I'm almost ready to BAR my 2000 GSR in my 2000 Civic hatch. The last parts I installed today were the Magnaflow CA complaint OBD2 CAT and the secondary o2 sensor. However, I ran into some trouble. After bolting up the CAT and the downstream o2 sensor, I got a CEL for the secondary o2. After resetting the ECU, the light comes back on almost immediately. I'm sure the wiring is correct since I bought a universal BOSCH unit and had to solder the wiring to an existing pigtail connector I had laying around. Any ideas? CAT is brand new and so is the secondary o2 sensor.

 

sounds like its wired wrong try unpluging it see it the code comes back right away . i saw an electrical engineer wire an o2 wrong.

 

and bosch blows big ***** when it comes to hondas and o2.

 

This is exactly why I don't like universol o2's

Double check the wires

 

What engine harness are you using, how do you have it wired? Whats the DTC?

 

Here's exactly how I wired according to OBD2b Civic harness diagram (since I"m using the Engine harness from my 2000 Civic).

BOSCH -----> HONDA SECONDARY O2 CONNECTOR

(SIGNAL) Black ----> White (Sensor Heater O2 Signal (SH02S)
(GROUND) Grey ----> Green (Sensor Ground (SG2)
(HEATER) White ---> Black (Secondary Heater 02 Control (S02HTC)
(HEATER) White ---> Black (Power Source 1 (1GP1)

I just checked the entire circuit today and there is continuity going through the entire o2 circuit, to ECU as well....so wires are good. I'm not really sure where to go from here. I'm sure I did the wiring correctly, unless someone can point out something that might be wrong with what I posted above. Thanks, everyone, I greatly appreciate the help.

 

Maybe the o2's bad? My friends bosch was bad straight of the box.

Maybe try swaping with a freind or something?

 

yeah it crossed my mind that it could jsut be bad out of hte box. Can't I just swap in the primary one just to test to see if its working and whether it will throw a code, or are the downstream and upstream different?

 

bump for some more ideas

 

what is the dtc ? do you have resistance on the 2 white wire's - ref voltage power for heater circuit ?

 

Bad O2 sensor from the box. We had power going to the heater wires and there was continuity, decided to just change the O2 sensor and exchange it for another one, it works now -_-. Stupid Bosch, at least the 2nd one works now. Thanks for all the help, everyone.

 

Glad to hear that

 

^ NO....thank YOU hahaha. It did cross my mind the O2 could be bad from the box, but didn't think too much of it unitl you mentioned it. The voltage signal from the o2 sensor in the first one was reading high at 1.2 volts. The second one read below 1 Volt, at .460-.600, so within operating range. After I saw the voltage reading from the second one in the correct range, I reset the ECU, and it works now. Lets just hope BAR goes well, I will def post an update with BAR soon to see whats up.

 

No problem lol, That would be cool, im interested to know when it passes.