P0140
COMPONENT DESCRIPTION
The heated oxygen sensor 2 (rear), after three way catalyst, monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the heated oxygen sensor 1 (front) are shifted, the air fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 2 (rear). This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions.
Under normal conditions the heated oxygen sensor 2 (rear) is not used for engine control operation.
Consult-II Reference Value In Data Monitor Mode:
ECM Terminals And Reference Value:
ON BOARD DIAGNOSIS LOGIC
The heated oxygen sensor 2 (rear) has a much longer switching time between rich and lean than the heated oxygen sensor 1 (front). The oxygen storage capacity before the three way catalyst causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2 (rear), ECM monitors whether or not the voltage is too high during the various driving condition such as fuel-cut.
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
Always drive vehicle at a safe 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-II.
2. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
3. Maintain the following conditions for at least 5 consecutive seconds.
ENG SPEED: 1,000 - 3,000 rpm
VHCL SPEED SE: 32 - 120 km/h (20 - 75 MPH)
B/FUEL SCHDL: 3 - 12.5 msec
COOLAN TEMP/S: More 70 °C (158 °F)
Selector lever: Suitable position
4. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
OR
OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the heated oxygen sensor 2 (rear) circuit. During this check, a 1st trip DTC might not be confirmed.
Without Consult
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Set voltmeter probes between ECM terminals (52) (sensor signal) and ground.
4. Check the voltage after revving 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 below 1.4 V during this procedure.
5. If NG, go to "Diagnostic Procedure" below.
EC-HO2S2-01:
EC-HO2S2-01 Connector View:
WIRING DIAGRAM
DIAGNOSTIC PROCEDURE
COMPONENT INSPECTION
Heated oxygen sensor 2 (rear)
With Consult
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Select "FUEL INJECTION" in "ACTIVE TEST" mode, and select "HO2S2 (B1)" as the monitor item with CONSULT-II .
4. Check "HO2S2 (B1)" at idle speed when adjusting "FUEL INJECTION" to ±25%.
"HO2S2 (B1)" should be above 0.56 V at least once when the "FUEL INJECTION" is +25%.
"HO2S2 (B1)" should be below 0.54 V at least once when the "FUEL INJECTION" is -25%.
CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
OR
Without Consult
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Set voltmeter probes between ECM terminals (52) (sensor signal) and ground.
4. Check the voltage when revving 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 0.56 V at least once. If the voltage is above 0.56 V at step 4, step 5 is not necessary.
5. Check the voltage when racing up to 6,000 rpm under no load. Or keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in 3rd gear position (M/T), D position with "OD" OFF (A/T).
The voltage should be below 0.54 V at least once.
CAUTION:
- Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
- Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.