P0420 Diagnostic Trouble Code Discussion for May 2017
Catalyst Efficiency Below Normal (Bank 1)
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| Help Request | Posted | |
| 2009 Audi A4 2.0L No Start, Misfire, MIL Lamp on VIN: WAUJF78K59 P0420: Catalyst System Efficiency Below Threshold Bank 1. The car came in with misfire codes and oil pressure codes. I replaced the oil separator and changed oil. Drove the car for a day and returned it to the customer. A few days later the car would not start. Cleared the codes and car starts and runs fine. Customer... |
May 03, 2017 | |
| 2003 Nissan Frontier SE 3.3L Hesitation, Surge, Stall, Misfire, Poor Fuel Economy VIN: 1N6ED29Y83 P0420: Catalyst Efficiency Below Normal (Bank 1). This truck will start and run fine as long as the alternator isn 19t charging heavily. If you apply any electrical loads when running above about 900-1000 rpm the engine speed will surge and act like it 19s hitting the rev limiter and the customer reports it w... |
May 24, 2017 | |
| 2009 Audi A4 2.0L No Start, Misfire, MIL Lamp on VIN: WAUJF78K59 P0420: Catalyst System Efficiency Below Threshold Bank 1. The car came in with misfire codes and oil pressure codes. I replaced the oil separator and changed oil. Drove the car for a day and returned it to the customer. A few days later the car would not start. Cleared the codes and car starts and runs fine. Customer... |
May 25, 2017 |
