No communication with PCM
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
No communication with PCM
First, I tried the search tool, I really did...haha.
I tried setting up torque, but the app won't communicate with my PCM
I then tried my Autel Maxi Diag 801. It showed MIL Status: ON with 127 codes. I do not have a check engine light on. I have seen this before with a fan relay setting a code on the body control module rather than the PCM, on a Jeep Liberty. So I found this on a forum:
Straight out of the 97 EVTM for C227, Data Link Connector:
Pin 2: Circuit 914 (T/O), Data (+) from PCM pin 16, through C202 (firewall feedthrough connector)
Pin 4: Circuit 57 (BK), Ground
Pin 5: Circuit 570 (BK/W), Ground through C202
Pin 10: Circuit 915 (PK/LB), Data (-) from PCM pin 15, through C202
Pin 13: Circuit 107 (P), PCM Input from PCM pin 13, through C202
Pin 16: Circuit 40 (LB/W), Hot at All Times from Underdash fuse 16 (15A)
All other pins are NOT USED
Broke out the meter and everything seems to check out EXCEPT, no voltage from pin 2 to pin 4, 5 or ground. Maybe I'm nuts, but that looks like it would explain a lack of PCM communication.
So is there a common place to start, or is it just wire chasing?
Which firewall bulkhead is C202. I see three on the drivers side.
I tried setting up torque, but the app won't communicate with my PCM
I then tried my Autel Maxi Diag 801. It showed MIL Status: ON with 127 codes. I do not have a check engine light on. I have seen this before with a fan relay setting a code on the body control module rather than the PCM, on a Jeep Liberty. So I found this on a forum:
Straight out of the 97 EVTM for C227, Data Link Connector:
Pin 2: Circuit 914 (T/O), Data (+) from PCM pin 16, through C202 (firewall feedthrough connector)
Pin 4: Circuit 57 (BK), Ground
Pin 5: Circuit 570 (BK/W), Ground through C202
Pin 10: Circuit 915 (PK/LB), Data (-) from PCM pin 15, through C202
Pin 13: Circuit 107 (P), PCM Input from PCM pin 13, through C202
Pin 16: Circuit 40 (LB/W), Hot at All Times from Underdash fuse 16 (15A)
All other pins are NOT USED
Broke out the meter and everything seems to check out EXCEPT, no voltage from pin 2 to pin 4, 5 or ground. Maybe I'm nuts, but that looks like it would explain a lack of PCM communication.
So is there a common place to start, or is it just wire chasing?
Which firewall bulkhead is C202. I see three on the drivers side.
Lead Driver
Joined: Mar 2006
Posts: 5,104
Likes: 1,521
From: western SD
Have you checked the in cab fuses? I seem to recall the diagnostic port being on the same fuse as the extra power point in the cab. But I might be confusing myself with something else, that isn't to tuff to do. LOL
Edit: The cigar lighter and data point are on the same fuse, #16, 15 amp in cab.
Edit: The cigar lighter and data point are on the same fuse, #16, 15 amp in cab.
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
Thanks Cowmilker.
Farmer T: I think fuse #16 is the power to the OBD and maybe the power port/cig lighter. That fuse is good, and I do have power at the cig, the power port and the OBD pin 16. I do not have power on pin 2 (data +). Not sure what that voltage should be, but pin 10 (data -) has 5 V KOEO. Pin 13 (Circuit 107 P PCM input) has 0.5 V KOEO. Both are zero with Key off. Just an educated guess, I'm betting pin 2 (data +) should have 5 v also.
Farmer T: I think fuse #16 is the power to the OBD and maybe the power port/cig lighter. That fuse is good, and I do have power at the cig, the power port and the OBD pin 16. I do not have power on pin 2 (data +). Not sure what that voltage should be, but pin 10 (data -) has 5 V KOEO. Pin 13 (Circuit 107 P PCM input) has 0.5 V KOEO. Both are zero with Key off. Just an educated guess, I'm betting pin 2 (data +) should have 5 v also.
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
Based on this: i have the following with KOEO each pin to chassis
Pin 2: Circuit 914 (T/O), Data (+) from PCM pin 16, through C202 (firewall feedthrough connector) : .05 V (basically 0, but enough trace to make me curious?)
Pin 4: Circuit 57 (BK), Ground : O V (expected)
Pin 5: Circuit 570 (BK/W), Ground through C202 : O V (expected)
Pin 10: Circuit 915 (PK/LB), Data (-) from PCM pin 15, through C202 :5 V
Pin 13: Circuit 107 (P), PCM Input from PCM pin 13, through C202 : 0.45 V
Pin 16: Circuit 40 (LB/W), Hot at All Times from Underdash fuse 16 (15A)12V
So if pin 2 should be 0, why can I not communicate with the PCM? What's next?
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Don't know anything about the torque App so no help there. Here is a recent thread with some good information on setup that might help ...
https://www.ford-trucks.com/forums/1...umb-olman.html
https://www.ford-trucks.com/forums/1...umb-olman.html
Trending Topics
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
QUOTE=Hussler;15778150]Don't know anything about the torque App so no help there. Here is a recent thread with some good information on setup that might help ...
https://www.ford-trucks.com/forums/1...umb-olman.html[/QUOTE]
thanks for the help. I'll read it again, but as I remember most of his issue was getting that ELM327 connected to His ipad. I also cannot get communication with my scan tool. That makes two devices that both seem to connect to the truck but will not connect to the PCM
https://www.ford-trucks.com/forums/1...umb-olman.html[/QUOTE]
thanks for the help. I'll read it again, but as I remember most of his issue was getting that ELM327 connected to His ipad. I also cannot get communication with my scan tool. That makes two devices that both seem to connect to the truck but will not connect to the PCM
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Don't know if the Autel Maxi Diag 801 is compatible with the truck, most scanners aren't. OBS uses non-standard OBDII protocol. What year is your truck? 94.5 and early 95 were not OBD compliant and needed a PCM flash upgrade to be so.
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
mine is a 96. The scanner read that it had codes just would not tell me what the codes aresaid communication with PCM could not be established. the torque app connected with the elm327 just would not communicate with PCM
Tuned
Joined: Mar 2006
Posts: 466
Likes: 0
From: PNW
Have you checked the in cab fuses? I seem to recall the diagnostic port being on the same fuse as the extra power point in the cab. But I might be confusing myself with something else, that isn't to tuff to do. LOL
Edit: The cigar lighter and data point are on the same fuse, #16, 15 amp in cab.
Edit: The cigar lighter and data point are on the same fuse, #16, 15 amp in cab.
field expedient repair attempt (not by me)
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
You can just see the break in the fuse, just off the left leg. But "appear" is the key word. Very small breaks like that can be hard to see, esp. in the lighting in the cab. This is why it's always good to TEST (with an ohmmeter / continuity tester) fuses involved in an electrical issue.
Thread Starter
|
Senior User
Joined: Oct 2015
Posts: 320
Likes: 8
You can just see the break in the fuse, just off the left leg. But "appear" is the key word. Very small breaks like that can be hard to see, esp. in the lighting in the cab. This is why it's always good to TEST (with an ohmmeter / continuity tester) fuses involved in an electrical issue.
Tuned
Joined: Mar 2006
Posts: 466
Likes: 0
From: PNW
Yup that was the #16 fuse for the OBD port and the cig lighter. There was a dime sitting in the bottom of the lighter which must have popped the fuse. Then PO decided to jump with that thin copper wire. It looks burned too on the wire so it must have melted and did not connect good. cig lighter was unplugged when I went to disconnect it so i can put a new fuse without blowing to hook up to the OBD. Connected with the torque app and it seemed to read fine, no codes.