DTC Description

The ECM monitors the switching frequency ratio of air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2.

Courtesy of NISSAN NORTH AMERICA, INC.

A three way catalyst (manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. When the frequency ratio of air fuel ratio (A/F) sensor 1 and heated oxygen sensor 2 approaches a specified limit value, the three way catalyst (manifold) malfunction is diagnosed.

DTC DETECTION LOGIC 

POSSIBLE CAUSE 

• Three way catalyst (manifold)
• Exhaust tube
• Intake air leaks
• Exhaust air leaks
• Direct fuel injector
• Port fuel injector
• Direct fuel injector leaks
• Port fuel injector leaks
• Spark plug
• Improper ignition timing

FAIL-SAFE 

Not applicable

DTC CONFIRMATION PROCEDURE 

1. PRECONDITIONING 

   If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test. TESTING CONDITION: Do not hold engine speed for more than the specified minutes below.

   1. Turn ignition switch OFF and wait at least 10 seconds.
   2. Turn ignition switch ON.
   3. Turn ignition switch OFF and wait at least 10 seconds.

   Will CONSULT be used?

   >>

   GO TO 2.

   >>

   GO TO 5.

2. PERFORM DTC CONFIRMATION PROCEDURE-1 

   With CONSULT

   1. Turn ignition switch ON and select "DATA MONITOR" mode of "ENGINE" using CONSULT.
   2. Start engine and warm it up to the normal operating temperature.
   3. Turn ignition switch OFF and wait at least 10 seconds.
   4. Start engine and keep the engine speed between 3, 500 and 4, 000 rpm for at least 1 minute under no load.
   5. Let engine idle for 1 minute.
   6. Check that "COOLANT TEMP/S" indicates more than 70°C (158°F).If not, warm up engine and go to next step when "COOLANT TEMP/S" indication reaches to 70°C (158°F).
   7. Open engine hood.
   8. Select "DTC and SRT CONFIRMATION" then "SRT WORK SUPPORT" mode of "ENGINE" using CONSULT.
   9. Rev engine up to 2, 000 to 3, 000 rpm and hold it for 3 consecutive minutes then release the accelerator pedal completely.
   10. Check the indication of "CATALYST".

   Which is displayed on CONSULT screen?

   CMPLT>>

   GO TO 4.

   INCMP>>

   GO TO 3.

3. PERFORM DTC CONFIRMATION PROCEDURE-2 

   With CONSULT

   1. Wait 5 seconds at idle.
   2. Rev engine up to 2, 000 to 3, 000 rpm and maintain it until "INCMP" of "CATALYST" changes to "CMPLT".
      NOTE: It will take approximately 5 minutes. If "CMPLT" is not displayed after 5 minutes, turn ignition switch OFF and cool down the engine. Retry from step 1 when "COOLANT TEMP/S" indication reaches to 70°C (158°F).

   Does the indication change to "CMPLT"

   >>

   GO TO 4.

   >>

   GO TO 2.

4. PERFORM DTC CONFIRMATION PROCEDURE-3 

   Check 1st trip DTC.

   Is 1st trip DTC detected?

   >>

   Proceed to Diagnosis Procedure .

   >>

   To check malfunction symptom before repair: Refer to Intermittent Incident .

   >>

   Confirmation after repair: INSPECTION END

5. PERFORM COMPONENT FUNCTION CHECK 

   Without CONSULT

   NOTE: Use component function check to check the overall function of the three way catalyst (manifold). During this check, a 1st trip DTC might not be confirmed.
   1. Start engine and warm it up to the normal operating temperature.
   2. Turn ignition switch OFF and wait at least 10 seconds.
   3. Restart engine and keep the engine speed between 3, 500 and 4, 000 rpm for at least 1 minute under no load.
   4. Let engine idle for 1 minute.
   5. Open engine hood.
   6. Check the voltage between ECM harness connector terminals as per the following condition.

      ECM			Condition	Voltage (V)
      Connector	+	-
      	Terminal
      F52	77	76	Keeping engine speed at 2500 rpm constant under no load	The voltage fluctuation cycle takes more than 5 seconds. 1 cycle: 0.6 - 1.0 → 0 - 0.3 → 0.6 - 1.0

   Is the inspection result normal?

   >>

   To check malfunction symptom before repair: Refer to Intermittent Incident .

   >>

   Confirmation after repair: INSPECTION END

   >>

   Proceed to Diagnosis Procedure .