Vss signal loss issue

oilwell1415 said:
Have you had your alternator tested? It generates an AC signal that is converted to DC by a rectifier bridge using diodes. If one of the diodes fails it will send an AC signal that could confuse things when you are stopped and the VSS is no longer sending a signal. Once you are moving the VSS signal washes out the alternator.
Click to expand...
What an interesting idea.

I presume this could be tested by just disconnecting the alternator and going for a short drive?
 
FMOS Racing said:
What an interesting idea.

I presume this could be tested by just disconnecting the alternator and going for a short drive?
Click to expand...
I guess you could do that. I would just take it to the parts store and have it tested. If they can't find a reason to sell you a new one, you can bet it's good. You could probably also put a DVOM on it in AC mode and see if you get a reading.

Bad alternators cause a lot of phantom problems, especially in circuits that are looking for an AC signal. Checking the alternator was always one of my first steps when I got something in with a problem like this. I think I found a bad alternator causing the problem maybe 5 or 6 times in 10 years that was the problem, but that 5 minute test saved me hours of pointless trouble shooting in those 5 or 6 times. Another random problem generator is the MLPS. I had one cause a headlight problem on a Taurus once. There is no way in hell an MLPS should cause a headlight problem. I have no idea how the two are related, but apparently if you take just the right combination of powers, grounds and signals they eventually lead both of them to the BCM and cause problems.
 
I did a diode test yesterday when I got home from, looked up how to do it, and that test out good too. If I get a chance I'll try and get it to that parts store just to double check it
 
The mlps was another thing I wondered about but wasn't sure it could have anything to do with the vss signals circuits
 
alarcont91 said:
I'm still trying to confirm that the wire are placed in the connector right
Click to expand...
It doesn't matter - it will work the same either way.

alarcont91 said:
...found all the ground location for the major components like g200, g100, driver kick panel, battery to fender to frame to engine block and cleaned everything up.
Click to expand...
Post pics of the battery terminals.

Raymond_B said:
...my book does not show the C404 connector pin out
Click to expand...
Ford does not provide EVTM pinouts for connectors with fewer than 5 pins. Some are shown in the service manual or PCED, but not all.
 
Oem connector has a cap on back of connector so it would need to be remove to see how the wires are pinned
 
Steve83 said:
It doesn't matter - it will work the same either way.


Post pics of the battery terminals.


Ford does not provide EVTM pinouts for connectors with fewer than 5 pins. Some are shown in the service manual or PCED, but not all.
Click to expand...
Is there something in particular with the battery terminals I should be looking for
 
i can't find the article sent to me from a bad mlps. but it stated that it caused all kinds of wierd issues that were very difficult to diagnose. ford had a tsb on it because so many dealerships were at a loss on the issues from a bad mlps.

my mlps went out and my 4low quit working as well as my cruise control......replaced it with a new one and both of them worked again? i still don't understand it, and its crazy odds that it fixed it, because i didn't do anything else to either of those.
 
Well I got the new ecm from stinger and now at soon as I turn the key on the overdrive off light is on and stays on doesn't blink or nothing and still have the same vss issue. Wtf. I bout to burn it to the ground. So annoyed right now
 
alarcont91 said:
Well I got the new ecm from stinger and now at soon as I turn the key on the overdrive off light is on and stays on doesn't blink or nothing and still have the same vss issue. Wtf. I bout to burn it to the ground. So annoyed right now
Click to expand...

Yeah I was worried it's not the ECM. Let's go back to where you mentioned there were repairs to some portion of your VSS circuit, I asked before, but not sure you answered.
 
Look like someone installed a new connector pig tail at the vss in the rear. Wires orientations are correct. They connection they made are shrink wrapped. Also I don't know why the overdrive off light is on as soon as I turn the key on. Checked the wires in the collumn but nothing look wrong there.
 
The od off light doesn't blink or anything just stays on till I turn it off have did anything else to the truck other and swapping ecms
 
alarcont91 said:
The od off light doesn't blink or anything just stays on till I turn it off have did anything else to the truck other and swapping ecms
Click to expand...
You loaded your same tune as you had previously right? Also look through the Stinger instructions, is there a jumper that needs to be set for an analog range sensor?
 
You must log in or register to reply here.
Back
Top