Component Inspection

■ Check HO2S (B1/S1) Heater resistance 

1. Ignition "OFF"
2. Disconnect HO2S (upstream) connector.
3. Measure resistance between power and control terminals of HO2S (upstream) heater (Component Side).

   Specification: 

   Temp. (°C)	Temp. (°F)	Heater Resistance (Ω)
   20	82	Approx. 2.4 ~ 4.0Ω

4. Is resistance within specification?

   YES 

   • Check for poor connection between PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure

   NO 

   • Check HO2S for contamination, deterioration, or damage. Substitute with a known-good HO2S and check for proper operation. If the problem is corrected, replace HO2S and then go to "VERIFICATION OF VEHICLE REPAIR " procedure