Vag - Com Scanning: 1991 200 20V
Can you help us trouble shoot this car?
John has a hesitation:
"Check eng light is OK.
If I disconnect the ecu and plug it back in the light comes on for a sec.
Had a Vag-com on it last week (thanks Scott from Boston) and
it pulled codes just a couple times out of about 20 times.
I managed to get a 2231 code out of it the other day but can't pull any more codes.
Car has a stumble at 3500-5000 rpm. In boost, out of boost, hot, cold.
All sensors check out. Do I have a bad ECU?"
I was able to communicate and pull codes (No DTC's) it said:
with Vag-Com a few times. I'd get the "Motor" controller:
Most other times there was "no response from controller."
Hex-Com connector would go green, yellow, green, yellow then "no response"
If the data or controller was logged/read, it would blink red-ish then display data.
Full-scan of the car would produce no DTC's (fault codes)
although the menu said "may not be communicating with controller....."
I could occasionally, by restarting Vag-Com - version 303.1
or his unplugging and reconnecting the ECU harness, get these measuring blocks to work:
Don't worry, power (by key) & Vag-Com was disconnected each ECU connect.
Block 1 is temp
Block 2: okay Block 3 RPM? Okay.
Block 3,4,5,6 all were 1/2 the 120 or so value Bentley lists. This points towards ISV & related.
Blocks 8 & 9 are O2. Again these values were supposed to be 120 or so.
Block 10 supposed to be between 35 & 37. OKAY.
Vag-Com on really old Laptop with super slow, like Audi likes, baud rate.
Offical 2x2 ugly cable. Hex-Com
able to pull codes and monitor Engine Channel 1, measuring blocks at: "000" occassionally.
Worked well as a test on another 200 20v in the driveway.
Codes (extrapolated data from Engine 1 as the Vag-Com could talk to the
"controller"/"motor", but wouldn't register a
fault code (DTC)).
Channel "000" were O2 sensor readings flat & steady low 15 & 7 in fields/channels 8 & 9
and channels 4,5,6 were 1/2 the 120 or so value they needed to be 57. 60 -ish.
this leads towards the ISV (air leak). He
checked this and carb cleaned the ISV valve.
Check the Bentley Volume 1, reference tables in trouble shooting,
in the back: D2-Page 440 for chart for above fields of data.
Car runs and drives except for the hesitation described above.