This diagnostic code is used only by GMT-560 applications.
The ECM detects the following:
•The Secondary Fuel Level signal voltage is below the acceptable range for more than 10 seconds.
The fuel level sensors are OEM installed components for the vehicle. The sensors are selectable through a customer programmable parameter and the customer programmable parameter may be protected by customer passwords.
Possible Causes:
1) Loose ECM Connection/Harness
2) Fuel level sensor failure
3) WIring between fuel level sensor & ECM