Truck is a 2003 Expedition Eddie Bauer, 5.4 4x4

Wife driving truck and apparently it went bang and then was loud like an exhaust issue.
- tracked that to the #4 plug backing out and the COP breaking.

However, the truck has in the message display "PRNDL error no back up aid" and the truck will not start. Hooked up two different code readers and neither will read at all, so I am guessing that the PCM is not being found?

- Checked the fuel cut off switch
- Checked Starter motor (Jumper) and it turns under battery power just fine
- Checked all fuses, they are fine
- Relays appear to be fine - nothing blackened or melted
- Checked backup lights when in reverse and they work
- Tried starting in all P,R,N,D,L positions with no luck
- Replaced the Auto Trans Gear Position Sensor, thinking it may be bad, no change

Any ideas, I am quickly running out of other things to check and going to the dealer is sadly becoming a realistic solution!!!!

My only other thought is to remove the Fuse panel and see about any other relays on the back (the theoretical R 301, 302, 303)

Please help!

Anyone with an idea??? Please, otherwise this is likely to go to the dealer this afternoon.

 

So now the best I can figure is that the PCM is not getting power somehow. Maybe this happened during the #4 plug backing out? I haven't found anything that looks severed or disconnected, of course that is against the firewall.

Any advice?

 

Try swapping the ASD relay with another similar one and see if you get power back.

 

Not sure where the ASD relay is, this is the Auto Shutdown Relay, right?
Not seeing a reference to it in the manual that I have. Any chance you have a picture or diagram to help me find it?
Thank you

 

Ok, still have not found the ASD relay, did hook up to a jump box and getting 12.5V and at the battery, when I go to key on (no start) nothing happens, headlights and climate control will come on.

So I decide to start checking fuses with voltmeter and find the passenger side floor very wet (rained last night). Pulled the kickplate and found standing water in the channel for the wiring harness.

Will look at vacuming out the water and blowing with cmpressed air to dry out and start looking again, Any other ideas?

 

R203 is the ASD/PCM relay. Fuses 32, 33, and 34 all tie to this relay so double check those to see if any are blown.

 

Relay 203 is in fact faulty, tried switching with the 202 Relay for Fog lights, no luck, maybe noth need to be in in order to work? Heading to the dealer to get a coule of the 203 style relays, cant find them anywhere else. Hopefully this will give me some progress.

 

Update - still no start with PRNDL no backup aid error on message center, I have since done the following

- Vacuumed up the water, really not much after-all, but gone now
- Sprayed down the wiring that had any water contact with WD-40 and then wiped down after sitting for a few hours
- Replaced the 203 relay, still no start
- Put battery on charger overnight, now at full charge - reading 12.51v
- Took out the fuse panel, inspected no dark areas no corrosion at all, but sprayed electrical cleaner around the R300-305 relays anyway to remove any doubts, swabbed with Qtips
- Put everything back in place, triple checked that all relays are clicking over fine, all fuses in correct place with correct size fuses, clean etc.
- reconnected the fuse panel
- went to start the truck and nothing
- starter still spins fine when jumped
- tried pulling the TPS and starting (recommended to me - not sure why)
- rechecked the backup aids and no problems with them, no frayed wires

Still get the same PRNDL no backup aid error, all gauges work, radio plays, climate control works fine, but will not start or even try to start.

Any other ideas before I have to give up and send it in for repair???

 

So I got it to the dealership and the good news is that I have not missed anything.

The bad news is that the service department is stumped as well; apparently the PCM is coming up blank and they have no idea how that could happen.

Looks like I will know more tomorrow and hopefully can get Ford to pony up for a new PCM.

Thank you all for the help.

 

A blown fuse, a bad PCM, or broken wires, choose your poison.

 

guessing a bad PCM, broken wire but at this point I am just hoping that they can take care of it and see if Ford can cover it in some way since this should not happen, not like we drove into an MRI and wiped the system out. I'll let you know what they find for future reference.

 

So apparently the dealer has diagnosed a bad PCM. They gave me a totally useless quote that say:
Other - $757.00
diagnostic - $109.95
diagnostic - $190.00
subtotal - $1056.95
Shop charges - $40.00
tax -$0.00
total - $1096.95

Since I brought it in with significant detail and testing on where to start and had the techs call me twice for background and details I can not imagine why I would be charged twice for diagnostics at different costs. Then other, what the hell, This is exactly why I don't bring things to the dealer. In theory the service manager is calling me this morning to review and get me a detailed quote.

Anyone else have an idea of what a PCM replacement should run? Seems like they need to be coded when installed to the VIN# so I am guessing this is not something I can really take care of myself.

Thanks

 

Got the bill down on the PCM replacement, seemed to work fine until we tried going somewhere after the dealer and wouldn't start. They towed it in on their dime, tightened the connection left loose and seems to be back up and running fine now.

Until further notice issue is fixed. Thanks yo all who helped with this.

 

I got the same message in the message center. I bought a used PCM and it was flashed for my vin#. I checked the fuse panel for burnt connections at R203. I put fuse panel back together and now no lights or anything working on instrument cluster. Removed fuse panel again and found no issues. Reinstalled fuse panel, new pcm. I still have no instrument panel lights and still wont start. Any ideas.

 

Do the illumination lights work?