This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
Connect scan tool to DLC.
IG KEY : ON
Warm up engine to normal operating temperature
Check for HO2S control at idle.
If the waveform of rear HO2S looks similar to that of front HO2S,catalytic converter may be broken.
Service standard
For front HO2S
When decelerating suddeniy from 4000rpm : 200mV or less
When engine is suddenly raced : 600~1000mV
1500rpm : The fluctuation between 400mV or less and 600~1000mV
For Rear HO2S
Part load(Approx. 2000rpm) : 500~1000mV
In idle RPM,if the waveform of rear HO2S is similar to that of reference wave asm shown above,the Catalyst converter is in good condition.
In case there is no symptom and wrong data about HO2S but DTC P0420 is shown
The problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection"
In case the front HO2S signal and rear HO2S signal are same.
Catalytic converter faulty.
Go to "Circuit inspection"
