QuestionQUESTION: I have a 2004 dodge neon that will not shift up from 1st or 2nd gear. I replaced the transmission control module and also the input and output speed sensors,but the problem remains.The diagnostic codes I get are po720-output speed sensor circuit malfunction and p0731-gear 1 incorrect ratio.How can I remedy this please?
ANSWER: Hi Danny,
I am not sure which Neon model (engine?) you have as so far I have found one that has only a combined powertrain/transmission control module, not one with a separate transmission control module. In that model, the output speed sensor wires go to pins 32 and 34 of the fourth plug (green color) of the combined module. Is that what you are working with?
In any case, because you have replaced the output sensor and I trust that you erased the codes by disconnecting the battery briefly after doing that, correct?, but the code recurs it suggests that either the wiring of the output sensor is not making solid connection or that there is indeed a problem that is internal to the transmission (the 0731 code). So you would want to verify that the wiring of the sensor is reliable (check with a ohm meter or continuity tester while gently shaking the wiring harness) as your first priority. If that checka out, then there are a number of possible issues inside the transmission to consider which I can share with you.
Let me know your email address so I can share the instructions for dealing with the 0731 code, but don't use the @ symbol, instead use "at" or the address will be erased.
Roland
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QUESTION: The engine is a 2.0,the car is the SXT model.The transmission control module I replaced contains the shift silenoid or silenoids I believe. It is mounted to the transmission just below the two speed sensors I replaced.I will try what you suggested and get back to you.Thanks.beauxrillaatgmail.com
ANSWER: Hi Danny,
The part you changed was the solenoid pack/pressure switch assembly, not the transmission control module (which is not a separate part anyway) which is fine. Now do check the wiring from the output speed sensor to the PCM. The light green/white wire on pin 2 of the plug goes to pin 32 of that green plug, while the dark blue/black goes to pin 34. So verify there is no intermittency in those connections when you shake the harness gently.
If the 0731 code comes back (after you disconnect the battery briefly and then drive it) and the output sensor wiring is good, then it does point toward a problem inside the transmission.
However check the fluid level, and then there are a couple of other items to check out before concluding it is an internal problem. I can give you a couple of pages from the manual to follow but you would likely need to have a competent transmission shop do all those tests because they involve the use of a diagnostic readout box.
Roland
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QUESTION: I've did as you suggested and the codes did clear except for the 731. Guess its time to get this vehicle to a transmission shop?
AnswerIf you would like I can send you pages about the 0731 code and also pages about the gear shift lever adjustment which is the one other thing you could try.
You might also erase the code, and then try driving it from the dead stop in gear position 2 and then shift to D. That would avoid driving in first gear which is what sets the code and that is saying is the problem. When you slow to a stop, shift back into 2 again before dropping below 15 mph, etc. That would temporarily avoid setting the code which then puts you into 'limp-in mode' where the trans will only operate in 2nd gear.
How many miles are on the vehicle?
Roland
