Component Inspection

■ Visual Check 

1. IG "OFF" & Disconnect HO2S (S1) connector.
2. Check that HO2S (S1) is contaminated or damaged by foreign materials.
3. Has a problem been found?

   YES 

   • Go to "Check HO2S (S1) Performance" procedure below.

   NO 

   • Substitute with a known - good HO2S (S1) and check for proper operation. If the problem is corrected, replace HO2S (S1) and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check HO2S (S1) Performance 

1. IG KEY "OFF".
2. Connect probe to signal terminal of HO2S (S1) connector and select oscilloscope function with GDS.
3. Warm up the engine to normal operating temperature.
4. Measure signal waveform of HO2S (S1) with GDS.

   Specification:  Refer to SIGNAL WAVEFORM & DATA 

5. Is the measured signal waveform within specification?

YES 

• Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage. So, check poor connections and the related circuit between ECM and component thoroughly. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

NO 

• Substitute with a known - good HO2S (S1) and check for proper operation. If the problem is corrected, replace HO2S (S1) and go to "VERIFICATION OF VEHICLE REPAIR " procedure.