New Member: A8 2005 D3 Starting Issues

[MikeyA8]

Hi to one & all,

New to the forum and this is my first post.

Just picked up an Audi A8 2005 D3 3.0Tdi.

The car has keyless go, which only worked once after I got the car, so I changed the keyfob batteries and charged the main battery as well.

Since changing the remote fob batteries the keyless go still doesn't work but more importantly it's developed a starting issue.This is what happens:

1. Keyfob unlocks & locks the car fine.
2. Put the key in the ignition, the radio comes on and the MMI kicks into life.
3. Try to crank the engine but nothing happens. No lights on the dash or anything.
4. keep trying and then suddenly there is a "clunking noise" and then the ignition fires up.
5.Once started it's fine and then even after short stops it starts fine but leave parked for a period then back to the same starting issue.

I had read there is a risk of the keys transponders losing their memory during battery replacement and then need recoding but I would imagine if it locks/ unlocks the car then that must be okay.

Another issue which my or my not be related is the MMI, when first started I cannot scroll down the menu's just go to the next option but cannot scroll further then after driving a while it works fine.

Had the diagnostics done and it's come up with the following fault code:

Fault code 00166
Access start authorisation switch
E415 open circuit intermittent

Hope someone can help , incidentally after performing the scan and clearing the keyless entry has starting working except the passenger door !!

Any help would be much appreciated.

Thanks

[Guest 2]

Welcome to VWAF :)


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[snapdragon]

The fault code description sounds like a faulty START/STOP switch.
Does that sound plausible?
I din't think it can be the transponder code reset as it would never work at all until fixed, rather than be intermittent.
Do you ever have "key not in vehicle!" warning when the key is in the vehicle? If not I think the KESSY and antennas can 'see' the key and it points to that switch. Maybe a spilled drink has got into it in the past?

[MikeyA8]

Thanks A6_Chris

[MikeyA8]

Hi sanpdragon,
When we were buying the car the pervious owner actually said that it didn't have keylessgo and he had the car for 5 years, so I am assuming it hasn't worked or he never knew how to use the option !
So after collecting we realised it had that function and changed the batteries on the keyfob to see if that helped. Must mention that after collecting and prior to changing the keyfob batteries it was working fine although didn't use the car much.
Trying to use the START/STOP switch worked intermittently with a message no key identified when it didn't work.
It's just like the immobiliser is still on when the key is in the ignition, radio and MMI work but nothing else and will not turnover. The only time I know it is okay is when the steering lock is released and I hear this "clunck" then I know the ignition etc will work.