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P0420 Diagnostic Trouble Code Discussion for June 2009

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2000 GMC Yukon SLT 5.3L Poor Idle Quality, hard start when cold VIN: 1GKEK13T5Y
P0420: Catalyst System Low Efficiency (Bank 1). The complaint is that they have to pump the gas when it is cold to start it. When testing we found that you had to hold the throttle open for it to start when cold. In checking the data stream on our Modis we found the Idle Air Temperature (this sensor is part...
June 03, 2009
2003 Toyota Matrix 1.8L code pending VIN: 2T1KR32E43
P0420: Catalyst Efficiency Below Normal (Bank 1). car came in for mil lamp on condition and has po420. the cat was rattle inside, installed aftermarket obd11 certified cat, pre and post o2 sensors, cleared code, road test to run monitor for 60 miles and still cat monitor is not ready and has a pending code po...
June 11, 2009
2001 Subaru Outback 2.5L MIL Lamp on VIN: 4S3BH67511
P0420: Catalyst Efficiency Below Normal (Bank 1). ... hearing about P0420 on Subarus, but I have a real albatross around my neck here, so it's my turn on the stump. I have a 2001 Outback, with a P0420 code that has been haunting our shop for 2 years now. We replaced both O2's to start with, but the code came ...
June 17, 2009
1999 Toyota Solara SE 3.0L MIL Lamp on VIN: 2T1CF22P4X
P0420: Catalyst Efficiency Below Normal (Bank 1). Toyota guru's--- car keeps setting p0420 code. came in last week for code. scanned it and saw both front o2s reading around .050 volts. thinking that these are air/fuel sensors working on a 2-5 volt scale we replaced the sensors. after replacing sensors scan d...
June 25, 2009
2001 Chevrolet Impala 3.4L MIL Lamp on VIN: 2G1WF52E61
P0420: Catalyst System Low Efficiency. This is a new customer in for a inspection, The mil light was on. I scanned the car and it was PO420. The cat efficency. The customer stated that the light had been on for about 6 months. He said another shop had replaced the intake manifold gasket and radiato...
June 28, 2009
2001 Chevrolet Impala 3.4L MIL Lamp on VIN: 2G1WF52E61
P0420: Catalyst System Low Efficiency. This is a new customer in for a inspection, The mil light was on. I scanned the car and it was PO420. The cat efficency. The customer stated that the light had been on for about 6 months. He said another shop had replaced the intake manifold gasket and radiato...
June 29, 2009
2000 GMC Yukon SLT 5.3L Poor Idle Quality, hard start when cold VIN: 1GKEK13T5Y
P0420: Catalyst System Low Efficiency (Bank 1). The complaint is that they have to pump the gas when it is cold to start it. When testing we found that you had to hold the throttle open for it to start when cold. In checking the data stream on our Modis we found the Idle Air Temperature (this sensor is part...
June 03, 2009
2003 Toyota Matrix 1.8L code pending VIN: 2T1KR32E43
P0420: Catalyst Efficiency Below Normal (Bank 1). car came in for mil lamp on condition and has po420. the cat was rattle inside, installed aftermarket obd11 certified cat, pre and post o2 sensors, cleared code, road test to run monitor for 60 miles and still cat monitor is not ready and has a pending code po...
June 11, 2009
2001 Subaru Outback 2.5L MIL Lamp on VIN: 4S3BH67511
P0420: Catalyst Efficiency Below Normal (Bank 1). ... hearing about P0420 on Subarus, but I have a real albatross around my neck here, so it's my turn on the stump. I have a 2001 Outback, with a P0420 code that has been haunting our shop for 2 years now. We replaced both O2's to start with, but the code came ...
June 17, 2009
1999 Toyota Solara SE 3.0L MIL Lamp on VIN: 2T1CF22P4X
P0420: Catalyst Efficiency Below Normal (Bank 1). Toyota guru's--- car keeps setting p0420 code. came in last week for code. scanned it and saw both front o2s reading around .050 volts. thinking that these are air/fuel sensors working on a 2-5 volt scale we replaced the sensors. after replacing sensors scan d...
June 25, 2009
2001 Chevrolet Impala 3.4L MIL Lamp on VIN: 2G1WF52E61
P0420: Catalyst System Low Efficiency. This is a new customer in for a inspection, The mil light was on. I scanned the car and it was PO420. The cat efficency. The customer stated that the light had been on for about 6 months. He said another shop had replaced the intake manifold gasket and radiato...
June 28, 2009
2001 Chevrolet Impala 3.4L MIL Lamp on VIN: 2G1WF52E61
P0420: Catalyst System Low Efficiency. This is a new customer in for a inspection, The mil light was on. I scanned the car and it was PO420. The cat efficency. The customer stated that the light had been on for about 6 months. He said another shop had replaced the intake manifold gasket and radiato...
June 29, 2009