Hello all,

Every once in a while (seems like when it rains.. and it rains alot on the wet coast of Canada) my 1997 F-150 with the 4.2 V-6 (not the original engine-a Ford Quality Renewal engine) throws on the check engine light. Check the code and PO 135 - O2 sensor heater circuit malfunction (Bank 1, sensor 1) and PO 155 (O2 sensor heater circuit malfunction (Bank 2, sensor 1) comes up. Ignore the light for a few trips and it turns itself off.

Now the questions...
Is the sensor heater a part of the O2 sensor?

Need I worry about this since the check engine light resets itself when things dry out?

Is there a way of sealing the sensor better?

Thanks for your help!

Cheers,
Roy in Mission, B.C.
Canada, eh?

 

i would replace the two front o2 sensors and call it a day.

JH

 

I would also change both upstream O2 Sensors. The rain probably isn't doing anything to the sensors, it is probably the humidity.

 

Trying to avoid replacing them. Looking at over $200 for both from Ford, $120 from the local jobber shops. ouch!


Roy in Mission, BC

 

I got both upstream sensors from advance auto parts for 52.00 each. They were bosch and he been on my truck for many weeks without any problem. Even came with anti-seeze on them.