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.
- Observe the DTC information on the scan tool.
- If there are any other DTCs set, diagnose those first.
- Inspect for any condition that can reduce idle speed by increasing engine load.
- Incorrect torque converter clutch (TCC) operation
- Accessories that require additional torque to operate
- Excessive deposits in the throttle body
- Restricted exhaust
- Mechanical conditions that limit engine speed
- Repair any conditions, if necessary.
- Inspect for the following conditions:
- Vacuum leaks
- A faulty positive crankcase ventilation (PCV) valve