With CONSULT

ON-BOARD DIAGNOSIS LOGIC
The rear heated oxygen sensor has a much longer switching time between rich and lean than the front heated oxygen sensor. The oxygen storage capacity before the three way catalyst causes the longer switching time. To judge the malfunctions of rear heated oxygen sensor, Engine Control Module (ECM) monitors the sensor's voltage value and the switching response during the various driving condition such as fuel-cut.




OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the rear heated oxygen sensor circuit. During this check a DTC might not be confirmed.
1) Start engine and warm it up sufficiently.




2) Select "FUEL INJECTION" in "ACTIVE TEST" mode, and select "RR O2 SENSOR" as the monitor item with CONSULT.




3) Check "RR O2 SENSOR" at idle speed when adjusting "FUEL INJECTION" to +25%.

"RR O2 SENSOR" should be above 0.6 V at least once when the "FUEL INJECTION" is +25%.
"RR 02 SENSOR" should be below 0.55 V at least once when the "FUEL INJECTION" is -25%.

NOTE: After starting the engine, the output voltage of the rear heated oxygen sensor indicates higher voltage (approx. 5 V at highest) than the normal operating range for about 7 seconds. This is due to checking for open circuits in rear heated oxygen sensor by on-board diagnosis. Therefore, if you measure the voltage (at ECM terminal (52)) during this diagnosis, the higher voltage will appear. (CONSULT will also show the higher voltage, Generic Scan Tool (GST) may show approx. 0 V.) This is not a malfunction even though it is out of the normal range.