aejeffor

So, Im getting a P0135 error code which means o2 sensor heater circuit sendor 1 bank 1.

It's a new denso 02 sensor that I put on thinking that would fix the error code, but no luck. Even when I reset it with the scan tool, it pops back up the moment I crank the car again. I've even tried leaving the batter disconnected for over an hour. No luck.

I pulled every fuse in the driver cabin box, and every fuse in the engine compartment. All are good.

I checked the connection between the wiring harness from the car, and the o2 sensor plug. Its tight and no loose, frayed, or melted wires.

What else can I try?

skinny_pedal

1. Verify that there is battery voltage when the engine is running to the White wire on the harness side of the air/fuel ratio sensor. If there is good voltage there, then the air/fuel ratio sensor relay and fuses are OK.

2. Next test the heater circuit of the A/F sensor, most A/F sensors have between 0.8 and 4 ohms of resistance, it is always good to check the heater resistance to see if it is open or out of specification. If the heater is open or out of specifications, replace the A/F sensor.

3. If the A/F sensor resistance checks OK, then verify that the Black/White wire back to terminal A10 of the ECM is not open or shorted. Always verify that the connections at the ECM are clean and tight.