: P0155 + P0332 OBD codes

07-05-13, 04:28 PM
After a few days out at Summit Point, I threw OBD codes P0155 (02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)) and P0332 (Knock Sensor 2 Circuit Low Input (Bank 2)) and they keep coming back. I'm trying to think this through before pulling the intake to replace knock sensor 2.

Something tells me this is from a fried wire... but the only damage I can find is months old: to the black loom over the Bank2 Sensor1 O2 extension - the wires inside appear to be fine. I do see some "fresh" melting on my CAGS eliminator but don't think that's related (and I'd have thrown a CAGS code, I think). Does anyone know if either

a bad knock sensor can cause the P0155?
the knock sensor 2 and Bank2 Sensor1 O2 wires run in a common loom? This is what I'm thinking but, like I say, the 02 wires (at least) look fine.

I think the P0155 code is secondary to the P0332 - that's why I'm thinking about "both" before tackling them 1 by 1. Next step for diagnosing P0155 alone is to swap Sensor 1 with Sensor 2 and see if the code moves. I've thrown just P0155 in the past after a day at the track and have been able to clear it and keep it off, no problem.

07-06-13, 08:45 AM
I've noticed that track days eat up my O2 sensors. I'd replace that one and see what happens. It's not that expensive and it's not like you're just throwing parts at it because there is a code for it. There might also be a damaged wire under your intake.

The wires do run together in the engine harness, up the back of the motor (over the bell housing), forward along the driver side fuel rail, across the throttle body, downward near the fuse box, into the fuse box then back across the motor to the PCM inside the driver side front fascia.

You could find the pinouts and wire colors from the service manual and check for opens/shorts from the PCM multiconnectors to the sensor connectors. It takes an engineering degree to follow the manual to the different pages to find all the pinouts and wire colors.

You might find it helpful just to disconnect and reconnect the PCM connectors (with the battery disconnected).