PCM Replacement?

Tiny
THORN616
  • MEMBER
  • 2002 FORD F-250
  • 7.3L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
I bought this from a dealer for a great price a years ago. Current issues I can name are. Key fob and inside toggles for lock and unlocks haven’t worked. The windshield wipers would randomly stop working. 90% sure it’s fuse 302/power train EEC relay is ticking constantly but stops when brakes are applied. The taillights stay on with no power to them but the brake lights don’t work. The turn signals don’t work. When driving down the road, the headlights went out. The running lights still and when toggled to park lights I have running lights but the main headlights don’t work when toggled. The door open light is always on but I’ve used a snap on computer with the OBD and the computer says they’re closed when I have all for open. Had a code to replace ECU and I did that today. Nothing has changed and I’m stuck. All fuses were checked. There was another relay in the engine compartment ticking but couldn’t find out what it was. Swapping relays fixed the one in the engine compartment from what I see. I can provide pictures or details for anything else, I’m just lost. Could it be a bad PCM?
Wednesday, April 8th, 2020 AT 6:33 PM

61 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Wow, I'm not sure where to start with this one. Have you checked all grounds? I ask because there are so many unrelated issues. It doesn't seem like a power issue. You mentioned the ECU. Are you referring to the body control module?

Let me know.
Joe
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Wednesday, April 8th, 2020 AT 7:53 PM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
I have but I would need a document to make sure I’ve covered all grounds. Yes, sorry ECM.
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Thursday, April 9th, 2020 AT 3:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

Here are the schematics for all grounds on the vehicle. Take a look through them and let me know if it helps or if you have questions. Note that I had to cut each page in two so you can read them. I did overlap them to make it easy to follow.

________________________________________

Let me know if this helps.

Joe
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Thursday, April 9th, 2020 AT 7:52 AM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
Thank you. Just for reference, I was able to get codes using a snap on scanner.

Memory codes from PCM:
P0381, glow plug indicator
P0603, internal control module KAM error

Switch test codes:
P1536, parking brake switch circuit fault
P1780, TCS our of self test range
P0571, cruise brake switch circuit fault
P0703, brake switch input fault
P0565, cruise on signal fault
P0566, cruise off signal fault
P0567, cruise remain signal fault
P0568, cruise set signal fault
P0569, cruise coast signal fault

memory codes from GEM:
P1820, T-case CW shift relay circuit fault
B1483, brake pedal input circuit fault
P1876, T-case 2wd solenoid circuit fault
P1832, T-case differential lockup solenoid circuit fault
B1359, ignition run/ACCY circuit duly
P1808, 4wd low indicator circuit fault
P1828, T-case CCW shift relay circuit fault

Codes from hybrid electronic cluster AND PATS anti theft, these appear to be active and memory:
B1342, faulty control module
C1284, oil pressure switch fault

Parking aid module, active and memory:
C1710, rear inner right sensor fault
C1709, rear inner right sensor circuit
C1707, LR center sensor circuit fault
C1706, rest inner left sensor circuit
C1704, rear outer right sensor fault
C1703, rear outer right sensor circuit
C1701, rear outer left sensor fault

Cannot get any reading from the VSM. Code reader tells me no response, not equipped.
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Thursday, April 9th, 2020 AT 4:07 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

Honestly! Wow, I never saw so many at one time. I'm going to ask a friend to jump in with us and see if he has any suggestions.

Joe
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Thursday, April 9th, 2020 AT 5:09 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

I read all the posts and I have one suggestion to start.

I would load test both batteries first and check the cables. Make sure they are clean and tight.

https://www.2carpros.com/articles/car-battery-load-test

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

Low voltage is something in common to all the codes you have listed.

Joe gave you all the ground connections and locations but I do not think it is a ground.

Check the charge rate of the alternator. Make sure it is between 14 to 14.5 volts DC. Then change the scale to AC volts and see if there is any AC voltage.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Roy
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Thursday, April 9th, 2020 AT 5:33 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,520 POSTS
If everything checks out it sounds like PCM is bad. Here is the location and how to replace it. Programming is required. Check out the diagrams (below). Please let us know what happens.
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Thursday, April 9th, 2020 AT 6:37 PM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
Roy, I will check but new batteries last January and new alternators (discovered it had 2 last year, one was fried) in the last 2 years. I do live in Iowa so it’s exposed to extreme cold every year.
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Thursday, April 9th, 2020 AT 7:27 PM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
Also Ken, I finally purchased an ECM flashed to my vehicle off of eBay. There were no changes in anything when I popped the new one in so I had it sent back. What about the VSM?
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Thursday, April 9th, 2020 AT 7:30 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Okay. Now you have two of the best helping. Thank you Ken and Roy for joining. Roy, could the low voltage issue be related to a ground / weak ground? That is what I was thinking because he replaced the ECM.

Thorn616: When you say VSM, are you referring to the Vehicle Security Module? If so, I personally don't see a correlation. Perhaps Ken or Roy can confirm that. Here is what the VCM covers:

2002 Ford Truck F 250 2WD Super Duty V8-7.3L DSL Turbo VIN F

VEHICLE SECURITY MODULE
The Vehicle Security Module (VSM) controls the following Systems:
perimeter alarm
remote keyless entry (and panic feature)
computer-operated locks
autolamp

_________________________________

Joe
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Thursday, April 9th, 2020 AT 8:20 PM
Tiny
ASEMASTER6371
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I see you replaced the batteries and alternator year ago. That was then and this is now.

You need to start testing as I suggested.

Roy
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Friday, April 10th, 2020 AT 3:51 AM
Tiny
THORN616
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Will start testing. Every problem I had before replacing batteries and alternators existed after they were replaced.
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Friday, April 10th, 2020 AT 6:53 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, got it.

Does this mean this issue has been going on for the past year or so?

Roy
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Friday, April 10th, 2020 AT 6:58 AM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
At least 2 years since I’ve had it, but the only “new” issues that I’ve experienced myself are: the turn signals stopped working, which sometimes the hazards flash a couple times before totally not working, the taillights and the front signal lights, below the headlights having, power with no switches turned or key on, and the headlights stop while going down the road, which now when you turn the knob the headlights do not turn on. I believe everything else was there when I bought it just kind of masked. Mechanically I have no issues.
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Friday, April 10th, 2020 AT 10:04 AM
Tiny
ASEMASTER6371
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Okay, then I would also look at the body control module as well. Most of all the items in the list of problems have the BCM as a common denominator.

Do the other checks I suggested as well.

Roy
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Friday, April 10th, 2020 AT 10:11 AM
Tiny
THORN616
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Got it. Thank you sir.
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Friday, April 10th, 2020 AT 10:13 AM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
Would this also be the GEM module, Roy?
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Friday, April 10th, 2020 AT 10:21 AM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
I may get one coming just to try and return if it doesn’t work. Does that need programmed to my vehicle? My apologies, were diving for into areas I haven’t toyed with yet.
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Friday, April 10th, 2020 AT 10:26 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The GEM module is the body control module. Just a different name for the same part.

Roy
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Friday, April 10th, 2020 AT 10:30 AM
Tiny
THORN616
  • MEMBER
  • 30 POSTS
Okay Roy. I’m struggling. I’m reading 2002 doesn’t have GEM, but a VSM. I apologize being green in this department. If this is not the case, where’s the GEM?
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Friday, April 10th, 2020 AT 4:02 PM

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