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Matt
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22160
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a 2007 S Type Jaguar 2.7 Diesel, owned friom new with

Customer Question

I have a 2007 S Type Jaguar 2.7 Diesel, owned friom new with 112,000 miles on the clock. I have a niggling problem with the parking brake. This occasionally fails with the logo "cannot apply parkbrake" or I think "parkbrake fail" (hasn't happened recently) appearing along with an ***** *****ght and the red brake logo flashing. This always occurs on starting when I turn over the engine. It only happens when the engine is hot and if the car has been parked for a short period such as in a service station. As I turn over the engine about 3 bleeps are sounded and the logo comes up. If the parkbrake is on at the time it cannot be released which is embarrassing. It can be restored using the reclibration procedure (disconnect battery etc). I have an iCarsoft i930 scanner and this shows EPB failure management mode 10 - power connection fault. Everything else looks OK but there are some voltages: Motor sense at 2.9v and primary/secondary appy/release voltages which are all about 4v. Don't know if these voltages are correct.
I would really like to cure this. It is driving me mad!
Submitted: 4 months ago.
Category: Jaguar
Expert:  Matt replied 4 months ago.

hello

as you may have read the actuation motor on these brakes has a tendency to seize up as its a little exposed under the car

So I'd 1st suggest applying a dose of penetrating oil into the unit where the cable exit and apply some grease to where the cables run

then run through the reset procedure

1. Reset the EPB module as detailed below
a. Switch off the ignition.
b. Disconnect the battery for 30 seconds .
c. Re-connect the battery.

2. Start the engine.

3. Firmly apply and release the footbrake five times.

4. Confirm that the message 'NOT CALIBRATED' or 'APPLY FOOT
AND PARK BRAKE' is displayed on the instrument cluster
message centre. This indicates that the parking brake is in
calibration mode.

5. Lightly press the footbrake pedal.

6. Apply the parking brake by using the EPB switch.

7. Release the parking brake.

8. Release the footbrake

9. Confirm that the brake warning lamp is no longer illuminated on the
instrument pack and that the 'NOT CALIBRATED' message is no
longer displayed in the message centre.

10. Apply and release the EPB five times to ensure no error is present

Customer: replied 4 months ago.
Hello Matt, I am afraid that you have not helped me at all with this. I have completed the EPB re-calibration procedure on numerous occasions as this sorts the problem temporarily, but as stated it keeps recurring. I have also lubricated the brake cables. The actual operation of the brake unit appears to be fine. Before starting up I release the brake and this works fine. I use the brake quite a lot, sometimes even waiting at traffic lights and it always performs flawlessly. I suspect some units seize up because they are not used enough! However, the parkbrake failure always occurs when I crank the engine when it is hot. It appears to be a control system malfunction rather than the brake unit itself failing, although it might be an electrical connection issue. What does the Failure Management Mode 10 mean? What connection does it refer to and are the voltages recorded by the scanner correct. What I think I need is a method of correcting the Mode 10 failure.
Expert:  Matt replied 4 months ago.

Hello

OK if the issue only occurs during cranking then it sounds like its struggling when the battery voltage is low, as cranking will drop teh battery voltage below the norm until the engine starts

so this low battery voltage may be exposing an issue with the motor power supply

So I'd begin by 1st checking the condtion of the main battery connections ensuring that they are bright and clean

measure the battery voltage with everything off as the 'resting' voltage should be at least 12V if its not and if the battery is more than 3 years old then it may be time to replace it

If this is all OK then I'd disconnect the EPB module and check the connections are bright and clean

this video shows its location

Customer: replied 4 months ago.
Hello Matt. I have already done a lot on voltage as I thought this might be the problem too. I have changed the battery, the replacement being 100 AH which is 10% up on the previous unit, and as the problem occurred during cranking I also changed the starter motor and this resulted in a noticeable improvement in cranking speed and seemed to alleviate the problem - but only temporarily. I have checked the module connections and all seems fine. I also considered changing the module but it is quite expensive and I could only find a module with a different number to mine - probably previous model.
I monitor battery voltage with a plug-in voltmeter in the cigar lighter - it is reading 12.4 volts this morning after the car has been sitting for nearly 2 days.
The most recent failure occurred after the battery had been on trickle charge overnight, and on only the second start of the day having driven about 20 miles. So it might be a voltage issue but if it is, why does it only occur when the engine is hot, and when the battery must be pretty well fully charged?
Do you have access to the meaning of the Mode 10 failure?
Expert:  Matt replied 4 months ago.

Hello

I do have access to the meaning of that mode 10 failure I'm afraid.

I'll opt out to open this up to others to see if can be answersed

however one thing to consider is the EPB motor connections in the tunnel?

as arguably they would be effected by heat as they are quite close to the exhaust