Lexia connection problem

[tich731]

1999 Citroen XM 2.0l TCT

My new Lexia gives an error message "No dialogue with ECU during initialisation".
I have used different cables to connect to the diagnostic socket - 16pin OBDII to 30 pin square and 30pin round to 30 pin square.

The 30pin square plugs do not seem to match the populated pins in the car's socket. Not all of the 30 ways in the plugs are populated. The car has 20 pins and 3 of these line up with blank ways in the plugs, so no connection is made)

I conclude that if some of the car's pins are not connected, then that would produce the error code mentioned?

Does anyone have any advice on this? Are there different types of cable available? Is the error unrelated to the cables? Are later XMs so much different to earlier cars?

Any advice would be much appreciated.

[Mandrake]

Not all of the pins in the 30 pin connector are used by a Lexia, relatively few in fact.

Including power and ground I believe only about 4 of the pins are used for a Lexia session, so I doubt whether this is your issue especially if you've tried two different adaptor cables.

Is it possible to try your Lexia on another car, or another Lexia on your car ? That's about the only way you're going to narrow down on which side the problem lies...

One thing you could check is whether there is power to the diagnostic socket, unfortunately I don't know off hand which pin it is on a 30 pin socket.

[CitroJim]

Titch, where are you?

If you're within range of Milton Keynes then pop round and see me. I have a variety of diagnostic tools here and they between them can see what the issue is. I'm also well familiar with the XM.

First thing is to ensure the Lexia is trying to talk to the car using the right protocol. It may be trying to speak S1 XM that used 2-pin diagnostic connectors rather than the later 30 pin protocol. As long as you are careful to enter the full VIN and RP number the Lexia will choose the right protocol. If you leave the VIN and RP blank, enter a generic VIN or enter zeros then it'll default to something that will not work. The full VIN and RP relating to that car must be entered always.

The diagnostic socket is powered with switched and permanent live feeds. These go via fuses and these supplies must be present for the Lexia to work. I can't recall off the top of my head the fuse numbers now but I can find out and also find out which pins in the connector they go to.

I've also known the 30 pin adaptor leads supplied with Chixias (Chinese copy Lexias) to be duff. Mine was initially..

[tich731]

Thanks for the replies.
Mandrake,
I am interested that only 4 or so of the 20 connected pins at the socket are used by the Lexia. Do you know which 4 and what the other 16 are there for?
I don't have an option yet for trying it on another car.

Citrojim,
I'm in Suffolk and if I cannot resolve the problem, I'll take up your kind offer.
I think that I've entered both the ORGA number and VIN correctly. Presumably its just the digits of the ORGA number and 17 characters for the VIN,
I'll check fuses and voltage at the socket tomorrow.
I've tried 3 cables thus far between the Lexia and the car - 2 are square plug to OBDII socket that then link to a converter cable to the 30pin round plug on the Lexia. The other is a square plug to a 30pin round socket which connects directly to the30pin round plug on the Lexia and is only 6" long.

[CitroJim]

I'm in Suffolk and if I cannot resolve the problem, I'll take up your kind offer.

You're more than welcome to...

Yes, just the four digits of the RP/ORGA and the full VIN.

Sounds like the socket itself has a problem. If you want pin-outs and diagrams and so on then give me a shout...

Have you tried it in reverse and checked the Lexia on a known good car?

[tich731]

I have now checked voltage at the socket.

With the ignition fully off I have 12v on pins A1 and G1.
With Ignition on first position there is 12v on A1, 11v on H3, 9.5v on I1, 8.8v on E1 and smaller voltages on many other pins.
With ignition on second position there is 11.5v on A2, 10v on C2, 9v on E2, C1 and I3.

I have checked that these voltages are seen at the Lexia end of the connecting lead.

The error message appears whether or not the USB lead is connected to the laptop. The green light on the Lexia does flash 3 times upon connection and then stays illuminated.

I am unable to try it on another car so am at a loss what to try next.

[CitroJim]

Titch, I'll check the connector pinouts next time I'm up in the study and among the manuals. Looks OK at first glance though but also check the earths on the 30 pin plug too. XMs are notorious for bad earths

I'll tell you the earthed pins later...

[tich731]

Citrojim,
I have just checked for earthing at the socket (and at the Lexia end of the connecting lead) and found these pins to be earthed when the ignition is off - A2, A3 and D3.

Thanks for your advice thus far.

[harryp]

Ah, excuse me for butting in, but I have exactly the same problem on my Xantia 110 HDI. I can in fact read and clear the ABS, but cannot communicate with either the engine ecu or aircon ecu though I can "see" them. I will watch with interest as My "new" lexia is a pig to get started, throwing up many errors.

[Mandrake]

Regarding the Aircon ECU - even on a Lexia that works properly communication with the Aircon ECU in a Xantia is "temperamental" shall we say.

You usually won't get communication with it with the key on but the engine not running, nor after the engine has been running a while. I find what works best is to turn off the engine then start the engine then immediately go to the Aircon ECU via the test by function (not global test) route. If it says no communication with ECU just press enter to try again, sometimes it might take two or three attempts.

My Aircon ECU rarely responds when I try to connect via global test.

[harryp]

Engine ECU is still a problem! I may have to reload as you suggested a while ago. Difficulty is that my laptop wont read the supplied DVD's or the Citroen Service ones recently purchased..... so have to load them onto a "stick". Will have to sort it out. Used it yesterday. Took so many attempts to get it going that I have no idea how!! Think I told it to shut down, and it started. Could not get either of the mentioned ECU's going though. May have been too long with the engine on. Could do with someone close to check the Lexia with and/or the plug! Thanks for your help. Car went through the MOT last week, no problems at all, but I still have the o/s suspension rumble. Will have to get the garage to replace the lower ball joint as I cannot shift it - unless it's the suspension leg; but how do you check that? Well, gutters beckon for the moment! As an aside, have purchased an HDI Exclusive, but that is a project... tape on sun-roof and dehumidifier in, needs suspension pipe, drivers door seal and probably quite a bit more. Well, keeps me off the streets!