With GST

Start engine and warm it up to the normal operation temperature.
Turn ignition switch OFF and wait at least 10 seconds.
Start engine and keep the engine speed at between 3, 500 to 4, 000 RPM for at least 1 minute under no load.
Let engine idle for 1 minute.
Set voltmeters probes between ECM terminals 91 [HO2S1 (bank 1) signal], 92 [HO2S1 (bank 2) signal] and ground, and ECM terminals 88 [HO2S2 (bank 1) signal], 90 [HO2S2 (bank 2) signal] and ground.
Keep engine speed at 2, 000 RPM constant under no load.

Fig 1: Checking Voltage Between Terminals 91, 92 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
Make sure that the voltage switching frequency (high & low) between ECM terminals 88 and ground, or 90 and ground is very less than that of ECM terminals 91 and ground, or 92 and ground.
Switching frequency ratio = A/B

A: Heated oxygen sensor 2 voltage switching frequency

B: Heated oxygen sensor 1 voltage switching frequency

This ratio should be less than 0.75.

If the ratio is greater than above, it means three way catalyst (manifold) does not operate properly. Go to "DIAGNOSTIC PROCEDURE ".

Fig 2: Checking Voltage Between Terminals 88, 90 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

NOTE: If the voltage at terminal 91 or 92 does not switch periodically more than 5 times within 10 seconds at step 5, perform trouble diagnosis for DTC P0133, P0153 first. (See DTC P0133, P0153 HO2S1 .)