Starting Mode

The ECM supplies voltage to the fuel pump driver control module when the ECM detects that the ignition is ON. The voltage from the ECM to the fuel pump driver control module remains active for 2 s, unless the engine is in Crank or Run. While this voltage is being received, the fuel pump driver control module closes the ground switch of the fuel tank fuel pump module and also supplies a varying voltage to the fuel tank fuel pump module in order to maintain the desired fuel line pressure. The ECM calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), manifold absolute pressure (MAP), mass air flow (MAF), and throttle position sensors. The system stays in starting mode until the engine speed reaches a predetermined RPM.

Model Year 2020 and Later 

Starting mode occurs when the below conditions are present:

• The vehicle has been sitting for a predetermined length of time
• Engine coolant is below a specific temperature

Starting mode is only allowed once per key cycle, or up to three accessory wake up events. Below are examples of a wake up event:

• Unlocking the doors using the key fob
• Unlocking the doors through passive entry
• Opening the truck / hatch / tailgate using the key fob
• Opening the truck / hatch / tailgate through passive entry
• Commanding a remote start event using the key fob
• Accessory mode is enabled

Below are the conditions why Starting mode would be disabled:

• The vehicle has been in a collision
• Coolant temperature is out of starting mode range
• DTC present in the fuel system
• Hood ajar or Hood switch DTC is present
• Number of Starting Mode attempts exceeded
• Power mode switch, not in off or accessory mode