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Q: My transmission won't go in reverse. Our mechanic said the ECM is bad. Would that cause that?

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Would a bad ECM cause the transmission to go bad? Our mechanic said it's not communicating with the transmission to change gears. Thanks you sergio

My car has 120000 miles.
My car has an automatic transmission.

Hello. No, the ECM by itself should not cause a transmission failure. I suspect the low/reverse band has gone out on your transmission. The newer electronic transmissions have the ability to adjust to wear in the various clutches and bands in the transmission - until it can’t adjust anymore. Then it will fail. However it should give you a powertrain/transmission warning that shows up as a Check Engine or other instrument panel warning. I would recommend you have your transmission diagnosed by a reputable transmission shop.

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