usmma2013

Hey guys,
I'm having a problem with my 1994 22re pickup. The ECU is throwing a code 27, which I've learned is the sub-oxygen sensor - the sensor before the cat. I installed a new bosch OE style sensor to no avail, cleared the ECU and after about .5 seconds of running the code is back. Looked around some more for wiring/connection problems and found an extra set of wires for another oxygen sensor. They've been cut and have nothing connected to the connector on the end. I'm thinking maybe I have a cali emissions vehicle with after market exhaust, although it certainly looks like a standard exhaust system. Would a non-cali vehicle still come with the wiring for the second sensor? If it is cali, do I have to weld a new bracket for the second sensor in after the cat or can I trick the ECU somehow?
Thanks in advance guys,
MJK

4Crawler

iTrader: (3)

Yep, 2nd O2 sensor after the cat. That is what the ECU uses to check on the cat. convertor condition and makes sure it is working OK. A muffler shop should be able to weld on a new bung for the 2nd sensor or pick up the cat-back piping from a similar vehicle in a junkyard.

Also, Denso is a better sensor for a Toyota, Bosch seem to cause problems for many folks on Toyota engines.

drmix

Yeah denso is definitely the way to go. I got my 02 sensor for around 40-50 shipped and works perfectly.

Not sure if it will work or not but im thinking you could swap the ecu with a non cali and be good. Im sure someone can chime in and correct me if im wrong

usmma2013

Thanks guys! I have a spare system I will probably cut out the section of pipe with the bung in it and weld it in after the cat. Would there be any harm in hooking up a sensor beforehand to see if the cel clears?
Hopefully getting this fixed will improve my crappy mpg! (14 city and I drive like a grandma!)
Thanks again,
MJK

canyonwaters

How do I go through the pinpoint checks for this code? I am not sure if it is my rear sensor or not and it is so rusted that I highly doubt I will be able to get the rear O2 sensor off? Any advice would be lovely. Thanks

4Crawler

iTrader: (3)

Simple check would be to measure the resistance of the heater circuit for that sensor:
- http://www.4crawler.com/4x4/O2SensorWireColors.html