Cruise Control stops working

[a8 tech]

In MY 08 (A8 MY 07) the "active" cruise control was introduced. It can be identified by the speed display in the dash insert.

After changing gear the speed is automatically controlled again.

If the accelerator pedal is pressed during the gear change and the clutch is not fully released, the engine control unit recognises an implausibility between engine speed and vehicle speed. For safety reasons the cruise control is switched off.

This can happen when the cruise control is switched on or off.

It is necessary safety feature.

The cruise control unit can be reactivated on by switching the ignition off and on or by pressing the clutch once when driving. This restores the plausibility between engine speed and vehicle speed.

The complaint only occurs on vehicles with manual gearbox

Depending on the engine ecu sw version you can update the software to prevent this but the dealer needs to refer to the latest documentation or submit a technical report on your behalf to the manufacturer.

Please don't submit my post to your dealer, just mention the above

[Bratty]

Juniperz, I am not a lawyer or indeed an expert on ANYTHING!! but I can quite confidentely say that in Germany it is not illeagal to have your mirror dipping when you reverse!, to not have a chime when you do not secure your seatbelt!, Etc. Etc. Your Bullshitometer should be on FULL alert!! with your dealership.

If my dealership said to me that they were willing to sacrifice my life and that of my family in an accident caused by a failure of the cruise control (or any other aid shown to be faulty??) to save some piffiling amount of money then I am sorry! They would be getting both barrels.

Dunk

[a8 tech]

The dealer has refused the changes due to protocol.
Audi are very strict with unauthorised changes and every time a coding alteration is made the sw records the dealer number.If any changes are made which contribute to a fault or failure then the dealer is liable.


Remember this members, vcds has the function of long code helper and vas has no such function for 8k platform
The dealer codes the controllers via online server which records and monitors any changes from build date so once the operator submits a code or update change the server returns the vehicle specific coding.

Not all dealer techs understand what bytes do what and nor are they required to as the process is covered via the factory on line connection and alterations could affect future factory updates.

[Bratty]

Totally see where you are coming from A8 Tech. But why can the dealerships not say that instead of the "its illegal in Germany cack".

With such a technically advanced car its understandable that not everyone will be up to speed with the latest updates or mods, but there is no need for them to ********, just say "I do not know the answer but I can find it out"

Dunk

[juniperz]

If the accelerator pedal is pressed during the gear change and the clutch is not fully released, the engine control unit recognises an implausibility between engine speed and vehicle speed. For safety reasons the cruise control is switched off.

Thanks A8 Tech, for this and the rest of your fantastic support in this forum.
The difference though, is that in the 3 cases when this has happened to me, I haven't touched the clutch - I have just tried to accelerate using the control stalk.

The cruise control unit can be reactivated on by switching the ignition off and on or by pressing the clutch once when driving. This restores the plausibility between engine speed and vehicle speed.

Useful to know - if it does happen again, I can at least try this instead of having to pull over, switch off / switch on.

Please don't submit my post to your dealer, just mention the above

Of course...

The dealer has refused the changes due to protocol.
Audi are very strict with unauthorised changes and every time a coding alteration is made the sw records the dealer number.If any changes are made which contribute to a fault or failure then the dealer is liable.

Out of interest, if your dealership received a request to enable the mirror dip and lock beep, would they stick to protocol or give the customer what they wanted? (It's OK; I have no plans to travel to the north west in the near future!).

[juniperz]

Juniperz, I am not a lawyer or indeed an expert on ANYTHING!! but I can quite confidentely say that in Germany it is not illeagal to have your mirror dipping when you reverse!, to not have a chime when you do not secure your seatbelt!, Etc. Etc. Your Bullshitometer should be on FULL alert!! with your dealership.

It certainly was. The reception lady claimed to have been on all sorts of courses, but I think she would have learnt more from browsing these pages!

If my dealership said to me that they were willing to sacrifice my life and that of my family in an accident caused by a failure of the cruise control (or any other aid shown to be faulty??) to save some piffiling amount of money then I am sorry! They would be getting both barrels.

I had assumed that if it happened again and they refused to try replacing one or other of the suspect parts, I would take it up with Audi UK in writing.

[Bratty]

I find cruise control to be amazing.

It is a fairly cheap option (available on most makes of modern cars!) but it has so many interactions like Brake, Accelerator, Clutch and control stalks. But how does it actually work? is it just inputs into a computer that is told what is happenning by switches or pneumatics?

The disturbing fact for me in your situation is an A4 will apply the brakes for you (if the accelerator is applied whilst in cruise mode and you then allow the car to return to cruise speed), so the car is thinking for you, if there is a malfunction in the loop it COULD? just default to the off position. Or it might throw a wobbly and put all four brakes on.

Possibly not, I certainly do not know? (but try holding your handbrake switch up whist you are travelling at speed it is truly devastating!!) Why is Audi asking you to live with a fault that could affect your safety seems like a fob off.

Bratty

[juniperz]

Why is Audi asking you to live with a fault that could affect your safety seems like a fob off.
Bratty

The dealer I was using (Swansea) obliquely suggested that the supplying dealer may be a better bet, which sounds like another cop-out. It is a company car - it came from Newbury and I never go anywhere near there. Surely any dealer should be able to handle warranty work.
Maybe I should get the lease company involved...

[a8 tech]

Thanks A8 Tech, for this and the rest of your fantastic support in this forum.
The difference though, is that in the 3 cases when this has happened to me, I haven't touched the clutch - I have just tried to accelerate using the control stalk.


Useful to know - if it does happen again, I can at least try this instead of having to pull over, switch off / switch on.


Of course...


Out of interest, if your dealership received a request to enable the mirror dip and lock beep, would they stick to protocol or give the customer what they wanted? (It's OK; I have no plans to travel to the north west in the near future!).

Yes we would activate and simply add a note on the history of the activation for future reference, if a control unit replacement is required in the future so the technician can re code for the changes you requested

[B6Andy101]

The lack of cruise control has been closely followed by a TPMS system failure warning

The cruise will not reactivate despite switching the ignition on and off. The stalk is funtionless. Booked in for Friday.

Thanks for the heads up A8 Tech.