POWER STEERING ASSIST GOES AWAY WHEN PARKING - 2004 Saturn ION

Question edited for clarity, add maker, add CAPS.

This is a well known issue with this electric power steering.

https://www.google.com/search?q=2013+Ford+Mustang+V6+power+steering+assist+fault+when+its+cold

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It could or could have electric power sterring , look up under the dash below the steering wheel an see if it has a electric motor on the steering column .
Power Steering System Description and Operation (with EPS)
The Electric Power Steering (EPS) system reduces the amount of effort needed to steer the vehicle. The system uses the power steering control module (PSCM), torque sensor, power steering motor rotational sensor, power steering motor, discrete battery voltage supply circuit, and the GMLAN serial data circuit to perform the system functions. The PSCM and power steering motor are each serviced separately from the steering column assembly. However, the motor rotational sensor is serviced as part of the power steering motor, and the torque sensor is serviced as part of the steering column assembly. The PSCM also monitors vehicle speed from the engine control module (ECM) via the GMLAN serial data circuit. At low speeds more assist is provided for easy turning during parking maneuvers. At higher speeds less assist is provided for improved road feel and directional stability.

ELECTRIC POWER STEERING (EPS)
The TSX uses Electric Power Steering (EPS) which regulates steering via a computer-actuated electric motor. With the computer-controlled system, advanced algorithms built into the operating software allow for continuous fine-tuning of the steering assist forces so that minimal force is required at low speeds- such as when parking or maneuvering. Conversely, progressively higher steering effort is generated at higher speeds (such as when driving on the freeway) to deliver a sport-minded driving experience.
The EPS system found in the TSX is an evolution of an earlier EPS system found on the Acura NSX supercar. Its key features and advantages include:

• The EPS system reduces the steering effort at low speeds, improving agility and ease of effort when parking or maneuvering in tight areas
• Rigidity of the steering mount is higher, which allows a more precise and "connected" feel during high-speed maneuvers (such as during lane changes or when on winding mountain roads)
• The EPS steering assist incorporates computer algorithms based on vehicle speed rather than engine speed, allowing TSX engineers the flexibility of tailoring the steering feel to match actual driving conditions- especially high-speed driving. The EPS steering algorithms incorporate steering assist changes for every 0.6 mph.
• The EPS system is different (and uniquely tuned) for each of the TSX models: 2.4L I-4 sedan, 3.5L V-6 sedan, and the new Sport Wagon.
• EPS employs a sporty, 13.5:1 steering ratio which further improves performance driving agility
• In its evolution from the original NSX system, the TSX's EPS system uses a significantly more powerful electric motor teamed with a far more sophisticated microprocessor
• By eliminating the conventional power steering pump assembly, EPS uses less engine power which improves acceleration and fuel efficiency

it is an electric pump without a pulley or belt or fluid apparently

Check your fluid level, and belts. If the pump is making noise it is probably weak and will need to be replaced.

Your PS pump is fine.

This vehicle has:

Variable-assist power steering: A power steering system that uses valves and speed sensors to vary the amount of steering assist according to engine or road speed. At slow speeds more steering assist is delivered and steering the wheels is easier; necessary for parking, etc.. At higher speeds, steering assist is reduced and more steering effort is required to steer the car, giving the driver greater feel of the road. Also known as Speed-sensitive power steering.

Loss of current to the magnetic coils would cause a loss of power assist at low speed. Coil resistance can be checked with an ohmmeter, and should read about two ohms. An infinite (open) reading indicates a bad coil (requires replacing the rack since the coils are not serviceable). Checking for shorts between both sides of the coil assembly and rack housing is also recommended.

Best wishes

if the steering assist only goes out one way, and has assist the other direction the rack & pinion is faulty. You will need to have it replaced. It is not particularly difficult to replace, although you do have to lower the subframe to get it out. If you do not have access to a vehicle lift this could be tough to accomplish safely. After replacement you will also need to have the car aligned. You may be better off taking it somewhere for the repair.

Replace power steering pressure switch or check connection,

you need a new pump

It is an electric assist steering. On very heavy use the motor can become overheated and goes into "safe mode" only partial assist until it cools down. Repeated attempts at parrallel parking have been know to cause this.

Hi Dan

You did not indicate whether you checked the fluid level for your power steering. Please check this first. Please read your owners manual for specific instructions!

You may be low on fluid.

The next step would be to check your engine belt. The power steering pump is driven by a belt. It is possible that you have a loose or worn belt that is not able to turn the pump sufficiently at idle, but when you rev the engine higher, the pump produces sufficient power. One way to test this is to rev the engine, then try to turn the wheel, see if you notice any difference. Let me know.

Brian