Code 21, O2 #1, Is It The RH Or LH Sensor

[1FZj80]

Anyone know if code 21 for the #1 O2 sensor is the RH or LH side. Truck is '94 1FZJ80.

Thanks,
Mark

 

[CJF]

#1 refers to the sensor for cylinders 1-3. (#2 is for cylinders 4-6.)

So, follow the front downpipe and see where it ends up.

Oh, and most folks replace both sensors at the same time.

Curtis

 

[sdbrassfield]

Heed the advice given you above ^ ^ ^