Catalytic Converter System - Dtc Troubleshooting; Dtc P0420: Catalytic System Efficiency Below Threshold - Honda S2000 Service Manual

Catalytic Converter System
DTC Troubleshooting
DTC P0420: Catalytic System Efficiency
Below Threshold
NOTE: lf some of the DTCS listed below are stored at
the same time as DTC P0420, troubleshoot those DTCS
first, then recheck for DTC P0420.
P0137, P0138: Secondary Heated oxygen Sensor
(secondary H02S) (Sensor 2)
P0141: Secondary H02S (Sensor 2) heater
1 . R e s e t t h e E C M { s e e p a g e I 1 - 4 ) , t h e n c o n t i n u e t o
steps 2 through 5 to reset the readiness code.
2. Start the engine. Hold the engine at 3.000 rpm with
no load (in neutral) until the radiator fan comes on.
Drive on a highway for about 10 minutes without
stopping. Your speed can vary.
With the transmission in 4th gear, drive at a steady
s p e e d b e t w e e n 5 0 6 2 m p h ( 8 0 1 0 0 k m / h ) f o r 3 0
seconds.
Repeat step 4 three times. Between each repetition,
close the throttle completely for
'1
2 seconds. lf
the engine is stopped during this part of the
procedure, go to step 3 and do the procedure again.
Check for a Temporary DTC with the scan tool.
Does the scan tool indicate Tempotary DTC
P0420?
YES - Check the three way catalytic converter
(TWC). lf necessary, replace the TWC.I
NO - Check for readiness code completion. lf the
readiness is complete, it was a intermittent failure,
system is OK at this time. lf the readiness is
incomplele, repeal steps 2 through 5. !
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