VAG-COM software and 1991 coupe with the 7A 20V engine, Hitachi ECU and Bosch ISV

[cgharibo]

VAG-COM on 1991 coupe 7A 20V cars

---

I have a 1991 coupe with the 7A 20V engine, Hitachi ECU and Bosch ISV.

The Ross-Tech VCDS software (VAG 1551 emulator) can connect to the ECU and check/clear engine codes, perform output tests, read measuring blocks and enter basic settings mode. These are all documented in Bentley.

The software also reads channels 1-15 and I have no idea what those numbers mean. The software also enters ECU adaptation and I don't know what I am doing there either. These areas are not documented in Bentley or anywhere else I checked. Does anyone on this forum have any links or PDFs they can send me so I can get the most out of 15 channels VAG-COM reads, adaptation and my 1991 7A 20V?

Thank you!

[Bowie69]

See my post here, and linked pdf:

https://www.s2forum.com/forum/techni...r-the-b4/page3

[cgharibo]

Very helpful! Thank you!

There are undocumented features to VAG-COM/VCDS software as well. There are 15 channels that give out readings on the 7A that are different than the ten numbers on the measurement blocks. There also seems to be adaptation reset but I cant read the extent of the adaptation.

Does anyone have any information on the 7A engine 15 channels and the adaptation features that are not documented in Bentley?

[varia]

You can see very basic things, like coolant temp, engine speed, icv, etc.
The ecu is very early and primitive, nothing to be excited about it.

With vagcom its easier to check the codes, in case of .... But I never had any major issues with my 8 cq.