Hi all, looks like I'm getting on my back to remove the brake switch. Just wondered if anyone can tell me whether the aftermarket replacements advertised on ebay are worth using?
Also ive an abs light on that the code reader says is the two rear abs sensors. I've cleaned all 4 sensors but the rears keep returning. Could this be in anyway related to the cruise issue?
would a bad earth be a possible?
many thanks for any help.
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As long the brake pedal switches in one way or another are new it should be ok, as i learned on this site that old switches usually have issues with "microcurrents" leaking through causing annoying issues. I bought and replaced thoose microswitches myself (about $3 each).

Make sure the ABS transmitters are of the correct type, on a 2003XK they are not the same as the earlier XK´s.
All my OEBD/CAN bus issues went away after a new battery, new generator and cleaning of plugs, mainly ABS unit and gearbox plug... hmm.. i do remeber resoldering one spot on the instrument cluster cirquitboard... something was mentioned in the servicenewsletter.. ABS unit and the instrument cluster represent each end of the CAN bus with 120ohm terminators, when measuring across the bus you should have about 60ohm.

 

If you have the message "cruise unavailable" or the brake lights aren't working with the pedal, then it's likely the brake switches as you have already identified.

For your ABS sensors it's possible it is the cable that goes to the sensor - they do fail. I'm not sure where a bad earth could affect the wheel sensors in this way - I would expect more fault codes.

At the moment I would be treating these as two separate faults, but you need to fix the brakes anyway, so no harm in starting there.

 

Hi and thanks for the reply.
I've got the switch off this morning and ordered two new micro switches. I can't see anything wrong with them but let's hope this fixes it. I need to look at my connections aswell and do some cleaning, fingers crossed.

 

Hopefully your new switches will fix the cruise problem.

If you haven't already done so, squirt some electrical contact cleaner into the wheel sensor connectors. It's always worth doing this as a routine when you have connectors apart.

 

Thankyou both very much, I will persevere.

 

Just an update on this, ive replaced both the micro switches but ive still got Cruise unavailable . Cleared the abs codes but ive got u1135 and u1041. These won't clear? Icarsoft says function failed? Ive cleaned the gearbox earth and there was a two wire plug at the back of the gearbox that was full of oil , ive also cleaned that. Speedo has been intermittently working too. Any suggestions folks!

 

Using your scan tool see what the live data is for the speed and compare it to the speedo. If the live data is ok when the speedo is going wrong, that would suggest your instrument pack is faulty. I don't know if you have recently had the instrument pack out, but it would be worth checking all the connectors for bent or damaged pins. If you can't find any problems, then maybe worth getting a replacement instrument pack and swapping it? The instrument pack acts as a bridge between the SCP and CAN networks - a fault there might explain your codes.

 

Thankyou. I cleaned the electrical plugs a while ago. Will remove the instrument panel and have a good look. Any grounds to check?

 

On the XKR, is there a separate control unit for the gearbox or is it integrated inside the gearbox? If so there maybe is a big plug on it that carries the CAN data.. well worth to check out..

 

There are separate grounds for data and power for the instrument cluster, worth checking. You can find their approximate locations in the electrical guide for your car, although it might be obvious if you follow the harness. Also inspect the instrument cluster for any shorts etc as per this TSB:-

http://jagrepair.com/images/TSB/XK8/...%20failure.pdf

It doesn't cover your model year, but worth checking anyway.

 

Great. Thanks guys.

 

I've had the clocks out today and found this,


jackpot! that's got to be it is thought. No such luck. I cleaned it up but still got a check engine light and cruise unavailable. Codes u1041 and u1135. Will have another look at the gearbox plug and start cleaning some earth's.

 

That looks like flux? Did it clean up ok with isopropyl alcohol? If that was flux I might be tempted to reflow those joints just in case they have been done (badly) before. You could also check for shorts at those joints.

 

^^^^
Someone's been in there with a tin of flux and a plumber's blowlamp...

 

Yes it cleaned up ok. Starting to get out of my leauge.going to have another look at gearbox connections.would taking it for a drive be necessary to re set things?

 

Maybe chasing the same problem.

all cleaned up ok

 

That looks like it needs to be reflowed - you can see the leftmost one of the group of 4 looks dull. It should be shiny.

 

Ok. I need to get a meter that buzzes on connectivity and I agree it looks a bit suspect. Thought the flux was corrosion at first. Cleaned it up with isopropyl. Looks like there coming back out. Will report back lol.

 

I don't know how much experience you have with soldering, but if not, you might be better off finding someone local who repairs electronics (maybe even a phone repair shop) and ask them to reflow those joints for you and check for shorts at the same time. Otherwise buy a £20 soldering kit on Amazon, complete with desolder pump, desolder braid and solder and practice on some junk electronics before tackling your instrument cluster. You want to reflow those joints as quickly as possible to avoid overheating whatever they are. Apologies if this is teaching you to suck eggs.

Coincidentally I just reflowed the solder joints on a couple of SMD resistors on my Mitsubishi Shogun's instrument pack to fix the temperature gauge going crazy. Even the Japanese sometimes make things that don't last 20 years.