TCM Changes P0733 and P0734 DTC codes?

Tiny
SANDSTORM1958
  • MEMBER
  • 1998 CHRYSLER TOWN AND COUNTRY
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 136,000 MILES
Just had a used transmission installed because of a blow out of one of the cooler lines losing nearly half the ATF +4. The shift solenoid pack is brand new direct from BorgWarner as are the Speed Sensors (from AutoZone). This transmission only has 90,000 miles on it.

Symptoms-
Showing signs of slipping, hard shifts, erratic behavior that prior to the blow out of fluids never had happened before. Keep getting P0733 and P0734 DTC codes telling me that the errors in shifting in gears 3 and 4. Funny thing is it was getting those same codes with the original shift solenoid on the transmission when it arrived at the shop. I had to drive it home with that shift solenoid pack because the new one had not arrived yet.

This seems to tell me the TCM got damaged during the blowout situation or from the faulty shift solenoid we recently found out was a remanufactured piece of garbage put on 4 years ago with new speed sensors. So, having never changed a TCM in a 3rd Gen Chrysler (unlike PCM malfunctions in old Grand Caravan of same year) I need to know if replacing the TCM is most likely then does this particular year require it to be "flashed" or can it be installed and go through relearn stage. I know at some point Chrysler changed the TCM to the scanner required type just don't know when.

Trying to avoid another $100 per hour mechanic bill. This is a disability entry conversation van. We need this fast since it's getting colder and this van has been down 3 months.
Tuesday, November 21st, 2023 AT 1:18 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

Both codes are related to line pressure issues. Have you tried flushing the transmission cooler and cooler lines?

I have diagnostics for both of the codes and have attached them below. Note that test 53 is specific to the P0733 and test 54 is specific to P0734.

Take a look through them and let me know your thoughts. In my mind, since the same problem is present and related to line pressures at specific times, I'm questioning if there is a restriction in the cooler. It's only a theory at this point.

Let me know.

Take care,

Joe

See pics below. (Test 53 / pics 1 and 2. Test 54 / pics 3 and 4) Additionally, the codes identified in the diagnostics are manufacturer codes. The P codes you provided took me to these manufacturer codes and tests.
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Tuesday, November 21st, 2023 AT 9:12 PM
Tiny
SANDSTORM1958
  • MEMBER
  • 35 POSTS
I don't have any possible way to do all this. One, it's beyond my basic mechanic skills and Two I'm not sure if my Autel AL519 can do all that or not plus I don't have a specific pressure gauge that does 300 PSI as described. What I might be able to do is flush and blow out the cooler system which in this car is through the radiator (fins I believe) but I highly doubt there's a blockage. The reason I say I doubt there's a blockage is because when the "blowout" of the return line to the transmission happened it blew tranny fluid all over to the rear of the car, literally. The line came off the hose pipe because the clamp popped loose. The reason I'm thinking the TCM may have been damaged is previous electrical issues building up to the transmission burning out. I want to know if this model TCM requires a scan tool if I put another OEM TCM on it or do they require a reflashing? I know that Chrysler switched to the scan type but don't know what year. If I put another TCM match for the model and year OEM can I just do a simple reset and relearn without the scan tool. As mentioned, I'm not sure if the AL519 is capable of doing that reset/relearn I haven't used it much. $2,200 put in this so far $900.00 for the used transmission and $1,000 in labor getting it installed. This car isn't worth even 20% of that. All I want to do at this point is eliminate possible culprits based on known symptoms, that's all. I'm ordering a used TCM that should be here after the holiday. I can do the installation myself, no problem, as long as it doesn't pour rain or snow.
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Tuesday, November 21st, 2023 AT 9:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
The pinion factor must be set for all new transmission control modules. If the pinion factor is not set or if it is set incorrectly, any speed-related accessories will not operate or will operate inaccurately. This includes the speedometer, speed control, rolling door locks, and other devices.

I attached the directions below for setting it. I'm not familiar with your scan tool's ability.

Let me know if this helps.

Happy Thanksgiving!

Joe

See pic below.
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Wednesday, November 22nd, 2023 AT 9:12 PM
Tiny
SANDSTORM1958
  • MEMBER
  • 35 POSTS
I didn't need to do all that Pinion Factor Procedure business. The TCM I put in it is an exact match right down to the alpha characters at the end (Firmware Version), it was a used one from exact same year, model vehicle as ours. TCM is functioning correctly now, the old one got damaged from electrical problem during the burnout of the transmission. As soon as my new scanner arrives, I'll run it through the software checks.

I believe your initial theory of a clogged cooler, not just the lines, is on the mark. This one is in the radiator and I'm not changing that combo, so I'll install a new auxiliary cooler which I did on my '98 Grand Caravan Sport. That solved a lot of overheating problems I was having in the Sport and pressure problems got solved too in a swapped-out transmission I had put in it after a shop put the wrong fluid in the original killing it. Hopefully this new cooler and lines will solve the problem. The transmission we had put in this car has been flush and a new torque converter put in it, so I know it's not the transmission itself. If it is it is under a 3-year warranty including the certified flush. I'll let you know in a week or so once I complete this step and scan the TCM.
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Tuesday, December 5th, 2023 AT 11:10 AM
Tiny
SANDSTORM1958
  • MEMBER
  • 35 POSTS
The Speedometer is working correctly and TCM replacement is used from the same make and model right down to the firmware version characters on the part number.
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Tuesday, December 5th, 2023 AT 11:24 AM

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