TPS VSS speculation questions (E4OD)
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From: Wanatah In,
TPS VSS speculation questions (E4OD)
I have been having a problem getting codes 625 EPC open and 628 Coverter clutch failure off and on for the past year and a half, It will go away and then just reapear for a period of time. Now the trans seems to be working fine it shifts good and doesnt slip or anything so this is leading me to believe it is a electrical problem, not hardware. I have already replaced the MLPS and solenoid pack so I can rule those out.
I am suspecting either the TPS and/or VSS, I assume that the TPS is similar electrically to the vacume modulator on the older mechanical transmissions.
And I suspect possibly the VSS because the light never comes on when Im driving slow (under 40 mph or so) but as soon as I speed up to merge on the highway it comes on and stays on until I shut it off and start over.
One question is can I have a bad VSS and still have a properly working spedo?
Any suggestions would be great
Thanks
I am suspecting either the TPS and/or VSS, I assume that the TPS is similar electrically to the vacume modulator on the older mechanical transmissions.
And I suspect possibly the VSS because the light never comes on when Im driving slow (under 40 mph or so) but as soon as I speed up to merge on the highway it comes on and stays on until I shut it off and start over.
One question is can I have a bad VSS and still have a properly working spedo?
Any suggestions would be great
Thanks
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From: duncan oklahoma
is the wiring that connects to the solinoid pack in tacked.i have seen the o-ring that seals the solinoid pack to the case leak trans fluid to the wiring harness and cause the wiring insulation to swell and pull back causing the wires to short together.
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From: Wanatah In,
I pulled the plug off and checked it out and everything looked pretty good, I even pulled the rest of the plugs apart and checked them and everything looks pretty good with them as well.
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From: Willamette Valley, Oregon
well one thing to remember
your converter wont start engaging until you hit 45mph and above so that would explain the converter clutch failure at higher speeds. you may need to replace the torque converter due to an excessive slippage issue that may be setting the code 628 you are seeing.
the EPC code 625 is caused by the computer checking for voltage across the EPC circuit and after a period of time rechecking this circuit and comparing the voltage results. if these results differ then it sets the code 625. I think you may have a wirng concern with a high resistance causing you voltage to change periodically.
your converter wont start engaging until you hit 45mph and above so that would explain the converter clutch failure at higher speeds. you may need to replace the torque converter due to an excessive slippage issue that may be setting the code 628 you are seeing.
the EPC code 625 is caused by the computer checking for voltage across the EPC circuit and after a period of time rechecking this circuit and comparing the voltage results. if these results differ then it sets the code 625. I think you may have a wirng concern with a high resistance causing you voltage to change periodically.
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From: Wanatah In,
I just had the converter out when I changed engines, figures. I can feel the converter engage and the engine lugs down, could it be its just so slight its not physically noticable but enough to cause a code. I have put 282k miles on this tranny 1/3 of that pulling, so I guess I should be grateful its taken me this far.
Does the TPS have any thing to do with line preasure? Could that being faulty cause the voltage variation?
Does the TPS have any thing to do with line preasure? Could that being faulty cause the voltage variation?
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From: Willamette Valley, Oregon
the manual is showing that the TPS would be a code 23 or 121,33,43,53 or 123,63 or 122,124,125. all these codes refer to harsh shifts, firm shift feel and abnormal converter clutch operation.
The 628 code refers directly to your transmission slippage, erratic or no converter clutch operation.
I am not positive but I dont think the TPS is your trouble. I worked on transmission for a Ford dealership for three years and never replaced a TPS for a trans concern, but that doesnt mean that i would be an expert on it.
If you had a bad VSS and sense the sensor sends the same signal to the computer I dont think that a bad VSS would cause this trouble and not effect the electronic speedo (PSOM).
The 628 code refers directly to your transmission slippage, erratic or no converter clutch operation.
I am not positive but I dont think the TPS is your trouble. I worked on transmission for a Ford dealership for three years and never replaced a TPS for a trans concern, but that doesnt mean that i would be an expert on it.
If you had a bad VSS and sense the sensor sends the same signal to the computer I dont think that a bad VSS would cause this trouble and not effect the electronic speedo (PSOM).
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From: Wanatah In,
I may change the tps just for good measure since Ive never changed it since the truck was new, if it helps great, if not oh well I supose. I guess I'll just pull the check engine bulb out and drive it since thats the greatest aggrevation.
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The TPS is telling the computer engine load along with the MAP. These combine with the VSS and coolant temp sensor to tell the converter to lock up once you have satisfied all the requirements.
If the VSS was bad it would show up at all speeds not just highway and your speedo would act up as well. I would suggest you get a hold of the resistance for each plug and throw a multimeter on to see if you have anything wrong with the wiring for the solenoid packs. And I agree that your torque converter might have had all it can take and is just on its way out.
If the VSS was bad it would show up at all speeds not just highway and your speedo would act up as well. I would suggest you get a hold of the resistance for each plug and throw a multimeter on to see if you have anything wrong with the wiring for the solenoid packs. And I agree that your torque converter might have had all it can take and is just on its way out.
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From: Wanatah In,
Now if the converter clutch is going bad, will the truck just eventually not move or will the converter function like the older non-lockup converters? Im assuming it would since the truck will move when the converter isnt locked.
Im questioning if putting a new converter in a trans with 282k is worth the money and effort, if the current converter will continue to work without turning to schrapnel or anything.
Im questioning if putting a new converter in a trans with 282k is worth the money and effort, if the current converter will continue to work without turning to schrapnel or anything.