Alliance/Encore L4-1721cc 105 CID (1985)
Oxygen Sensor: Testing and Inspection
1.
Test continuity of harness between sensor connector and ECU connector terminal J2-9, and ensure harness is not shorted to ground. Repair or
replace harness as necessary.
2.
Test continuity between sensor ground and ECU connector terminal J2-13 and repair wiring as necessary.
3.
Test fuel system pressure and correct as necessary.
4.
Check operation of sensor by driving vehicle with a test lamp connected between diagnostic connector terminals D2-2 and D2-4. Lamp should be
out when engine reaches normal operating temperature.
5.
If lamp stays lit or lights up when engine reaches normal operating temperature, replace sensor. Additional testing may be necessary to locate
the cause of an oxygen sensor failure. Other system failures that may cause a sensor failure include EGR solenoid control, PCV system,
secondary ignition circuit and fuel delivery system.
