Sometimes I really hate this car. This should not be so fricken hard to do.
I just changed all of my brake pads including by parking brake. No issues with the job. Easily turned in the caliper for the parking brakes and installed the new pads. Now I can't get the damned thing to calibrate. I can hear a ratcheting sound from the drivers rear when I apply the switch and then it goes into fault mode. I have tried 5 times after disconnecting the battery and it isn't working. Ideas?

 

I figured it out. After you turn the parking brake caliper pistons all the way in to put the new pads in, the computer faults if there is too much travel. I crawled under the car and manually ratcheted the caliper until it was tight. Then I went through the calibration and it worked fine.

 

When I did this job, after reassembling everything, I pressed the brake pedal about 50 times which does the same thing, it ratchets out the adjuster until it sets up.

 

Hi oldmots,

Does pressing the brake pedal ratchet the park brake pad adjusters as well as the brake pad adjusters?

Don

 

I don't believe it does anything to the parking brake. I must have stepped on the brake 100 times and it did nothing. When I got under the car and manually did it, it only took about 4 or 5 "cranks" to tighten up. When I was trying to run through the calibration process, I could hear the car triggering the parking brake calipers. It must have just been too far from contacting the rotor and triggered a fault.

 

Drb007,

What year and model is your car? Just curious to know if your rear brakes have the combined brake/EPB calipers or two separate calipers (as on the Brembo brakes).

Don

 

If it's like an S-type, the calibration process might need to be repeated 4-5 times or more to resolve the fault. Depends on how much clearance there is between the pads and the rotor.

 

Mikey,

By the calibration process, do you mean disconnecting the battery, reconnecting it, starting the engine, and when the APPLY PARKBRAKE message appears on the dash, pressing the brake pedal and either pulling up the EPB handle once, or pulling up, pushing down and pulling it back up?

After I disconnected our ECM to clean its connector, we were rewarded with the PARKBRAKE FAULT message that I haven't been able to clear following either the short calibration method or the longer one using SDD.

I had used SDD to turn off the automatic engagement of the EPB after reading horror stories of the EPB getting stuck in the applied position. I suspect that one or more of the following things happened:

1. Either I swapped the rear brake pads while I had the ECM programmed to not apply the park brake, disturbing the EPB pad clearance (I don't think I did), or

2. When I reconnected the ECM, it defaulted to the automatic apply setting and assumed the brake was applied when it was not, leading it to trigger C1802, "Motor engage current not reached or traveled too far upon apply." I'm not sure if this makes any sense at all.

3. I have used SDD to set the EPB to the service position and I can hear the motor running, so I don't yet suspect that the EPB motor assembly has a problem, though perhaps the Hall effect sensor developed a problem while the EPB was set to never automatically apply.

4. The EPB pads dragged and wore significantly while I had the auto-engage disable, causing the motor to have to travel further than it expected based on stored memory.

I've run the On Demand Self Test for the EPB and SDD says the test completes, but then says the test failed.

Our car has the Brembo brakes with separate calipers for the EPB. The levers move freely on both calipers, and when I press on them they move at least 1/4" before the pads contact the rotors. Does that seem right, or is that too much movement? From my initial inspection, I do not see a mechanical means of adjusting the levers or cable to reduce this travel distance. Have I missed something?

Any thoughts would be most welcome!

Thanks,

Don

 

Here's the procedure I've used:

https://www.jaguarforums.com/forum/s...750/#post75508

 

Thanks Mikey.

I think that procedure is similar if not identical to the long version in the X350 Workshop Manual.

I just tried repeating that procedure 5 times with no success. I can hear the EPB motor running when I pull up on the switch, but the fault appears soon after. I think I'll check the EPB pad thickness next in case they've somehow worn too thin.

Cheers,

Don

 

If I read your post correctly, the car initially seems to be OK, but the fault reappears soon afterwards?

That's not a calibration problem if so.

 

The APPLY PARKBRAKE warning appears on the dash, indicating that the EPB is in calibration mode. I follow the calibration sequence, but after I either pull up on the EPB switch to activate it, or pull it up to activate then push down to deactivate, PARKBRAKE FAULT appears on the dash. I can hear the EPB motor running under the rear seat when I pull up on the switch, but shortly after is when the fault appears.

I noticed tonight that the motor does not always run the first time I pull up on the switch. I wonder if the switch is intermittent?

Interestingly, I have previously had the C1802 DTC indicating "Motor engage current not reached or traveled too far upon apply," but tonight, after several repeated attempts to calibrate but PARKBRAKE FAULT continually reappearing, no DTC is stored.... Hmmm.

Don

 

Don, my car is a 2004 XJR with the brembo brakes and it does have separate calipers for the parking brake.

 

Same as ours.


What exactly do you adjust on the park brake calipers? I took an initial look and couldn't see any obvious adjustment on the cable where it passes through the bracket, or on the caliper lever or body. I'd love to know what to "crank" 4 or 5 times to see if that will work on our car.

Thanks!

Don

 

Possibly the bellcrank on the caliper is not returning home fully after each 'pull' by the cable. If so, the ratchety thing inside will not advance the pads towards the rotor.

 

That does seem possible, but the levers on both our RH and LH calipers have the same travel (about 1/4 inch to guess), and multiple manual movements of the levers seemed to make no difference in ratcheting the cable tighter on either side.

 

The "arm" that the cable attaches to has a short travel distance. I simply moved it as far as it would go, released it, and repeated until I felt the pads snug up. I probably did this 5-7 times. Then I repeated the recalibration process and everything worked fine. I had done the calibration repeatedly (more than 5 times) with no luck before that. I would assume at some point that it may have gotten set if I had kept up the calibration attempts, but I was certainly losing patience.

 

Thanks for the clarification, Drb007! I'll try moving our arms again as far as they will go to see if they will crank in.

Cheers,

Don

 

Don,

I'm doing my rear EPB pads soon so did that trick

work for you?

 

Hi hafren,

I haven't had time to try it yet - you'll probably beat me to it. Let me know how it goes! :-)

I've just been living with the Park Brake Fault message - too many more important things to deal with.

Cheers,

Don