AC and P0354 Ignition Coil D Primary circuit fault
Sorry this is long but it could save you hundreds. I just thought I would post this as I'm sure it has happened before and will certainly happen again (just not to me). Hopefully, it will save someone time, money and aggravation. The issue here is something that leaves me questioning Ford engineering. Ok, so here we go. I have a 2008 Expedition EL and this past Friday while on the interstate I noticed my air not as cold as usual, at the same time I noticed a hesitation / stumble at speed. Upon exiting, at idle, the car had a bad miss and the AC now was nothing, just blowing hot air. It wasn't until I made it home (which was only a few miles away that the amber engine light came on. Ok, off to Advance and I will have the code read to figure out what was going on. The guy at advance relayed the code to me (P054 Ignition Coil D Primary circuit failure) and promptly informed me that the likely culprit was the coil pac as they are notorious for going bad on the 5.4. Although he did not know which cylinder I later deternined D was #4 on the pass. side closest to the firewall. Great, I thought $45 and some struggling against the firewall and I will have fixed one of the two isssues.
So, what happened to my AC? Maybe I have a leak and just need to recharge it I thought, but after looking into it, the compressor would not engage. Perfect, $300 plus to fix that one.
Oh well, back to the coil pac, in 15 minutes the new one was installed the truck fired up and..yep, still a miss. So, maybe the plug is bad and not firing. This in itself is a crime, the plug could not be found locally. Seems that Ford had an issue with plugs and mid 08 changed to a different design, of course no one had it except the local Ford dealer. Yep, $20 later and I had ONE plug (so between coil pacs and plugs this thing would be a $500+ tune up). Anyway, back to the truck to swap out the plug..you guessed it, fired it up and still a miss. So what is going on? Only then, after spending $70 and many choice words the problem revealed itself. When unhooking the connection to the coil pac for the third time, the BS tape used to guard the wires peeled back and there it was bald copper with a millimeter of just plain yellow insulation. How did this happen? A quick look at the AC lines and the puzzle was over. The wires in all their natural glory laid up next to the AC line, which got hot and melted the insulation and wire, killing #4 and grounding the compressor all at once. Two seemingly different problems yet, one cause. After struggling to reconnect the broken yellow lead and placing a 1 cent cable tie to keep it off of the AC line all is well. Cold AC and no miss. Now I can only wonder how much my local dealer would have taken me for. So, if your AC quits and you get a miss on #4, maybe you can save the $70 I spent and come away with only a modest dent in your electrical tape roll and a 1 cent cable tie!
Just had to post a huge thank you! My 2008 just did the same thing and sure enough, it was the same wire. We checked it first after reading your post. You definately saved us alot of time and money. Just had to say thanks a bunch!
Thanks from My family too. We have a 07 Expedition w/ the same problem. The link above should take you to a picture of mine. I do have to disagree however w/ the cause of the A/C not working. I pulled my wires loose and started the vehicle still had the miss and no A/C. I then reconnected the rubbed in half wire and restarted. Everything worked again. My theory is that when the engine gets the dead miss from the wire being severed the computer cuts out the accessory that requires alot of horsepower in order to maintain as much as it can. Thanks again!
Thank you for posting this thread!! Exact same problems on my 2007 Expedition. Yellow wire was completely burned through. I spliced in another yellow wire I had laying around and wrapped it up good with electrical tape. Taped the lead to the harness so it would not happen again.
Why on earth do these problems always occur in the back of the engine compartment with tight access
Wow, thanks 1lrover1 for the post. I know you posted it two years ago, but it was my situation exactly! I replaced the ignition coil because the code said #4 was bad, then when that didn't fix it I started to switch coils to see if the coil I bought was bad. That wasn't it. Returned the coil and searched the internet for a second time. That is when I found this post. Went to the truck ('07 Expedition) and took a close look at the wires coming off of #4 and sure enough that was it. It was a bear to try and work in the tight space. I got two butt connectors and cut the two wires, reconnected with the butt connectors and started the truck to test my fix. Sure enough, no misfire and the AC was working again. Shut it off, taped the crap out of it with electrical tape and made sure it was it wasn't touching the AC line. Good to go. Dealer suggested the plugs needed to be changed and wanted $600. I spent $3 on the connectors! Dealer probably would have found the bad wire and not told me and still would have changed the plugs to make the money...not this time! Thanks again for the post.
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