Hello.

I was following the instructions on this site (Part 1 -P0135, P0155 -Upstream O2 Sensor Test (2003-2005 GM 4.8L, 5.3L, 6.0L)) to test my O2 sensor but I'm not getting exactly what they describe.

The DTC is P0135 which is supposed to be the driver side PRE-cat O2 sensor. I confirmed 12v and ground to sensor and then tested OHMS. The result was 15.5 k OHMS - NOT OL. The new sensor I got in case needed tested at 5 OHMS (no little "k" before the omega symbol for OHMS).

Is this just a sensor not completely bad yet or what?

Thanks

 

If your new one is reading 5 ohms and the suspect one is reading 15.5K ohms the old one is bad... that K stands for 1000... so it means there is very high resistance like nearly being open....

see the attached chart