Hello,
I was hoping for some help here. I had a clutch installed on my 2005 honda s2000 recently. The shop was not very good and left engine mounts, subrame mounts loose, left some connectors unplugged, etc.
I pick up the car and check engine light is on. P0135. This was not on when I gave them the car. I check under car when I got home and the ecu harness for upstream o2 sensor is plugged into the ecu harness for downstream o2 sensor..
The o2 sensors were plugged into each other...
I fixed that, code still in. Then I replaced the upstream sensor, code still in. Then I went thru testing procedure. Resistance in heater circuit on both o2 sensors was not what the manual recommended.
There was 12v on the ecu Harness side as there should be. But the c1 pin on 35p ecu connector is continuous to ground, which seems to mean I have a short.
I checked resistance between ecu harness pins for upstream o2 sensor connector and 3 of them have little to no resistance between each other.
I think this means the harness may be shorted to itself and/or ground? Is it possible the shop messed up my harness somehow?
Thank you in advance

 

The harness wire for the primary O2 sensor may have gotten damaged (e.g., Blk/wht wire or terminal). Also, take a close look at the connector terminals.

 

Thanks for the info, wiring diagram is especially helpful as I couldn't find it

 

hello, sorry for bringing this back up but I was wondering what did you end up finding that was causing the p0135 code? It’s just I too have somewhat of the same issue due to the same mess up by plugging ecu harness to ecu harness except I have a p0141 code which is for secondary o2 heater circuit