Trans Codes P0743, P0753, P1765


1 Tired Ram
05-12-2004, 09:30 PM
1997 5.9L Dodge Ram 1500 4X4 134,000 miles
A little history (very brief) - Last winter my the thermostat froze. I didn't realize until my heater never warmed up. I noticed the problem and was able to shut the truck off before it over heated. I replaced the thermostat and had the radiator flushed. Before I turned the truck off I noticed that the transmission was not downshifting and thought it may have been due to the sub zero weather in northern illinois. With the radiator flushed and engine not over heating, I thought the problem was fixed but the transmission was still not shifting and the GEN light started coming on. I took the truck to the dealer ship and they read the codes P0743, P0753, and P1765. They told me that they were sensor and selonoids for the transmission but said they probably failded due to low voltage caused by bad alternator output. I left and went to Autozone to have the alternator checked and they said it was good. But believing what the dealership said I bought an alternator and put it on. I went back to the dealer ship with the new alternator on and the same codes came out. THIS time the dealership said it was a bad PCM. I bought a reman PCM from Chrysler and that didn't solve the problem. I have since checked the ground leads from the battery and all seem to be good.

As a side note the GEN light doesn't stay on all of the time. It only comes on when the battery voltage gets extremely low; low enough where if I turn the truck off, it will not restart.

Has anyone heard of this problem or know if the codes are the actual problem and not a voltage problem. The dealer has managed to make me doubt what the computer is saying is wrong.

Any help or direction would be greatly appreciated.

trannyman52
05-12-2004, 11:08 PM
first things first,,,why is the battery going dead ???? is the battery bad??? are you getting a "check engine " light ????
THEN a live data test to check the turbine input and vss ///
if these don't work,, the trans will fault to "take home" 3rd gear

1 Tired Ram
05-12-2004, 11:23 PM
first things first,,,why is the battery going dead ???? is the battery bad??? are you getting a "check engine " light ????
THEN a live data test to check the turbine input and vss ///
if these don't work,, the trans will fault to "take home" 3rd gear

I bought a new battery, installed it, and still have the same problems. I am getting the check engine light; I should have stated that in the earlier post. That was part of my reasoning for taking it to the dealership.

Live data test? When I took the truck back to the dealership the second time, they kept if for 1-1/2 days and checked the wiring to/from the alternator and I assume they checked the wires to/from the PCM. That was when they said the PCM was bad, and then I replaced it.

How and where do I check for turbine input and vss?

RexNfx400
05-13-2004, 12:39 AM
It sounds like you need a good electrical tech. If its not as simple as a fuse or relay. There is a tranny relay in power distribution center(PDC). If that was bad it should throw more tranny codes it would seem. I would bet it related to the charging problem. Maybe the alternator output is not reaching the PDC. It don't take much power to mess this system up. Why all you have to do is go to the parts store and say gimmi a 100 amp alterantor instead of the 65 amp stock because I'm putting a camper on it, and then the tranny don't know what to do.

TSS on a 46RE?

good luck

1 Tired Ram
05-13-2004, 11:06 PM
I had the high output alternator as a factory option with the trailer towing option. When I replace the alternator, I replaced it with the same size alternator. I may try the relay in the PDC.

Any other ideas?

Thanks for the help

Sam S
02-05-2013, 01:45 PM
I just had the same problem with my truck I would replace the PCM and it would work for a while tell I hit bump and it would blow the PCM (voltage regulator) i found there is a plug on the drivers side of the transmission with 9 wires in it. wire are shorted where the wires go in to to the plug you can get harness repair kit from the dealership for about 75.00 dollars I hope this help somebody because I lost a lot of hair over this one

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