Hi everyone,

For the last year I have been having issues with the parking brake. It all started when I somehow managed to apply the EPB whilst still moving (low speed) and stopping for a traffic light. The EPB warning flashed up and it refused to apply any more.

A rest cured it for a few months, but every time it came back the time between the error code returning got shorted and shorter. Now it comes back pretty much the first time I apply the EPB after a reset.

I have replaced the rear discs and pads, checked that the actuator on the caliper is moving freely. The only thing I can't check is if the cables have stretched, there is no visual sign of damage and they all move freely in the outer cable.

If anyone has had similar codes I'd love to know what the solution was. Do I need to replace the EPB motor itself?

The car is a MY 2006 STR.

 

Which of B, C, U, P are the codes?

 

It started as C1801: Motor engage current reached before full apply travel reached (under-travel) and more recently C1802: Motor engage current not reached or traveled too far on apply (over-travel) has appeared too.

How I can have codes for under travel and over travel at the same time is one of life's many mysteries.

 

High torque DC motors can do some strange things under load when the supply voltage is insufficient.

Have you seen this thread?:

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


The most common root cause is a tired battery with one foot in the grave. I'm not saying to rush out and replace it, but definitely work through some of the tips in that thread. Are you getting the fault message like most other people?

 

Maybe start with a good battery charger - a CTEK 10A or 15A charger and keep monitoring the battery voltage in relation to your problem re-occurring.
What is your battery voltage with ign. OFF and ign. ON?

 

Another thought on the two codes you're seeing: Most forum members (self included) don't have scanners capable of retrieving Jaguar specific codes like those. If you peruse that scorecard thread linked in my earlier message, you will see most cases were resolved without ever knowing what codes were present. In other words, don't get too sidetracked chasing those codes when a good fix is possible simply by checking some basics.

 

Thank for the replies, the battery was replaced at the same time as the pads and discs, I also have a CTEK to keep it topped up every weekend. Using the live data on my scanner I can't see any noticeable drop in voltage to the motor when the error occurs. In fact I can't see a change in any of the parameters except it stops working.

The Jaguar TB says "DTCs C1801 and C1802 may have been set because of an actuator power or ground fault or because of a hall-effect sensor fault. If any combination of DTCs: C1784, C1785, C1786 and C1799 have been set along with any combination of C1801 and C1802, the cause of power, ground or hall-effect sensor faults should first be diagnosed and repaired." I have only had the 1801/2 codes and nothing else which makes me feel like I'm chasing a symptom and not the cause.

The TB also says that if the C1801/2/3 codes return after re calibration to replace the EPB actuator, so I guess that is the next step. I've been unable to find anyone with the same issue previously to confirm the fix though which is annoying.

 

That is a rare code!

This TSB is NOT for the S-Type but it has a few things you could try? They make a distinction between temporary and permanent codes and how to tell the difference.
As you posted without all those extra codes I think it's pointing to a bad actuator.
This maybe the same TSB you are talking about?
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Remember, most forum members haven't mentioned those codes because few of us have scanners capable of reading them. You are in somewhat uncharted waters, a pioneer so to speak.

Might be worth giving the actuator a good visual inspection. It lives in a very hostile environment under the car, exposed to heat and lots of moisture. Several forum members have reported seeing rust stains from the seams on the actuator gearbox. That means water has got in, displaced the lubricant, and corroded the gears. That would certainly make the poor motor work harder than normal and possibly set those codes.

Absence of rust stains doesn't mean the actuator is good. But the presence of same means it is bad. Apparently replacement is not easy, so it would be nice to know ahead of time.

Please be sure to update with what you find, to help the next guy.

 

I suppose the actuator would struggle if the (Bowden?) cables are not as free to move as they should be. So, maybe another cause of those errors?

 

I had problems with my electric parking brake a few years ago too. I took it to a local shop that had a Snap On computer who checked it out and told me that the problem was the actuator itself. If you haven't noticed, it sits on top of the rear diff which has to be lowered to work on it. A new actuator, if you can still find one is quite expensive too, it seems a waste to get a 20 year old one for $200 or whatever they cost. No more epb for me. I found out from a good source that parking the car on a slight incline with no epb won't hurt the trans or anything. I keep my foot on the brakes and slowly release the brakes after I turn off the car. I carry around some wood for wheel chocks for the rare times I need them or park with the wheel against the curb when needed. I pulled the fuses for the epb so I don't see the warning anymore and keep the brakes and fluid in good condition. Good luck