P0159
COMPONENT DESCRIPTION
The rear heated oxygen sensor (Rear HO2S), after three way catalyst, monitors the oxygen level in the exhaust gas on left and right bank.
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 each 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 (128) (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 the switching response of the sensor's voltage is faster than specified during the various driving condition such as fuel-cut.
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
CAUTION: Always drive vehicle at a sate speed.
NOTE:
- "COMPLETED" will appear on CONSULT screen when all tests "COND1", "COND2" and "COND3" are completed.
- 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.
TESTING CONDITION:
- Never stop engine during this test. If the engine is stopped, refer form this test from step 2).
- Always perform at temperature of more than -10°C (14°F).
Procedure for COND1
With Consult
1) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch "OFF" and wait at least 5 seconds.
3) Turn ignition switch "ON" and select "RR O2 SEN-B1 (-B2) P0139 (P0159)" of "REAR 02 SENSOR" in "DTC WORK SUPPORT" mode with Consult
4) Touch "START".
5) Start engine (TCS switch "OFF") and let it idle for at least 30 seconds.
6) Rev engine up to 2,000 rpm 2 or 3 times quickly under no load.
If "COMPLETED" appears on CONSULT screen, go to the following step.
7) When the following conditions are met, "TESTING" will be displayed at "Condition" on the CONSULT screen. Maintain the conditions continuously until "TESTING" changes to "COMPLETED". (It will take approximately 60 seconds.)
CMPS.RPM (POS): 1,400 2,200 rpm
Vehicle speed: 78 100 km/h (48 - 62 MPH)
B/FUEL SCHDL: 1.0 - 4.5 ms
Selector lever: Suitable position
NOTE:
- If "TESTING" is not displayed after 5 minutes, retry from step 2).
- If "COMPLETED" already appears at "COND2" on CONSULT screen before "Procedure for COND2" is conducted, it is unnecessary to conduct step 8).
Procedure for COND2
8) While driving, release accelerator pedal completely with "OD" OFF from the above condition [step 7)] until "INCOMPLETE" at "COND2" on CONSULT screen has turned to "COMPLETED". (It will take approximately 4 seconds.)
NOTE:
- If "TESTING" is not displayed after 5 minutes, retry from step 2).
- If "COMPLETED" already appears at "COND3" on CONSULT screen before "Procedure for COND3" is conducted, it is unnecessary to conduct step 9).
Procedure for COND3
9) Stop vehicle and let it idle until "INCOMPLETE" of "COND3" on CONSULT screen has turned to "COMPLETED". (It will take a maximum of approximately 6 minutes.)
If "TESTING" is not displayed after 5 minutes, retry from step 2).
10) Make sure that "OK" is displayed after touching "SELFDIAG RESULTS".
If "NG" is displayed, refer to "DIAGNOSTIC PROCEDURE", EC-216.
OR
OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the rear heated oxygen sensor circuit. During this check, a 1st trip DTC might not be confirmed.
Without Consult
1) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminals (89) RH, (90) LH (sensor signal) and (128) (ECM ground).
3) Check the voltage when racing up to 4,000 rpm under no load at least 10 times. (depress and release accelerator pedal as soon as possible)
The voltage should be changed at more than 0.06V for 1 second during this procedure.
If the voltage can be confirmed in step 3, step 4 is not necessary.
4) Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D position.
The voltage should be changed at more than 0.06V for 1 second during this procedure.
DIAGNOSTIC PROCEDURE
WIRING DIAGRAM - Right Bank
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 SEN-B1 (-B2)" as the monitor item with Consult
3) Check "RR O2 SEN-B1 (-B2)" at idle speed when adjusting "FUEL INJECTION" to ±25%.
"RR O2 SEN-B1 (-B2)" should be above 0.48V at least once when the "FUEL INJECTION" is +25%. "RR O2 SEN-B1 (-B2)" should be below 0.43V at least once' when the "FUEL INJECTION" is -25%.
OR
Without Consult
1) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminals (89) (RH), (90) (LH) (sensor signal) and (128) (ECM ground).
3) Check the voltage when racing up to 4,000 rpm under no load at least 10 times. (depress and release accelerator pedal as soon as possible)
The voltage should be above 0.48V at least once. It the voltage is above 0.48V at step 3, step 4 is not necessary.
4) Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D position.
The voltage should be below 0.43V at least once.