Fail safe mode

[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.

[srmmmm]

Originally Posted by bcredliner

What false error codes were there?

Reported convertor clutch failure and excessive turbine speed difference when there really wasn't anything wrong with the transmission at all. An ABS error even came up! It was shorted out pins at the harness connector. The tech polished the pins and used electrical contact cleaner on the socket and all was well.