One problem related to automatic transmission control module has been reported for the 2003 Ford Mustang. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Ford Mustang based on all problems reported for the 2003 Mustang.
Problems with vehicle's transmission. The first time the consumer took the vehicle in for service was for a noisy transmission and it was running rough. The dealer was unable to find a problem but topped of the fluid and reprogrammed the pcm. The dealer instructed the consumer to continue driving the vehicle and it would work itself out. The second visit was for the transmission again, however this time it was griding between first, second and third gears when cold. The dealer was unable to find a problem, but informed the consumer other Mustangs were having the problem and they were waiting on a bulleitn to see what could be done.