P0136 Subaru -

Question

I've gotten a PO 136 code (O2 Sensor, Circuit Bank 1, Sensor 2) intermittently a couple of times in the last two months. I've cleared it, then in a few weeks it reappears. All operations are normal with the exception of a [seemingly] noisier under-vehicle exhaust sound than I recall being normal.

Answer 1

P0136 would be a circuit malfunction If the exhaust is affecting anything it would code a catalytic code. This can be a intermittent malfunction of the 02 sensor itself or the harness to the 02 sensor.