Oxygen Sensor: Testing and Inspection

A faulty oxygen sensor will set code 32 in the on-board diagnostic system. Refer to the schematic diagram and test the sensor with the diagnostic chart.

Wire color code identification:

L: Blue
B: Black
Y: Yellow
G: Green
R: Red
W: White
Br: Brown
Lg: Light green
Gr: Gray

Diagnostic Chart:

OXYGEN SENSOR DIAGNOSTIC CHART

CHECK ECU VOLTAGE

With engine warmed up and idling, measure voltage between ECU connector terminal (E30)10 and ground. It should read 0.1-1.0V.

NOTE: Problems with the oxygen sensor heater circuit will cause the sensor to deactivate.

CHECK OXYGEN SENSOR

Voltage Test:

1. With engine idling at operating temperature, disconnect oxygen sensor connector.
2. Measure voltage between oxygen sensor terminal #4 and ground. It should read 0.1-1.0V.

CHECK HARNESS BETWEEN ECU AND OXYGEN SENSOR

Harness Test:

1. Disconnect ECU and oxygen sensor connectors.
2. Measure resistance between ECU and oxygen sensor connectors and ground as follows:

Connector & terminal: Resistance:
(E30)10-(E23)4 0 Ohms
(E23)4-Ground 1M Ohms min.