Oxygen Sensor Control

WARNING: This page is about a different car, the 1997 Volkswagen Passat. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Also, perform testing under any Heated Oxygen Sensor (HO2S) related DTCs in appropriate SELF-DIAGNOSTICS article.

Disconnect HO2S 4-pin harness connector (front - Black; rear - Brown). Connect voltmeter between HO2S harness connector terminals No. 3 and 4. See Fig 1 . Start engine. If voltmeter reads .40-.50 volts, replace HO2S. If voltmeter does not read .40-.50 volts, check HO2S wiring. Repair as necessary.

Fig 1: Checking Oxygen Sensor Circuit Voltage

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