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P0420 Diagnostic Trouble Code Discussion for April 2007

Catalyst Efficiency Below Normal (Bank 1)

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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
1998 Toyota Sienna CE 3.0L MIL Lamp on VIN: OT3ZF13C6W
P0420: Catalyst Efficiency Below Normal (Bank 1). ... , I really like your site, you are doing a great job : Here is my problem ,The check engine is on , P0420 catalytic efficiency low bank # 1.I changed all the oxygen sensors and the catalytic converter the first time,2 weeks later it came back with the same...
April 05, 2007
2000 Subaru Forester L 2.5L MIL Lamp on VIN: JF15F6359Y
P0420: Catalyst Efficiency Below Normal (Bank 1). This vehicle has been in to us about six times over the last six months with the same problem. Runs ok but MIL light comes on and goes off intermittently. Always has to same inefficient converter code. Sometimes MIL stays off for a month only to reappear again...
April 11, 2007
2002 Volkswagen Golf GTI 1.8T 1.8L MIL Lamp on VIN: 9BWDE61J82
P0420: Cat efficiency. ... a p0420 code. On test drive cold the car boggs. After warm up it's ok. Also the temp light is flashing. I cleaned the connector and have had no problem with the light since. The frt o2 reads @1.5v and rhe rear @.6-.7. Any suggestions? Thanks in advance
April 11, 2007