Test Step 3 - O2 SENSOR

Fig 1: Measuring Voltage On (K902) O2 Sensor 1/1 Return Circuit In O2 Sensor Harness Connector

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

• Measure the voltage on the (K904) O2 Sensor 1/2 Return circuit in the O2 Sensor 1/2 harness connector.

Is the voltage at 2.5 Volts?

Yes 

• Verify that there is good pin to terminal contact in the O2 Sensor 1/2 and Powertrain Control Module connectors. If OK, replace the O2 Sensor 1/2. Refer to Removal and Installation .
• Perform the Powertrain Verification Test. Refer to PCM Verification Test (2009 - 2011) & PCM Verification Test (2012 & Up) .

No 

• Go to Test Step 4 - (K904) O2 SENSOR 1/2 RETURN CIRCUIT SHORTED TO GROUND