done this to me a couple of times over the past year I've had it. The trac failure message shows up and the ABS light comes on. When this happens the speedometer doesnt work. I scanned it and the code was C1159, IIRC. That code is for the RR wheel speed sensor, I believe. I pulled the sensors and "cleaned" them, even though there wasnt much of anything on them and swapped sides. After restarting all was well. If it does it again, I am going to see what code it throws. I had no idea these ABS modules were known for failures though. Do you know what codes you were getting? Thanks in advance.

 

Motorcarman
Your posting on ABS code scanning.
"Ask the module what it thinks is wrong!!!
C codes (chassis DTCs) can be read with PDU,WDS,IDS,AutoEnginuity etc."

Is AutoEnguity at $600 (with the Jaguar enhancement) the least costly option to read all of the sensors located in our Jaguars?
What is the cost of the others (PDU, WDS, and IDS) and are they usually only purchased by repair shops?

I found an article from Jag-lovers.org (list of types of DTC) when I was trying to learn more about DTCs related to Jaguars.
read full text of article
http://www.jag-lovers.org/obd.php

Also here is a weblink to the list of Jaguar sensors that AutoEnginuity supports has on their website:
Jaguar Engine Module List

 

Replaced a bad LED in gauge cluster (ABS) light. Got the module last week and managed to get it installed just before we headed out for a weekend in the mountains. Before the module was sent, I got ABS light in gauge cluster and ASC/TRAC unavailable warning with key on. ABS light stayed lit and warning cycled as usual. AFTER installing rebuilt module, ABS light lit during system test, went off and I haven't seen the ASC/TRAC warning once. I'm waiting for an expansion tank hose, and want to put a new serpentine belt in, so I'm about a day or so from testing out my timing chain job, but it looks like the rebuild was worth it.

 

Based on my resource, and results I'd say you were experiencing an issue with the module.

 

Hi there all!
I cleaned all four sensors today, and there wasn’t anything on them, I drove about 4ml, the ABS light and TRAC/ASC massage still there, I am going to take the car to Jag shop, to get the code out of it probably tomorrow.
Thank you for update bluerdg,
how many days it took to send the module and get it back