Can connect to Pektron SCU but not Engine, ABS, Airbag ECU’s

So I have a 2005 MGZR 1.4 and had a go with my new pscan tool. Install all went easy, connected up to the car, flashing LED on the box, but I can only connect to the SCU.

I have tried for at least a couple of hours for Engine, ABS, Airbag connection, but they all seem to do the same thing, after slow initialisation it moves to fast intialise and and it hangs, no connection, can not go back, can not close the app.

I tried all the combinations of engine running, not running, following the screen to switch ignition off and press next, turn ignition on, wait 10 secs etc but no joy

Not sure if there’s a simple explanation of its a quirk but I wanted to get to my fault codes in the engine and check them etc however I am scuppered. I looked through the forum couldn’t find any obvious matches for the problem.

Anyone who can help ? I am I doing something obviously wrong ?

Many Thanks

I only have a wiring diagram for a year 2003 Rover 25 but I suspect it's the same.
All of the ECUs are using the same pin on the diagnostics socket.
If you look at this picture below the interesting thing is that the SCU connects sort of directly to the diagnostic socket whereas all the other ECUs go through header K109.
I suggest that first of all you validate that this is the same for your car (find a wiring diagram) and then locate header K109 and see what's going on.
To confirm my suspicion you would need to locate the appropriate pin the engine ECU connector (for example) and then do a continuity check from the the ECU connector to pin 7 of the diagnostic socket.

Here are the details of the engine ECU connector. You should have a good connection from C0913 pin 58 to pin 7 on the diagnostics socket. Please can you check it with a multimeter.

Thanks for the info. I will take a good look at the car when I get it back (its in the garage at the moment having some bits sorted). Can not find any specific wiring diagrams on line for the MG ZR, but like you say unlikely to be fundamentally different than the 25.

The C0286 connector on the K109 header looks a likely place to look as its common to the engine, abs and airbag. I will do the continuity check from the C0913 pin 58 through to C0040 pin 7 as well.

Locating the connector is probably going to be quite a challenge, I am not familiar at all with ZR’s (or car electrics in general to be honest!), but will take on the challenge !!

It's probably easier to do the connectivity check first. If there is a break in the circuit then it doesn't necessarily mean that it's at the connector. A wire could be damaged anywhere between the diagnostic socket and K109.

Agree, continuity first.

My main point is I can not connect to the Engine or the ABS or the Airbag. So it seemed unlikely they all had broken wires as i guess they come from different parts of the loom. The common point for those 3 systems is the connector C0286 on the K109 Header (and maybe the earth on the K109).

The Pektron SCU I can connect to, comes direct into the port.

It’s a few days before I get the car back, so I need to find some wiring diagrams which are not obvious to find anywhere so far.

Understanding of course if it were the wire coming from the C0286-1 that was broken, it would be common to the 3 systems not communicating.

304202169141

David Aiketgate wrote:

304202169141

Thanks. Yes I did see that. I no longer have any pc’s with a disc drive. Of course I could get an external drive etc etc. but was hoping to find something online. I didn’t want to keep spending money after money for something that maybe available by others. (I’ll keep it in mind if. Don’t locate anything else)

You don't really need the wiring diagram.
We know what pin on the engine ECU connector must connect to pin 7 on the diagnostic socket.
With or without the wiring diagram the solution is the same:-
You need to check that there is connectivity, and if not trace the wires until you find the break in the circuit.

This is the pin that you need to check:-

Thanks car not back for another week, but as soon as it’s back, I will work through it 👍