XJ Saloon 2007 - Climate communications Failure

[alamn2]

Hi

I just picked up an XJ 2007, where the heater blower / climate control just stopped working , the screen is off with a backlight and when the button is pushed get the message Communication fault contact the dealer.. additionally since that has happened the cigaret lighter has no power and the air suspension fault message has come up.. the air suspension is fine , its even and feels good .

I hooked up to the iCar no faults reported, for the air con module test get message check if its connected and vehicle is on .. I guess its not even detected.(satnav and tv / dvd work fine)

All fuses are ok, could this be a simple grounding issue if so where should I be looking . its. a2007 xj saloon sovereign, not a LWB has all the optional extras

[Andy P]

Hi alamn2,
I'm afraid you have posted in the XJ Series Forum for the S1-S2 and S3 models.
Perhaps a moderator can move your post to the correct one which is here:
viewforum.php?f=215
In reply to your post:
Might be the earthing points behind the headlights.
On the left hand side as you look at the engine under the plastic cover.
There is a clump of earths attached by ally posts and nuts.
These quietly corrode away and fail.
Apparently this is a common problem as almost every item under the bonnet earths in that area.
I believe it's a fairly easy fix.
New nut and bolt and a drill bit.
Might be worth investigating in that area.
Also check the battery making sure it is in tip-top condition.
I would do a hard reset afterwards to wipe the slate clean and start afresh.(make sure you have the radio code before you do that)
Hope that helps a bit and good luck.
Enjoy your new car.
Take care and stay safe.
Andy

[davidr]

Moved to the X350 section as requested

[Andy P]

Thank you David.
Take care.
Andy

[alamn2]

Hi alamn2,
I'm afraid you have posted in the XJ Series Forum for the S1-S2 and S3 models.
Perhaps a moderator can move your post to the correct one which is here:
viewforum.php?f=215
In reply to your post:
Might be the earthing points behind the headlights.
On the left hand side as you look at the engine under the plastic cover.
There is a clump of earths attached by ally posts and nuts.
These quietly corrode away and fail.
Apparently this is a common problem as almost every item under the bonnet earths in that area.
I believe it's a fairly easy fix.
New nut and bolt and a drill bit.
Might be worth investigating in that area.
Also check the battery making sure it is in tip-top condition.
I would do a hard reset afterwards to wipe the slate clean and start afresh.(make sure you have the radio code before you do that)
Hope that helps a bit and good luck.
Enjoy your new car.
Take care and stay safe.
Andy

Hi


Many thanks for the response , and apologies for the wrong Forum.

When I start the car the backlight on the climate control screen goes green but nothing is displayed, none of the buttons for blower or screen demister work , ciggaret lighter also gone.

Checked the earthing behind right headlamp undid sprayed, cleaned , tightened there was no rust
Battery is brand-new Bosch 6 months old, when I picked up the car was all working then suddenly went
the code reader says make sure there is an air con module or the car is turned on so does not detect it
I took the battery off for 10 min reconnected , it did not resolve the issue

I will check the relays and fuse .. also one additional fault appeared when this happened the Air suspension fault also came on and code reader saying " missing ionisation temperature'

Just need a starting point to investigate

[alamn2]

Hi

So here is something I found , in the engine fuze box there is a 20A fuse on right back of the fuze box was blown , I replaced this started the car and for 10 seconds when climate button was pressed the communication error dissapeard then reappeared and went back to check the new fuse was blown.

not this fuze not only knocks out the zircon/header , climatronic, screen demisters but also the cigaret lighter. so there must be a short somewhere rather then a bad earthing , is there anyway to isolate and investigate

[andypryce]

Definitely agree over the earth point, had same on my X350, when I tried to tighten the earth point it came away in my hand, drilled a new earth point and all sorted. The electrical issues I had weren’t the same, but still worth checking.

[andypryce]

One other quick check, is make sure nothing has got into the cigarette lighter that could short the terminals, eg small piece of foil. Had that happen on another car and kept blowing the fuse. Look for obvious things first.

[andypryce]

Note to self: read the whole post before rushing to reply, sorry!

[alamn2]

Update:

the fuse blowing in the engine bay is for the headlights .. explains why Headlights for dipped someone has run a new wire bypassing that fuse .. anyway this is separate issue that I will have to rectify and reinstate but this wire was bolted on to the driver cabin fusebox earthing point and large portion of the wire by the fusebox had no sleeve it was running pass the climate control (10A fuse ) and one fibre had wedged into the fuse , cleaned up put new fuse in now the climate control is back to life. (The garage suggested new control unit for the climate control and a big bill) I decided to investigate and cost me 40 mins and a 20p fuse.

That fuse and clean up has fixed the climate control, cigaret lighter power and air suspension error

Next items is the low coolant sensor (this was a new tank 2 months old) maybe bad connection or after market box sensor not good, anyway to test this

MAF sensor - engine light on you clear the code and code comes back up even before the engine has started , either a new maf sensor or there is a short that's causing this.. surely once code cleared should only return after engine is fired up.

Headlights : the side lights and full beams work from the stalk, the dipped someone has installed a switch on the righthand side I guess they had that blowing fuse so didn't fix just bypassed or could not diagnose the issue

thanks all for looking, I will update as I fix any of these issues

[JimMann]

Hi Alam, there was an article in the Modern XK column of the magazine early in 2021 regarding working on the MAF of these cars - should be similar between XK8 and X350. Can't remember which month, but I will go look and post back.
Jim

[JimMann]

It's in May 2021.
Jim

[alamn2]

It's in May 2021.
Jim

Thanks , I’ll find the magazine.. Iv also got my xk8 1996.. need to sort the leaky brakes and get it back in for an MOT..

Maf sensor update I opened it up the top sensor looks bad had green deposit all along the wire .. I cleaned and cleaned made no difference.. before I replace I think maybe another underlaying issue . There are number of fault codes relating to “short” indicating maybe some earth /shorting in the circuit somewhere

[Andy P]

Hi alamn2,

(The garage suggested new control unit for the climate control and a big bill) I decided to investigate and cost me 40 mins and a 20p fuse.

Great result,very well done.
Hope the other issues are reasonably easy to resolve for you.
Good luck and take care.
Andy

[alamn2]

MAF still an issue cleaned both MAF's but when OBD connected there is no response from the MAFS.. definitely no power to either MAFs