Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for July 2010

Catalyst Efficiency Below Normal (Bank 1)

Note: This is a professional automotive technician's resource.
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2000 Infiniti QX4 3.3L Poor Idle Quality, Stall VIN: JNRDR09Y71
P0420: Catalyst Efficiency Below Normal (Bank 1). Hey there infinti techs i have a nice problem for you. Vehicle was towed in complaining it stalled when the customer was getting off the freeway. When we got the vehicle we started it, revs up to about 1000rpm and then dies. vehicle had codes for mass air flow...
July 01, 2010
2001 Volkswagen Golf GL 2.0L Misfire, MIL Lamp on VIN: 9BWGT61J71
P0420: Catalyst System Bank 1 Efficiency Below Threshold. Of course, this is a relatives car. Tried another new MAF sensor. Same thing. We are at a loss on this. It does it on first start, stops after a few minutes.
July 17, 2010
2000 Mazda Miata 1.8L MIL Lamp on VIN: JM1NB3535Y
P0420: Catalyst Efficiency Below Normal (Bank 1). ... comes on when it rains, coils were replaced about 6 months ago at another shop, when i scanned the car found misfire on #3, replaced plug wires with dealer part, customer picked up car and called back a day later stating that mls on, scaned and found p0420...
July 20, 2010
1997 BMW 318i 1.9L MIL Lamp on VIN: WBACC9328U
P0420: Cat efficency. ... come in severla times since last October with a P0420 I put 4 cats in and the last time in I put in a themostat it was not getting up to operating temp. It does need plugs. The cats keep rattling I put in afer market cats. I ran it with my scanner and the ...
July 23, 2010