I am currently trying to diagnose an electrical fault with a 2007 XKR.

Symptoms:
DSC and intermittent parking brake fault, followed by a whole host of faults (gearbox, abs, battery not charging, brake fluid low, cruise not available, heavy steering, struggle to get the engine to turn over, gets stuck in park, starting without pressing brake pedal, brake lights stuck on after getting out (ign off),

I measured the resistance between pins 6 and 14 (can high and can low) on the diagnostic port as 105.6 Ohms. (During fault condition)
Am I right in thinking this indicates one of the 120 Ohm resistors is 'missing', indicating a module containing one of the terminating resistor is faulty, or wiring fault in the circuit?
Which modules or wires contain a terminating resistor?
What are my next steps to locating the issue (will check feed and earth good.
Check each leg of wiring?

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Two 120 ohm terminating resistors on the bus would be 60 ohms as they are in parallel. How you would find the ends of the bus I dunno.

That's if they are in fact 120 ohm, which they probably are:




https://www.kmpdrivetrain.com/paddle...-tips-can-bus/

 

Found 'em- 120 ohms

 

Thanks, I guess I will unplug one of those control modules and measure resistance across CAN hi/low to check integrity of the loom (I should expect around 120 ohms back through the loom with 1 terminating control module unplugged?

I need to make a correction, my measured value was 105 Ohms so this would indicate high resistance on the bus?

 

Ideally, I think you'd want to unplug each of those modules in turn and measure the resistance at the module, expecting 120R in each case, and then re-connect one module and measure at the loom connector for the other, expecting to see the same resistance there, and vice-versa.

 

In your previous post on the same topic, you noted that you had:

C1D15-64 intermittent brake switch status
C1803-00 intermittent motor disengage full travel distance not reached upon release

Did you fix these? You also asked if there were resistors in any modules and of course there are, but specific to those codes, there is a variable resistor in the park brake actuator. The actuator doesn't use HS CAN but the park brake switch does - both feed off the Park brake Module. I don't see the connection (no pun intended) but confirm you're fixing codes before moving on and also consider aging the moderator to merge the two threads.

 

Both foot and park brake communicate via can bus/parking brake module Sean, so it's possible the unterminated bus could be showing up as errors on both foot and park brake.

 

just start kicking nodes off the bus till the problem goes away

pass floor wet?

 

​​​​​​Agreed @McJag222 Fix the known issues first then follow @xalty 's recommendations.

 

Thanks for the suggestions. I'm fairly sure the specific parking brake codes have not appeared again, I had assumed this isolated incident was a symptom rather than a cause.

By 'kicking nodes off the network' I take it this would be a case of unplugging modules one by one to see if the network returns to 60 Ohms (across can hi/low)?
If my problem lies with the instrument cluster I guess I'd be looking for 120 Ohms unplugged?

 

I have a very similar isssue car sometimes comes up with loads of warnings brake fluid low ..etc can network dropped out , some times when diagnostice equipent attached causes it to do it ...suspect instrument pack biut cannot prove it ...diid you cure yours

 

Hi, yes the issue was eventually fixed. Initially the instrument cluster was sent to Autotronics, which fixed the issue for a few months. The issue came back, and I left the car with an independent jaguar specialist who took the internals from my cluster and spliced this into a second hand cluster and successfully reprogrammed.

To diagnose, I put a multimeter across the canbus terminals on the OBD port to measure the resistance of can hi/low. When hitting the top of the dash the resistance would intermittently change/drop out indicating a bad connection within the cluster.