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P0420 Diagnostic Trouble Code Discussion for June 2010

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Subaru Outback 2.5L No Start VIN: 4S3BH675X2
P0420: Catalyst Efficiency Below Normal (Bank 1). Monday: Car was hard to start and seemed to behaved like a flooded car. Finally started after charging batt. Moved into the shop. Tuesday: Went on to replace thermostat. Wed.: Subsequently replaced the rad. Now it will not start. Coughs out of the intake and s...
June 09, 2010
2005 Pontiac Grand Prix 3.8L MIL Lamp on VIN: 2G2WP52205
P0420: Catalyst System Low Efficiency (Bank 1). Customer brought in the car with a check engine light on, po420, we thermal tested the cat & found a 30 degree rise in temp, front to back, replaced the converter, roadtested and the code came back within 20 miles, we monitored the o2 sensors and found a g...
June 14, 2010
2001 Nissan Sentra GXE 1.8L Poor Idle Quality, Stall, MIL Lamp on VIN: 3N1CB51D71
P0420: Catalyst Efficiency Below Normal. Hi every one, Vehicle described above has stalling problem at Idle in drive. When idling in drive seem like its starving from fuel. scantool oxygen sensor both banks goes flat line (leas than 100 mV Lean)when idle in drive. I asumed that less fuel , induced pr...
June 16, 2010
2000 Honda Odyssey EX 3.5L MIL Lamp on VIN: 2HKRL1860Y
P0420: Catalyst Efficiency Below Threshold (Bank 1). Customer complained his TCS light comes on- Honda told him to ignore MIL (!). I have tried scanning with different tools, tried Identifix- finally got a code 31 in TCS/ABS, identified as communication failure between TCS and PCM. also got old codes from ABS, d...
June 23, 2010
2001 Volvo V40 1.9L MIL Lamp on VIN: YV1VW29581
P0420: catalyst efficiency below threshold. This car keeps setting p0420 code. While monitoring the upstream and downstream sensors the scope pattern is pretty much identical. Converter - right? The downstream sensor is right after the front converter and there is some distance between the downstream se...
June 25, 2010
2001 Buick Century Limited 3.1L Hesitation, Surge, MIL Lamp on VIN: 2G4WY55J31
P0420: Catalyst System Low Efficiency. Vehicle came in with check engine lamp on and the complaint of hesitation and lack of power only when engine is cold. As soon as the engine reaches opperating temp. the symptoms vanish and the car runs great and has lots of power. Tried replacing mass air flow...
June 26, 2010
2001 Buick Century Limited 3.1L Hesitation, Surge, MIL Lamp on VIN: 2G4WY55J31
P0420: Catalyst System Low Efficiency. Vehicle came in with check engine lamp on and the complaint of hesitation and lack of power only when engine is cold. As soon as the engine reaches opperating temp. the symptoms vanish and the car runs great and has lots of power. Tried replacing mass air flow...
June 29, 2010
1997 Buick Century Limited 3.1L Hesitation, Surge, Cuts out, Stall, Misfire VIN: 2G4WY52M7V
P0420: Catalyst System Low Efficiency (Bank 1). Good afternoon all. I've got me a little gem that has reduced me to throwing parts at it. What it's doing is it bucks and backfires when moderate throttle is applied and then it'll do it at very little throttle and somtimes at idle. Then it becomes grey diffic...
June 30, 2010
2002 Subaru Outback 2.5L No Start VIN: 4S3BH675X2
P0420: Catalyst Efficiency Below Normal (Bank 1). Monday: Car was hard to start and seemed to behaved like a flooded car. Finally started after charging batt. Moved into the shop. Tuesday: Went on to replace thermostat. Wed.: Subsequently replaced the rad. Now it will not start. Coughs out of the intake and s...
June 09, 2010
2005 Pontiac Grand Prix 3.8L MIL Lamp on VIN: 2G2WP52205
P0420: Catalyst System Low Efficiency (Bank 1). Customer brought in the car with a check engine light on, po420, we thermal tested the cat & found a 30 degree rise in temp, front to back, replaced the converter, roadtested and the code came back within 20 miles, we monitored the o2 sensors and found a g...
June 14, 2010
2001 Nissan Sentra GXE 1.8L Poor Idle Quality, Stall, MIL Lamp on VIN: 3N1CB51D71
P0420: Catalyst Efficiency Below Normal. Hi every one, Vehicle described above has stalling problem at Idle in drive. When idling in drive seem like its starving from fuel. scantool oxygen sensor both banks goes flat line (leas than 100 mV Lean)when idle in drive. I asumed that less fuel , induced pr...
June 16, 2010
2000 Honda Odyssey EX 3.5L MIL Lamp on VIN: 2HKRL1860Y
P0420: Catalyst Efficiency Below Threshold (Bank 1). Customer complained his TCS light comes on- Honda told him to ignore MIL (!). I have tried scanning with different tools, tried Identifix- finally got a code 31 in TCS/ABS, identified as communication failure between TCS and PCM. also got old codes from ABS, d...
June 23, 2010
2001 Volvo V40 1.9L MIL Lamp on VIN: YV1VW29581
P0420: catalyst efficiency below threshold. This car keeps setting p0420 code. While monitoring the upstream and downstream sensors the scope pattern is pretty much identical. Converter - right? The downstream sensor is right after the front converter and there is some distance between the downstream se...
June 25, 2010
2001 Buick Century Limited 3.1L Hesitation, Surge, MIL Lamp on VIN: 2G4WY55J31
P0420: Catalyst System Low Efficiency. Vehicle came in with check engine lamp on and the complaint of hesitation and lack of power only when engine is cold. As soon as the engine reaches opperating temp. the symptoms vanish and the car runs great and has lots of power. Tried replacing mass air flow...
June 26, 2010
2001 Buick Century Limited 3.1L Hesitation, Surge, MIL Lamp on VIN: 2G4WY55J31
P0420: Catalyst System Low Efficiency. Vehicle came in with check engine lamp on and the complaint of hesitation and lack of power only when engine is cold. As soon as the engine reaches opperating temp. the symptoms vanish and the car runs great and has lots of power. Tried replacing mass air flow...
June 29, 2010
1997 Buick Century Limited 3.1L Hesitation, Surge, Cuts out, Stall, Misfire VIN: 2G4WY52M7V
P0420: Catalyst System Low Efficiency (Bank 1). Good afternoon all. I've got me a little gem that has reduced me to throwing parts at it. What it's doing is it bucks and backfires when moderate throttle is applied and then it'll do it at very little throttle and somtimes at idle. Then it becomes grey diffic...
June 30, 2010