Circuit/System Testing
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
Engine operating, command the engine speed up to 1,400 RPM, down to 600 RPM, up to 1,400 RPM, and then exit with a scan tool. The engine speed should steadily increase and decrease as commanded.
- If the idle does not increase or decrease steadily, verify that one of the following conditions is not present:
- Vacuum leaks
- The throttle valve for the correct operation-A throttle valve that does not close correctly sets this DTC.
- Restricted air intake system
- The throttle body for damage and/or tampering
- Incorrect or malfunctioning PCV valve
- Excess deposits in the throttle body
- A parasitic load on the engine-For example, a transmission condition, a belt driven accessory condition
- Repair the condition as necessary.