[russconde]

2002 Tundra 65K miles. I've had a PO155 (Driver/Front sensor) code for many months and finally have addressed. Dealer replaced BOTH front sensors under the extended warranty. The next day my engine light comes back on and now reads PO136 and PO156, both rear O2 sensors. That seems crazy. Could it be that the rear sensors were also originally bad but only the PO155 code was being logged? Could there be some other factor that is making the ECM generate the 136/156 codes? Obviously the two rear sensors didn't ACTUALLY both fail the day after changing the front sensors. Either they were also bad all along or they are not really bad and something else is amiss.

Thanks,
Russ