Operating sequence
 

Can anybody please confirm the operating sequence to use the code reader build as above to read the codes - obviously the ignition needs to be on (I assume key position 2) . Do I then just push the big red button for 2 seconds, then release it and wait? Do I need to do anything else? I thought I knew this - but perhaps I don't!

That's basically it, yes.

But as you can see here, it can do a lot more:
https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

Testing the operation of the cooling fan for example.

Thanks but
 

The FAQ (which I had seen) appears to be pretty specific to the box-on-the-transmission-turret diagnostics, and strongly suggests that the detail there is not right for cars with the not-quite-OBD2 socket in the cubbyhole. Indeed it says (and that surely is wrong) that proprietary code readers can be used.

The 240 is a 1988 car, so it had a k-jet system originally. I didn't use either a 940 loom or a complete late 240 loom, either of which would have been easier and quicker than the approach I took given the wonders of hindsight... Ah well. It's a late 240 engine loom mated to an ecu plug for a 940 turbo. The fuel injection and associated wiring has been replicated so there is a white fuel injection relay turning on the fuel pump and a radio suppression relay turning on the injectors.

I didn't wire in an obd connector when I did the wiring originally, but will create something now- will use an easier to get hold of multi plug rather than an obd connector given that I'm not going to be connecting it to an official tool anyway.

So, comments welcomed- as in my previous post I'm currently looking at just wiring in the four wires from the ezk, the ecu, live and ground. I don't have cruise control or abs to worry about.

Cheers,

S.

My homemade OBD box works exactly as per the FAQ, but I must admit I haven't tried the testing functions. Maybe I'll have a go this evening.

Ahhh, in that case, what you've suggested should work fine. If I were you I'd add the light and button somewhere on the dashboard permanently. One of the switch blanks perhaps? There's no point making it removable.

Great, thanks all shall buy some bits and build a box, read through the faq and let you know how I get on.

Permanently wired in button and light is a good idea, the rotary - actually, only needs to be two way- switch can be hidden somewhere with the button and light for the tester.

Shall wire in the engine check light to a dash blank- good suggestion.

Ok, all set- shall buy some bits and do some soldering. Shall let you know...

Cheers,

S.

Yep, sure enough, press the button three times and the radiator fan comes on. Presumably followed by the other things it tests, but they're not so obvious.

http://imagizer.imageshack.us/v2/640...907/klKh8E.jpg

Well, that's the box built... really simple circuit to wire up, thanks for the wiring diagram earlier in the thread. Also got an orange 12V LED panel light that will be fitted in a dashboard blank as a check engine warning light.

Maplins didn't have anything more than 2-core wire in stock, hence the two pieces of 2-core exiting the box - one is for the 12V supply and one is one wire each for the ECU and the EZK.

Not in the same place as the car currently, but might get a chance to install the light and read some codes in the coming week - shall report back :)

It works! Only tried to read the fault codes this evening, didn't try out the other functionality.

Ezk just showed 111, so no faults

Ecu showed

311- no speedo connection. I didn't think this mattered so didn't connect it up, but I found this thread this evening:

http://forums.turbobricks.com/archiv.../t-191366.html

And since I have a speedo late enough to have the spade connector on the back of it to connect to, I'll connect it up to pin 34.

311 - fuel trim too rich or too lean (I know that's it's waaaaay to rich) and suggested fault is wiring to lambda sensor which I can certainly go over and check.

232- fuel to too rich or too lean, suggested fault leaking injector. I don't think this is the case as at the start of this troubleshooting I took the plugs out and they're all ludicrously sooty and black, but uniformly so suggesting that all the injectors would have to be leaking if that was the fault.

I think the fault lies with the lambda sensor or its wiring so shall look at that first.

Cheers :)