Most Likely Causes:
* Low Power Steering Fluid: This is the first thing to check. Open the hood and locate the power steering fluid reservoir (usually a clear or translucent tank). If the fluid level is low or completely empty, you've found the problem. Check for leaks around the pump, hoses, and steering rack. Refilling the fluid might solve the problem temporarily, but you'll need to address the leak.
* Power Steering Pump Failure: The pump is responsible for pressurizing the fluid. If it fails, you'll lose power steering. This is a more serious issue and requires replacement. You might hear unusual noises (whining, groaning) from the pump before complete failure.
* Blown Power Steering Hose: A burst or severely deteriorated hose will prevent fluid from circulating. Inspect all hoses carefully for cracks, bulges, or leaks.
* Power Steering Fluid Leak: Even a small leak can eventually drain the system to the point of failure. Look for wet spots under the vehicle, particularly around the pump, hoses, and rack and pinion. A leak could be caused by a damaged hose, a faulty seal in the pump or rack, or a damaged rack and pinion itself.
Less Likely (but still possible) Causes:
* Power Steering Rack and Pinion Failure: The rack and pinion is a complex mechanism, and internal failure can lead to loss of power steering. This is usually accompanied by other symptoms, such as unusual noises or difficulty steering even without power assist.
* Electrical Issues (less common on this generation): While less common on older Tahoes, a faulty power steering control module or a wiring problem *could* be involved, but these are typically accompanied by other electrical problems or warning lights.
* Stuck Valve in the Power Steering Rack: A valve within the rack and pinion could get stuck, preventing fluid flow.
Troubleshooting Steps:
1. Check the Power Steering Fluid Level: This is the absolute first step.
2. Inspect for Leaks: Look for wet spots or signs of fluid leakage.
3. Listen for Noises: Unusual noises from the power steering pump (whining, groaning) suggest a failing pump.
4. Check the Belt: Ensure the power steering pump belt is properly installed and not slipping or broken.
5. If Fluid is Low, Don't Just Refill: Find and repair the leak before refilling. Simply refilling without addressing the leak will just lead to the same problem again quickly.
If you're not comfortable performing these checks yourself, take your Tahoe to a qualified mechanic for diagnosis and repair. Ignoring a power steering problem can lead to more significant damage and costly repairs down the road.
