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Has Anyone Ever Tested Their Pps Solendoid?


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My '96 LS is returning to center very poorly and is hard to turn at lower rpm's. Hard to tell at highway speeds but it feels like there is more power to the rack at higher speeds. I've got the factory manual and followed the test procedure for the PPS system. The resistance on the solenoid is within spec but when I put straight 12v power to it the plunger inside moves maybe 1mm tops down and does not make a clicking sound. Would this cause the steering to feel very hard at lower rpms? There is also no screen on the solenoid around the holes. That was odd to me. The rack was replaced after a shop used power steering fluid in the system and it ate the seals up and started leaking like crazy everywhere.

Has anyone tested their solenoid and does it actually click or should it only move 1mm or so slowly. Seems like mine is faulty but Lexus wants $580 for a whole pressure control valve w/ solenoid. Think I might go to a junkyard for this one. Any ideas?

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Just got back inside after working on the car. There havn't been any replies but there are some views so I'm guessing some poeple are curious as to what comes of this issue. I know that alot of my posts are problems but I'm just trying to start subjects and have several educated opinions on the issue and just try and add to this great resource for others to find under the search function. Even if you don't know what the issue is any post is better than none if it can raise other questions and possibly help each other come to a conclusion. Alot of these issues are common but sometimes have different techniques and possibilities to solve. Anyway's, no to my steering issue.

The steering rack was replaced by a shop in town after another shop that serviced the car flushed the power steering with power steering fluid. The whole system took a crap and I know for sure that they replaced the rack but not too sure about the pump. They may have just replaced the seals or something. I HIGHLY doubt they replaced the rack with an OEM part, probably aftermarket. I removed the solenoid on the rack today with channel lock pliers after unplugging the connector and unclipping it from the bracket. I had an oil pan ready to catch the 1/2 qt or so of mercon that drains out. Try and keep the draining fluid out of the connector obviously. After pulling it I find that there is NO screen around the holes on the solenoid. The aftermartket rack must have came with the pressure regulating valve w/ solenoid because they shop used crimp connectors to splice the connector on to the new rack. I thought the climp splices were some of the problem with extra resistance to the solenoid. I measured the resistance on the solenoid between the connector pins and then stripped the insulation past the splices and the resistance was pretty much exactly to the same.

The factory manual states resistance between the connector pins should be between 6-11 ohms. Mine was around 8.5 ohms. Then connect a 12v power source to the solenoid and make sure it clicks. To make sure you know which pin is negative and positive you would be better off being able to refer to the manual. I don't really know what may happen if you hook it up backwards.

Anyway's, mind did not "click". My solenoid would slowly try and move less than 1mm. It appears the valve should move down much more than 2mm. Only enough to cover the holes and block flow. I sprayed carb cleaned up inside and then some WD-40 and it sit. I then soldered the connector and got rid of those crimp connectors. Gives me more piece of mind. I then took a nail and pushed down through the top of the solenoid down on the valve. I was able to kind of break it lose and pump it up and down without electrical power applied. The WD40 started to break some of the stuff up. I poured the WD40 that was inside out and it was pure dark black. I cleaned it out and sprayed some more WD40 inside and pumped the valve up and down and it came out black again. After this the solenoid had more of a "click" to it. I reinstalled the solenoid and hooked it all back up. The resevoir took about 1/2 or so, not exactly sure, then jack up the car so the front wheels are off the ground. Turn the wheel back and forth lock to lock several times, with the engine off. Then check the fluid again. Put the car on the ground, started it up, and drove around the yard holding the steering at left and right lock for 30 seconds several times. After driving the car after all of this it steered soo much better. Before it wouldn't return to center as it should, you had to manually steer it back to center. Now it steers much much much easier at all speeds, especially near idle.

Here is a question for you after my experience tonight. The car used to not only be hard to steer but it had a "ratchet" type of feel to it. As the wheel turned it felt tight-lose-tight-lose-tight-lose then lock. This happened slightly more to the right than the left. What was weird was that you also feel it turning the wheels while they're off hte ground with the engine off. No pump or anything is involved then. After working on the solenoid the car steered much easier but still had a little of that lose-tight-lose-tight feel. I'm pretty sure the rack is aftermarket and my mother (it's her car) drove it into a hole in the yard pretty hard. I'm thinking this may have warped the rack somewhere. It may just have been built and installed that way since the rack is aftermarket. I'm pretty sure it's just a quality issue with the current rack than anything else since you can feel it with the engine off and wheels off the ground. Would you guy's agree with that? It just has a little catch every half turn of the wheel or so. Not a big deal to me as long as it's easier to steer and doesn't leak etc...

Here is what I feel may have happened. As I mentioned, the solenoid did not have a screen. It should... I think some grit, dirt, metal shavings, etc... got down into the solenoid and kind of got it stuck. The carb cleaner and WD40 and pumping with the nail seemed to clean alot out. Not it works more as it should. The factory manual doesn't really point towards the solenoid screen with hard to steer and poor return to center. It just points to the PPS (Progressive Power Steering) system. I definetly think this screen should be part of somewhat regular maintenance and first looked at for any power steering feel issues. It also allows you to add some new fluid. Mine was still nice and red so I didn't flush the whole system this time. Those of you with black fluid should consider flushing with the return line disconnected.

Any comments or suggetsions?


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