please help 05 mountaineer no crank, security light flashing fast, had bad ground term

[orion1998_1]

ok, cold weather cheap battery cranked didnt start, replaced battery twice. ground terminal lose replaced it too. tried to start, no crank dash light on. security light blinks fast. was told pats/keys need reprogram. call locksmith he tells me it shows two keys programmed/ clears them tries to program first and says it wont take. tells me get another computer and call him to program keys to it. does this sound right? ive been pulling my hair out, lost job in dec. had cancer last year- removed and clear now. but money is so tight.

ps i see 2 bolts under hood removed them un hooked 3 plugs what else is needed to remove

 

[TechGuru]

Does your odometer show your mileage or ------ dashes?

remove for what? The PCM is not under the hood it's in the passenger side wall just behind the rear seat.

BTW, the only battery to use is the
Motorcraft BXT65-850

 

[orion1998_1]

when you when you first put the key in it shows the mileage but after it goes through need oil change low wiper fluid Etc there's just dashes is it the main computer three plug-ins looks like it's on the passenger side firewall pulls in through the passenger compartment but there was two bolts under the hood of holding a bracket also thank you very much for the response

 

[TechGuru]

Dashes mean no communication with PCM.

I'd be sure the PCM is getting power, have to check fuses, relay, and diode.

I believe those plugs are just for a firewall pass though.

 

[orion1998_1]

would continuity test work on these?

 

[TechGuru]

would continuity test work on these?

Pull the fuses and check them yes, same with diode but should only show continuity one way.

Relay you'll need a way to put 12V on the coil while checking for continuity.

 

[orion1998_1]

all seemed to check out, except may be diode, did not read continuity either way but has a diode setting, read one way .646 , this is whats behind rear seat in wall, isnt it the pats box?

View attachment 154264

 

[TechGuru]

A diode should read continuity one way but not the other. Sounds like it may be bad... Check the A/C diode and compare the results.

The part number is 14A604.

Dealer MSRP shows $10.58 at the dealers. Diode Assy | FordUS

I see some on EBay cheaper.

 

[orion1998_1]

ac one does the same, no continuity either way reads one way under the diode setting

 

[orion1998_1]

so according to this diagnosis id need a new pcm? on the 2005 mountaineer the pcm is under dash on passenger side? behind rear seat under panel was what i posted the picture off, looks like pats module

 

[orion1998_1]

MERCURY MOUNTAINEER ENGINE CONTROL MODULE 5L2A-12A650-KB

is this correct for waht i nee? i see some say need to program to vin? some dont, should i be able to replace then has keys programed?

 

[h82loseejr]

Before replacing the PCM you need to verify all of the power and grounds to the PCM at the PCM. just checking fuses is while is required part of diagnosis is not end all. Is the PCM communicating with a scan tool in any other way? can you pull codes and or get any live data and or trigger functions? Another module on the Data lines can disrupt communication to the PCM. Do you have communication with scan tool to any other of the modules? The instrument cluster? Transmission? Abs Controller? If you are not familiar with wiring diagrams and how to read them I suggest phoning a friend or someone who is good with diagnosing electrical issues. Way too many unknowns to be advising PCM replacement at this point. There are a number of things that can cause no communication not just limited to a bad PCM

 

[h82loseejr]

Also you would need to disconnect all of the other modules on the data lines then test for communication to PCM

 

[h82loseejr]

If you need the wiring diagrams I can get them for you. A good place for free wiring diagrams is BBB industries