Power Steering issue's

[hock]

The problem I am having is that the steering gets loose then tightens back up. If I turn it all the way to lock it will tighten back up.

Now as far as I know, this steering should be firm not loose. So where should I start looking, the fluid is good.

 

[naval-avi8or]

You either have a VSS (vehical Speed Sensor) or a power steering auxiliary actuator.

Here is how the two interact.
As vehicle speed increases the VSS input signal provided to the GEM causes the power steering auxiliary actuator gradually open, allowing an increasing amount of fluid to the secondary circuit. This secondary circuit requires more effort to reach a given level of assist.

 

[nik97]

Is this condition constant? I mean do you have min assist at speed and max at very low speed for the majority or does it constanly seem to fluctuate? It sounds like you are intermittently loosing your'e VSS signal somewhere(as it is multiplexed) or a bad connection in the actuator circuit.
How was your'e steering feel before this happened?

 

[hock]

Is this condition constant? I mean do you have min assist at speed and max at very low speed for the majority or does it constanly seem to fluctuate? It sounds like you are intermittently loosing your'e VSS signal somewhere(as it is multiplexed) or a bad connection in the actuator circuit.
How was your'e steering feel before this happened?

The steering was firm and very responsive before this started. The problem is intermitent and mostly occurs after I park the vehicle for a few minutes then start it up and leave. After that I can feel it fluxuating back and forth until it gets firm again.

 

[nik97]

As you may know, at low speed, you should have max assist and visa versa.
It sounds to me like you have a loose connector somewhere and you are loosing a signal or having a bad connection to your'e VAPS actuator. Unfortunately, the only quick way to tell is with an NGS(unless someone knows a good method otherwise). Your'e steering will always default to firm so it's hard to tell what's causing it.

 

[hock]

As you may know, at low speed, you should have max assist and visa versa.
It sounds to me like you have a loose connector somewhere and you are loosing a signal or having a bad connection to your'e VAPS actuator. Unfortunately, the only quick way to tell is with an NGS(unless someone knows a good method otherwise). Your'e steering will always default to firm so it's hard to tell what's causing it.

Ok, now I am kinda lost.

Since I bought the car the steering has been firm and required some effort to turn, kinda like my Supercoupe with the firm ride on. It has never had a lite feel to it until this started.

SO, should there be a time when its requires little effort to turn the wheel? OR, should it be firm all the time?

 

[nik97]

The SHO and all other taurus' have VAPS or variable assist power steering. The idea behind it is to have very low assist at highway speeds for stability and over correction prevension and max assist at low speeds like parking manuvers. This is controlled by the GEM or generic electronic module. There is an vehicle speed input to the GEM and an actuator on the steering rack as an output. The gem controlls the level of hydraulic assist based on vehicle speed.

You should normally notice a big difference in the required steering effort between 10mph and 65 mph. If the steering has always been firm that means the VAPS is not working and has defaulted to it's "firm" mode. Now, something has happened and it is intermittently working and you notice it at low speeds because of the sudden decrease in steering effort.

There are a few different possible causes of this. You may have a loose or bad connection between the GEM and the steering actuator or a bad power supply to the SARC module. How is the suspension/ride? Tho it is a possibility, I sort of doubt it is a bad VSS signal since you say the steering has always been firm.

 

[hock]

Well, as far as I know it does not have the ride control. I notices that a buddies sho had some "extra electronic" parts on his front suspension and mine didn't so I come to the conclusion that mine does not SARC (semi active ride control?)

But yeah, until just a few days ago the steering has always been firm. Now I'm understanding that it should be low effort at low speeds and firm like my SC at highway speeds.

So now I need to find what the problem is. THAT SUCKS! I thought my SC was bad when it came time for under hood work, but this thing is crazy!

 

[nik97]

Is it a '99? 99s did'nt come with SARC.

 

[hock]

Unfortunatly they don't.

 

[nik97]

So it is a '99? That eliminates a SARC power supply issue. I think it's probably an issue between the GEM and the actuator. How are your'e Multimeter skills?

 

[hock]

How are your'e Multimeter skills?

GOOD! What do I need to do?

 

[nik97]

Well, there are two ways you can go about this. 1, you disconnect the actuator connector and have firm feel all the time like before(easy). 2, you hunt down the problem in the circuit, repair it and have VAPS(not as easy).

 

[SHOZ123]

VAPS is controlled by the SARC controller in the trunk. Even though the struts are not.

Pull the fuse under the hood and see what happens to the steering.

 

[nik97]

Correct. According to Ford's description and operation, GEM controlls VAPS on non SARC vehicles. Then I noticed the diagrams show the SARC module in the 99's. Makes sense to keep the module I guess.

 

[naval-avi8or]

VAPS is controlled by the SARC controller in the trunk. Even though the struts are not.

Pull the fuse under the hood and see what happens to the steering.

Paul could you explain how the SARC module interacts with the VAPS/GEM. I have two different manuals and neither show the SARC module as part of the Steering system.

Thanks

 

[SHOZ123]

The SARC module has inputs from the ABS module (VSS on the Duratec) for vehicle speed. It then has outputs to the ZF gear solenoid on the steering rack to contol steering effort.

There also is a connection throught the Data Link network that communicates to the connected modules such as the GEM and PCM.

 

[hock]

Well, there are two ways you can go about this. 1, you disconnect the actuator connector and have firm feel all the time like before(easy). 2, you hunt down the problem in the circuit, repair it and have VAPS(not as easy).

So what do I need to do to find the problem?

 

[nik97]

Well, being an intermittent problem, it is a bit tricky. First, if at all possile, get the steering to firm(you mentioned turning to lock). That way, you can hopefully get the problem to exist.

Locate the SARC module in the trunk. Should be on the passenger side, behind the rear seat -under the interior. Disconnect the both module connectors. Then Disconnect the ZF actuator located on the steering gear(rack) near the linkage(PITA, I know).

1. Find a good ground somewhere in the trunk. Both SARC connectors should be 26 pin. The connectors are c450, and c451. c450 has a solid orange wire and a dark green with yellow stripe wire. With the key on, check voltage at both of these wires(ORG, DG/YEL). You should have 12V at each -Key on. The DG/YEL wire should have 12 at all times.

If this check is good, you have a good power supply to the SARC module.

2. Leave all connecors disconnected. Now check for a cross short in the actuator circuit. You will use both module connectors to do this(c450 and c451). Place one lead on the voilet with yellow stripe wire in c450 and the other lead on the grey with orange stripe wire in c451. You should read "OL" or zero continuity.

3. Check each individual circuit for continuity. The grey/orange wire is circuit 86, actuatot feed. The violet/yellow wire is circuit 153, actuator return. You will need a long jumper wire for this. Check circuit 86(GRY/ORG) by placing one lead onto c451(top right-GRY/ORG wire) and the other lead/jumper wire into the steering actuator connector(2 pins-GRY/ORG wire). Should have continuity, less than 5 ohms. Now check circut 153(VLT/YEL). Place one lead into c451(top left-VLT/YEL) and the other lead/jumper into the other pin on the actuator connector(VLT/YEL). If either reads OL or has >5 ohms, you must repair the circuit(there are 2 other connectors between the SARC module and steering actuator).

4. Check circuit 86 for a short to ground(No test light). One lead in 86(GRY/ORG) and the other to a good ground. Should be OL, naturally. If circuit 153 was shorted to ground, you would have a light feel all the time so there is no need to check this circuit for a short.

Post any questions

 

[SHOZ123]

So what do I need to do to find the problem?

First pull the fuse and see if the steering effort is then consistent. If so this rules out the steering hardware.