With CONSULT

COMPONENT DESCRIPTION
The rear heated oxygen sensor (Rear HO2S), after three way catalyst, monitors the oxygen level in the exhaust gas.

Even if switching characteristics of the front heated oxygen sensor are shifted, the air fuel ratio is controlled to stoichiometric, by the signal from the rear heated oxygen sensor.

This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions.

Under normal conditions the rear heated oxygen sensor is not used for engine control operation.






CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.






ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values and are measured between each terminal and (25) (ECCS ground).









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, ECM monitors whether or not the voltage is too high during the various driving condition such as fuel-cut.


DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

CAUTION: Always drive vehicle at a sate speed.

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.






With CONSULT
(1) Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
(2) Meet the following conditions once.

CKPS-RPM (POS): 1,400 - 2,700 rpm
VHCL SPEED SE: 78 - 100 km/h (48 - 62 MPH)
B/FUEL SCHDL: 1.2 - 4.5 ms
COOLAN TEMP/S: 70 - 100°C (158 - 212°F)
Selector lever: Suitable position

(3) Stop vehicle with engine running.






Electrical Diagrams






Circuit Connectors






DIAGNOSTIC PROCEDURE


COMPONENT INSPECTION
Rear heated oxygen sensor






With CONSULT
(1) Start engine and warm it up to normal operating temperature.
(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 0.48V at least once when the "FUEL INJECTION" is +25%.
"RR O2 SENSOR" should be below 0.43V at least once when the "FUEL INJECTION" is -25%.