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500 Miles From Home Power Steering Going Out?


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I apologize if this is not the place to post this or if this is considered a no-no, but I’m desperate! Help. I have no idea what to do. I’m on a road trip and my power steering is going out? I’m spending the night searching the internet and posting to find help. Please, Please, Please… HELP….I have a 91 LS400 about 100,000 miles. For the last few months after driving high speed in mostly straight roads. If I pulled off the highway and made a slow speed tight right turn, I would loose power steering for a second or two. This only happened after driving at least 80 miles and then not every time. And never on a left turn. I called a few dealers about it 3 had no idea. One told me to flush the power steering fluid. And the last one told me to bring it in and get ready to pay $2000.00 for a complete new power steering unit and rack! Thought the last guy was nuts. Took it to a locale guy to flush the system (I live 100 mile from the closest dealer). After the flush, the power steering was really bad when the car was at low rpm or at a stop. Garage told me air got in the line. Just drive the car and it will be O.K. air will work out of the lines. I have driven the car (500 miles). I have simply sat parked and turned the wheel left to right full lock over 50 times. It has been 2 days. Steering is getting worse not better!!!!! Also fluid looks really dirty?? Strange as it was not only replaced but flushed???? Reservoir is full. Help. I have to drive another 800 miles. May arms are getting sore and this can’t be safe. Please any thoughts?????? System makes no noise or strange sounds runs quite. Works good at speed over 2,500 rmp. :shutit:

Thank you

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Yes, thank you that would help. I have now done just that. I was so burned out and sleepy that did not relize I was on the UK side. But to update you...

Strange, but the problem has almost gone away. I was making a right hand turn at about 5 miles an hour when suddenly I got my power steering back. I have driven about 50 miles today and it is staying good. Before I had no power steering under about 2,500 rpm. Now it is almost all back. I only loose power steering under 900 rpm. I am positive it is the assist valve located on the drivers side of the rack. I’m sure the screen on it was clogged and it is clearing itself. But I still plain on getting the unit fixed before I leave L.A. Again thanks for the help.

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Thanks to everyone that has been helping me. On Monday I tried calling the mechanic recommended to me. But Walt was out sick and I talked to a Brian. He did not sound like he knew about the Solenoid. As such I really did not want to make the drive out to him. I then called a friend I used to know in the valley. He builds race cars and does some work on American cars. He told me the lift was free and to come over with the info on how to do the work on the Solenoid.

It took more time to get the car on the lift then to remove the solenoid. Now that I have seen it done I would say that if you can change your own oil. You can do this.

Strange. On looking at the solenoid, we could see that it had been removed before (chisel mark on it). At any rate he removed it and cleaned it. On cleaning it we could see that on the last cleaning someone pushed two if the screens in.

We called around but it is almost imposable to get just the Solenoid. It only comes two ways. As part of the valve at around $500.00 to $600.00 or in a complete rack with the valve and Solenoid for about $400.00 though Lexus dealers.

I was not going to deal with a fast decision to spend $400.00 on a rack, and $300.00 to install. So we just put the cleaned solenoid back into the car.

It helped a small mount more. So now I even had some power even at a stand still, but it was not what it should be.

I then drove home.

I took this car over from my dad after his stroke. Going over the paperwork I found that at 60,000 miles Vista Lexus rebuilt the power steering pump. The car now has just over 106,000 miles on it. I called Vista this morning, and asked about the job. I was told that they always remove and clean the Solenoid whenever they replace or rebuild a pump. But they felt no responsibility about the screens. They told me that the screen deteriorate and get holes in them naturally over time.

So now we know that the dealers know about cleaning the Solenoid and it’s apparent relationship to pump failure.

I would love to hear all your thoughts on this and the comment the dealer made about the screen on the solenoid.

My plan:

Jack the car up on stands. Pull and re-clean the Solenoid. Check it electronically. In cleaning the Solenoid this time I will apply low current to it to open it when I clean it. I may even soak the top part in cleaner. As the screens are partly gone, it could have gunk in it. Then reinstall. Flush the system, and re-clean.

If this does not do it, and the unit checks O.K. electronically, then I’m stuck with a bad valve, and It’s time to do the full rack (they can be found rebuilt with warranty for $200.00 to $300.00). So, worst case I’m looking at a $600.00 bill, still better then $2,000.00 at a dealer.

If the Solenoid cleans O.K. and the system works I will still try to find a replacement one with good screens.

I’ll let everyone know the outcome. I have spent a lot of time finding out everything I could on this, and visiting at least 15 user groups around the world. I found the following information. As I never found it all in one post or on one site I thought it would be good to post it. Please understand this is from mutable sources and more then one contributor. I believe it is very accurate. But check for yourselves.

How to service Solenoid:

Disconnect the wires

Take a sharpie and mark a registration line across the nut & on the steering rack for positioning.

The Solenoid is connected by a thin nut, use either very thin channel lock pliers or just take a flat screwdriver or small chisel and "tap" the nut to loosen - then remove by hand.

Behind the solenoid or attached to it, will be the screen and a gasket, just be careful with it and remove. You'll loose 1/4 quart+ of PS fluid....a little messy, so be ready!

Clean the screen, replace, and tighten solenoid back to registration mark. Tap it back tight with the screwdriver or chisel you used.

Good cleaner to use:

Suggest 3-M Adhesive Cleaner instead of Brake Cleaner. The brake stuff is fairly 'mean' with toluene in it !!!! And it evaporates too fast for an overall cleaner. The 3-M product # is 08984 in a qt. or 08987 in a spray can

Reconnect electrical.

Then flush system.

Directions on flushing system:


It takes about 7 to 8 quarts to flush most systems clean one time. Use Dextron III Transmission fluid. Valvoline makes a good one for High Mileage cars.

After flushing system it is best to re-clean the screen again.

Checking the Solenoid electrically:

Measure the resistance on the solenoid. It should be between 6 and 11 ohm. After this check the operation. Connect Battery terminals to the solenoid. when you look at the connector the left one is - and right one is +. Check that the solenoid makes clicks sound.. don’t apply voltage for more then 30 sec otherwise you will burn it.. if you have to repeat the procedure wait till it cools down so you can touch it with your hand. If there is no click sound replace the pressure control valve with the solenoid valve.

Checking the power steering ECU. There is a PPS ECU specifically put there for the purpose of switching the solenoid on and off. Its located under the steering wheel right next to tilt & telescopic ECU. Check the voltage between the ECU - and ground connectors. - connector is in the upper left corner and ground is in lower left corner if you look at the connector while its plugged in into the ecu. voltage should be between 0.15 and 0.2 V with the engine idling. lift the car and put it in Drive. check the voltage while car running at 60 mph. it should be between 0.04 and 0.16 V. If its no you have to get yourself a new ECU. Don’t forget to check the wire from the ECU to the solenoid and make sure its ok might be just a wire problem

Picture of solenoid and nut (in this photo here he asks is this the Solenoid and do you pound here, the answer is yes) :

If needed rebuild of Power steering pump:

If needed information on the Air Control Valve (located on the side of the Power Steering Pump).:


and this guy states he can get parts… I have no idea if he is good or bad…….

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