SES Codes P0740, P0700, P0305

[budmaca1]

I posted last week with a sudden loss of cruise control and auto door lock. The auto door lock works again (thanks for the tip).

Now all of a sudden the SES light came on. I went to the auto parts store to borrow the OBD II code reader and:

P0740 Torque Converter Clutch Circuit Malfunction
P0700 Transmission Control System Malfunction
P0305 Cylinder 5 Misfire Detected

The vehicle seems to run fine.

I have 3.3L and 41TE, original, 160000 miles.

Coincidentally or not, I needed to replace the battery two months ago, then days later the starter crapped out and was replaced. Now no cruise (light comes on but cruise does not set) and temporarily no auto door lock (fixed with the key).

I found another link to common 4-speed Chrysler/Plymouth/Dodge 41TE problems here:
http://www.allpar.com/fix/trans.html

I recently passed my emission test. I don't want to invest in a significant repair on a 13-year old vehicle. However, in the last year I have replaced all four tires, front brake pads, A/C compressor, battery, and starter. Major big bucks. I want to keep this vehicle to recoup my repair investment. I can live without cruise control. If the vehicle has no perceptible problem and I am not damaging the transmission, I have almost two years to my next emission test date and can extend it a year, by which time I can put this vehicle out of its misery.

Any thoughts on near term action? I have a trusted mechanic, but if this involves computer settings and transmission, I don't know his track record. There's the local Chrysler dealer, but as George Costanza observes, I might as well be flushing my money down the toilet.

Advice?

[andyg]

The P0700 code means that there is more error info stored in the TCM that a dealer or trans shop will be able to access. You may just want to get that scanned to see what the problem is, then decide upon fixing it. First thing, I would say to disconnect the battery for 10 mins to clear the codes and see if they come back.

[budmaca1]

I borrowed the code reader again, erased the codes, and they came back.

Took the vehicle to the dealer today. They also saw code P1738, Hi Temp Logic.

They indicate the Torque Converter Clutch is failing and rather than replace it, recommend replacing the entire transmission. I declined. My local mechanic agrees replace, but with a refurb trans. He's giving me an estimate tomorrow.

Also, my no cruise was diagnosed as a vacuum hose.

I called Aamco, and they indicate they don't replace transmissions but repair them. I might consider this, but am concerned if the torque co-yynverter damage has already damaged the trans.

I might get an Aamco estimate to repair.

This vehicle is 13 years old, has 161000 miles, and I had just given it to my 16 year old daughter. I would rather not junk it and buy her a low-cost car with unknown problems. I'll probably end up getting the trans fixed or replaced and hope I get many more years/miles out of the old gal.

[andyg]

When the clutch goes bad, the whole trans should be gone through because little chunks of it make their way everywhere. You can get a low cost rebuild, or go the used trans route like I did. I got a working trans for under $225 if you can do the install yourself.

Make sure the mechanic replaces the radiator or puts in a separate trans cooler with the new one. Those bits of clutch can also make their way into the cooler for storage and then come loose into the new trans, or clog the cooler and make the trans overheat. I recommend a good size external cooler only instead of putting in a new radiator.

[budmaca1]

I have noticed that the radiator fan is running more. I'm a novice at this. I assume the trans problem is causing the radiator fan to run more? Now do I have a radiator problem too? If replacing the trans won't fix the problems, maybe it's time to put the ol' gal out of her misery.

[andyg]

The converter not working may cause the engine to run hotter and thus the fans to come on more often. Not a very likely situation but could happen. Although it may just be because of the temperatures warming back up or maybe you had the a/c of defrost on?

[2002CaravanSE]

More transmission heat may be transferring that heat to the radiator and heating the coolant thats supposed to be cooled.

[budmaca1]

I took it to Aamco today. They said the P1738 code (Hi Temp Logic) automatically turns the radiator fan on. Nothing to do with the heat of the trans.

They said mechanically the trans is working fine. They want $800 to take it off and diagnose further, where the $800 would then go toward the repair.

I'm going to just leave it alone and drive it until it dies. Don't know whether this is hours, days, weeks, months, or years. I'll keep highway driving to a minimum.

[andyg]

If you have another vehicle for highway trips and keep the van at speeds below converter lockup, it may last awhile yet. If the TCM keeps trying to lock it, that will only further reduce its life. You could even go as far as unplugging the TC solenoid, but that may throw it into limp mode.

[alvin]

There are other ways for diagnosing the transmission before it needs to be pulled, such as pressure testing. AAMCO, I'm afraid, just wants to get you on the hook.
P0740 is an electrical code, and there could be a chance
for fixing it by replacing the solenoid unit. As to P1738, it could indicate a bad temperature sensor, but in this case it could be a genuine overheating if the TC clutch
does not apply. I hope you can find someone who can diagnose the trasnsmission by the book. It should cost way less than $800.