QuestionQUESTION: Hello- i have a service engine soon light- i took the car to my mechanic who adivsed me that the transmission is not communicating with the engine- the part would be about $565 as they think its a computer problem- the car has 39,500 miles thanks
ANSWER: Hi Nancy,
Without knowing if the mechanic did anything other than attempt to readout the transmission controller (computer) for fault codes it is difficult to judge whether that is the proper remedy. If he is not a Chrysler/Dodge mechanic with a Chrysler DRB III readout box to do the communication testing I would be leary of such a diagnosis unless he guaranteed that the computer replacement would solve the problem and you wouldn't have to pay for the part if it didn't cure the problem. I would furthermore put a mark on the existing computer that is subtle and ask for the return of the bad part so you can be sure that it was indeed replaced.
There are of course five different wire connection and power supply voltage circuits that could explain this non-communication that should be checked before buying a new computer according to my Chrysler Corp. transmission shop manual, and a specific series of 8 test steps to do with the DRB III reader to determine exactly what is wrong. If those were not performed then it is premature to replace the computer without having done them.
So I will leave you to contemplate on the abilities and knowledge of the mechanic and then decide whether to go with that or get a second opinion at a dealership or another independent transmission shop.
Let me know if the mechanic would like the procedure for gong thru those tests and I can xerox and postal mail those to you. I would expect that the car would be driving poorly qua the transmission if this was really the problem. It may be something entirely different and his problem may be he doesn't have the correct reader.
The computer for the transmission is at the front of the engine compartment on the driver's side of midline. There is a rectangular electrical power box that had fuses and relays inside, and directly inboard of the that box is the trans computer which has one multipin plug on its side; directly outboard of that power box is the engine computer that has two multipin plugs on its top side. So that is how to find and mark the computer if you choose to do so.
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QUESTION: thanks for the response and i will rate the answer- i just drove the car went in someplace came out and turned the car on and know there is no light at all- i am supposed to go to mechanic tomorrow to have him check it again - he did advise that he would have to run tests before he could specially tell me what it is -
AnswerHi Nancy,
If the light stays off and the car shifts well then you could wait some more to see what happens, if anything. Another alternative is to get a free code readout at an Autozone Parts store where they will hook up a reader to a socket under the dash, just as your mechanic did, and maybe come up with another code. If so, ask them the 4-digit number, what the code name is, what it means, what should be done, and the cost. Then write me back with the results of that. I would be cautious about messing with the transmission or its control unit without cause. These are very complicated and expensive to repair transmissions so I would be content to leave well enough alone if it is functioning well and there are no transmission fault codes.
Thanks for evaluating my earlier response.
Roland
