hammersb
11-05-2009, 01:33 PM
This turned out to be a three month adventure that I will document for other X5 owners.
My problem began at 130,000 miles on my 2002 X5 3.0 with a fairly new battery failure.
Since the battery was only 2 years old I suspected an alternator problem and thats what it turned out to be. The problem did not surface until the alternator was put under a stress test and it was determined it was not generating enough current.
The shop kept the car over the weekend with the battery disconnected and then replaced the alternator and gave me a new battery under the original battery warranty (nice independent mechanic).
After a day or so while driving I got transmission fail safe mode which locks the transmission in 4th gear and limped home. Jumped on the internet, found that by turning the car off and on i could clear the code so I did. Took it back to the mechanic and he saw a tranny slip when he read the error code. He reset the code and told me to see what happens. I drove for another day and it slipped again. Took it back and he said leave it and he needed to call his tranny specialist. Both these guys worked at the BMW dealer as mechanics for 15 years before going into business themselves.
His transmission guy said that because the battery was disconnected the settings in the adaptive transmission controller returned to default and lost the adaptions built up after 130,000 miles. He recoded the transmission and drove it for awhile to begin the adaption process. Since then the tranny is back to normal with a total cost of $90.
So anyone experiencing a battery problem who then gets a transmission or engine fail safe code should consider the relationship between the loss of power from the battery and it's effect on the computer controllers before having the "stealer" replace your transmission for $$$$$.
My problem began at 130,000 miles on my 2002 X5 3.0 with a fairly new battery failure.
Since the battery was only 2 years old I suspected an alternator problem and thats what it turned out to be. The problem did not surface until the alternator was put under a stress test and it was determined it was not generating enough current.
The shop kept the car over the weekend with the battery disconnected and then replaced the alternator and gave me a new battery under the original battery warranty (nice independent mechanic).
After a day or so while driving I got transmission fail safe mode which locks the transmission in 4th gear and limped home. Jumped on the internet, found that by turning the car off and on i could clear the code so I did. Took it back to the mechanic and he saw a tranny slip when he read the error code. He reset the code and told me to see what happens. I drove for another day and it slipped again. Took it back and he said leave it and he needed to call his tranny specialist. Both these guys worked at the BMW dealer as mechanics for 15 years before going into business themselves.
His transmission guy said that because the battery was disconnected the settings in the adaptive transmission controller returned to default and lost the adaptions built up after 130,000 miles. He recoded the transmission and drove it for awhile to begin the adaption process. Since then the tranny is back to normal with a total cost of $90.
So anyone experiencing a battery problem who then gets a transmission or engine fail safe code should consider the relationship between the loss of power from the battery and it's effect on the computer controllers before having the "stealer" replace your transmission for $$$$$.
