Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- 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