how do i know if the pcm is bad for sure on a 2002 ford expedition 4.6L

Asked by Jul 25, 2013 at 09:28 AM about the 2002 Ford Explorer XLT

Question type: Maintenance & Repair

truck wont crank all lights come on, battery is good . Starter is good, however antitheft
light is blinking. when i turn the key nothing happens.

14 Answers

sounds like a classic case of a corroded 1/0 battery to chassis ground being corroded from over 300 amps going through that spot again and again...in effect "welding" the lug in that spot...only trouble is there is not enough area to pull 300 amps thru that spot anymore...get a coarse wirebrush...disconnect the 1/0 lug that goes to the frame and wirebrush that spot to be able to pull 300 amps----also make sure the battery is newer than five years old~ may be good but will not see the full potential unless it is new...or newish...check the push off labels on the top of the battery indicating the date of the first charge to be sure~

5 out of 5 people think this is helpful.

the pcm is NEVER bad....the ground connection to the PCM could be bad~

6 out of 6 people think this is helpful.

Judge Roy is correct, but if that does not do it, You can try to re set the Anti Theft system. Might work, especially if you accidentally put the wrong key in, it 'arms' the anti theft until re set Inside the head of the key is a transponder chip that is programmed to a certain code so that the PCM/ECU in the car recognizes the key. When you are sure you have the correct key, try to start the car with it. If the Explorer still refuses to start, move on to this: Wait 15 minutes, until you see the flashing rate on the red light on your dashboard decrease to normal speed and then try both keys again. If this still fails to start the car, raise the hood and disconnect the battery for 15 minutes, then reconnect it and try again.

3 out of 3 people think this is helpful.

howdy David~ :)

2 out of 2 people think this is helpful.
87,075

I have to disagree with you on a PCM never going bad, I've seen quite a few go bye bye, so symptoms were no idle control, timing over advance, injector signal full pulse, and some just down right dead. So they do fail. This rig sounds just like my neighbor Ford F250 his was doing the same thing only occasionally it would start and run normally then all of the sudden while driving the alarm system would go off. Long story short it was the PCM.

9 out of 9 people think this is helpful.

...well tarNfeather and run 'em out on a rail~ there really should be a "mark hurtful" button~

...or ground to the unit~

1 out of 1 people think this is helpful.
405

i have an 04 explorer that wont turn over or crank. worked great sunday night and on monday morning, it turned over 3 times then nothing. theft light flashes rapidly. battery was bad. replaced it. starter is good. starter relay is good. not turning over. can anyone help me? i was told to try the starter switch?? my truck threw the B1601 code.ford dealership couldnt figure it out. ALSO, my door ajar light is on. ive sprayed all door locks, opened and closed a million times, etc. so because of that, my lock and unlock switch on driver side does not work and neither does the keypad. someone please help me.

33 out of 33 people think this is helpful.
140

I have a 2002 ford Explorer and the no crank symptoms only occur when it drops below 15 degrees in the winter time. I have lights and gauges but will not crank. Was told PCM is bad.

14 out of 14 people think this is helpful.
10

My car doese kinda the same one day its good rhe other its bad like it dont wanna go in gear an down shift on its ain a 2006 ford explore

1 out of 1 people think this is helpful.
20

I have a Ford Explorer XLT 4.6L 3V V8. ODM shows a P0645 code. Hay I can solve this Issues?

2 out of 2 people think this is helpful.
10

How

1 out of 1 people think this is helpful.
10

Hey I have a 2000 Ford Expedition that just died the other morning been running fine until that point. They anti theft light came on and it would just turn over not start. Then once I got it back to the house unhooked the battery and performed reset on theft system.....now it starts but runs like crap, no communication from obd port and no instrument cluster (mileage, rpm's etc.....)

1 out of 1 people think this is helpful.

My obd gave me the wrong cord. No communication. What is the problem..?

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