Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSINFINITI2008FX45 AWD V8-4.5L (VK45DE)REPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSTECHNICAL SERVICE BULLETINSCUSTOMER INTERESTENGINE CONTROLS - MIL ON/DTC P1421 STORED IN MEMORY
2008 Infiniti FX45 AWD V8-4.5L (VK45DE)
Engine Controls - MIL ON/DTC P1421 Stored In Memory
2008 Infiniti FX45 AWD V8-4.5L (VK45DE)SECTION Engine Controls - MIL ON/DTC P1421 Stored In Memory
Classification: EC11-013
Reference: ITB11-026
Date: April 1, 2011
2007-2008 FX45; MIL 'ON' WITH DTC P1421 STORED
APPLIED VEHICLES: 2007-2008 FX45 (S50)
IF YOU CONFIRM
An Applied Vehicle has the MIL 'ON' with DTC P1421 (Cold Start Control) stored in the ECM.
AND
There are no drivability issues.
ACTION
1. Refer to Step 2 in the SERVICE PROCEDURE to confirm this bulletin applies to the vehicle you are working on.
2. If this bulletin applies reprogram the ECM.

CLAIMS INFORMATION
IMPORTANT:
The purpose of ACTION (above) is to give you a quick idea of the work you will be performing. You MUST closely follow the entire SERVICE PROCEDURE as it contains information that is essential to successfully completing this repair.
SERVICE PROCEDURE
1. Connect CONSULT III (C-III) to the vehicle to begin the reprogramming procedure.

CAUTION

2. When you get to the ECM Reprogramming screen shown in Figure 1 confirm this bulletin applies as follows:
A. On your C-III screen look at the Part Number column (see Figure 1 example).
^ If this column is blank (no part number listed) this bulletin does not apply. If a Part Number is listed write it on the Repair Order and then go to Step B.

B. Compare the Part Number you wrote down to the numbers in the Current ECM P/N column in Table A above.
^ If there is a match this bulletin applies. Continue with the reprogramming procedure.
NOTE:
If there are two lines (two reprogramming options) on your 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.

3. If this bulletin applies and you have performed ECM reprogramming the screen in Figure 2 appears when reprogramming is complete.
NOTE:
If the screen in Figure 2 does not display (reprogramming does not complete).
4. Make sure to erase all DTCs from all Systems.
NOTE:
During reprogramming DTCs will set in several systems. These DTCs must be erased from all systems.
5. Test drive the vehicle and make sure it operates correctly and the MIL is OFF.
^ If the MIL comes ON, go back to ASIST for further diagnostic information. Refer to the applicable Electronic Service Manual (ESM) as needed.
^ Diagnosis and repairs beyond ECM reprogramming are not covered by this bulletin.
Reference: ITB11-026
Date: April 1, 2011
2007-2008 FX45; MIL 'ON' WITH DTC P1421 STORED
APPLIED VEHICLES: 2007-2008 FX45 (S50)
IF YOU CONFIRM
An Applied Vehicle has the MIL 'ON' with DTC P1421 (Cold Start Control) stored in the ECM.
AND
There are no drivability issues.
ACTION
1. Refer to Step 2 in the SERVICE PROCEDURE to confirm this bulletin applies to the vehicle you are working on.
2. If this bulletin applies reprogram the ECM.
CLAIMS INFORMATION
IMPORTANT:
The purpose of ACTION (above) is to give you a quick idea of the work you will be performing. You MUST closely follow the entire SERVICE PROCEDURE as it contains information that is essential to successfully completing this repair.
SERVICE PROCEDURE
1. Connect CONSULT III (C-III) to the vehicle to begin the reprogramming procedure.
CAUTION
2. When you get to the ECM Reprogramming screen shown in Figure 1 confirm this bulletin applies as follows:
A. On your C-III screen look at the Part Number column (see Figure 1 example).
^ If this column is blank (no part number listed) this bulletin does not apply. If a Part Number is listed write it on the Repair Order and then go to Step B.
B. Compare the Part Number you wrote down to the numbers in the Current ECM P/N column in Table A above.
^ If there is a match this bulletin applies. Continue with the reprogramming procedure.
NOTE:
If there are two lines (two reprogramming options) on your 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.
3. If this bulletin applies and you have performed ECM reprogramming the screen in Figure 2 appears when reprogramming is complete.
NOTE:
If the screen in Figure 2 does not display (reprogramming does not complete).
4. Make sure to erase all DTCs from all Systems.
NOTE:
During reprogramming DTCs will set in several systems. These DTCs must be erased from all systems.
5. Test drive the vehicle and make sure it operates correctly and the MIL is OFF.
^ If the MIL comes ON, go back to ASIST for further diagnostic information. Refer to the applicable Electronic Service Manual (ESM) as needed.
^ Diagnosis and repairs beyond ECM reprogramming are not covered by this bulletin.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.