Nissan cold start DTCs
his TSB applies to 2008-2010 Nissan Altima vehicles equipped with the QR25DE 4-cylinder engine. For a 2008-2009 Altima, DTC P1421 (cold start control) may be stored in the ECM. For a 2010 Altima, DTC P050E (cold start control) may be stored.
Refer to Step 2 in the Service Procedure to confirm that this bulletin applies. If this bulletin does apply, reprogram the ECM.
- Connect the CONSULT PC to the vehicle to begin the reprogramming procedure.
- When you get to the ECM Reprogramming screen, confirm that this bulletin applies as follows:
- 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.
- Compare the part number that you wrote down to the numbers in the Current ECM Part Number column. If there is a match, this bulletin applies. Continue with the reprogramming procedure. 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 NTBXX-XXX.” If there is not a match, this bulletin does not apply. Close C-III and refer to ASIST for further diagnostic information.
- If this bulletin applies and you have performed ECM reprogramming, the screen in the following Figure 1 appears when reprogramming is complete.
- Make sure to erase DTCs from all systems (during reprogramming, DTCs will set in several systems and must be erased).
- Test drive the vehicle for proper operation and verify that the MIL is off.