OBDII code=P0420

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Feb 15, 2004 | 04:36 PM

MuffZ28

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Registered User

Joined: Apr 2003

Posts: 62

From: Tulsa,ok

OBDII code=P0420

I keep getting the P0420 code. My book tells me "Catalyst System Efficiency Below Threshold, Left Bank". I've replaced that O2 sensor, but keep getting code after resetting. What could it be?

Feb 15, 2004 | 05:02 PM

96TurboTA

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Joined: May 2003

Posts: 647

From: Brockton, Ma

a bad cat, or no cat.

Feb 18, 2004 | 10:44 AM

quicksilver97ta

Registered User

Joined: Aug 2002

Posts: 662

From: dallas, tx, usa

Just to clarify, you replaced the rear O2 on the left side, not the front O2 sensor on the left side.

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