Should I replace all four O2 sensors on the truck, the 2 pre-cat sensors, or just the one sensor that is faulty.

Besides the possibly faulty sensor, do you think that an exhaust leak would trigger this code? No other codes are popping up at this time

 

This code if for a "slow reponse" by the offending front sensor. If cleared, it may return in two driving cycles. Should be able to just change the one. See attached from the ECU manual.

However, cost of additional labor, vehicle down time, fear of SWMBO seeing check engine light when you are far away on road warrior business; these are all things that might make replacing the companion front sensor or all of them.

 

Workinghard,

I am a product specialist with Walker Products, a manufacturer and worldwide distributor of oxygen sensors. I would reccomend that you change O2's in pairs, in the case the two pre-cat sensors. Also, a leaking exhuast can definetly set off a code, but not the heater code that you are getting.

 

I agree, do them in pairs, especially at your mileage.