V6 quattro sedan is calling to me...

**gunman** · 27 January 2009, 20:11

Right, now thats me confused. I bought a decent battery charger on the way home, left it chrging for a couple of hours as all the cranking had discharged it. I put the cam sensor back on the car and did the test as Paul suggests, was getting a constant 11v from + and - and a conatsnt 5 from the signal wire. I connected a bulb up to the - and signal but got no light at all so put the meter back on, still 5v so got the wife to crank it over....5v...3v....5v..... up she fired

.

Now where does that leave me as the diagnostic socket still isnt working? The 2 main factors are;

a; the battery was disconnected for near 24hrs. (was disconnected overnight at the weekend with no effect)

2: the cam sensor was off the car overnight on my computer desk (all nice and warm).

Wouldnt really trust using it at the min in case it dies again but its not easy to find a fault that doesnt present itself when theres no error codes

.

I'm not 100% convinced we tested the right wires lat night as I had it in my head the red/black was signal. Does the diagnostics not working point to ecu?

**S2central.net** · 27 January 2009, 20:27

Well well well.... it could be a few things matey...

G40 sensor getting all nice and cosy in the house for a night... The S2/RS2 ones can be niggly when really cold or really hot.

Could just be a ropey connection in the loom between ECU and G40 - thats the worst thing - I'd give the cable a good few test wiggles and jiggles to see if you can provoke a failure... The engine will likely keep running, but if you can get blink codes working (or better with a MIL in the cluster) then you'll see the fault appear if and when you break the link to G40.

Leaving the battery off is a red herring.

The OBD not working is something else entirely... I do recall there being some dopey issues getting 7A (its Sshitachi MPI also) to work with VAGCOM. I'll see what I can dig up on that.

Look at www.s2central.net and follow the tech info about VAGCOM, then blinkcodes and how to wire up the MIL bulb - there will be a spare cluster lamp for it alright. Its a surprisingly useful lil feature - it lights up on ignition, then goes off when the ECU fires up happy - and hopefully you never see it again until next start cycle - unless you get a fault code.

The really freaky thing about all of this is that digging thru the AAH factory info uncovered some new way of thinking about MAF readings on the S2/RS2 which were previously completely baffling me - I have some theories to test on that, but what a bonus !

**Glen Chamberlain** · 27 January 2009, 20:37

MIL Lamp?

I have tried doing the MIL lamp on my MY92 80 2.8 V6. Problem is the wire at the Black T5 connector is not there? There is a yellow wire there un terminated as described but it doesnt earth the MIL lamp when the ignition on? Thats why i asked for the ECU pin out to try and find it at the ECU and follow it back from there but i couldnt find it?

**S2central.net** · 27 January 2009, 20:51

Well the CA spec V6 had the MIL bulb from factory according to info I have, but I don't have US schematics to check... Just the UK ones.

I doubt the MIL circuit would have used same T5 connector - that would be TOO logical - even for zee Audi electricians.

I'll see what other AAH info I can get (or buy if it comes to that). The ECU pinout shouldn't be hard to create from the schematic now that I know how many pins are at each block. http://www.s2central.net/S2_Schematics/B/B50.PDF

Paul

**S2central.net** · 27 January 2009, 21:12

The best candidate for MIL function on AAH is that yellow wire from B11 that tracks to T5/3 - as opposed to T5/4 where it is on ABY.

Theres a good number of other 'undeclared pins' on the AAH schematic though worthy of investigations.

A1

B7, B8, B12-B14, B16, B19

C6, C9, C14, C16

D14

**Glen Chamberlain** · 27 January 2009, 21:14

Cheers Paul, this forum would be a poorer place without you!

**S2central.net** · 27 January 2009, 21:27

B14, B16, B19 and C9 are used to set coding on the ECU... One of which is for California with EGR enabled (spit) and the MIL bulb... The MIL function looks like its tied to that code... Some ECU reverse engineering required to hack this by looks of things..... Bit more tricky for me on Hitachi MPI. Drat.

Oh and there are two ECU variants (at least) for fun and games too. Anybody see why I like to focus on S2/RS2 stuff - so much pain otehrwise !

**S2central.net** · 27 January 2009, 21:28

Encoding table for control unit no. 8A0 906 266 A (up to 08.92)

Coding
with
without

1010
Manual gearbox
Exhaust gas recirculation system

1111
Manual gearbox, EGR system
Temperature sensor for EGR system

1011
Manual gearbox, EGR system, temperature sensor for EGR system (California version)

1110
Manual gearbox (ECE version)
Lambda probes, solenoid valve 1 for activated charcoal filter system, EGR system

0010
Front wheel drive, automatic gearbox
Exhaust gas recirculation system

0111
Front wheel drive, automatic gearbox, EGR system
Temperature sensor for EGR system

0011
Front wheel drive, automatic gearbox, EGR system, temperature sensor for EGR system (California version)

0110
Front wheel drive, automatic gearbox (ECE version)
Lambda probes, solenoid valve 1 for activated charcoal filter system, EGR system

0000, 0001
0100, 0101
1000, 1001
1100, 1101
Incorrect coding

**S2central.net** · 27 January 2009, 21:30

Encoding table for control unit no. 8A0 906 266 B (08.92 onwards) - this type can be recoded over OBD...

Coding
Gearbox
with
without

000
Manual gearbox
Lambda probes, solenoid valve 1
Exhaust gas recirculation system

001
Automatic gearbox 097
for activated charcoal filter

003
Manual gearbox
Lambda probes, solenoid valve 1 for activated charcoal filter system,

004
Automatic gearbox 097
EGR system,
EGR temperature sensor, speed restriction (USA and California version)

009
Manual gearbox

Lambda probes, solenoid valve 1

010
Automatic gearbox 097
for activated charcoal filter system, EGR system

**S2central.net** · 27 January 2009, 21:36

Here's my suggestion... whatever the ECU flavour - put it into California mode to see if that enables the MIL signal...

It also enables EGR so to avoid a false alarm we need to fake the ECU into thinking its connected. Connect a ~30ohm resistor between ECU pin D14 and 0V.

**S2central.net** · 27 January 2009, 21:47

FYI... ECU is behind glovebox / evaporator on the AAH.

Early Typ A ECU has manual CO adjustment on the MAF
Later Type B ECU has adaptive lambda control with no manual adjustment for CO (funny enough)

**S2central.net** · 27 January 2009, 21:51

Looks like old style MAF had 4-pin connector and newer style MAF only had 3-pins - strange but true apparently.

**gunman** · 27 January 2009, 22:02

Paul, you sure are a wealth of information, but here's the thing, my mate came down again and we fire dthe car up many times but still no diagnostics. He phoned a boy he knows a few mins away and we went down to test his *0, both terminals on the white plug are again around 11v.

Once we came back we fired it again and he had the idea to try and start it without the cam sensor connected (I knew it wouldnt start but humoured him :mischeif

needless to say no start, reconnected the sensor and NO START AGAIN!. tested voltage in again, 11v, tested signal lead out, 5v. Cranked and checked signal lead, steady 5v, no fluctuation like before. This yoke is getting replaced just as soon as I can get a new one. Would have been a lot easier had the diagnostics worked but would have been near impossible without your advice Paul (well, for me to work out anyway).

**S2central.net** · 27 January 2009, 22:13

SOunds like G40 is on the blink alroght, but could equally be the cabling so I'd advise you check on that before changing the sensor only to find its not the root cause...

Make sure the 12V, 5V signals (and earth) are solid on the G40 plug while it gets jiggled to make sure cabling is good...

Only too happy help you fix my car - errrrrrrrrghhh I mean your car - its your car...........

Send me a PM of the chassis number on that thing... The OBD wiring changed in the fusebox from 08.92 (the 1993 model year) and I have seen the odd car that has the K&L pins on the white plug wired up the wrong way round.

Do you have a BLUE OBD plug on that puppy ?

**gunman** · 27 January 2009, 22:22

Make sure the 12V, 5V signals (and earth) are solid on the G40 plug while it gets jiggled to make sure cabling is good...

Jiggled the life out of it and still got good readings, the black socket on the top is broken off so it makes jiggling that much easier.

No blue plug on it, unsell its somewhere I havent seen?

I'll PM you the chassis no. but it will probs be tomorrow.

Thanks again.

mark

V6 quattro sedan is calling to me...

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