Trouble Code (P0420)
#1
Trouble Code (P0420)
While driving my 05 max today my service engine light came on. At the stop light, I could also tell it was running a tab bit above normal RPM at idle. Nothing to drastic though. I took it to Auto Zone for the free diagnostic check to see what code they would be able to pull up. Below is what they printed out. I am trying to do a little trouble shooting before taking it straight to the shop. Any info will be greatly appreciated.
Trouble Code: P0420
Definition: CATALYST SYSTEM EFFICIENCY
BELOW THRESHOLD BANK 1
Probable Causes:
1) A/F RATIO CONCERN
2) AIR LEAK NEAR HO2S
3) IGNITION SYSTEM CONCERN
4) FAULTY CATALYTIC CONVERTER
Trouble Code: P0420
Definition: CATALYST SYSTEM EFFICIENCY
BELOW THRESHOLD BANK 1
Probable Causes:
1) A/F RATIO CONCERN
2) AIR LEAK NEAR HO2S
3) IGNITION SYSTEM CONCERN
4) FAULTY CATALYTIC CONVERTER
#5
Just to confuse you a little more, there could be several other things that can throw that code.
1. Bad O2 sensor - The computer compares values between the 2 O2 sensors, so 1 bad one can throw a code.
2. Faulty ignition coil - A misfiring cylinder will dump unburned fuel into your precat causing it to fail.
3. Vaccuum Leak - Will cause fuel air mix to be thrown off causing a rich mixture and, again, dump fuel into your precat causing it to fail prematurely.
Had 2 & 3 happen to my 01 Maxima.
1. Bad O2 sensor - The computer compares values between the 2 O2 sensors, so 1 bad one can throw a code.
2. Faulty ignition coil - A misfiring cylinder will dump unburned fuel into your precat causing it to fail.
3. Vaccuum Leak - Will cause fuel air mix to be thrown off causing a rich mixture and, again, dump fuel into your precat causing it to fail prematurely.
Had 2 & 3 happen to my 01 Maxima.
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Kyle Lee Cleveland
6th Generation Maxima (2004-2008)
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09-28-2015 09:01 PM