Manual High Idle Speed Enable and Disable
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
To enable or disable the manual high idle system perform the following procedure:
- Turn the ignition ON, with the engine OFF.
- Depress the accelerator pedal to the floor and hold down.
- While the accelerator pedal is depressed, depress the brake pedal 3 times in less than 8 seconds.
- Release the accelerator pedal.
- Start the engine.
When the procedure is followed the engine idle speed will slowly increased to the calibrated high idle speed. This is 1,200 RPM for light duty, and 1,500 RPM for medium duty trucks.
The idle speed will return to normal if any of the following conditions occur:
- There is brake, clutch, or throttle input from the driver.
- The automatic transmission is shifted out of Park or Neutral.
- The air temperature is more than 7°C (45°F).
- The engine coolant temperature (ECT) is more than 68°C (154°F).
- The vehicle speed exceeds 0 km/h (0 mph).
The high idle system will reactivate automatically when the following conditions occur:
- The engine has been idling for more than 30 seconds.
- The transmission is placed in Park or Neutral.
- The vehicle speed is 0 km/h (0 mph).
- The ambient air temperature is less than 3°C (37°F).
- The ECT is less than 68°C (154°F).
- The brake, clutch and throttle pedals are not depressed.