P0421 Mazda 6 Forums

Mazda 6 P0421. Need help with codes p1487 and p0421 for Mazda 6 2004 The P0421 fault code is triggered by the Engine Control Module (ECM) when it detects that the rear HO2S (Heated Oxygen Sensor) value is getting closer to the value of the front HO2S To diagnose and repair the root cause of the P0421 code in your Mazda 6, follow these steps: Verify the code: Use a scan tool to check for the P0421 code and any accompanying codes if present.; Inspect the oxygen sensors: Check the pre- and post-catalytic converter oxygen sensors for signs of damage, and use a scan tool to view their live data.

Unfortunately, the P0421 is a fairly straight forward code, and a fairly common problem The P0421/P0431 is almost never the fault of a faulty O2 sensor

got code p0421 Mazda 6 Forums

As sensors age and reach the end of their lifespan (50,000mi for a 2 lead, 70,000mi for a 3-lead, 100,000mi for a 4 lead) or (0.1V-1.0V response > 300 milliseconds) they. TWC means the catalyst, PCM means the engine computer. This code points to a failing Warm-Up Catalytic Converter

P0421 and P0431 code Mazda 6 Forums. I drive a 2007 Mazda 6, 4-cyl, CA Emissions with over 150,000 miles (I bought it with only 39,000) The P0421 fault code is triggered by the Engine Control Module (ECM) when it detects that the rear HO2S (Heated Oxygen Sensor) value is getting closer to the value of the front HO2S

Mazda 3 purge control valve 911701 P0455 P0421 P0422 YouTube. A P0421 happens when the downstream O2 sensor inverts its signal too quickly (basically matching the upstream O2 sensor) The computer reads this as a catalytic converter that is no longer reacting and just allowing un-catalyzed exhaust to pass by. 2.2M posts 103K members Since 2002 Mazda6club.com is a forum dedicated to the.