Possible limp mode?
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Mountain Pass
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Possible limp mode?
I’ve got a 1999 Ford F-250 super duty 5.4 2v w/ 4r100 trans and I think my trucks in limp mode
I’m getting these codesP0743 torque converter clutch solenoid circuit electrical
P0755 shift solenoid B
P1747 pressure control solenoid A short circuit
the motor runs and idles fine but but when I give it gas and does not move at all. I can unplug everything on passenger side with no effect on the motor but if I unplug anything on the driver side and it dies out or idles super low like it’s not firing on that side at all (35’s w/ 8 inch lift) fuel pump and filter are new, upgraded injectors were already ordered prior to this problem and should be here Monday.
I’m getting these codesP0743 torque converter clutch solenoid circuit electrical
P0755 shift solenoid B
P1747 pressure control solenoid A short circuit
the motor runs and idles fine but but when I give it gas and does not move at all. I can unplug everything on passenger side with no effect on the motor but if I unplug anything on the driver side and it dies out or idles super low like it’s not firing on that side at all (35’s w/ 8 inch lift) fuel pump and filter are new, upgraded injectors were already ordered prior to this problem and should be here Monday.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,738
Likes: 2,668
From: SE Florida
You have three electrical fault codes for the transmission. The P1747 is causing your problem. If the pressure control solenoid is shorted it will be stuck at low pressure. The failure mode software limits engine torque to save the transmission. You MUST fix the wiring problem that is causing this code to fix this.
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Mountain Pass
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Well I did a compression test today on the side that doesn’t get affected when everything unplugged and cylinder 1 had 165 psi, cylinder two have just under 120 psi and cylinder 3 was at 100 psi at this point I know I have a problem with the motor itself and I believe it jumped a tooth or more possibly
Senior User
Joined: Dec 2003
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From: Kearney NE
You have three electrical fault codes for the transmission. The P1747 is causing your problem. If the pressure control solenoid is shorted it will be stuck at low pressure. The failure mode software limits engine torque to save the transmission. You MUST fix the wiring problem that is causing this code to fix this.
this should help with drivability issues, then you will see how the engine is affected by the low compression numbers.
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Mountain Pass
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So I just finished redoing the timing and I know it is 100% correct it sucks I didn’t see the last reply until now. So correct me if if wrong but your saying that since it’s in limp mode it’s limiting the performance of the motor? And I need to replace the shift pack in the trans? I’m now getting codes for shift solenoid a-b and the torque converter clutch solenoid. Motor is freshly rebuilt and bored 20 over everything besides the block is new so I’m thinking of putting in a shift kit in it along with a shift correction kit while I’m in there https://www.thoroughbreddiesel.com/k...saAinNEALw_wcB
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,738
Likes: 2,668
From: SE Florida
I don't think I said to replace ANYTHING. You first need to diagnose what's wrong. I said it is most likely a wiring issue. IF you replace the solenoids and the problem is the wiring you'll still have the same problem.
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Mountain Pass
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10-4 I’ve looked at the connectors and the wiring on the trans but didn’t follow it all the up so I’ll do that when I get a chance
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Mountain Pass
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So here’s my follow up I pulled the trans wiring harness out of the vehicle completely to thoroughly inspect it found no freys anywhere there was a section that the wire loom was torn and that looked fine too so I’m gonna clean up the connectors and reinstall. What’s the next thing I should check?
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Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,738
Likes: 2,668
From: SE Florida
You should check the harness. Looking for frays and problems is nice, but it sure doesn't tell you that the harness is good. You need to check the harness electrically or you are just wasting your time.
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Mountain Pass
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UPDATE: finally got to taking the pan off and checking the solenoids I pulled it out and checked the ohms and put 12 volts to them all are right around 21 ohms and have a good healthy click except the bigger one on the plug side that was was reading about 4 ohms and was a lot less of a click
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,738
Likes: 2,668
From: SE Florida
Sure, rebuild the trans. Once that's done and you still have the same problem, and you will, you can troubleshoot the wiring harness to find the original problem.
THE PROBLEM IS THE SHORT CIRCUIT.
THE PROBLEM IS THE SHORT CIRCUIT.
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Mountain Pass
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i took the harness out and unwrapped it completely and still haven’t found anything what else could I do to check for shorts? There is a spot on the harness that’s black from an exhaust leak but it isn’t melted it’s just built up soot. Also the only gears I have is park and reverse I can feel drive engage because it moves a little but that’s it