Slt club CAB, just had both O2 sensors replace

ANONYMOUS

MEMBER
1999 DODGE DAKOTA
83,000 MILES

Slt club cab, just had both o2 sensors replace. Getting 22 mpg combined, starts and runs fine. Check engine light comes on shortly after reset. Code p0420 has come up twice. Eight different fixes with five different causes. I can't afford wholesale guessing for fix. Where would you think the problem is? Thank you! Ron

Tuesday, April 2nd, 2013 AT 7:54 PM

1 Reply

CARADIODOC

MECHANIC
34,206 POSTS

P0420 � Catalyst System Efficiency Below Threshold (Bank 1)

Which engine do you have? If it's a V-8 you have four oxygen sensors, two in front of the catalytic converters and two after to monitor their efficiency. Those are the "messengers". You don't replace them because you don't like the message. The code is telling you to diagnose why the catalytic converter isn't doing its job. Fault codes never say to replace parts, but about half the time that is what the diagnosis will show is necessary.

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Tuesday, April 2nd, 2013 AT 8:07 PM