Code 0901

SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the front heated oxygen sensor heater corresponding to the engine operating condition.




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 43 (ECM ground).




ON BOARD DIAGNOSIS LOGIC




DTC CONFIRMATION PROCEDURE

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is between 10.5 V and 16 V at idle.

With CONSULT
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
2. Start engine and run it for at least 5 seconds at idle speed
3. If 1st trip DTC is detected, go to "Diagnostic Procedure".

With GST
1. Start engine and run it for at least 5 seconds at idle speed.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Start engine and run it for at least 5 seconds at idle speed.
4. Select "MODE 3" with GST.
5. If DTC is detected, go to "Diagnostic Procedure".

Without Scan Tools
1. Start engine and run it for at least 5 seconds at idle speed.
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.
4. If 1st trip DTC is detected, go to "Diagnostic Procedure".
- When using GST, "DTC Confirmation Procedure" should be performed twice as much as when using CONSULT or ECM (Diagnostic Test Mode II) because GST cannot display MODE 7 (1st trip DTC) concerning this diagnosis. Therefore, using CONSULT or ECM (Diagnostic Test Mode II) is recommended.







WIRING DIAGRAM

1 CHECK POWER SUPPLY:

2 DETECT MALFUNCTIONING PART:

4 CHECK FRONT HEATED OXYGEN SENSOR HEATER:

5 CHECK INTERMITTENT INCIDENT:

DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION

3 CHECK GROUND CIRCUIT:

Check resistance between terminals 3 and 1 .
Resistance: 2.3 - 4.3 Ohms at 25 °C (77 °F)
Check continuity between terminals 2 and 1, 3 and 2.
Continuity should not exist.
If NG, replace the front heated oxygen sensor.

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.