UrS4boy

Yesterday I was trying to help someone figure out why their UrS4 wasn't starting and, perhaps more importantly, why he wasn't able to get his code reader to pick up the ECU. We concluded that he didn't have switched power from the S64/115 fuse (yellow fuse holder above the ECU) at the ECU pin T55/27, as per this AAN pin-out diagram:



He checked for power at the S64/115 fuse holder (the yellow one above the ECU). I suggested to him that power comes into the S64/115 as a thick black wire and leaves as a thick black wire with a green stripe, as shown here:



He said that he had switched power (12V) coming into and out of the S64/115. When I asked about power at the ECU in pin T55/27, he said that he couldn't find a thick black wire with a green stripe at the T55 ECU connector. I suggested that it was very likely the thick black/green wire was crimped to several smaller green/black wires in the harness and that he should look for a thin(ner) black/green wire at Pin T55/27.

To make that clearer, I dug out my spare AAN harness and found the S64/115 and the crimp (1 fat wire in, 7 out, 1 towards the ECU connector (for Pin 27) and 6 back into the harness (ALL those go to the COILs - in the white power connector connections (- all 6 are hot with the ignition on, but only 5 actually get used).

To demo the process of checking for continuity, I took this photo. Hopefully he will find the issue, e.g. broken wire, bad factory crimp, etc.

Finding Pin 27 (middle row where 20 = end closest to the harness)





This might help someone here in the future.