DTC 0902

SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the rear heated oxygen sensor heaters corresponding to the engine speed.






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






OPERATION



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.

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


Without Scan Tools
(1) Start engine and run it 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.
- When using GST, "DIAGNOSTIC TROUBLE CODE 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.







Electrical Diagrams






Circuit Connectors






DIAGNOSTIC PROCEDURE


COMPONENT INSPECTION
Rear heated oxygen sensor heater
Check the following.






1. Check resistance between terminals (4) and (1).

Resistance: 2.3 - 4.3 Ohms at 25°C (77°F)






2. Check continuity.
If NG, replace the rear 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.