Footnotes — Maintenance Schedule Additional Required Services — Severe

a) Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. Check that the purge valve, if the vehicle has one, works properly. Replace as needed.

b) Or every four years, whichever comes first.

c) Or every five years, whichever comes first. See Cooling System .

d) Or every 10 years, whichever comes first. Inspect for fraying, excessive cracking, or damage; replace, if needed.

    See also:

    Navigation
    This display is used for the OnStar or Navigation System Turn-by-Turn guidance. See OnStar Overview or the navigation manual, if the vehicle has navigation, for more information. ...

    When the System Does Not Seem To Work Properly
    Occasional missed alerts can occur under normal circumstances and will increase in wet conditions. The system does not need to be serviced due to an occasional missed alert. The number of missed ...

    Checking Coolant
    The vehicle must be on a level surface when checking the coolant level. Check to see if coolant is visible in the coolant surge tank. If the coolant inside the coolant surge tank is boiling, do not ...