Hey guys maybe you can shead some light on my problem. I have a 98 Z28. My check engine light came on three days ago. I scaned the code and it came up as P0135 (Oxygen sensor heater circuit malfunction pre-converter sensor, left bank). I have long tube headers with the off road Y-pipe. I have Casper o2 simulators. I also had the car tuned a year ago and the guy that tuned it said he deleted the o2 sensor codes so I dont even need simulators but I left them on anyways. I've had this set up for about a year now and never had a check engine light. I checked all the wires and they look intacted and pulled the o2 sensors wiped a little carbon build up off them but not much. The o2 simulators have these red lights on them that blink off and on when the car is on, not sure if thats normal or what. Any info is much appreciated. Thanks

 

The code is for the pre-cat sensor on the driver's side. When you delete O2 sensors and substitute "sims", you only do it to the after-cat sensors. If they delete the codes, they only do it for the after-cat sensors.

The code for a heater circuit failure has nothing to do with whether the sensors are clean, so wiping them off doesn't help anything. There's a possibility that the heater in the O2 sensor has burned out. To check, swap the pre-cat sensors side-to-side. If the code follows the sensor, its a sensor problem. If the code stays on the driver's side, its a wiring problem.