kaivorth

I have a 2001 Civic EX Coupe Manual with 150k miles.

About a year ago, my car would stop accelerating randomly, and I'd have to pull over, and turn off the car, turn it on, and I'd be set to go. Eventually the car wouldn't start (timing). Turned out to be a crankshaft sensor, found the code for it.

Year later (today) same issue. I'm pulling up the following codes:

Code 1: P0133 O2 Sensor Circuit Response Bank 1 Sensor 1
Code 2: P0420
Code 3: P0420(PD)


It possible that Code 1 is triggering the other 2? I had the P0420 for the last year, maybe its's been caused by Code 1, and code 1 is just now popping up? What O2 sensor should I be looking at?

I know they're other threads similar, but I'm not sure if last years issue has anything to do with these new ones. Thanks all!

lazlong

The dreaded P0420 code. P0420 (bad catalytic convertor) leads to P0133 (bad O2 sensor). Chances are the cat is bad being that you had both codes a year ago, replaced the sensor and now a year later the bad cat has ruined the sensor.

Easiest way to see if the cat is bad is to get under the car and gently knock on the cat. If you hear stuff rattling around then the the cat is bad. Barring that, you'll have to disconnect the resonator and actually look in the cat.

tech8

P0133 is Primary Heated Oxygen Sensor slow response. As this sensor is before the cat, it is unlikely a bad cat will be the cause for the primary H2OS to go bad.

kaivorth

Thanks for the responses. I only had the P0420 for a year. The cat wasn't clogged a year ago, had a back pressure test done. Would a bad primary O2 sensor make a P0420 though?