H61 - HO2S Check

- Key Off.

- Suspect HO2S disconnected.

- Connect DVOM to HO2S Signal circuit and HO2S SIG RTN at the HO2S sensor connector.

- DVOM on 20 volt scale.

- Disconnect vacuum hose from vacuum tree.

- Start engine and run at 2000 rpm.

- Does the DVOM indicate less than 0.4 volts within 30 seconds?

YES -- Go to H70. H70 - Monitor HO2S (PID)

NO -- REPLACE HO2S. RECONNECT vacuum hose. DRIVE 5 miles/55 mph. Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes