Hey all. quick question. I just had my jag inspected and there were NO fault codes. It passed inspection. However, the ASC and TRAC not available messages come on intermittently along with the ABS light. The weird part is when it comes on:

Sometimes it will flash when I start the car and then immediately go out,
Sometimes it comes on when I'm going 70MPH,
Sometimes it comes on when I'm going 30 MPH,
And sometimes it comes on when I'm parking.

There is no rhyme or reason to it. However, it will go out when I restart the car and may not come on again for days. It's the weirdest thing. I can't pinpoint what the problem is because it doesn't come on at any particular time. We had the front brakes replaced about a month ago. We have not done the rear brakes. Any suggestions about what this could be?

2001 Jaguar XJ8 Vanden Plas

 

Mine does the very same thing. Mine SEEMS to do it more when it has rained or the weather is humid. I suspect that some connector needs to be cleaned, but of course, which one?

 

I've had that problem also. Mine seems to be related to battery charge. If I put the trickle charger on it for a few hours, it never comes on. I guess I'll have to replace the battery, but I'm trying to make sure I need one first.

 

"ASC and TRAC not available" plus ABS

1. failing battery
2. dirty wheel speed sensor
3. ABS module
top 3 things to check.

 

Same problem on mine! It comes on if I push the gas to hard and when I am parking. I will try cleaning the sensors, rear ones are prone to get dirty I heard.

 

You do realize that the module stores codes for any fault in the system!!!

bob gauff

 

Where exactly are these sensors and how to clean them? Q-tip with alcohol, or something else?

Pics would be awesome

 

same thing here, that only thing I am so sure is it happens in the raining/humid days


even the check engine light is on . it will be gone when weather dried up.

definitely has to do with the humidity but don't know exactly where and what to fix

i checked the battery and it works fine

 

Mine started doing this too after the winter. Mostly happens when parking in the underground garage of my building, but sometimes while cruising too. Always clears on the next start.

I've been meaning to do a hard reset on my car, so I guess I'll take my multimeter with me when I'll do that and check the battery.

 

I cleaned the rear sensors yesterday, no improvement. Today, following some other thread information, I unplugged the ABS module and on the harness connector, I measured the resistance of each wheel sensor, 1-1,1 kOhms.
One of next days, I am going to open the module and to solder the pins that are known to be broken.

 

I checked my battery voltage, and it's 12.47V. Is that low enough to cause these problems?

 

Your battery voltage is just right; when it is low, the "Trac not available" will appear only first seconds after starting the engine.

Today, I open the ABS modulator circuit box and ... surprise, it was not the broken pins.
I soldered a little the pins, adding more compound just to be safe. Lucky me, I was cutting just a little square on the top of the contacts so the re-sealing was easier.

Finally, the problem found was left front wire broken, the measurements on the pins 17&18 on the connector made some variations.The correct one is 1,1-1,2 Kohms.

I just soldered a piece of cable from an old lamp, keeping just the connectors and all is working right now!

My tip, before opening the modulator just measure the values on the 26 pins connector, 3&4, 6&7 17&18 21&22, looking on the connector count from top right.
Ask someone to move the cable to be sure that the broken wire appears.

 

I have a OBDII reader and I have the OBD II command set . I do not see how to access the other processors. Can you help?

 

I have the same problem. Intermittent, but until
2 days ago I never had this ABS warning light.
Must be all those thunderstorms.

https://www.jaguarforums.com/forum/x...ors-faq-37434/

Here is instruction on cleaning the wheel speed sensors...
a task I cannot complete, because my sensors are in there
and will not budge, due to rust/ years of aging.

Ian

 

The rear sensors should be easy to be removed and cleaned; the front ones, if are blocked in the front vertical arm, can be cleaned with some cleaning aerosols and also with a sheet of sand paper going between the ABS wheel and the sensor.
I recommend measuring the wheel sensors on the module connector, a lot of saved work.

 

Finally, the problem found was left front wire broken, the measurements on the pins 17&18 on the connector made some variations.The correct one is 1,1-1,2 Kohms.
My tip, before opening the modulator just measure the values on the 26 pins connector, 3&4, 6&7 17&18 21&22, looking on the connector count from top right.

-----------------
Does anyone have a photo of the ABS connector with pin numbers shown for the wheel sensors?
Thanks.

 

http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf
RJ__________________
97 XK8 Conv 85 K mi

 

I forgot to mention, this is for XK8, but I think they are identical. He finds resistance of 2 Kohm plus, but I and several others found 1.1- 1.2.
RJ

 

RJ237, thank you very much!

 

I have a 2000 XJ8.

To add to the above, I had this same intermittent acs off/trac off warning. Before joining the forums, I took it to the dealer, who suggested to change the brake fluid. Changing the brake fluid made it worse. Now the acs off/trac off light is on constantly. Dealer came up with a C1095 code and suggested that the pump motor resistance was high.

On another site, I found that the pump resistance of the flylead go to the pump (that's below the ABS module main conneector) should be between 9 and 24 ohms. I got 16, so I think the dealer was steering me to a very expensive repair.

I then tackled the wheel sensors. One of the rear ones were filthy, but that didn't do it. By the way, I suggest to check the resistance of the sensors on the sensors themselves after you have cleaned them and before reconnecting. The reason for this, is if you measure them at the ABS module connector, you can't be sure if the problem is the wire or the sensor. Anyway all the sensors checked out ok.

The electrical diagram on the site for the ABS module connector for the XK8, is the same as that for the XJ8. (figures I can't find the link right now) but just type in the trac off/acs off and it should show up in a post. Anyhow, all the sensors checked out ok on ABS module connector. I also checked all the fuses related to the ABS module and pump control. They were ok.

Finally, something I found on another site which confused me. It said to measure the voltage across 9 and 24 on the ABS module connector and if near 12 volts then to replace the hydraulic contol unit. I measured 12.54 volts which was essentially my battery voltage. Since the connector was not connected to anything, (not to the module), I didn't get this comment.

Anyhow, the next step is probably to remove the ABS module and crack it open to see if it has problems with the solder points. If it doesn't or if repairing those doesn't do anything, then I will send the module for reconditioning.

On a final note, I also noticed on another site that any battery voltage on the car below 12.5 volts may cause computer issues. My battery was at 12.43 volts. I charge the battery to about 12.7 volts (and it held), put it back in, but the acs/trac off didn't change. Also the ABS light is on.

One thing, I am pretty sure of, if the acs off/trac off light go on immediately when turning the ignition (before actually starting the car), then my gut tells me that the ABS module is defective. I guess it could be the hydraulic pump, but with the car not turning over, you have no pump pressure anyhow, so how it could be the pump makes no sense. I suppose it could be a wheel sensor, but if you've already checked them (and yes 1.1-1.4 kohms seems to be the correct setting), then it all goes back to the ABS module.

I think removing it might be a bit easier on an XJ8 than an XK from what I saw in the photos of an XK having it removed. I will try to take some photos and post them as I do it.

Cheers.