MG & Rover - XPower Forums banner

Car not communicating with any computer, what could the prob be?

1649 Views 11 Replies 9 Participants Last post by  dizmo
Hey guys iv been having a problem getting the car to talk to a T4 or any other type of computer. Does anyone have a clue of what the problem could be and how i might get it to talk. I really need some advice on this so if anyone has come across this problem i would be very grateful of some wise words.

Cheers D
1 - 12 of 12 Posts
Sounds like ECU failure to me. Been through any deep water lately?
Sometimes MG's will talk to one make of code reader but not others the blue ZR i have now wont talk to Chargers reader but will talk to my mates
Had the same issue with mine recently. A coil pack went (2 days before the head gasket went!) and neither the RAC or the garage could talk to the ECU and said, "Some do and some don't"
Sounds like ECU failure to me. Been through any deep water lately?
I think if the ECU had failed there would be more serious symptoms than the OBD2 port not allowing the ECU to communicate with a T4 computer.
right firstly are they independantly powered computers or is the power coming from the obd port, there is a fuse for them if i remember right, i also remember someone saying to me that mg had a bad batch of cars where the obd was not wired up corectly, ie 2 of the wires where in the wrong location however to get to being at least 5 and never being on a computer is suspect to me, have you tried turning ignition on and off for at least 15 seconds before trying, you can also try disconnecting the battery for a period of around half an hour to try resetting, if you can then id be tempted to start tracing wires and looking at the connections going into the ecu for signs of chaffing, water ingress at connectors and corosion
the wires do chafe at the bracket going into the ecu where the loom rests on the bracket, just bend the bracket out the way and inspect the wiring, youll see it as euther blue marks or black burning marks , what is the car doing for it to need to go on the diagnostics for
See less See more
Hey guys iv been having a problem getting the car to talk to a T4 or any other type of computer. Does anyone have a clue of what the problem could be and how i might get it to talk. I really need some advice on this so if anyone has come across this problem i would be very grateful of some wise words.

Cheers D
You could try giving us a call. We are in North Kent so possibly not too far away,
www.mgr-service.com
01634 388999.
right firstly are they independantly powered computers or is the power coming from the obd port, there is a fuse for them if i remember right, i also remember someone saying to me that mg had a bad batch of cars where the obd was not wired up corectly, ie 2 of the wires where in the wrong location however to get to being at least 5 and never being on a computer is suspect to me, have you tried turning ignition on and off for at least 15 seconds before trying, you can also try disconnecting the battery for a period of around half an hour to try resetting, if you can then id be tempted to start tracing wires and looking at the connections going into the ecu for signs of chaffing, water ingress at connectors and corosion
the wires do chafe at the bracket going into the ecu where the loom rests on the bracket, just bend the bracket out the way and inspect the wiring, youll see it as euther blue marks or black burning marks , what is the car doing for it to need to go on the diagnostics for
The computers I have plugged into have all been externally powered. the reason i need a diagnostic was initially to reset the srs light, the car is behaving normally. I just need assurance that i can get in to the cars ecu for any future problems. if the ecu had failed what problems night i be seeing?

Its interesting what you say about a batch not being wired correctly because its just like the car is not talking at all. would you know which wires might need switching over? Im going to have a look at the wiring this afternoon to see if i can see some wear and tear.

Andy, what did you do when your cars ecu could not be read?

Could it be that the readers im using are just not compatible with the car, would anyone know if the zs is known for being reader specific at all? Cheers D
Had few times with the Modus system we use where its taken a few times to get the computer and ECU to start communicating but never failed. If the car has some non standard tunes then T4 will not read it.

If its still playing up we now have the facility to get the original spec software engineer and hardware to get into any MEMS 3 system and do anything to it.
i dunno if it is that the wrong wiring and i dunno what it was, ma dad had mentioned it befoire i was even in the trade, the chance of it not being on any computer for its whole life is remote id think
have the ignition turned off, connect the blue t4 connector, turn the ignition, n also check the obd port isnt fused, if it was a codereader n it was lighting up off the cars power it should be okay.
Could it be that the readers im using are just not compatible with the car, would anyone know if the zs is known for being reader specific at all? Cheers D
Now if you were just using normal readers then there can be problems as rover wired one of the wires to a different pin. Pin 7 rings a bell but I can't remember. There is some threads on here about it. Basically you will need one that is self switchable or wired particularly for rovers.

However, you say its been on a T4 and won't talk to that either, so that confuses me tbh.
Checked the wiring all seems to be fine, i think a trip to a mg specialist is requiered!
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top