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P0420 Diagnostic Trouble Code Discussion for March 2011

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2003 Jaguar S-Type 4.2L Excessive Emissions, Poor Idle Quality, Misfire VIN: SAJEA01U03
P0420: Catalyst efficiency. Keep in mind this is a new used car for a customer that bought the vehicle in this condition, so I have no history of when/what symptoms started. Vehicle was brought in with restricted performance light on, rough idle condition, and a rubbed through radiator h...
March 01, 2011
2003 Pontiac Vibe 1.8L Misfire, MIL Lamp on VIN: 5Y25M628X3
P0420: Catalyst System Low Efficiency. has anyone run into a problem that will cause multiple coil and or plug failures ?? powers and grounds are good . is there a TSB that i can't find ?? Misfire seems to move from cyl to cyl.Possible injector or regulator issue ?? Any help would be appreciated !
March 04, 2011
2000 Volkswagen Jetta GLS 2.8L Poor Idle Quality, Cuts out, Stall, MIL Lamp on VIN: 3VWSE29MOY
P0420: Catalytic efficiency. Car barely starts/idles/runs, will start up and idle high and smooth for 1-10 seconds, then drops to 4-500rpm. No power in gear, was able to get runnability back by unplugging the air flow meter. Still runs in throttle limp mode, smooth but only barely opens t...
March 04, 2011
2000 Volkswagen Jetta GLS 2.8L Poor Idle Quality, Cuts out, Stall, MIL Lamp on VIN: 3VWSE29MOY
P0420: Catalytic efficiency. Car barely starts/idles/runs, will start up and idle high and smooth for 1-10 seconds, then drops to 4-500rpm. No power in gear, was able to get runnability back by unplugging the air flow meter. Still runs in throttle limp mode, smooth but only barely opens t...
March 07, 2011
2001 Subaru Forester S 2.5L MIL Lamp on VIN: JF1SF65591
P0420: Catalyst Efficiency Below Normal (Bank 1). This car is back with same code and not really sure where to go. Front A/F sensor is at 1.500 and rear appears to be working o.k. I unplugged A/F and still had 1.500 on the scan tool.Snap throttle and the A/F may drop to around 1.200 and goes up to 2.800 and t...
March 14, 2011
2000 Toyota 4Runner Limited 3.4L Excessive Emissions, MIL Lamp on VIN: JT3HN87R1Y
P0420: Catalyst Efficiency Below Normal (Bank 1). Replaced cat with Bosal # 099-211. Has a "pre cat" also,cant believe the rear would not be enough alone to reduce emmisions. Having a hard time locating the correct procedure to make sure the AF ratio sensor is operating properly. LT andST fuel trim va...
March 14, 2011
2005 Toyota Tacoma 2.7L Misfire, MIL Lamp on VIN: 5TEUX42N25
P0420: Catalyst Efficiency Below Normal (Bank 1). ... starts and never comes back once the engine approaches operating temp. Freeze frame data is the following (I recorded this when vehicle first arrived at shop): P0303, RPM 1610, Calc Load 31%, Injector (ms) 5.12, MAF 13.43 g/s, Vehicle speed 0 MPH, Coolant ...
March 14, 2011
2003 Jaguar S-Type 4.2L Excessive Emissions, Poor Idle Quality, Misfire VIN: SAJEA01U03
P0420: Catalyst efficiency. Keep in mind this is a new used car for a customer that bought the vehicle in this condition, so I have no history of when/what symptoms started. Vehicle was brought in with restricted performance light on, rough idle condition, and a rubbed through radiator h...
March 16, 2011
2005 Subaru Legacy i 2.5L Hesitation, Cuts out, Stall VIN: 4S4BP61C15
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer came in and complaint was after everytime they put fuel in the vehicle, it does not want to start. Vehicle will stall, cut out and sputter. Customer indicates if he holds down gas pedal vehicle will eventually start. I cleaned canister filter, blew ou...
March 16, 2011
2001 Subaru Forester S 2.5L MIL Lamp on VIN: JF1SF65591
P0420: Catalyst Efficiency Below Normal (Bank 1). This car is back with same code and not really sure where to go. Front A/F sensor is at 1.500 and rear appears to be working o.k. I unplugged A/F and still had 1.500 on the scan tool.Snap throttle and the A/F may drop to around 1.200 and goes up to 2.800 and t...
March 20, 2011
1998 Dodge Stratus ES 2.5L No Start, Cuts out VIN: 1B3EJ56H4W
P0420: Catalyst Efficiency Below Normal. ... home from work at hwys speeds in the rain a couple weeks ago and it died right on the side of the road. Cranked several times and wouldn't start. He could hear the fuel pump running when attempting to start. (pump has been replaced with one from the dealer...
March 24, 2011
1998 Dodge Stratus ES 2.5L No Start, Cuts out VIN: 1B3EJ56H4W
P0420: Catalyst Efficiency Below Normal. ... home from work at hwys speeds in the rain a couple weeks ago and it died right on the side of the road. Cranked several times and wouldn't start. He could hear the fuel pump running when attempting to start. (pump has been replaced with one from the dealer...
March 26, 2011
2000 Toyota Camry LE 2.2L MIL Lamp on VIN: 4T1BG22K3Y
P0420: Catalyst Efficiency Below Normal (Bank 1). hi guys, hopefully some toyota guys can shed some light for me. i have this camry, set code a few years back (2 years 8 months) replaced converter, its been fine since. came back recently with another 420 code. checked readings on 02 sensor and i can see its b...
March 30, 2011