Keyless Entry / Advanced Key

[74ns]

I have been having problems with the keyless entry / advanced key for the last few months.

The keyless doesnt work if the car had stood for more than an hour, however if I press the button on the remote I can unlock, drive off and when exit the vechicle I can lock the car / re-open the car with just touching the handles as should be used.

It has been in and out of my local Audi dealer who subsequently contacted Audi Tech (Germany) and replaced 3 door handles and sensors which seemed to cure the problem for 4 days and then, the other handle and sensor were replaced, then found a fault with the last replaced senor (which had an open circuit) and now the problem has returned.

I have a Audi mobile techi coming out tomorrow morning, but just wondered if anyone else has encountered this problem???

[a8 tech]

replace the start authorisation control including j393 control unit, simples

[74ns]

A8 Tech, thanks so much I will speak and advise the techie tomorrow!

If it is that simples why don't they know or done it already!!

[a8 tech]

If you see repeat o/c faults to the capacitor sensor's its either a poor connection or loss of signal feed back to j393.
As the handles have been replaced it would be wise due to the resting time that the j393 has a fault and possible can network not waking up which j393 would initiate.

As you approach the vehicle the keyless signal transmits and this wakes the vehicle network up.

When the fault occurs you operate the remote due to the keyless failure, but can you still start the vehicle from the stop start switch?

[74ns]

When the fault occurs you operate the remote due to the keyless failure, but can you still start the vehicle from the stop start switch?

Yes I can everything works ok.

[a8 tech]

This means the j393 cant determine the capacitor status to the doors handles.
What should happen from memory.

You touch the door and and j393 opens but also wakes the network up over the can

The remote serves the same process but this side is fine

The door handle sensors are wired separate so there is no hardwire linking each of the sensors.

If all the door sensors fail then j393 would be my focus especially with the resting time allowing the vehicle networks to shut down.

The start switch allows the vehicle to fire up because the aerial can see the key so the aerials are fine.

Please post the repair and I suspect there may be a svm update for j393 depending on the sw revision which may require replacement if no update can be run

This summary is from memory so it may not be 100% accurate

[74ns]

Forgot to mention that I can open the bootlid using keyless, walk straight up to car and open...

[a8 tech]

Well it time for j393 to be replaced to eliminate.
I will also add that these new type sensors fitted to b8, A5 and Q5 do not like steam cleaners.
First thing I do is remove the handles and inspect for water ingress.
I have fixed lots of these and found one repeat failure within 24 hours caused by a valeter blasting the door handles with the steam cleaner.

[troc]

My S4 has just started doing something similar

The touch sensor to lock the car is intermittent. All 3 other sensors work perfectly but this one requires me to rub my finger over it for a while before it decided to lock the door.

Bah.

[Bratty]

Sounds like you have bought a woman sensitive system Troc? They always need a bit of Pre-warming and button flicking.

Dunk