My car has 70,500 miles, and a few months back the Service Engine Soon Light came on, and the car was idling rough at stop lights or when parked. Also, the fuel efficiency has significantly decreased and the car seems to surge when I let go of the gas. The engine sluggishly shifts gears, and I took it in to get the code read and removed, which was P0420 (something with the Catalytic Converter) and had the code erased and it reappeared. The fuel cap is tight, so I know it is not a problem with that. Any suggestions as to what exactly could be wrong with the car?
Here's the description. What if it isn't a misdiagnosis by the ECM and the converter actually needs to be replaced? The 80-part of your 8/80 warranty is approaching pretty quick...
NTB00070
If an applied 2000-2001 Maxima has a MIL "ON" with DTC P0420 (Three Way Catalyst Function) stored in the ECM, it may be the result of an internal ECM Program Misdiagnosis. The catalyst should not be replaced. This bulletin provides updated ECM data toreprogram the vehicle's ECM to correct the condition. This bulletin replaces NTB00-070 which should be discarded. The ECM reprogram contained in this bulletin is different than the reprogram described in the earlier bulletin. In addition, it is notrequired to perform the P0420 DTC confirmation test after reprogramming has been removed. Use the diagnosis/repair flow chart on page 2 and the appropriate Service Procedure steps provided in this bulletin to diagnose and repair this incident, if it should occur, regardless of whether or not the vehicle was previously repaired in accordance with the earlier bulletin. See this bulletin for detail.
madbrewer wrote:
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Light came on, and the car was idling rough at stop lights or when parked. Also, the fuel efficiency has significantly decreased and the car seems to surge when I let go of the gas. The engine sluggishly shifts gears, and I took it in to get the code read and removed, which was P0420 (something with the Catalytic Converter) and had the code erased and it reappeared. The fuel cap is tight, so I know it is not a problem with that. Any suggestions as to what exactly could be wrong with the car?
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