DR-28 Checking Oxygen Sensor Operation

This test must be performed with engine warm.

1. Connect diagnostic read-out tool to engine test connector. Ensure read/hold switch is in Read position.
2. Start engine and wait two minutes, then place read/hold switch in Hold position.
3. If display is switching between 0 and 1 or remains on 1, proceed to Test 29.
4. If display is not switching between 0 and 1, replace oxygen sensor.