Join Now
International Automotive Technicians Network

P0420 Diagnostic Trouble Code Discussion for February 2013

Catalyst Efficiency Below Normal (Bank 1)


Note: This is a professional automotive technician's resource.
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2006 Acura TL 3.2L Flashing check engin VIN: 19UUA662X6
P0420: Catalyst Efficiency Below Threshold (Bank 1). Hi Guys Customer states under extreme acceleration and redlining the engine on freeway. [One can not have THAT much fun without consequence!!!] The check engine light flashed then turned off completely but now has a strange harmonic noise at freeway cruse spe...
February 06, 2013
2004 Dodge Caravan SE 2.4L MIL Lamp on VIN: 1D4GP25B34
P0420: Catalyst Efficiency Below Normal (Bank 1). ... 4 cyl here. I was given this car by another tech who said that it needed a PCM flash update for this p0420 code. So, me being me, I decided to check a little further into it. I can't find any flash updates available for a p0420 on an 04 Caravan. I hooked m...
February 06, 2013
2004 Dodge Caravan SE 2.4L MIL Lamp on VIN: 1D4GP25B34
P0420: Catalyst Efficiency Below Normal (Bank 1). ... 4 cyl here. I was given this car by another tech who said that it needed a PCM flash update for this p0420 code. So, me being me, I decided to check a little further into it. I can't find any flash updates available for a p0420 on an 04 Caravan. I hooked m...
February 07, 2013
1998 Oldsmobile Achieva S 3.1L MIL Lamp on VIN: 1G3NL52MXW
P0420: Catalyst System Low Efficiency. We replaced the catalytic converter with an AP OBDII compliant converter. The code came back. We replaced the upstream oxygen sensor. The code came back after 40 miles. If we replace the catalytic converter with a Walker or a Magnaflow direct fit converter, do...
February 09, 2013
1998 Oldsmobile Achieva S 3.1L MIL Lamp on VIN: 1G3NL52MXW
P0420: Catalyst System Low Efficiency. We replaced the catalytic converter with an AP OBDII compliant converter. The code came back. We replaced the upstream oxygen sensor. The code came back after 40 miles. If we replace the catalytic converter with a Walker or a Magnaflow direct fit converter, do...
February 11, 2013
2007 GMC Canyon SLT 3.7L MIL Lamp on VIN: 1GTDT13E37
P0420: Catalyst System Low Efficiency. ... customer that had a service engine soon light on he stopped at the shop and I pulled the codes they were a P0102 MAF sensor circuit low frequency and P0449 EVAP vent solenoid control circuit. He was in a hurry so I cleared codes and he made a apointment fo...
February 13, 2013
2004 Buick Rendezvous CX 3.4L No Start VIN: 3G5DB03E24
P0420: Catalyst System Low Efficiency. ... psi at 57 on the Schrader valve. Check for spark and it had it. Scanned the bcm data to make sure it wasn't an anti-theft issue. We are good there. I checked the pcm for codes and it has a p0420 cat eff code and a p1819 co...
February 14, 2013
2002 Volkswagen Jetta GLS 1.8L Hesitation, Surge, Cuts out VIN: 3VWSE69MX2
P0420: Catalsyst system cylinder b1 operation too low. Vehicle intermittenly stumbles and cuts out, stores a bunch of codes, some listed here, also has misfire codes on cylunders 1 and 4. Battery is low, have to jump of vehicle. Other than that vehicle fines 90% of the time. We are going to replace battery, batter...
February 17, 2013
2000 Honda Accord SE 2.3L Excessive Emissions, MIL Lamp on VIN: 1HGCG6699Y
P0420: Catalyst Efficiency Below Threshold (Bank 1). problem with cat? not after market cat ? engine Seems running rich ? O2 test working fine, but show voltage around .750 mv (bank 1)
February 19, 2013
2006 Cadillac DTS 4.6L MIL Lamp on VIN: 1G6KD57Y46
P0420: Catalyst System Low Efficiency (Bank 1). ... time to read this. I have this '06 DTS with a repeat P0420. The car is very well taken care of and is a regular customer. By all of my testing, this car is running properly and the new cat does not seem to be a problem. It was replaced 2 weeks and 900 mile...
February 20, 2013
2006 Acura TL 3.2L Flashing check engin VIN: 19UUA662X6
P0420: Catalyst Efficiency Below Threshold (Bank 1). Hi Guys Customer states under extreme acceleration and redlining the engine on freeway. [One can not have THAT much fun without consequence!!!] The check engine light flashed then turned off completely but now has a strange harmonic noise at freeway cruse spe...
February 06, 2013
2004 Dodge Caravan SE 2.4L MIL Lamp on VIN: 1D4GP25B34
P0420: Catalyst Efficiency Below Normal (Bank 1). ... 4 cyl here. I was given this car by another tech who said that it needed a PCM flash update for this p0420 code. So, me being me, I decided to check a little further into it. I can't find any flash updates available for a p0420 on an 04 Caravan. I hooked m...
February 06, 2013
2004 Dodge Caravan SE 2.4L MIL Lamp on VIN: 1D4GP25B34
P0420: Catalyst Efficiency Below Normal (Bank 1). ... 4 cyl here. I was given this car by another tech who said that it needed a PCM flash update for this p0420 code. So, me being me, I decided to check a little further into it. I can't find any flash updates available for a p0420 on an 04 Caravan. I hooked m...
February 07, 2013
1998 Oldsmobile Achieva S 3.1L MIL Lamp on VIN: 1G3NL52MXW
P0420: Catalyst System Low Efficiency. We replaced the catalytic converter with an AP OBDII compliant converter. The code came back. We replaced the upstream oxygen sensor. The code came back after 40 miles. If we replace the catalytic converter with a Walker or a Magnaflow direct fit converter, do...
February 09, 2013
1998 Oldsmobile Achieva S 3.1L MIL Lamp on VIN: 1G3NL52MXW
P0420: Catalyst System Low Efficiency. We replaced the catalytic converter with an AP OBDII compliant converter. The code came back. We replaced the upstream oxygen sensor. The code came back after 40 miles. If we replace the catalytic converter with a Walker or a Magnaflow direct fit converter, do...
February 11, 2013
2007 GMC Canyon SLT 3.7L MIL Lamp on VIN: 1GTDT13E37
P0420: Catalyst System Low Efficiency. ... customer that had a service engine soon light on he stopped at the shop and I pulled the codes they were a P0102 MAF sensor circuit low frequency and P0449 EVAP vent solenoid control circuit. He was in a hurry so I cleared codes and he made a apointment fo...
February 13, 2013
2004 Buick Rendezvous CX 3.4L No Start VIN: 3G5DB03E24
P0420: Catalyst System Low Efficiency. ... psi at 57 on the Schrader valve. Check for spark and it had it. Scanned the bcm data to make sure it wasn’t an anti-theft issue. We are good there. I checked the pcm for codes and it has a p0420 cat eff code and a p1819 co...
February 14, 2013
2002 Volkswagen Jetta GLS 1.8L Hesitation, Surge, Cuts out VIN: 3VWSE69MX2
P0420: Catalsyst system cylinder b1 operation too low. Vehicle intermittenly stumbles and cuts out, stores a bunch of codes, some listed here, also has misfire codes on cylunders 1 and 4. Battery is low, have to jump of vehicle. Other than that vehicle fines 90% of the time. We are going to replace battery, batter...
February 17, 2013
2000 Honda Accord SE 2.3L Excessive Emissions, MIL Lamp on VIN: 1HGCG6699Y
P0420: Catalyst Efficiency Below Threshold (Bank 1). problem with cat? not after market cat ? engine Seems running rich ? O2 test working fine, but show voltage around .750 mv (bank 1)
February 19, 2013
2006 Cadillac DTS 4.6L MIL Lamp on VIN: 1G6KD57Y46
P0420: Catalyst System Low Efficiency (Bank 1). ... time to read this. I have this '06 DTS with a repeat P0420. The car is very well taken care of and is a regular customer. By all of my testing, this car is running properly and the new cat does not seem to be a problem. It was replaced 2 weeks and 900 mile...
February 20, 2013