O2 Sensor, Bank 1. Sesnor 1 location

[chumblewot]

I got the dreaded PO135 Code, Bank 1, Sensor One O2 sensor heater circuit malfunction. Can anyone tell me where this sensor is located on a 1999 LC? Also, any thoughts on aftermarket sensors. My dealer warns against them, but they would...

[Frofan]

I just did both of my "before catalytic converter" 02 sensors. Which I BELIEVE is the location 1 sensor. I also believe bank 1 is the same side as the number one (1) cylinder. The oxygen sensors on the LC (and many others) are heated to properly regulate fuel mixture when the engine is not up to normal operating temp. There are actually four oxygen (02) sensors on the LC. two before the cat (catalytic converter)...two after. Get under your truck. Follow the exhaust from front to back. You will find the four wire heated 02 sensor first (before the cat) it sort of looks like a sparkplug sticking out of both exhaust pipes. They are a snap to replace as long as they aren't seized up. There are two after the cat one on each pipe. I am not positive about the location codes...so please verify. I am right about the physical location of the sensors and their ease of replacement. After replacing them (you can get them way cheaper on the net~ oem denso or bosch) you will need the error code reset.

Just buy the needed parts.

Unplug then unscrew.

Put anti seize on new sensor(s)

Reverse procedure

Have error code reset.


Hope this helps,

Frofan