Transmission switch fault

[amacman]

I got the trans failsafe prog message whist shifting from D to P .
switched off ignition for a minute then started again with no issues .
code reader says BMW code 80 transmission switch so any ideas which switch is causing the fault welcome .
thanks .
2002 4.4i .

[RRPhil]

Sorry I don't know the code but presumably it’s referring to the inhibitor switch which is mounted on the end of the transmission’s selector shaft on the right-hand side of the transmission (beneath a tin cover which protects it). The ECU interprets the continuity between the different wires to determine which gear is selected at the transmission. For example, it uses this signal to ensure that it only allows the starter to operate in P & N.












The switch in the photos above is actually on a Ranger Rover 5HP24 but the E53 is identical except for the length of the wires (it therefore has a different part number). The wires are longer on the Range Rover as the connector is mounted up above the transmission bellhousing - rather than below it on the X5 - presumably for ‘off-road’/wading reasons.

If you want to test the function of the switch just unplug the connector underneath the vehicle and use a multimeter to check that the continuity between the wires is as shown in the table.

Incidentally, on the GM 5L40-E transmission used in the 3.0 litre models the switch is mounted inside the casing so the sump has to be dropped to access it.



Phil

[amacman]

Thank you ,
I hope it is an easy fix .
I need to find my multimeter which has not seen the light of day for many years and try to remember how to use it .
Could be the oil on the connector at front of gearbox causing issue .some left over from previous leaking valve covers and more from a recent spill whilst topping up .
I referenced the code getting 3 definitions as follows , scary .
Internal control module memory checksum error.
Transmission control module self - test .
Internal control module memory checksum / EEPROM error .
All 3 definitions are listed as BMW FC 80 but have different P code numbers .

[amacman]

I have had this fault happen a few more times .
I found the following codes with INPA - signal AGS code 80 90 2C .
And the following with BMW DIS -
Code 60 selector lever switch
EGS - 3C EGS transmission switch .
Digging deeper into DIS tells which of the L switches should be open or connected to terminal 15 in the relevant selector positions . The pic you posted for connection summary shows L1 L2 L4 connected to terminal 15 in the park position .
The times when the fault happened showed L1 open in the park position when it should be connected to terminal 15 .
L1 is the suspect , just need to figure how to test continuity .
I could dig deeper with DIS if I can catch it with the fault present .

[Blademan007]

Originally Posted by amacman

I have had this fault happen a few more times .
I found the following codes with INPA - signal AGS code 80 90 2C .
And the following with BMW DIS -
Code 60 selector lever switch
EGS - 3C EGS transmission switch .
Digging deeper into DIS tells which of the L switches should be open or connected to terminal 15 in the relevant selector positions . The pic you posted for connection summary shows L1 L2 L4 connected to terminal 15 in the park position .
The times when the fault happened showed L1 open in the park position when it should be connected to terminal 15 .
L1 is the suspect , just need to figure how to test continuity .
I could dig deeper with DIS if I can catch it with the fault present .

Did you ever find the solution for this? I now have the fault 0080. My tranny has very hard 1-2, 2-1, 2-3, and 3-2 shifts. It was much worse in more gears, but after a reset of shift adaptations, I only have 1-2 and 2-3 issues.