Diagnostic System failures...confused!!

2.0_hippo said:

try the SRS ECU, you'll be fine

my ECU was getting damp from water entering the pollen filter intake and running down the pipe work and onto the ECU buried under the handbrake.

its worth a try, the SRS faults are self resetting anyway if the fault isn't present


Good luck

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SRS should be independant should it not?

This shows the folly of interconnecting all the different ECU's on a bus structure, just like the good old unions, one out all out.
Trouble is, the way it's configured, I'm not at all sure that disconnecting ECU's will actually lead you to the fault.
If the car works I'd be inclined to leave it and see what happens if you continue to use it assuming it has an MOT.

Datatek said:

This shows the folly of interconnecting all the different ECU's on a bus structure, just like the good old unions, one out all out.
Trouble is, the way it's configured, I'm not at all sure that disconnecting ECU's will actually lead you to the fault.
If the car works I'd be inclined to leave it and see what happens if you continue to use it assuming it has an MOT.

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+1

stupid design isn't it.

why not run each data bus cable back to a central hub, that way atleast if there is a failure of one component you dont loose diagnostic connections to the rest !

surely if these ECU's are linked together don't all the ECU's need to be operational for the data network to work and transmit data to and from the diagnostics ? if so, removing a fuse to one of the ECU's would surely make it inoperative thus causing the same data connection issues your experiencing now ?

2.0_hippo said:

+1

stupid design isn't it.

why not run each data bus cable back to a central hub, that way atleast if there is a failure of one component you dont loose diagnostic connections to the rest !

surely if these ECU's are linked together don't all the ECU's need to be operational for the data network to work and transmit data to and from the diagnostics ? if so, removing a fuse to one of the ECU's would surely make it inoperative thus causing the same data connection issues your experiencing now ?

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That's the way I understand it, in fact I seem to recall bridging kits for some of the stuff.

Datatek said:

That's the way I understand it, in fact I seem to recall bridging kits for some of the stuff.

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yes, i can remember some sort of connector that you plugged inline to the in and out side of the bus connections to bypass that piece of equipment...

pretty sure i had heard it used when diagnosing faulty DSP Amps etc..

Thanks for the comments chaps.

if you read my first thread and the PDF document attached to it, you see that the K/I bus structure generally doesn't operate on a one out all out manner....as long as the master or standby controller is in the system and working then the non defective ECUs will continue to operate....as the master or standby send out a voltage at a set level, when an ECU wants to send data, it switches this voltage to earth to cause a lower voltage on the bus....it does this multiple times to create the 0's and 1's of the data stream.

so as long as the master or standby are providing the line voltage, then you can have as many defective ECUs on the line as you like, the others can still coomunicate.

problems come when one ECU faults and permanently switches the line voltage to earth or low meaning you cant communicate on the bus as technically its busy.

you have to disconnect each ECU in turn until you find which one is dragging the bus down.

The CAN Bus is different in that the ECUs themselves provide their own line voltage and the messages go to all ECUs and the ECU decides if it wants the message or not, so if one ECU goes pop, the CAN clogs up....

my suspicions are with the Instrument Cluster as the is the gateway to all the buses, but it is working spot on, just cant connect to diagnostics.

whilst the car is working, I do still get EAS ABS HDC failure every now and then, and it would be nice to figure out why, also its a Range Rover and will need diagnosing at some point!!

Good luck - may the force be with you!

I presume you cannot swap the instrument cluster temporarily with another car because it'd mess the mileage up? (The cluster and car ECM will revert to the highest recorded mileage?)

its not something coincidental like a faulty OBD port pin, or the lead from the allcomms, i am in kent if you want to try an alternative lead, or i have a laptop with allcomms on, straw clutching basically...
i am around surrey most weeks on and off

holidaychicken said:

its not something coincidental like a faulty OBD port pin, or the lead from the allcomms, i am in kent if you want to try an alternative lead, or i have a laptop with allcomms on, straw clutching basically...
i am around surrey most weeks on and off

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Hi Andy, I have a generic OBDII scanner that does connect to the engine ECU and will read live data etc...so I know at least that diagnostic bus works...the only common denominator in the other systems is the Instrument Pack.

I work near Heathrow during the week, so if you are local I would really appreciate you trying your All Comms just to rule mine out! You'd have to give me notice as I don't normally take the Range Rover to work so you'd have to let me know when so I can take that to work.

Or alternatively if you are willing to send it I would be more than willing to pay all courier costs.

StuckAgainSteve said:

Good luck - may the force be with you!

I presume you cannot swap the instrument cluster temporarily with another car because it'd mess the mileage up? (The cluster and car ECM will revert to the highest recorded mileage?)

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Not sure it works like the P38...from what I have read, you first plug the original IP into the Testbook, download all the pertinent information, install new IP and then upload all the data.

Not sure how it works with a secondhand IP...will have to research further....

Its fun owning a Range Rover, all this researching and finding stuff out is quite fun....then once you realise how much it all costs that's when the fun wains...

ant might be a shot in the dark but in rear left compartment with the amp/tuner/spagetti etc etc there are 2 loose Purple = Diagnostic DS2 Bus connectors think 1 is mil c-17 but not 100% sure on other,you will have to try & get your hand down to retrieve as they lye on the floor,if you have any water in there & submerged this maybe the prob through conduction,i moved mine up out of the way when found ,gotta be worth a look I think

wil2813 said:

ant might be a shot in the dark but in rear left compartment with the amp/tuner/spagetti etc etc there are 2 loose Purple = Diagnostic DS2 Bus connectors think 1 is mil c-17 but not 100% sure on other,you will have to try & get your hand down to retrieve as they lye on the floor,if you have any water in there & submerged this maybe the prob through conduction,i moved mine up out of the way when found ,gotta be worth a look I think

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That's a good point

wil2813 said:

ant might be a shot in the dark but in rear left compartment with the amp/tuner/spagetti etc etc there are 2 loose Purple = Diagnostic DS2 Bus connectors think 1 is mil c-17 but not 100% sure on other,you will have to try & get your hand down to retrieve as they lye on the floor,if you have any water in there & submerged this maybe the prob through conduction,i moved mine up out of the way when found ,gotta be worth a look I think

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many thanks Will, shall take a look later....anything is worth a punt at the moment.

Also purple was just a colour I choose for the fuse list so people could see which piece of equipment was on what bus.

Saint.V8 said:

Hi Andy, I have a generic OBDII scanner that does connect to the engine ECU and will read live data etc...so I know at least that diagnostic bus works...the only common denominator in the other systems is the Instrument Pack.

I work near Heathrow during the week, so if you are local I would really appreciate you trying your All Comms just to rule mine out! You'd have to give me notice as I don't normally take the Range Rover to work so you'd have to let me know when so I can take that to work.

Or alternatively if you are willing to send it I would be more than willing to pay all courier costs.

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hi saint, i do quite often go past heathrow at least once during the week from kent and back, i also drive down to portsmouth on a tuesday late afternoon and back again via the A3 on the wednesday, also around the surrey, sussex area so wouldnt be a problem to drop in during the day or after work.
i work as a rep so it varies where i go so will get in touch as soon as i know where i am going to be next week and i'll pm you my mobile number mate.
i dont mind sending you my allcomms but thought it might be best to try with my laptop as well so we know its all good, i wont be in my range either, i do 600 miles a week in a vw diesel, imagine that in a 4.4..

Saint, whats the latest? i apologise for not getting in touch, i completely forgot, do you still want to try my allcomms?

holidaychicken said:

Saint, whats the latest? i apologise for not getting in touch, i completely forgot, do you still want to try my allcomms?

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Still no comms on diagnostics....also, if I turn the lights on, after a couple of minutes I get bells and whistles for EAS HDC ABS DSC failure....

Turn engine off and on again it resets itself back to normal, or sometimes i need to do the lock to lock to reset it.....turn lights back on....bells and whistles....leave them off, 9/10 it remains fault free.....

Will be unplugging the LCM to see if that shakes things up.....just seems like there is power or data interruption to either the EAS ECU, the ABS ECU or the Steering Angle Sensor when the lights are on causing it to fault cos as soon as you restart the car all is well until you turn the lights on again!

I would appreciate the chance to try your All Comms just to rule mine out as I could be chasing rainbows if mine is faulty!

ok mate, i have a bit of an unusual week next week but tuesday daytime is a possibility but i 'll get in touch sunday / monday to confirm

holidaychicken said:

ok mate, i have a bit of an unusual week next week but tuesday daytime is a possibility but i 'll get in touch sunday / monday to confirm

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Many thanks Andy...!

no bother, i'll check out my allcomms on mine before to make sure the new version works ok

Hi Saint.V8, I'm not sure if this will make you feel better, but I have EXACTLY same problem - my left xenon bulb (my car is LHD) exploded causing same "light effects" on instrument panel. These effects disappeared when I disconnected left headlight and were gone when bulb was replaced. Since that time I am not able to connect to diagnostics neither with Allcomms nor with official dealer's testbook or other serviceman's diagnostic system (I am not sure which brand it was). I am able to connect to engine and transmission ECUs via standard OBDII tools.
I, too, randomly receive ABS/HDC/... fault that disappears after engine is turned off. Probably it is not good news, but I am afraid it is not your allcomms that is broken.
I am not a pro like you and I was not able to have this fixed for almost a year, but if I could help anyhow, just let me know. I'd be so happy to find out what the problem is.