Stiff Steering; VAPS Codes

[theophile]

'02 V8 Sport.

A couple months ago I started noticing that the power steering would seem to go out intermittently and it would get hard to steer. After about a week of this, it just started staying stiff all the time (yeah yeah, that's what she said....) I finally got around to doing something about it. Scanner reports these codes:

C1924: VAPS Solenoid Actuator Output Circuit Short to Ground
C1925: VAPS Solenoid Actuator Return Circuit Failure

Shop manual prescribes two pinpoint tests at the Front Electronics Module--Pinpoint Test "A" for the C1924 code and Pinpoint Test "B" for the C1925 code.


PINPOINT TEST "A"





PINPOINT TEST "B"




Figuring they called it "A" for a reason, I started with Pinpoint Test "A":
Step A1 -- No continuity at all between Pin 9 and ground, so I go to step A2.
Step A2 -- With ignition switch in "Run," I get +11.55V at Pin 1.
Yikes! It wants me to replace the FEM!

So I move to Pinpoint Test "B":
Step B1 -- With ignition switch in "Run," I get no voltage at Pin 1. On to Step B3.
Step B3 -- With ignition switch "Off," I measure about 7-8 ohms between Pins 9 and 2.
This suggests I need a new P/S actuator, and if that doesn't fix it, then a new FEM.

I'm inclined to blame the actuator because my research on LVC indicates that the actuator is a common failure item. However, there do not appear to be any posts here discussing either of these two codes, except for the thread that lists out all the Ford DTCs. So I wanted to post and see if anyone has had any experience with this particular issue. I'm also interested to know if anyone has a lead for a good price on the P/S actuator. It looks like the actuator is part no. 6L7Z-3N803-A (supersedes XW4Z-3N803-BA). I haven't seen any aftermarket versions but I may not have looked in the right places.

Another question for those who might be more familiar with Ford's diagrams: Step A1 in the first diagram (for example) has pictures indicating that you should first turn the ignition switch to "Off," then disconnect FEM harness C201a, and then take the specific measurements described under step 3. Step A2 has pictures indicating that you should turn the ignition switch to "Run" and then take the described measurements, but it doesn't give any specific indication about the state of the C201a harness. When I did these tests, I interpreted this to mean that the C201a harness should remain disconnected as it was in Step A1. Is this correct? Or does the lack of an instruction to disconnect that harness mean that it should be connected for that step?

Sure would appreciate any comments or suggestions anyone might have!

 

[theophile]

I found a decent price on a new actuator on eBay, and the part arrived today. It looks like it's going to take a 48mm deep-well socket to get the old one off and the new one on. Yuck.

 

[theophile]

Well that was fun.

I got a 48mm wrench, which was so long it was hard to turn because the other end kept hitting the ground.

But I got the old actuator off and the new one on. Refilled and bled the system. Cleared the codes, ran the self test, and . . .

. . . the codes came back.

I drove it around the block. It felt OK but not like it's supposed to I don't think. I'm going to give it a day then try clearing the computer with a battery disconnect. If the codes come back, the manual indicates I need a new FEM. Is there some other way to verify this? Nothing else seems amiss and I'd really like not to have to replace the module before being certain it is malfunctioning.

 

[tbird6]

I am fighting this on my 2003 LS V-8. I can't get any codes but think the normal auto parts store scanners can't see that deep into the system?
What did you use to get those codes?

The system changed a bunch with the 2003 upgrade because it uses a different steering rack. But the trouble shooting is still very close because I am looking at replacing the FEM also but am not sure that is the problem. The later VAPS solenoid is simple to change and has 2 small Allen head screws holding it to the rack. My solenoid measure what the shop manual says so I think it's good but not completely sure.

Thanks for posting and I will be watching to see if you figure it out.
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[theophile]

I am fighting this on my 2003 LS V-8. I can't get any codes but think the normal auto parts store scanners can't see that deep into the system?
What did you use to get those codes?

The system changed a bunch with the 2003 upgrade because it uses a different steering rack. But the trouble shooting is still very close because I am looking at replacing the FEM also but am not sure that is the problem. The later VAPS solenoid is simple to change and has 2 small Allen head screws holding it to the rack. My solenoid measure what the shop manual says so I think it's good but not completely sure.

Thanks for posting and I will be watching to see if you figure it out.

I used a generic ELM327 Bluetooth OBD2 dongle and an Android app called Car Gauge Pro. It doesn't have the best interface and it's not intuitive, but it's powerful once you figure it out.

I have not yet solved this problem, though I have taken s break from hunting it down. My next step is to physically follow the wiring from the actuator to the FEM to verify its condition.

 

[tbird6]

Thank you and I did get my ScanXL software working and I did finally pull codes C1924 and C1925 the same as you did. I get the same two codes regardless if the VAPS solenoid is plugged in or not. I erased the codes several times and made sure they did come back and did repeat.

I was able to do detailed circuit checks too. The solenoid measure 8 ohms and is in range. Everything checks fine EXCEPT I have a dead short to ground on the BRN/GRN wire as measured from the plug end under the car. This wire goes directly to the FEM. If I remove the plug with this wire from the FEM the short goes away. I think my problem is inside the FEM.

I am currently looking for a used FEM Part #3W4T-13B525-AB. Of course as you know this is a programmed module so all I can do is check if the BRN/GRN wire still has a short in it or not when plugged in. If the short goes away I plan to take the used module to Ford with instructions to swap the FEM and load the used one with my car information. I don't think I can do this at home?

Reading your problems they seem identical to mine so I think you will also need to replace the FEM. Be sure and look at your old one so you can match the part number exactly as I have already found a couple of variations of the base part number. They may work but I will look for a module with the exact same part number on it.

Your wire colors are identical to the ones in my 2003.

I did find a place that will rebuild these FEM's too for $145.

http://www.midwestteckmart.com/#anchor_249

They even mention error code C1924!
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[tbird6]

Well I got it fixed!!!

The problem was the FEM. I got a used one off Ebay for a reasonable price. Matched the part number exactly. Paid Ford $90 to program it and the car is now fixed!

Steering just like it should and boy is the wife happy now!

With your codes I am very sure you also need a FEM to fix it. You might do what I did and unplug the VAPS actuator. When I did that the car steered the same and I got the same error codes plugged in or not.

What threw me was the VAPS system should be fail safe and go to full steering boost when anything goes wrong. Mine did not and seems to have gotten stuck somewhere in the middle settings.

Oh I was wrong above about the dead short. That pin is a ground inside the FEM and should be a short. This is an error in the LS factory shop manual procedures. That also threw me off.
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[DaleGrib]

Just wanted to say this was a very helpful thread I was having the same issues with a 01 LS V8 I purchased. I had the same 2 codes and Steering was hit or miss. Replaced the FEM and Programed the As Built Data with my ForScan tool and the issue went away. Thanks !