How-To: Replace Power Steering Pressure Sensor

[Fuzzy]

Hey guys I had this problem over the weekend and after searching on forum info was poor at best. Here is what I have found. This sensor is used by all the dodge cars that use this platform and this seems to be a common problem. The process is pretty simple.

First off this code will only come up when you are traveling at 50mph or higher and engine coolant is 86F and above.

The 0551 code will only come on for two reasons. bad sensor or something is actually wrong with the power steering system.

In my case, I wasn't having any indications that i was having a real problem. After reading in the service manual, one of the jobs of this sensor is to maintain idle when steering (like maneuvering in a parking lot) it tells the pcm to up the idle so the car doesn't bog down. Well I never thought anything of it but my car would bog down if i was setting still and moving the steering wheel. I replaced the pressure switch and it fixed it.

The pressure switch can be bought from Autozone for about 28 bucks (part#PS399). I called napa and O'riely and they do not have it. You can also get it from your dealer or from RockAuto Parts Catalog (under switches).

So you will need the switch, power steering fluid, 7/8" deep well socket, extension longer then 8" long, jack, jack stands, something to catch the fluid, and some rags.

1. Jack the car up on the driver side, enough for you to get under it
2. crawl under behind the front tire and look about the crossmember you will see the pump and a sensor coming straight out toward you(see picture below)
3. unplug sensor(its bitch due to the lack of space)
4. get your oil catching container ready and use your socket wrench to unscrew the sensor(the deep socket allows you to go over the connector)
5. let as much fluid drain as you want. Make sure the old rubber o ring came off with the old sensor and install new sensor BY HAND.
6. Tighten new sensor but be careful not to over tighten to damage the sensor or worse the pump.
7. Take your time and clean all the old fluid off car. the cleaner you get it will help you know if you have a leak
8. reconnect the sensor
9. lower the car back off the jacks and fill the power steering pump back up.
10. start the car and go from lock to lock on the wheel. Turn off motor and recheck fluid level.
11. After the fluid has reached the full mark let the car run and look under to see if you seeing anything leaking.
12. I turned the car off and rejacked the car up and checked to be sure.
13. reset the code and take a 30 minute highway cruise to see if the problem is fixed.

Here is a picture of the sensor from the service manual


Here is the two pages from the service manual for deeper trouble shooting of the switch and wiring and a little more details of what I just went over.

[cz3ch]

Thanks for this write-up! I have this code periodically and the PSS seems fine, I'll try the sensor, hopefully this takes care of the code.

[bordeniuk]

could someone possibly take a pic of what exactly your talking about.

[Hi N Mity]

I have witnessed this code a couple times at the roadcourse. both times, 2 different cars, topped off the PS fluid and the code has yet to come back almost a year later

[Fuzzy]

Quote: Originally Posted by bordeniuk

could someone possibly take a pic of what exactly your talking about.

the first picture i posted is a really good one. Although its a line drawing, if you were to jack the car up and look above the cross member behind the front driver side wheel you would see the pump and the switch staring at you in the face.

[bordeniuk]

well i think i know what sensor it is if its the right one mine is leaking, you think this could be a problem i havent had a CEL, but my afrs do act retarded when im turning at idle or pulling into a parking space

[Fuzzy]

well with mine, the extra load the motor gets when moving the steering wheel at idle, the motor would bog down. this sensor is suppose to idle up the car to counter act the lower rpm/load of the power steering. After I installed the new sensor this problem went away.

If yours is leaking i would replace it, the pressure switch may not be seeing the real pressure due to the leak.

This sensor has a rubber O-ring, which could be damaged in your case.