DTC Confirmation Test (Overall Function Check)

NOTE: Use the following test to check overall function of 3-way catalyst (warm-up 3-way catalyst on California models). During this test, DTC may not be confirmed.

Malfunction is detected when 3-way catalyst does not operate properly. Possible causes are:

Defective 3-way catalyst.
Exhaust system damaged or leaking.
Intake air leak.
Defective injectors.
Defective spark plug.
Ignition timing incorrect.

Start engine and drive vehicle at 43 MPH or more for 2 minutes. Stop vehicle and leave engine running. Using DVOM, backprobe PCM harness connector. See Figure. Connect DVOM between ground and terminal No. 86 (White wire). See Figure. Increase engine speed to 2500 RPM under no load. Make sure the voltage does not vary for more than 5 seconds. If the voltage fluctuation takes less than 5 seconds, go to DIAGNOSTIC PROCEDURE .

NOTE: One fluctuation cycle: 0.6-1.0 volt to zero-0.3 volt to 0.6-1.0 volt.