940 Diagnostic socket (imitation OBDII)

[niloc]

I'm going to make myself a 940 diagnostic reader, but would like to enquire as to which systems are connected to which pins?
What I mean is: which pin is for ABS, which for SRS, etc
I already know pin 1 and pin 3

[gpl1968]

You must be telepathic as I have just finished a diagram for the very thing.


The only pins used (on my car at least) are as per the diagram and Pin 7, which seems to be the main data bus from the ecu.
You cannot access SRS codes this way.
I bought the OBD connector from ECUfix.com

[stegreg]

I bought an "obd reader" off ebay, only cost £25 including the postage! and it reads virtually any car on the market, no problem. But if you are an electronics "whizz", then you beat me hands down [ha ha].

[gpl1968]

Originally Posted by stegreg

I bought an "obd reader" off ebay, only cost £25 including the postage! and it reads virtually any car on the market, no problem. But if you are an electronics "whizz", then you beat me hands down [ha ha].

But does it work on the late model 940 which is not OBD II compliant?
Maybe you could enlighten us as to the make and model of your reader and which fault codes it can read on the 940 (assuming you have actually tested it on a 940).
The reader I initially bought (Sealey VS8700) certainly couldn't communicate with the car.
I'm definately not an electronics whizz, in fact I just adapted designs already available in this forum for my reader.

[stegreg]

My reader checks for both obd1 AND 2 versions.
YES I have tried it on my 1995 940 and YES it reads for fault codes, but as yet, my own car has no fault codes for me to read...........................

i am unable to let you know name of ready at moment, as a freind has borrowed it to read their own car fault codes.
I admit it was purchased from a company in hong kong, but dont knock them, as what does not have a foreign circuit board in these days, as who needs to really pay for a designer label on a working piece of kit?

the only thing I found it would not do, was reset service lights, thats all,but being as my cars ive owned dont have need for this, it hasnt been a problem.

[niloc]

To test if it wil actually read codes off the 940, disconnect the air flow never with the engine running. Leave it disconnected, then test for codes.

[stevieturbo]

Originally Posted by gpl1968

You must be telepathic as I have just finished a diagram for the very thing.


The only pins used (on my car at least) are as per the diagram and Pin 7, which seems to be the main data bus from the ecu.
You cannot access SRS codes this way.
I bought the OBD connector from ECUfix.com

Maybe a silly question. But I assume the push switch is to activate the code reading sequence ?

ie push and it starts ? Or do you need to hold it ? Can you clear codes ? etc

Must the lamp be an LED or any form of lamp

[gpl1968]

Originally Posted by stevieturbo

Maybe a silly question. But I assume the push switch is to activate the code reading sequence ?

ie push and it starts ? Or do you need to hold it ? Can you clear codes ? etc

Must the lamp be an LED or any form of lamp

Yes the push button starts the process. It works in the same way as with the OBD box that was in the engine bay of earlier 940s. Just follow the instructions in the FAQ.

I believe it has to be an LED to make the circuit work as it only allows current to flow in one direction (I suppose you could use a bulb and an appropriately rated diode, but that would be even more complex).
if you get a 12v rated LED you are also saved the task of adding resistors in series to protest the LED.

I made a parts list for an earlier posing. If it helps here it is:

Maplin
Small Narrow Box-------FT31J----£1.59
Rotary SW12B----------FF73Q----£1.79
Grn Mom Push Switch---N02AR----£1.99
12V Orn Plas Pan LED---N03BB----£2.19
Multi-Core 9-Way-------XR27E----£2.54
Knob RN15 Red---------FE76H----£0.79
Open Grommet 0705----QT93B----£1.79

ECUfix.com
OBDII Plug--------J1962 16-Pin Male----£2.49
Delivery--------------------------------£3.50 approx

Apart from the OBDII plug, which I found online, The rest of the parts came from Maplin.
I just found a shop assistant and we went through my rough list. My final choice was dictated by what was in stock as mush as aesthetics.
I could probably have used cheaper components and got a similar result.

[stevieturbo]

Ok cheers.

Just decided to order a 16 pin breakout box. Will adapt it for the lead. Means it can serve 2 purposes, and the OBD cable itself is a fully moulded plug etc. Hate soldering those fiddly connectors.

Should have switches and LED's here anyway, so main one will be the multi position rotary switch and an enclosure.

Hopefully the ABS problem will be a cheap fix

Have to say though, given the simplicity of the reader, I'm surprised that even Autodata says special equipment is required to read the ABS codes on these cars without the underbonnet DLC connector.
It really gives very little information at all.

Also quite shocked at the simplicity ( or crudeness ) of the injection system fitted to these cars lol

Thanks

[davebslater(uk)]

ive just been to maplins too....