Other XC90 Problem: Faults with XC90

[cornerwaysuk]

Hi All,
I have posted about this previously but didnt get many responses. Any help or suggestions would be gratefully received. The car is a 2005 XC90 2.5T AWD with an LPG conversion. I have owned the car for 3 years and no problems until recently.
I started the car in the morning and drove 100yards stopped at a junction and the red triangle came on and the message was "Brake system......stop " it was accompanied by "Automatic Transmission needs serviceing" "Engine System needs service" anti skid needs service" . I may have the wording wrong but I am sure you get the picture. I switched the car off and started again but it was very difficyult to start the engine would not turn over all the time. I eventually got it going and the Red Traingle gone but all the messages remained. Driving the car appears fine with the messages. Since this episode the red triangle does come on occasionally and occasionally it wont start. It has imobiliser warnings as well. I can eventually get the car started but with messages. The car will drive with the red triangle on but in limp mode. If the Red triangle doesnt come on it drives normally just got all the codes on. Once stopped and turned off and then on again the problems all start again.
I took advice and took it to a Volvo specialist in Huddersfield, he said 80% sure its the CEM. I took the CEM off and it was showing some signs of corrosion. I sent it to Volvodiagnostics and it has returned but the problems remain.
I have VIDA/DICE software etc and plugged the car in its 2011a version.
These are the errors that showed up....
BCM-0094 Communication Between Control Units Communication Problems with DEM.
BCM-0100 Communication Between Control Units Communication Problems with ECM.
BCM-0109 Communication Between Control Units Communication Problems with SAS. Internal Fault
BCM-0115 Communication Between Control Units Communication Problems with SAS. Signal Missing
BCM-0148 Communication Between Control Units Wrong Configuration ID.
BCM-E000 Communication Between Control Units Communicational Problems.
CEM-1A62 Communication with ECM Control Module Signal Missing.
CEM-1A64 Communication with AOC Control Module Signal Missing.
CEM-DF17 CAN-H, High Speed Network Faulty Signal
CEM-E000 Communication with Control Module Faulty Signal.
SAS-0016 Control Module Communication Fault.
SAS-E000 Control Module Communication Faulty Communication

Now I know there are a lot of codes but I dont know where to start to look for the fault or identify which component is faulty or even where it is on the car. I have read that it could be an earth wire, battery problem corroded terminals etc but just havnt a clue where to start.
Any help or advice would be much appreciated. Or a suggestion of somewhere to take it where I wont get ripped off, I have spent £200 already and got no where.
Many Thanks Eric

[victor olvo]

In a previous life I too have owned LPG converted cars, notably 3.0 V6 Renault (very under rated car but not without annoying habits) The gas conversion was installed by experts, cost a fortune and worked remarkably well except for causing havoc with engine management lights. They would come on at will and disappear when they felt like it. Renault dealer told me to go and see my "gas man" as the faults were stemming from the additional ECU which had been installed. (important to note this issue/problem did not manifest until some 18 months after the gas conversion).
On examination by the "gas man" Yes you sometimes get these glitches, you get rid of them by clearing the fault in the gas ECU but they could return.
In other words I had to live with it - luckily there was no limp mode on the Renault only a dashboard light.
Try disconnecting elec supply to gas and see what happens and/or talk to your conversion people first. That would be my first call.
I appreciate you have a lot of errors but these gas conversions are "one size fits all" or not as the case may be.
Good Luck

[DC850]

I would start by looking at the High Speed CAN as this is one of the commmuication buses within the system, this could result in most if not all the comms errors between devices. As there is a number of units failing I would suspect the issue at the CEM module, or CAN connector/cable at the CEM end.

Hope this helps

DC850

[cornerwaysuk]

That sounds good, I have had the CEM off the car and it has been sent to Volvo diagnostics for whatever they do with them, re fitted to the car but no difference, worse still the VIDA will not now read the car.
Do you know where I can find a check list of wires to check or clean in relation to the high speed bus? or CAN network? I havnt a clue how it works! Any suggestions greatfully received. I have bought a Nissan Merano as a stop gap while I sort this out and I dont like it!!! I want my volvo back.

[Chesney46]

CAN wires are easy to spot, they'll be twisted together to help stop interference. There are 2 voltages. The high CAN will be around 5 volts and the low CAN around 2. If you have an LED test light, they can be used to check a signal is being sent/ received, it will flash rapidly. A normal test light normally won't pick up the low voltage. Or a good quality multi meter.
In my experience, the CAN wires are also made of a silver cable rather than the usual copper.
As for a wiring diagram, I may have one on Autodata, I'll check later. Although they aren't very in depth sometimes.