1992 Audi 80 Question

[S2central.net]

Bit of an open one this... not S2 specific. My brain has run out of ideas on something.

Got this V6Q with an ECU that fails to talk to me. Have good 12V on the black OBD connector and the K/L pins are wired up correctly to the with plug.

Something I noticed when checking the OBD wires is that there is something other than ECU connected to the K-wire, but I am flummoxed as to what it would be. This car is too old for immos & airbags. It also has the older ABS system (with cancel switch) that doesn't have OBD to my knowledge.

What have I missed here ?

I'll probably disconnect the unknown wire - it might be locking out comms on the ECU.

[S2central.net]

Just twigged it myself...

Manual aircon on S2/RS2 does NOT use OBD, but it does exist on the manual aircon of the V6Q - tadah... I remembered something about this just now - the old systems with compressor speed signal support OBD comms, but this doesn't exist on S2/RS2 compressor for some unknown reason.

Just checked AAH aircon schematics and sure enough the K-wire is shown.

[S2central.net]

Bit of an update on this one... I never got VAGCOM to work with this AAH engine, nor an eBay special code reader. TOday I hooked up a proper VAG1551 machine - it talks happily to the aircon unit, but no dialog whatsoever with the engine ECU so the loom must be damaged somewhere. Would be a simple enough job with the breakout box except I don't have £350 spare to buy the only two frickin adapter cables that I don't have in my kit. Never anything simple is it ?

[Rusty]

A good one-man thread effort that Paul

[john881000]

connecter

Hi


Just a thought


could you make a direct line to the engine ecu plug to bypass the cars wiring harness?




cheers
john

[spink]

can you not pull the ecu connector cover off and tap the 2 wires directly off that?

[spink]

lol,its like waiting for a bus (3 answers come at once)

[S2central.net]

Very funny.... Wouldn't be the first time I got caught talking to myself - but thanks guys for taking the bad look of it here

I don't really want to rip into the ECU connectors (dont forget there are four of them) - they are those fragile looking connectors on the 5hitachi ECU - and I am somewhat spoilt by the breakout box making this so easy on Bosch ECUs.

It would be cheaper to make my own breakout panel - if slightly tedious but would serve well for climate control wiring as it uses the same oddball 4 plug affair. Will have to think about it - tis quite time consuming but the upside would be good - plus saving a few hundred quid - unless I get very lucky on eBay.