i keep getting this cel. isn't the downstream oxygen sensor the one on the cat? i have a '96 btw. i replaced that o2 sensor and still get the 0902 code. why is that? could it be the cat itself? any help would be appreciated.

 

That o2 sensor has a 15A fuse. Did you check that?

 

Isn't it true that if the front 2 o2 sensors are working properly, the rear is only checked on ignition? Therefore an o2 simulator wouldn't provide any performance gains given that there is no CEL (4th gen with y pipe) Correct??

 

well it's not the o2 sensor fuse, i checked that. there shouldn't be any harm just leaving it as is right? i can put up with a cel.

 

0902
Diagnostic Trouble Code 0902 points to a problem with the Rear Heated Oxygen Sensor Heater.

The malfunction is detected when the current in the Oxygen Sensor heater circuit is out of the normal range.
Possible causes include ...
- the electrical harnesses
- the connector
- the Oxygen Sensor heaters

You may test the heater with an ohmmeter. This test is done with the engine off.

Raise the car and support it on sturdy jackstands. Slide under and disconnect the connector. Viewed with the connector latch at the 12 o'clock position, there are four terminals. They are numbered 1-2, top row, right to left and 3-4, bottom row, right to left. Be sure to measure the resistances of the Oxygen Sensor, not the harness which leads to the Engine Control Unit.

Measure the resistance between terminals 1 and 4.
The factory spec is 2.3-4.3 ohms at 77 degrees Fahrenheit.

Measure the resistance between terminals 2 and each of the other terminals.
The reading should be infinity (no connection).

Measure the resistance between terminals 3 and each of the other terminals.
The reading should be infinity (no connection).


Check fuse #31 (15 amps) in the passenger cabin fuse block. That fuse block has three columns of fuses.
The left-most column contains fuses 1 - 11, numbered from bottom to top.
The middle column contains fuses 12 - 26, numbered from bottom to top.
The right-most column contains fuses 27 - 40, numbered from bottom to top.

The numbers are molded into the plastic fuse block. They are not easy to read. A flashlight will be helpful.



You do all that?

 

kevlo, nope didn't do those you mentioned. i guess i got some work to do this weekend. thanks...i'll update the progress.

 

btw, would having a '97 ecu in a '96 matter?

 

Lol yeah. That is the reason.

The 96-97 Have a different rear o2 sensor. 1-2 wires are in different locations.

 

lol...so there's nothing wrong? if everything is ok...thanks.

 

Yeah, don't even worry about it. It wont hurt performance or mpg.