4.
Check for HO2S signal at idle.
caution
The data shown above is only for reference and there may be a little difference actually.
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
Start engine and warm up to operating temperature.
Check for HO2S signal at idle.
The data shown above is only for reference and there may be a little difference actually.
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
This inspection procedure is recommended when service data with scan tool is not enough.
Warm up engine to normal operating temperature
)Probe(+) : O2 sensor harness connector NO2.
Probe(-) : Chassis ground.
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
This figures show the waveform measured at terminal 2 of HO2S at idle RPM.
The average voltage of HO2S should be 0.5 V.
When sudden decceleration,the voltage at point ① should be below 0.2V.
The switching time marked ② from lean to rich should be within 200ms,if longer than 200ms HO2S may be not good.
The switching time marked ③ from rich to lean should be within 300ms,if longer than 300ms HO2S may be not good.
In case the average voltage of HO2S is over 0.6V.
Possible cause:Injector leakage,faulty Pressure regurator Faulty MAPS, ECTS.
The rear oxygen sensor output is usually not changeable like front oxygen sensor,however,if it moves like front oxygen sensor,the catalytic converter is broken.
In case there is no symptom and wrong data but DTC is shown
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection" procedure.
In case there is symptom and wrong data with DTC
Check open,short or connector’s connection for HO2S.
Check the deterioration of HO2S performance.
Go to "Troubleshooting Procedure" procedure.
This figures show the waveform measured at terminal 2 of HO2S at idle RPM.
The average voltage of HO2S should be 0.5 V.
When sudden decceleration,the voltage at point ① should be below 0.2V.
The switching time marked ② from lean to rich should be within 200ms,if longer than 200ms HO2S may be not good.
The switching time marked ③ from rich to lean should be within 300ms,if longer than 300ms HO2S may be not good.
In case the average voltage of HO2S is over 0.6V.
Possible cause:Injector leakage,faulty Pressure regurator Faulty MAPS, ECTS.
The rear oxygen sensor output is usually not changeable like front oxygen sensor,however,if it moves like front oxygen sensor,the catalytic converter is broken.
