QuestionQUESTION: Hi Roland,
I had the car for about 2 month. It had a code P0750 before and I had the solenoid Pack/Input Sensor/Output Sensor replaced to have the problem of not shifting gears fixed. Now the transmission is doing sort of the same thing again. The only difference is that it does not do it all the time. I noticed that if I hit on gas too hard (ie. try to gain speed quick), the problem appears (not shifting gear and RPM reaches 3500 at 70KM/Hour). The problem will stay until I shut down and re-start(sometimes immediate restart won't fix the problem). I had the OBDII code read again by a friend and I got code P1784/P0731. Could you please maybe pin-point possible problems for me? Since my last repair is still under warranty, I am wondering if the two codes are still from the old problem and should be covered under the warranty.
For the miss fire codes, the symptom is engine shaking at low RPM (Idle/stop on red light). Since I replaced the plug/ignition wires, air filter, PCV valve, etc, I will concentrate on ignition coil/and possible vacuum leak. Please suggest other possible checks I might need to carry out. Thank you very much, I appreciate your help.
ANSWER: Hi Song,
You may be able to argue that the 1784 is a holdover from the work on the 0750 if it can be shown that the issue is the low-reverse pressure switch sense which is located in the solenoid pack. It could be the wiring circuit to the switch, or a solenoid switch valve may be stuck, or a valve body bolt may be loose. So you could certainly take that approach. Unfortunately no code is absolutely specific as to cause. The 731 will hopefully be resolved by dealing with the 1784 because otherwise that one points to internal transmission issues or a variety of solenoid box possibilities that are too numerous to mention.
You might want to do a compression check on all the cylinders to see how the mechanicals are doing before looking at the coil or vacuum leak possibilities just to be certain that all the cylinder have a value of =/-25% of oneanother. Please let me know which engine and year and model you have if you write back with a follow-up.
Roland
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QUESTION: Hi Rolland, the car is a 1996 Chrysler Concorde LXI V6 3.5. I spent the past two weeks observing the problem and the transmission problem occurred about twice a week. After feeling a jerk of the car, the transmission failed and stayed in low gear. Pulled over and re-started the car, the problem is gone(I mentioned in my previous thread that immediate re-start sometimes does not help, I belive I made a mistake). I brought the car to the transmission shop that replaced my solenoid pack, and I/O sensor, the guy said it is not the solenoid pack problem, otherwise, re-start won't have fixed the problem. He suspect a computer problem and said I might have to have the computer replaced (he said for this car, there is a separate computer for transmission, I did not find any information on this). He suggested me to bring the car to the dealership to have the code pulled out again. My 3 month warranty is expiring in a few weeks. Is the mechanic telling the truth? what approach do you suggest to take now? How to check/show whether the issue is with the low-reverse pressure switch sensor? Thank you very much!
ANSWER: Hi Song,
To evaluate the pressure switch you have to use a diagnotic readout tool. I can send you a page that describes what has to be done to check that out. You can take that page to the shop or whoever is responsible for the warranty and ask them to go thru the tests to reach a conclusion. If they draw a conclusion and you implement the corrective action then you would see if the switch is or is not the problem and that code should disappear. Then if you still get the 0731 then there are a number of possible reasons, and I have a page for that code also. So use the "thank and rate" tab to tell me your postal mailing address and I will xerox copy and mail those pages to you. You can get a free code readout from the Autozone parts store if there is one near you. Before another readout, disconnect the battery for about 5 minutes, then drive the car until it misbehaves again. Then get the readout.
Roland
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QUESTION: Hi Roland,
It has been 5 months since our last conversation. I provided all the info you mailed me (thank you again for your kind help) and persuaded the mechanic to replace the solenoid pack. After that, the car was doing fine for about 3 weeks. Then the old problem came back, but at a much lower frequency (once/twice a month), and it did not happen for the last month or so. I just bought an INNOVA 3100 a diagnostic tool when it was on promotion and tried to pull out the code again. I did not get P0731/P1784. (Maybe the scanner is not good enough to get those transmission codes?). Instead, I got P1753 which according to the scanner is “Transmission Throttle Valve Mechanical Performance”. There is not much information on the web regarding this code at all. I erased all the codes, drove the car for a bit. No code comes back yet. I will keep monitoring and post my follow up once I have something. I would appreciate if you can provide some possible reasons for the code P1753. Thank you and happy holiday.
Song
AnswerHi Song,
I looked thru all my manuals and could not find a reference to the 1753 code nor could I find even a reference to Transmission Throttle valve, which almost seems like an oxymoron. How about trying an Autozone store or an independent garage to see what codes they come up with? I wish I could be of help, but so far nothing coming. forward. Do let me know if a different readout comes up with a new code.
Roland
PS May I ask a favor? I am in a neck-and-neck race to be 'expert of the month' for December. If you would use the 'thank/rate' tab below and answer "yes" where the question of a 'nomination' for me to that honor appears I would be most appreciative. Thanks in advance.
