Hello All,
2003 Jaguar S-Type 3.0 w/ 81,000 miles has parkbrake Fault warning on along with flashing red brake light and solid yellow ABS light. I ran a scan on it with a generic scanner and got no codes except for P1000 (System check not completed since Last Memory Clear).

So far, I raised the back end, took the wheels off and actuated the parking brake motor by connecting it directly to the battery by removing the harness from the module in the truck and jumping it directly to the battery, and I am able to get the motor to actuate. I released the brake and took the cable off of each caliper and tested out the levers on each caliper by hand and they both move freely. I re-attached the cables and reversed the battery connection, and I can get it to tighten and loosen at will this way.
After doing this and reattaching the harness to the module, upon starting the vehicle, I get the message to apply the parkbrake. After trying this, I get the Parkbrake fault message again.

One additional thing - the brake pedal is very mushy. I have to push it down far to get the regular brakes to catch. I bled each caliper and found no air in any of them and the reservoir is full under the hood. I doubt this is related to the parkbrake fault, but wanted to mention it. After fixing the parkbrake (hopefully), I was going to try to address the brake pedal.

Anyone know how to troubleshoot this any further?
Thank you,

Doug Slater

 

P1000 is not good. If you didn't cause it (battery off or code clear) then it needs investigating - as it does if it doesn't soon turn into P1111.

 

Take a look through this thread:

https://www.jaguarforums.com/forum/s...attery-193787/

One very common cause of the parking brake message is low prestart voltage. This can be due to a failing battery, but also anything else (such as a marginal charging system or a residual drain) that will leave the battery less than fully charged. From forum experience, you need to see at least 12.6V at the battery before engine start. That is a VERY high standard, much higher than is needed to crank the starter. Don't rely on starter cranking speed to convince yourself the prestart voltage is good.

 

Thank you for letting me know about the voltage. Battery seems very strong, Should I just check it with a multi-meter before starting to ensure it is 12.6v or higher? Also, to rule that out, could I put a trickle charger on it first and try starting it up that way?

 

Remember, don't judge the battery condition or state of charge by the starter cranking speed, if that's what you mean about the battery seems strong.

Yes.


A charger is a good idea for troubleshooting the parking brake, but I'm no fan of trickle chargers. They just don't put out enough oomph to recharge a partially depleted battery. I'm much more partial to an automatic charger with an output around 10 amps or so.

One way around this for troubleshooting is to use the alternator. First, make sure it is working properly. Your car has what's called a smart charging system. Right after engine start, you should see approximately 14.5v at the battery. After a few minutes, the charging voltage will decrease to around 13.7v. If good, go for a test drive, at least 20 minutes, longer if possible. The idea is let the charging system top off the battery. Next, stop somewhere convenient and turn off the engine momentarily and set the parking brake. Then start the engine and release the parking brake. If all is good now, with the battery hopefully topped off, you'd know low prestart voltage had been the culprit those other times. Your next step would be to determine if the battery itself is not holding a charge or there's an external drain running it down.