540i AT won't shift into 3rd Gear

[FJS407]

After solve all the commom problems (if I make a checklist, i've had all of them), one more appeared.
My 540i Auto just refuses to shift gears.

The first and second gears are fine, but in manual, for example, when I try to shift to third, the pannel shows "3" and immediately "2"... No matter what I do.

Starting with the cheapest solutions, what do I check first?
Speed sensors can cause this?

...if the transmission fluid overheat, can this be a simptom?

There are no warnings on panel or lights.

Sorry if something I wrote sounds strange, my english is not so good.

[edjack]

Your English is MUCH better than my Portuguese!

It may be the position switch on the left side of the transmission. Examine the switch and the cable for damage or water intrusion.

You mention a possible overheat condition. Does this occur when the engine is cold, as when you first start out in the morning? If it does, it may be the switch. What does the shift indicator in the cluster say?

Is this really a Protection model?

[FJS407]

Your English is MUCH better than my Portuguese!

It may be the position switch on the left side of the transmission. Examine the switch and the cable for damage or water intrusion.

You mention a possible overheat condition. Does this occur when the engine is cold, as when you first start out in the morning? If it does, it may be the switch. What does the shift indicator in the cluster say?

Is this really a Protection model?

I'll check the sensor!
It was the first time that happened.


About the possible overheat...
My Aux fan aparently isn't working.


Even without an error message in dash, I was thinking, if the transmission fluid overheats can this be a way to the car protects the gearbox from a worse problem?


Yeah, it is a Protection model.

[edjack]

The cable assembly inside the trans has a temperature sensor to protect the trans. I believe the correct scan tool can report the temperature.

[Chedley]

Which transmission do you have on this car : Is it the ZF-5HP24 ??

[FJS407]

Which transmission do you have on this car : Is it the ZF-5HP24 ??

Yes, it is!
I've found this topic and the "stop and go" mode its basically the issue that i'm having

https://www.bimmerforums.com/forum/s...ng-issue-fixed

My aux fan its really dead.
I bought a cable and will check the temperatures with INPA.
It will take a while to arrive...

[Chedley]

Meanwhile, I would try to fix or replace the aux fan and clutch, and check the transmission cooler and valve. To make sure the overheating is (or not) a bad reading by the temp sensor.

[FJS407]

Well... After a month the cable arrived.

I got some data with INPA and I didn't find errors in the transmission module.

In engine module I have:

Captura-de-Tela-16.png



Some time ago I had the same message (Trans Failsafe) and It was solved with a new battery and alternator (refurbished). At that moment, the abs and dsc lights turned on.
When I had the problem with the gears last time, I was surprised by the message about lamps (something that had never happened before).

With the car running, the voltage is actually around 13.8v (eventually oscillating).