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P0420 Diagnostic Trouble Code Discussion for August 2005

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Subaru Impreza WRX 2.0L Misfire, MIL Lamp on VIN: JF1GD29622
P0420: Catalyst Efficiency Below Normal (Bank 1). greetings. this one came in for check engine light. scanned, retrieved listed codes. checked data stream - front O2 sensor reading 3.67 to 3.89 volts. this reading does not change when sensor is unplugged from vehicle harness. very occassionaly, scanner will r...
August 03, 2005
2002 Subaru Impreza WRX 2.0L Misfire, MIL Lamp on VIN: JF1GD29622
P0420: Catalyst Efficiency Below Normal (Bank 1). greetings. this one came in for check engine light. scanned, retrieved listed codes. checked data stream - front O2 sensor reading 3.67 to 3.89 volts. this reading does not change when sensor is unplugged from vehicle harness. very occassionaly, scanner will r...
August 05, 2005
2002 Subaru Outback 2.5L MIL Lamp on VIN: 4S3BH66572
P0420: Catalyst Efficiency Below Normal (Bank 1). Has anyone else encountered a code P0420 on a late model Subaru Outback? The vehicle tied to this year and VIN was the first one I encountered with the code, but since then I've had another one come in with the same code. There is no associated driveability sy...
August 07, 2005
1998 Chevrolet C1500 Cheyenne 4.3L MIL Lamp on VIN: 1GEC14WZ24
P0420: Catalyst System Low Efficiency (Bank 1). ... setting the P0420 dtc, and I have a feeling it's due to the aftermarket catalytic converter that has been installed, it is one of those generic looking one's with an air pipe on it that is capped off since this truck is not equipped with an air pump. The s...
August 09, 2005
1999 Lexus ES300 3.0L MIL Lamp on VIN: JT8BF28G5X
P0420: Catalyst Efficiency Below Normal (Bank 1). ... found P0171 and P0420. I figured out that the maf sensor was giving a false reading. Replaced sensor. Customer wanted an injection service and fuel filter replaced also. Completed that ...
August 09, 2005
1995 Jaguar Vanden Plas 4.0L MIL Lamp on VIN: SAJKX1748S
P0420: Convertor efficiency. Thanks for taking your time to read this post. This XJ6 came in yesterday with no drivability complaint, just a MIL light on and the need for an Ohio E check. Hooked up scan tool and Pulled codes and found po420,430 and po138. Check O2 sensor operation(w/ scan...
August 11, 2005
2001 Subaru Forester L 2.5L MIL Lamp on VIN: JF1SF63561
P0420: Catalyst Efficiency Below Normal (Bank 1). I was reading the post on po420 and found Randy from Washington to be using remaned converters and would like to know where to get them. So Randy if you read this post would you please respond. And if any one else knows where to get these converters let me kno...
August 11, 2005
1996 Ford F-150 Eddie Bauer 4.9L MIL Lamp on VIN: 1FTEX14Y4T
P0420: cat system b1 below efficiency. Repeat failure...code p0420. Customer came in knowing he had a code p0420 and had us install a reman cat and all the o2s at his request. truck runs fine, and has no exhaust leaks. says fuel mileage is fine and has more power since the install. we drove the tru...
August 12, 2005
2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DRO9X81
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer complaint is the vehicle will not accelerate and cel on. I have not had this problem act up but the code for the swirl control solenoid has returned three times. The solenoid and servo are functioning properly. I have found nothing in the archives on ...
August 17, 2005
2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DRO9X81
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer complaint is the vehicle will not accelerate and cel on. I have not had this problem act up but the code for the swirl control solenoid has returned three times. The solenoid and servo are functioning properly. I have found nothing in the archives on ...
August 22, 2005
1996 Mercury Villager (Van) GS 3.0L Misfire VIN: 4M2DV11W1T
P0420: . hey guys hope you can help me with this one. we got a customer with a 96 mercury villager that is driven by an elderly women, this vehicle has been coming to use for about a year now with the same problem. we keep getting a p420 code saying there is a misfire ...
August 23, 2005
1995 Subaru Legacy L 2.2L extended crank VIN: 4S3BK6357S
P0420: cat effic. below treshold. first time to see vehicle--customer complaint is extended crank time very intermitten once every 6 or 7 starts in a day, says he has to wot to start smells like fuel at times. we pinpoint tested crank sensor, knock sensor and o2 sensors a pass perfectly, also ...
August 23, 2005
2001 Volkswagen Golf GTI GLX 2.8L MIL Lamp on VIN: WVWPG21J81
P0420: bank 1 catalytic effeciency. Car runs fine although engine sound a bit loose. Smoke checked both intake and exhaust several times for leaks: none. Can run 1 to 2 months without setting code.
August 23, 2005
2001 Volkswagen Golf GTI GLX 2.8L MIL Lamp on VIN: WVWPG21J81
P0420: bank 1 catalytic effeciency. Car runs fine although engine sound a bit loose. Smoke checked both intake and exhaust several times for leaks: none. Can run 1 to 2 months without setting code.
August 25, 2005
2001 Nissan Sentra GXE 1.8L Excessive Emissions VIN: 3N1CB51D51
P0420: Catalyst Efficiency Below Normal. DTC P0420, failed state emission test. This one has a bad catalyst indicated by excessive cycling of the O2 sensor B1S2. But the question I have is why isn't the MIL on? Both Modis scan tool and state machine indicate it is commanded on, but the bulb is not li...
August 31, 2005
2002 Subaru Impreza WRX 2.0L Misfire, MIL Lamp on VIN: JF1GD29622
P0420: Catalyst Efficiency Below Normal (Bank 1). greetings. this one came in for check engine light. scanned, retrieved listed codes. checked data stream - front O2 sensor reading 3.67 to 3.89 volts. this reading does not change when sensor is unplugged from vehicle harness. very occassionaly, scanner will r...
August 03, 2005
2002 Subaru Impreza WRX 2.0L Misfire, MIL Lamp on VIN: JF1GD29622
P0420: Catalyst Efficiency Below Normal (Bank 1). greetings. this one came in for check engine light. scanned, retrieved listed codes. checked data stream - front O2 sensor reading 3.67 to 3.89 volts. this reading does not change when sensor is unplugged from vehicle harness. very occassionaly, scanner will r...
August 05, 2005
2002 Subaru Outback 2.5L MIL Lamp on VIN: 4S3BH66572
P0420: Catalyst Efficiency Below Normal (Bank 1). Has anyone else encountered a code P0420 on a late model Subaru Outback? The vehicle tied to this year and VIN was the first one I encountered with the code, but since then I've had another one come in with the same code. There is no associated driveability sy...
August 07, 2005
1998 Chevrolet C1500 Cheyenne 4.3L MIL Lamp on VIN: 1GEC14WZ24
P0420: Catalyst System Low Efficiency (Bank 1). ... setting the P0420 dtc, and I have a feeling it's due to the aftermarket catalytic converter that has been installed, it is one of those generic looking one's with an air pipe on it that is capped off since this truck is not equipped with an air pump. The s...
August 09, 2005
1999 Lexus ES300 3.0L MIL Lamp on VIN: JT8BF28G5X
P0420: Catalyst Efficiency Below Normal (Bank 1). ... found P0171 and P0420. I figured out that the maf sensor was giving a false reading. Replaced sensor. Customer wanted an injection service and fuel filter replaced also. Completed that ...
August 09, 2005
1995 Jaguar Vanden Plas 4.0L MIL Lamp on VIN: SAJKX1748S
P0420: Convertor efficiency. Thanks for taking your time to read this post. This XJ6 came in yesterday with no drivability complaint, just a MIL light on and the need for an Ohio E check. Hooked up scan tool and Pulled codes and found po420,430 and po138. Check O2 sensor operation(w/ scan...
August 11, 2005
2001 Subaru Forester L 2.5L MIL Lamp on VIN: JF1SF63561
P0420: Catalyst Efficiency Below Normal (Bank 1). I was reading the post on po420 and found Randy from Washington to be using remaned converters and would like to know where to get them. So Randy if you read this post would you please respond. And if any one else knows where to get these converters let me kno...
August 11, 2005
1996 Ford F-150 Eddie Bauer 4.9L MIL Lamp on VIN: 1FTEX14Y4T
P0420: cat system b1 below efficiency. Repeat failure...code p0420. Customer came in knowing he had a code p0420 and had us install a reman cat and all the o2s at his request. truck runs fine, and has no exhaust leaks. says fuel mileage is fine and has more power since the install. we drove the tru...
August 12, 2005
2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DRO9X81
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer complaint is the vehicle will not accelerate and cel on. I have not had this problem act up but the code for the swirl control solenoid has returned three times. The solenoid and servo are functioning properly. I have found nothing in the archives on ...
August 17, 2005
2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DRO9X81
P0420: Catalyst Efficiency Below Normal (Bank 1). Customer complaint is the vehicle will not accelerate and cel on. I have not had this problem act up but the code for the swirl control solenoid has returned three times. The solenoid and servo are functioning properly. I have found nothing in the archives on ...
August 22, 2005
1996 Mercury Villager (Van) GS 3.0L Misfire VIN: 4M2DV11W1T
P0420: . hey guys hope you can help me with this one. we got a customer with a 96 mercury villager that is driven by an elderly women, this vehicle has been coming to use for about a year now with the same problem. we keep getting a p420 code saying there is a misfire ...
August 23, 2005
1995 Subaru Legacy L 2.2L extended crank VIN: 4S3BK6357S
P0420: cat effic. below treshold. first time to see vehicle--customer complaint is extended crank time very intermitten once every 6 or 7 starts in a day, says he has to wot to start smells like fuel at times. we pinpoint tested crank sensor, knock sensor and o2 sensors a pass perfectly, also ...
August 23, 2005
2001 Volkswagen Golf GTI GLX 2.8L MIL Lamp on VIN: WVWPG21J81
P0420: bank 1 catalytic effeciency. Car runs fine although engine sound a bit loose. Smoke checked both intake and exhaust several times for leaks: none. Can run 1 to 2 months without setting code.
August 23, 2005
2001 Volkswagen Golf GTI GLX 2.8L MIL Lamp on VIN: WVWPG21J81
P0420: bank 1 catalytic effeciency. Car runs fine although engine sound a bit loose. Smoke checked both intake and exhaust several times for leaks: none. Can run 1 to 2 months without setting code.
August 25, 2005
2001 Nissan Sentra GXE 1.8L Excessive Emissions VIN: 3N1CB51D51
P0420: Catalyst Efficiency Below Normal. DTC P0420, failed state emission test. This one has a bad catalyst indicated by excessive cycling of the O2 sensor B1S2. But the question I have is why isn't the MIL on? Both Modis scan tool and state machine indicate it is commanded on, but the bulb is not li...
August 31, 2005