First response: Infiniti ECM power supply DTC
If you have an Infiniti vehicle with the MIL light on that has a DTC P0603 stored in the ECM, perform the diagnostic steps in this bulletin FIRST. This DTC may have been stored due to a series of previous low battery voltage, dead battery or battery terminal disconnections.
This bulletin applies to the following Infiniti models:
2006-2008 FX (S50)
2009 FX (S51)
2006 G35 Sedan (V35)
2006-2007 G35 Coupe (CV35)
2007-2008 G35 Sedan (V36)
2008-2009 G37 Coupe (CV36)
2009 G37 Sedan (V36)
2006-2009 M (Y50)
2008 EX35 (J50)
2006 Q45 (F50)
Do not perform any other diagnostic procedures or repairs for this code until you have performed the ones listed in this bulletin.
1. Connect CONSULT III to the vehicle.
2. Turn the ignition switch to the ON position but do not start the engine.
3. Check for DTCs. Confirm that DTC P0603 is stored. If P0603 is not stored, this TSB does not apply. If additional DTCs are stored (in addition to P0603), document the DTCs before proceeding.
4. Erase all DTCs. Confirm that ENGINE has no DTC stored.
5. Turn the ignition switch OFF, and wait exactly five minutes after the display changes from “No DTC” to “Error.” This waiting period is necessary for the ECM to completely shut off. Do not disconnect either battery cable at any time during this procedure.
6. Turn the ignition switch to the ON position but do not start the engine. Wait 10 seconds after the display changes from “Error” to “No DTC.”
7. Repeat Steps 5 and 6 five more times to complete the system check.
If DTC P0603 does not display after the system check, this will indicate that P0603 was caused by a series of previous low battery voltage, dead battery or battery terminal disconnections. This also indicates that the vehicle harness, connections and ECM are operating properly. Do not replace the ECM. No further action is necessary concerning P0603.
If DTC P0603 does display after the system check, go to Step 8.
8. Refer to the appropriate Electronic Service Manual for further DTC P0603 diagnostic assistance.
9. If other DTCs were previously stored, refer to the appropriate Electronic Service Manual for further diagnostic assistance for those DTCs.