Infiniti cold start DTC

This TSB applies to the 2009 Infiniti FX50 equipped with the VK50 engine. If the vehicle has a MIL on with DTC P1421 (cold start control) stored in the ECM and there are no drivability issues, it may be necessary to reprogram the ECM.

  1. Connect C-III to the vehicle to begin the reprogramming procedure.
  2. When you get to the ECM Reprogramming screen shown in Figure 1, confirm that this bulletin applies as follows:
    1. On your C-III screen, look at the part number column. If this column is blank (no part number listed), this bulletin does not apply. Close C-III and refer to ASIST for further diagnostic information. If a part number is listed, write it on the repair order.
    2. Compare the part number that you wrote down to the numbers in the Current ECM Part Number column in Table A. If there is a match, this bulletin applies. Continue with reprogramming. If there are two programming options on the C-III screen, use the one that does not have the message “Caution! Use ONLY with ITBXX-XXX.” If there is not a match, this bulletin does not apply.


Vehicle configuration; FX50 with VK50 engine                      Current ECM part Number

Intelligent cruise control….Equipped w/ V-rated tires (1)…….23710-1CV0A, 23710-1CV0B

Intelligent cruise control…Equipped w/ W-rated tires (2)…....23710-1CV1A, 23710-1CV1B

Conventional cruise control..w/ V-rated tires (1)……………...23710-1CA9A, 23710-1CA9B

Conventional cruise control..w/W-rated tires (2)……………...23710-1CA7A, 23710-1CA7B

(1)   Original factory-equipped Bridgestone V-rated tires

(2)   Original factory-equipped Dunlop W-rated tires

  1. If this bulletin applies and you have performed ECM reprogramming, when reprogramming is complete the screen in Figure 2 appears.
  2. Be sure to erase DTCs from all systems.
  3. Test drive the vehicle for proper operation and confirm that the check engine light is off. If the check engine light illuminates, diagnose, perform repairs and erase DTCs.

When you enter the ECM reprogramming screen, confirm that this bulletin applies.
<p>When you enter the ECM reprogramming screen, confirm that this bulletin applies.</p>


 When reprogramming is complete, this screen will appear on the C-III.
<p>&nbsp;When reprogramming is complete, this screen will appear on the C-III.</p>

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