Fail safe mode

[Doonbugg]

What would cause a transmission to go into failsafe mode ? The vehicle had a battery problem and it went into engine and transmission failsafe. I changed battery and charged the new battery up. Now it runs great but transmission goes into failsafe within 3 miles.2005 X5 4.4

[srmmmm]

Dirt, water & grease contamination in the connector from the harness to the transmission.

2002 X5 331,000 miles
2014 428i 29,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird - Under restoration

[bcredliner]

Suggest you check for error codes.

[pearlpower]

Could be a few things.

.When my 4.4 hit 100k miles I was getting it often, changed the 'lifetime' fluid-pan drop, and it went away. Did another pan drop and changed the valve body seals this time which were cracked, and the entire demeanor changed for the better. Have done 3-4 more pan drops fluid changes since. 194k mies or so and still on the original trans. Also no more codes.

.Could also be debris as stated above.

.Low trans fluid

[brucemillar]

I had this on a 4.4, which was diagnosed by BMW in the UK as the stock BMW battery failing. They replaced the battery and I never saw the problem again.

To be 100% clear here.

My car would do this to order if I left it parked facing uphill for a few hours. When I called BMW they asked if the car had been left facing uphill? When I said yes, they immediately said it would be the battery and that it was a known fault with some BMW batteries.

When the car was parked facing uphill a plate in the battery would short causing the car to drop into 'limp home mode' this would always trigger the Transmission Failsafe Message and limp home. If I restarted the ignition then the message would clear and all would be fine until I parked facing uphill.

Good luck.

[bcredliner]

The reason to start by reading codes is there are several potential causes of many transmission issues.

[donmayor]

clear it via this:

but first check for any CELs, fix that and do the reset:

https://www.youtube.com/watch?v=r6mVEXhCY4o

[srmmmm]

Speaking from experience, clean the wiring harness plug and transmission harness socket first. Shorted out pins produce false error codes. Going through a car wash was enough to make my transmission go into fail safe because of debris that built up in the connector.

2002 X5 3.0 331,000 miles
2014 428i 29,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird - Under restoration

[bcredliner]

Originally Posted by srmmmm

Speaking from experience, clean the wiring harness plug and transmission harness socket first. Shorted out pins produce false error codes. Going through a car wash was enough to make my transmission go into fail safe because of debris that built up in the connector.

2002 X5 3.0 331,000 miles
2014 428i 29,000 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird - Under restoration

What false error codes were there?

[pearlpower]

There are no specific codes, that is the issue with pulling codes. They 'might' lead someone down the specific path, however in most instances will throw out generic trans codes which could be numerous items. Pulling codes is always a good idea, however they are not specific enough to assist backyard mechanics trace down an issue. There are no codes for debris in connector, or old trans fluid, or bad valve body seal.........

The number #1 scenario with all auto forums is exactly the same. OP starts a thread, people tell him/her to pull codes, OP goes to Autozone or similar which can only read generic OBDII codes, not specific manufacture codes. Then they invest in the equipment to pull manufacturer codes, only to find a code that is very ambiguous.

The next step is either go down the path of commonality which others have experienced which is often a successful path, or an indy.