Try disconnecting unplugging the headlamp module behind the R/H headlight (bolted to bracket on the inner wing near the washer bottle neck).

If its a CRD check the wiring harness has not rubbed through the the air con pipes beside the engine.

 

I've never heard of the "dreaded no bus on instruments" on our cars

 

Think Chrysler change their terminology a lot.
Think they sometimes call the Body Control Module a Front Control Module. Fuse 6 in some of the earlier 300C's fed the Front Control Module, but I think the FCM is relates to Petrol vehicles. Have you checked all the fuses ?.

Jack

 

Thanks for the help guys should have said it is a crd. Checked the wiring simon but couldn't fault it, and to UK CHRYSLER it is definitely ' dreaded 'when you've been working on it for nearly 4 hours . There is a fcm bolted to under bonnet fusebox jack and checked all fuses a couple of times, a feel I'm missing something simple, customer parked up one night next morning exterior lights are on permanently when started and instrument cluster has all lights on with no Rev counter no stereo or wipers. Any other problem areas for bus faults is very much appreciated

Thanks again
Don

 

Did you try disconnecting the headlight module I mentioned earlier? The problems you mention now are exactly what happens when that module fails and disconnecting it normally cures it.

 

Sorry simon didn't realise you meant to leave disconnected, I had checked connection on multi plug and wiring but did not leave disconnected will try when I get in to work in morning
Thanks again

 

BTW, The headlights will still work with it disconnected :wink:

 

Could well be a single module dragging the CAN BUS signal down. Well worth disconnecting the lighting module as suggested.

If the above doesn't fix it I think the only way would be to refer to diagram, disconnect modules from ECM one at a time until BUS signal returns, (BUS would be best checked with an oscilloscope but can be done with a DVM, or poss. just rechecking for error codes ?). As you appreciate though, really time consuming.

Hope the lighting module fixes it. It is know to fail and affect the BUS and affect starting.
Think could get a diagram of all modules on BUS and connections if you need one but would take a bit of digging out.

From what I recall, the CAN BUS connections read about 2.4V DC on a DVM on both the "High" and the "Low" to chassis. Obviously this is not a signal measurement, just a means of checking for obvious faults or shorts to chassis. But obviously to check this you need a wiring diagram anyway to find the connection/module details.

Good Luck.
Jack

 

Hi all again, simon I had high hopes this morning but guess what its still the same, tried disconnecting battery to reset lasts for about 5 secs then all lights back on. If someone is able too supply a wiring diagram i would be eternally grateful or even know I link to one.
Thanks for everyone's input so far

Don

 

Thats a bugger, that normally does the trick. Please let us know what it was when you find the cause.

 

See attached drawings which are a starting Point.
If you send me a Private Message with your email address I think I can help with info.

I would check the Front Control Module First if I was looking for fault.

Jack

 

You are a star jack that's exactly would I was looking for, on other jobs the now but will let you know how I get on any more info please send to my email. bucket@onetel.com

Thanks again

Don

 

Was gonna email you a Pdf manual but file is too big and will not send, Sorry.
I think you've got the relevant bits for now though.

If you struggle I may be able to extract the relevant bit but I havn't got the software for splitting the file. I feel sure I could do it if it becomes necessary but I don't like loading new Software on Computer unless its essential.

Jack

 

Hi jack do you have diagram with the instrument cluster in loads of ecu's with no coms with cluster and its the only ecu my diagnostic machine won't talk to. Fault codes I have are in pcm U110a lost comms with scm can c
Abs u0126 lost comms steering angle sensor
Airbag u0208 and u0209 lost comms with seat modules u0186 with audio amp u0212 with steering column control module u0155 with instrument panel
Bcm u1107 ecu in single wire mode u0019 low speed can communication bus u110a lost comms with scm can c
Wcm u0155 lost comms with instrument panel etc etc
Sorry for the long list just in case it springs something into place
Thanks

Don

 

Where are you located as I know someone with a diagnostic tool that will read your car....

 

haha i'm afraid i'm a bit far away if you look on your map of the uk at the very top left i stay on an island called the isle of lewis, hence the hassle of not being able to go to my local chrysler dealer but if anybody wants to come on holiday and fix this car ....

 

Sorry to be a pain again jack but do you have a diagram like above for can b bus
Thanks

 

See attached for CAN B Bus Don.

 

Thought I'd better get back in touch and but and end to this problem, by disconnecting each ecu and the fact there was no comms traced fault to instrument cluster customer didn't want to buy new so sourced a second unit finally after nearly two weeks arrived today fitted and all OK. Hope this helps someone in future. Huge thanks to Jack and everyone else that helped

Don

 

just a thought .... I cured a regular fuse blowing that knocked out several instrument functions. The fuse related to the steering control module which had no bearing on the defunct systems....the solution was to disable the 'courtesy' headlamps coming on when the remote entry was activated on the fob.
Try gradually disabling optional functions in the EVIC & see if theres a cure

 

Hi kaiser bill the fault I had was a can b bus fault and no comms with instrument cluster 'no bus' on cluster all lights on dash coming on no fuses blown. Replaced dash all good now and no can bus faults

 

Hi again,

When you disconnected faulty instrument cluster did the comms error codes disappear then ?
Just wondered how you narrowed it right down. Unless you eliminated all the the other units as talking OK?

Jack

 

Hi jack used a pico scope when instrument cluster disconnected signal all OK when connected still a can signal but very erratic with this and no communication with the cluster I bit the bullet and went for the cluster

 

Well Done.
Swine of a fault.

Jack