The first issue is my 1999 XK8 with 182,000 miles is showing an intermittent amber ABS warning light and a Stability Control Fail message. It just comes and goes. Most often, when the car first starts no warning lights until driven for a while, then they turn on. If I'm braking when they turn on, even on dry pavement, you can hear and feel in the brake pedal the ABS activating but then followed by the warnings. If I'm not braking when they turn on there is no feeling in the brake pedal that ABS has switched off. My second issue is that I am also experiencing an intermittent Engine Fail Safe warning with a loss of power. Stop the car, turn it off and then restart again, and all is back to normal. Now the mystery: An OBD2 check reveals NO codes thrown. I’ve read that the ABS, Stability Control Fail, and Engine Fail Safe conditions can be traced to the ABS system, wheel speed sensors, the TPS and also the Brake Stop Switch and failed wiring harness connectors. MY QUESTION is: has anyone experienced these issues when the OBD2 scanner finds NO fault codes? Thank you.

 

I had the ABS light come on last fall. At first it was intermittent and would go away after a restart. I did my research and was convinced the circuit board inside the ABS module due to vibration had cause a loss of contact with the two wires entering the module. It was eager to fix. with the module removed (not so easy to remove) you can see where the two wires enter the module. If you cut a hole in the module just on the other side and above the wire contact with the circuit board. You then just by using a needle soldering iron and some solder melt the old solder and add mores as needed. Now you have good contact again. Use a little glue or silicon to replace the plug you removed and replace the module (hard part). Worked for me.

Will answer questions if you have any.

 

Do you remember if any OBD2 codes were thrown?

 

Hi warren8959,

The Diagnostic Trouble Codes (DTCs) related to the Anti-lock Brake System cannot be read by most generic OBDII scan tools which can only read Powertrain (P-prefix) codes. You need a scan tool capable of reading the proprietary Jaguar DTCs, which include codes for the Chassis (C-prefix), Body (B-prefix) and Network (U-prefix).

If you have a good independent shop in your area that services European cars, they probably have a scan tool/system such as an Autel, Launch, AutoLogic or AutoEnginuity. If they specialize in Jaguars they probably also have SDD. If you can find a shop that can scan these codes, please post them here exactly as they appear and we'll try to help. Without knowing these codes, you can only guess as to the cause of the malfunction.

Cheers,

Don

 

Don, If the DTCs related to the Anti-lock Brake System cannot be read by most generic OBDII scan tools that sounds like a good place to begin. Also, it would make sense that the brake stop switch could also cause a problem without throwing a code. Am I correct that in a perfect world a problem with the Throttle body and associated TPS and connectors should throw a P-code? This is my first XK8 but I had an XJS for 12 years that I wrenched on and got really good at it and before that an MGB and a TR3. I love my British cars.

 

Yes, a problem with the TB or TPS should trigger a P-code.

You can download some of the DTC Summaries manuals at these links, courtesy of our member Gus:

Jaguar X100 DTC Summaries: Powertrain 1999

Jaguar X100 DTC Summaries: ABS/TSC 1999.2

Jaguar X100 DTC Summaries: SRS / Body 1997 on

Jaguar X100 DTC Summaries: Climate Control 1999

Cheers,

Don

 

I don't remember. But the OBS light being on was a firm warning. Go to search and you will find lots of data on failure of the OBS module including just how to do the circuit repair and pictures of the repair technique.

 

Warren, do you lose cruise control when this happens? Was just wondering if maybe you've got overlapping issues. The swinging restricted performance message got me thinking.

I imagine a 99 is close enough to discuss this, I understand they did away with the vaccum connection in later models.

There's a vaccum hose connection to the top of the throttle body. When it comes lose, mine did because of excessive engine movement from worn mounts, nothing shows inside the car until the car trys to increase throttle as commanded by c-control.

When this occurs you get restricted performance, and cruise control is disabled for an ignition cycle.

It's such an easy thing to check, I figured I'd mention it. As I recall it wont throw abs or stabilizer errors but that happens so frequently with dirty sensors I wondered if you could be dealing with overlapping issues.

Think you mentioned it takes a short travel to clear some errors- don't forget this is normal and as designed for ABS message.

Long shot but it's not like these cars don't surprise us. figured I'd bounce it off you.

John