 DTC DETECTION LOGIC
NOTE:
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If DTC P1421 is displayed with other DTC, first perform the trouble diagnosis for other DTC.
DTC No.
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Trouble diagnosis name
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DTC detecting condition
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Possible cause
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P1421
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Cold start emission reduction strategy monitoring
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ECM does not control ignition timing and engine idle speed properly when engine is started with pre-warming up condition.
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- Lack of intake air volume
- Fuel injection system
- ECM
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 DTC CONFIRMATION PROCEDURE
 1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test. - Turn ignition switch OFF and wait at least 10 seconds.
- Turn ignition switch ON.
- Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:Before performing the following procedure, confirm that battery voltage is more than 11 V at idle. >>GO TO 2.
 2.PERFORM DTC CONFIRMATION PROCEDURE
- Turn ignition switch OFF and wait at least 10 seconds.
- Turn ignition switch ON.
- Select “DATA MONITOR” mode with CONSULT-III.
- Check the indication of “COOLAN TEMP/S”.If it is between 4 °C (39 °F) and 36 °C (97 °F), go to the following steps.If it is below 4 °C (39 °F), warm engine up to more than 4 °C (39 °F) and retry from step 1.If it is above 36 °C (97 °F), cool engine down to less than 36 °C (97 °F) and retry from step 1.
- Start engine and let it idle for 5 minutes.
- Check 1st trip DTC.
Is 1st trip DTC detected?
YES >>Go to Diagnosis Procedure (GT-R certified NISSAN dealer). NO >>INSPECTION END
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