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P0420 Diagnostic Trouble Code Discussion for August 2009

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
1997 Mercury Grand Marquis GS 4.6L cat monitor VIN: 2MELM74W3V
P0420: cat efficency bank one. ... not run the cat monitor. The came in originally with a P0420 code, replaced both cats due to other bank not working so well. After replacing cats and front O2's (slow response), we have driven it for multiple drive cycles and so has the customer. It needs ...
August 11, 2009
2003 Volkswagen Jetta GLS 1.8L none VIN: WVWSE61JX3
P0420: Catalyst Efficiency. ... It had a heater issue. Now it came back with the p0420 code. I already know about the cat issues and it is under warranty. My question is I have 1.520 volts at idle. Under WOT it goes to just over 4 volts. This is using the MODIS with the newest updates. T...
August 17, 2009
2003 Volkswagen Jetta GLS 1.8L none VIN: WVWSE61JX3
P0420: Catalyst Efficiency. ... It had a heater issue. Now it came back with the p0420 code. I already know about the cat issues and it is under warranty. My question is I have 1.520 volts at idle. Under WOT it goes to just over 4 volts. This is using the MODIS with the newest updates. T...
August 18, 2009
2000 Nissan Frontier XE 2.4L MIL Lamp on VIN: 1N6DD2156Y
P0420: Catalyst Efficiency Below Normal (Bank 1). Yes, we have a P0420, and NO, it's not the catalytic converter. Brand new cat. What this thing does is it always has 300mV for the rear H02. It doesn't matter if it's cold or hot, it doesn't switch at all. Thus, we put a new front AND rear H02 on it, and it do...
August 26, 2009
1997 Mercury Grand Marquis GS 4.6L cat monitor VIN: 2MELM74W3V
P0420: cat efficency bank one. ... not run the cat monitor. The came in originally with a P0420 code, replaced both cats due to other bank not working so well. After replacing cats and front O2's (slow response), we have driven it for multiple drive cycles and so has the customer. It needs ...
August 11, 2009
2003 Volkswagen Jetta GLS 1.8L none VIN: WVWSE61JX3
P0420: Catalyst Efficiency. ... It had a heater issue. Now it came back with the p0420 code. I already know about the cat issues and it is under warranty. My question is I have 1.520 volts at idle. Under WOT it goes to just over 4 volts. This is using the MODIS with the newest updates. T...
August 17, 2009
2003 Volkswagen Jetta GLS 1.8L none VIN: WVWSE61JX3
P0420: Catalyst Efficiency. ... It had a heater issue. Now it came back with the p0420 code. I already know about the cat issues and it is under warranty. My question is I have 1.520 volts at idle. Under WOT it goes to just over 4 volts. This is using the MODIS with the newest updates. T...
August 18, 2009
2000 Nissan Frontier XE 2.4L MIL Lamp on VIN: 1N6DD2156Y
P0420: Catalyst Efficiency Below Normal (Bank 1). Yes, we have a P0420, and NO, it's not the catalytic converter. Brand new cat. What this thing does is it always has 300mV for the rear H02. It doesn't matter if it's cold or hot, it doesn't switch at all. Thus, we put a new front AND rear H02 on it, and it do...
August 26, 2009