hey guys, now that i have my evap code fixed. my 98 blazer just threw a p0135(o2 sensor heater malfunction). bank 1 sensor 1. does this mean that my entire o2 sensor is bad or just part of it and will this affect my mpg and driveablility. thanks in advance guys.

 

If the sensor itself is at fault, the whole sensor would need to be changed.

The first thing that I would recommend doing is swapping the two upstream sensors side to side. B1S1 is the driver's side sensor and B2S1 is the passenger side sensor, both of which are ahead of the 'Y' in the y-pipe. Disconnect, remove, and swap them side to side. If the code follows the sensor replace it with another AC Delco sensor. I have had bad experience with just about every other O2 sensor manufacturers when used in GM vehicles. RockAuto.com is a good source for AC Delco parts, or you can look up where the closest AC Delco retailer is from the ACDelco.com website.

 

i hooked up the scanner to it and and the sensors appear to be working properly. they are fluctuating between .1 and .9 as they should. so i believe just the heater portion is bad. it is not always on. just when it is cold outside and on initial start up. so i think the actual sensor is okay. what does that sound like to you guys.

 

O2 sensors need to be quite hot to work properly. With a faulty heater, the PCM will take longer to reach closed loop operation, increasing fuel consumption. Depending on your commute, for short trips, this increased fuel consumption can end up costing more in the long run than replacing the faulty sensor.

The reason I state to swap them side to side is for the possibility that it may be a wiring issue (power or ground).


*Moving to 2nd Gen Tech*