Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Oxygen Sensor: Testing and Inspection

NOTE: Oxygen sensor problems may set Diagnostic Trouble Codes 15 and/or 17.

TERMINAL VOLTAGE CHECK

Oxygen Sensor Terminal Voltage:






1. Warm engine to operating temperature.
2. Unplug sensor connector. Connect voltmeter between sensor terminal and ground.

NOTE: Use a high internal resistance type (more than 40K ohms) voltmeter.

3. Measure voltage while abruptly raising and lowering engine speed several times:
a. When speed is increased, meter should read 0.5 - 1.0V.
b. When speed is decreased, meter should read 0 - 0.4V.

5. If not as specified, replace sensor.