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P0420 Diagnostic Trouble Code Discussion for January 2008

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
1996 Subaru Legacy Outback 2.5L Poor Idle Quality, Hesitation, Cuts out, Stall VIN: 4S3BG6854T
P0420: Catalyst Efficiency Below Normal (Bank 1). looking for subaru guru. car came in for oil leak, crank seal actually fell out.when i first started the car it ran horrible for a few moments skipping, not taking gas well and falling on its face then straightened out and ran well. replaced timing belt and al...
January 09, 2008
1996 Subaru Legacy Outback 2.5L Poor Idle Quality, Hesitation, Cuts out, Stall VIN: 4S3BG6854T
P0420: Catalyst Efficiency Below Normal (Bank 1). looking for subaru guru. car came in for oil leak, crank seal actually fell out.when i first started the car it ran horrible for a few moments skipping, not taking gas well and falling on its face then straightened out and ran well. replaced timing belt and al...
January 10, 2008
1999 Honda Accord LX 2.3L Rich VIN: JHMCG5543X
P0420: Catalyst Efficiency Below Threshold (Bank 1). Thank you for your help. We had a code for cat efficiency, and determined we had a faulty cat by monitoring the o2 sensors. That problem is fixed, however, we are concerned about the ltft and stft reading we are getting. We usually do not see fuel trim numbers...
January 24, 2008
2000 Nissan Sentra GXE 1.8L MIL Lamp on VIN: 3N1CB51D2Y
P0420: Catalyst Efficiency Below Normal. ... on. code P0420 is in memory. all datastream seems normal. any ideas? Thanks
January 29, 2008
2001 Toyota Tundra 3.4L MIL Lamp on VIN: 5TBJN32141
P0420: Catalyst Efficiency Below Normal (Bank 1). After running a while the Data for the o2 sensors is backwards. the rear sensor switches moderately while the front sensor stays fairly constant. I unplug the rear sensor and voltage goes to 0, but when I unplug the front sensor the voltage goes to .05 to .10 ...
January 29, 2008
2000 Buick LeSabre Custom 3.8L p0420 VIN: 1G4HR54KIY
P0420: Catalyst System Low Efficiency. ... and check engine light on. replaced catalytic converter because it was plugged. replaced o2 sensors because slow reaction, ran on the rich side. returned a couple times for dieing problem replaced crank sensor. came back another time for bucking and surgin...
January 30, 2008
1998 BMW 528i 2.8L MIL Lamp on VIN: WBADD6327W
P0420: cat. eefciency bank 1. ... see a bmw. car came in a week ago with over heating problem & ses light. fixed coolant leak, which fixed overheating issue. ses was code for engine temp. at home & don't remember code as my lead tech had done repair. cleared code. car gone. week la...
January 31, 2008
2000 Mazda MPV DX 2.5L No Start, MIL Lamp on VIN: JM3LW28G7Y
... would not start. started after ten to fifteen minutes of cranking with fuel pump relay removed and throttle open. codes po420, po134, p1170. po171 & po174 were stored in computer. thanks for your help.
January 31, 2008
1996 Subaru Legacy Outback 2.5L Poor Idle Quality, Hesitation, Cuts out, Stall VIN: 4S3BG6854T
P0420: Catalyst Efficiency Below Normal (Bank 1). looking for subaru guru. car came in for oil leak, crank seal actually fell out.when i first started the car it ran horrible for a few moments skipping, not taking gas well and falling on its face then straightened out and ran well. replaced timing belt and al...
January 09, 2008
1996 Subaru Legacy Outback 2.5L Poor Idle Quality, Hesitation, Cuts out, Stall VIN: 4S3BG6854T
P0420: Catalyst Efficiency Below Normal (Bank 1). looking for subaru guru. car came in for oil leak, crank seal actually fell out.when i first started the car it ran horrible for a few moments skipping, not taking gas well and falling on its face then straightened out and ran well. replaced timing belt and al...
January 10, 2008
1999 Honda Accord LX 2.3L Rich VIN: JHMCG5543X
P0420: Catalyst Efficiency Below Threshold (Bank 1). Thank you for your help. We had a code for cat efficiency, and determined we had a faulty cat by monitoring the o2 sensors. That problem is fixed, however, we are concerned about the ltft and stft reading we are getting. We usually do not see fuel trim numbers...
January 24, 2008
2000 Nissan Sentra GXE 1.8L MIL Lamp on VIN: 3N1CB51D2Y
P0420: Catalyst Efficiency Below Normal. ... on. code P0420 is in memory. all datastream seems normal. any ideas? Thanks
January 29, 2008
2001 Toyota Tundra 3.4L MIL Lamp on VIN: 5TBJN32141
P0420: Catalyst Efficiency Below Normal (Bank 1). After running a while the Data for the o2 sensors is backwards. the rear sensor switches moderately while the front sensor stays fairly constant. I unplug the rear sensor and voltage goes to 0, but when I unplug the front sensor the voltage goes to .05 to .10 ...
January 29, 2008
2000 Buick LeSabre Custom 3.8L p0420 VIN: 1G4HR54KIY
P0420: Catalyst System Low Efficiency. ... and check engine light on. replaced catalytic converter because it was plugged. replaced o2 sensors because slow reaction, ran on the rich side. returned a couple times for dieing problem replaced crank sensor. came back another time for bucking and surgin...
January 30, 2008
1998 BMW 528i 2.8L MIL Lamp on VIN: WBADD6327W
P0420: cat. eefciency bank 1. ... see a bmw. car came in a week ago with over heating problem & ses light. fixed coolant leak, which fixed overheating issue. ses was code for engine temp. at home & don't remember code as my lead tech had done repair. cleared code. car gone. week la...
January 31, 2008
2000 Mazda MPV DX 2.5L No Start, MIL Lamp on VIN: JM3LW28G7Y
... would not start. started after ten to fifteen minutes of cranking with fuel pump relay removed and throttle open. codes po420, po134, p1170. po171 & po174 were stored in computer. thanks for your help.
January 31, 2008