Without CONSULT

OVERALL FUNCTION CHECK
This procedure can be used for checking the overall function of the three way catalyst. During this check, a Diagnostic Trouble Code (DTC) might not be confirmed.
1. Start engine and warm it up sufficiently.




2. Set voltmeter probes between ECM terminals 46 (front oxygen sensor signal) and 43 (engine ground), and ECM terminals 52 (rear heated oxygen sensor signal) and 43 (engine ground).
3. Keep engine speed at 2,000 rpm constant under no load.
4. Make sure that the voltage switching frequency (high & low) between ECM terminals 52 and 43 is much less than that of ECM terminals 46 and 43.

Switching frequency ratio =

Rear heated oxygen sensor voltage switching frequency
Front oxygen sensor voltage switching frequency

This ratio should be less than 0.86.

If the ratio is greater than 0.86, it means three way catalyst does not operate properly.

NOTE: If the voltage at terminal 46 does not switch periodically more than 5 times within 10 seconds at step 3, perform TROUBLE DIAGNOSIS FOR DTC 33 (Front oxygen sensor) first.