P0420 what does it mean?
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P0420 what does it mean?
P0420 (M) 1/1 Catalytic Converter Efficency Catalyst 1/1 efficency below required level.
What exactly does this mean, my check engine light came on when i was slowing down to a stop sign after the car had been running and driving for about a half hour. does this mean i need a new cat or something? the cars got 140,000 miles on it.
Any help would be great.
Thanks
What exactly does this mean, my check engine light came on when i was slowing down to a stop sign after the car had been running and driving for about a half hour. does this mean i need a new cat or something? the cars got 140,000 miles on it.
Any help would be great.
Thanks
Joined: Oct 2005
Posts: 2,019
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From: Honolulu
RE: P0420 what does it mean?
It means something is up with your down stream o2... Have you installed a test pipe or cut-out?
The upstream reads a paticular value, than the downstream should be reading a lower value due to the CAT. If this doesn't happen then the code is shown.
k3v
The upstream reads a paticular value, than the downstream should be reading a lower value due to the CAT. If this doesn't happen then the code is shown.
When Monitored and Set Condition:
P0420-CATALYTIC 1/1 EFFICIENCY
When Monitored: Engine Run time greater than 90 seconds. Engine Coolant greater than
70°C (158°F) Vehicle speed greater than 20 MPH and less than 55 MPH. Engine Speed
greater than 1216 RPM and less than 1952 RPM.
Set Condition: As catalyst efficiency deteriorates, the switch rate of the downstream O2
sensor approaches that of the upstream O2 sensor. If at any point during the test the
switch ratio reaches a predetermined value a counter is incremented by one. One Trip
Fault.
P0420-CATALYTIC 1/1 EFFICIENCY
When Monitored: Engine Run time greater than 90 seconds. Engine Coolant greater than
70°C (158°F) Vehicle speed greater than 20 MPH and less than 55 MPH. Engine Speed
greater than 1216 RPM and less than 1952 RPM.
Set Condition: As catalyst efficiency deteriorates, the switch rate of the downstream O2
sensor approaches that of the upstream O2 sensor. If at any point during the test the
switch ratio reaches a predetermined value a counter is incremented by one. One Trip
Fault.
k3v
i had installed a test pipe but then put a cat back on and it wont turn off even after i reset the computer
