O2 Operating Range

[jtmarten]

What is the normal operating range reported on a scan tool of upstream O2 sensors for a '96 K2500 w/7.4, also for fuel trims?

Thanks!

[777stickman]

http://alldatadiy.com/buy/

[Tech II]

Normally large swings from 900mv to 100 mv.....

Fuel trims usually less than 10%, plus or minus....zero % would be a perfect running vehicle, so it will vary slightly above and then slightly below zero....

OBD I, didn't use a %, they used 128 as a base line, and readings would vary slightly above and below the 128....

[jtmarten]

Thanks for the info. Was curious about it because I have one upstream O2 showing ~0.850 and the other showing ~0.08 at idle. I've been getting a bank lean code lately. I'm planning on replacing both upstream sensors.

[j cAT]

Originally Posted by jtmarten

Thanks for the info. Was curious about it because I have one upstream O2 showing ~0.850 and the other showing ~0.08 at idle. I've been getting a bank lean code lately. I'm planning on replacing both upstream sensors.

what you do when the readings are different is swap them . if the problem swaps it is the sensor if it is the same side you got engine problems.

could be vacuum leak.