P0134

COMPONENT DESCRIPTION
The front heated oxygen sensor is placed into the exhaust manifold. It detects the amount of oxygen in the exhaust gas compared to the outside air. The front heated oxygen sensor has a closed- end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The front heated oxygen sensor signal is sent to the ECM. The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.





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 (43) (ECCS ground).








ON BOARD DIAGNOSIS LOGIC
To judge the malfunction, the diagnosis checks that the front heated oxygen sensor output is not inordinately high.

DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

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".
(2) Select "DATA MONITOR" mode with CONSULT and wait at least 5 seconds.

OR

With Generic Tool
(1) Turn ignition switch "ON" and wait at least 5 seconds.
(2) Select "MODE 3" with GST

OR

Without Scan Tool
(1) Turn ignition switch "ON" and wait at least 5 seconds.
(2) Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
(3) Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.





WIRING DIAGRAM





DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Front Heated Oxygen Sensor








With Consult
(1) Start engine and warm it up to normal operating temperature.
(2) Select "MANU TRIG" and "HI SPEED" in "DATA MONITOR" mode with CONSULT, and select "FR O2 SENSOR" and "FR O2 MNTR".
(3) Hold engine speed at 2,000 rpm under no load during the following steps.
(4) Touch "RECORD" on CONSULT screen.
(5) Check the following.
- "FR O2 MNTR" in "DATA MONITOR" mode changes from "RICH" to "LEAN" to "RICH" 5 times in 10 seconds.
5 times (cycles) are counted as shown below:
cycle | 1 | 2 | 3 | 4 | 5 |
FR O2 MNTR R-L-R-L-R-L-R-L-R-L-R
R = "FR O2 MNTR", "RICH"
L = "FR O2 MNTR", "LEAN"
- "FR O2 SENSOR" voltage goes above 0.6V at least once.
- "FR O2 SENSOR" voltage goes below 0.35V at least once.
- "FR O2 SENSOR" voltage never exceeds 1.0V.

OR





Without Consult
(1) Start engine and warm it up to normal operating temperature.
(2) Set voltmeter probes between ECM terminal (46) (sensor signal) and (43) (engine ground).
(3) Check the following with engine speed held at 2,000 rpm constant under no load.
- Malfunction indicator lamp goes on more than 5 times within 10 seconds in Diagnostic Test Mode II (FRONT HEATED OXYGEN SENSOR MONITOR).
- The maximum voltage is over 0.6V at least one time.
- The minimum voltage is below 0.35V at least one time.
- The voltage never exceeds 1.0V.