Justy Hatchback 2WD L3-1.2L SOHC (MPFI) (1992)
Oxygen Sensor Testing
CHECK ECU VOLTAGE AND OXYGEN SENSOR
1.
With engine completely warmed up and idling, measure voltage between ECU connector (F121)4 and ground. Voltage should alternate between
0.3V and 0.6V.
2.
Disconnect oxygen sensor and measure voltage between sensor connector (F5)1 and ground. Voltage should remain above .47 volts most of the
time.
Oxygen Sensor Harness Testing
CHECK ECU HARNESS
1.
With ignition "OFF," disconnect ECU and oxygen sensor connector.
2.
Measure resistance between ECU connector and oxygen sensor connector:
Connector & terminal:
Resistance:
(F121)4-(F5)1
Below 1 Ohm
3.
Connect ECU and oxygen sensor connectors.
4.
Measure resistance between ECU connector and ground:
Connector & terminal:
Resistance:
(F121)1-Ground
Below 10 Ohms
(F121)2-Ground
Below 10 Ohms