Problem "ECU not present or not connected"

chicochapman · 25th March 2020, 20:56

Toaf won't talk to my airbag ECU. It reads everything else.
T4 won't connect either as I've been to see BigRuss a couple of times last year.
So I decided to do a bit of continuity testing but first job access the ECU
Fortunately I'd watched Russ do this and more fortunately, the fixing bolts down
by the side of each seat hadn't been replaced by a previous owner, so I was able
to get at it without removing the seats, the whole centre console as well as avoiding
sruggling with the gear knob. Still fiddly to undo the torx fasteners holding the DCU in place
but a bent 1/8thW ring spanner(pictured) came in useful!

To facilitate the point to point testing I made up these leads terminating in a stub
of guitar string of matching diameter.

First up was the K-Bus, testing for continuity between Cavity 7 of the diagnostic
socket(C0040) and cavity 9 of the harness connector (C0256) – all good.
Next tested for12V+ on cavity 5 of the harness connector – all good and then
tested the ground on cavity 6 – all good.
I had a new identical spare unit (YWC 107090) which I fitted but still Toaf wouldn't read it.

So I've still got the annoying airbag warning light and because I can't connect to the DCU,
no means of finding where the fault is.

Any help would be much appreciated.
Malc

25th March 2020, 20:56	#1
chicochapman Avid contributor MG ZT-T Join Date: Feb 2019 Location: Stockport Posts: 134 Thanks: 56 Thanked 22 Times in 20 Posts	Problem "ECU not present or not connected" Toaf won't talk to my airbag ECU. It reads everything else. T4 won't connect either as I've been to see BigRuss a couple of times last year. So I decided to do a bit of continuity testing but first job access the ECU Fortunately I'd watched Russ do this and more fortunately, the fixing bolts down by the side of each seat hadn't been replaced by a previous owner, so I was able to get at it without removing the seats, the whole centre console as well as avoiding sruggling with the gear knob. Still fiddly to undo the torx fasteners holding the DCU in place but a bent 1/8thW ring spanner(pictured) came in useful! To facilitate the point to point testing I made up these leads terminating in a stub of guitar string of matching diameter. First up was the K-Bus, testing for continuity between Cavity 7 of the diagnostic socket(C0040) and cavity 9 of the harness connector (C0256) – all good. Next tested for12V+ on cavity 5 of the harness connector – all good and then tested the ground on cavity 6 – all good. I had a new identical spare unit (YWC 107090) which I fitted but still Toaf wouldn't read it. So I've still got the annoying airbag warning light and because I can't connect to the DCU, no means of finding where the fault is. Any help would be much appreciated. Malc