2006, F150 5.4L, Lariat - weird starting issue - F150online Forums

Go Back  F150online Forums > Body > Electrical Systems
2006, F150 5.4L, Lariat - weird starting issue >

2006, F150 5.4L, Lariat - weird starting issue

2006, F150 5.4L, Lariat - weird starting issue

 
  #1  
Old 01-12-2019, 05:22 PM
Junior Member
Thread Starter
Join Date: Jan 2019
Posts: 5
2006, F150 5.4L, Lariat - weird starting issue

Truck starts ONLY if PCM relay is unplugged & plugged back in, or disconnect & reconnect battery. If truck sits the battery (new one) drains as if something is on.

Background. Few days after new battery install truck would crank but not start. Thought fuel pump because we couldnít hear it when key was on, but wanted to rule out fuses and relays. Visually checked fuel pump fuse and looked good. Next I swapped PCM relay with fog light relay and it started, but as soon as I turned it off same problem comes back. If I simply unplug the PCM relay and plug it right back in the truck will start. Once started it runs great. We used an OBD reader and only got a P1000 code, which is a result of unplugging the PCM relay. Tried second key, but same problem. Thoroughly cleaned terminal lugs, same problem. Iím thinking itís the PCM itself but thatís an expensive guess. Suggestions?
 

Last edited by Redleg7; 01-12-2019 at 05:31 PM.
  #2  
Old 01-12-2019, 06:09 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 38,154
Have you checked the FPDM for corrosion?
 
  #3  
Old 01-12-2019, 06:34 PM
Junior Member
Thread Starter
Join Date: Jan 2019
Posts: 5
Originally Posted by glc View Post
Have you checked the FPDM for corrosion?
no, sir but will do so - THANKS! Have to travel for work but will respond after I get back and take a look
 
  #4  
Old 01-19-2019, 11:43 AM
Junior Member
Thread Starter
Join Date: Jan 2019
Posts: 5
Originally Posted by glc View Post
Have you checked the FPDM for corrosion?
I dropped the spare and visually checked the FPDM outer body and unplugged it to check electrical connection. The body really doesnít look bad considering itís an 06 w/195K mi. No rust. The pins are clean and it was easy to remove. I really have no other means to check it that Iím aware of. Would you proceed with changing it out anyway, or move to another step?
 
  #5  
Old 01-19-2019, 01:46 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 38,154
Did you remove it from the frame and inspect the backside of the module?
 
  #6  
Old 01-20-2019, 11:25 AM
Junior Member
Thread Starter
Join Date: Jan 2019
Posts: 5
I removed FPDM from frame and no rust or corrosion, just the white oxidation type which wasnít that bad. Brushed it clean and reinstalled. Same issue with starting though I noticed that with radio off, the CD stack kept clicking as if it was changing CDs. Made me think this was the source of draining the battery but it finally stopped after about 10 min.

Since it will start with a disconnect/reconnect of power source to the PCM I think it rules out everything but the PCM. Think itís time to hand it over to the folks with all the tools, though I still prefer to whip this myself.
 
  #7  
Old 01-23-2019, 07:22 PM
Junior Member
Thread Starter
Join Date: Jan 2019
Posts: 5
I got the starting issue fixed and it was the ignition transponder. Apparently disconnecting the PCM relay or disconnect/re-connect of battery would reset the system that allowed a single start before falling back to the issue I had. I appreciate clc's help and hope this update assists someone else.
 
  #8  
Old 01-23-2019, 08:46 PM
glc's Avatar
glc
glc is offline
Senior Member
Join Date: Dec 2006
Location: Joplin MO
Posts: 38,154
I would recommend you remove the FPDM again and coat the back with something to seal it, then reinstall it with standoffs to keep it out of contact with the frame.
 

Thread Tools
Search this Thread
Quick Reply: 2006, F150 5.4L, Lariat - weird starting issue


Sponsors

Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: