How to tell your mild hybrid A4/S4 is coasting?

WarwickBoy

Registered User
See this review of the new RS6. At 12:15 in the video Rory shows the “coast”when the electric motor kicks and the engine switches off in the revs drop to 0 and an A is displayed in place of the gear number. This saves fuel.

I have a mild hybrid 2020 S4 and have never seen my car do this. Is that what indicates electric no engine cruise on this model too?

Perhaps my driving style is not “efficient” but I’ve only ever seen the hear number go blank with no rev counter drop?

 

Zippytoo

Registered User
WarwickBoy, my S4 TDI does this quite often. Conditions have to right though: your speed needs to be between 34-99mph with foot off the gas, so that you're coasting (which likely means you're going downhill, or perhaps on the level). I've travelled up to half a mile with the engine off (slight downhill, motorway).

Whilst engine off is engineered to last no longer than 40 seconds, the engine does kick back in early sometimes (even with your foot off the gas), either to idle or 'normal' according to gear and speed . Sometimes, but not always, this seems to be based on the satnav feed that also lights up the green 'foot off the gas' light on the VCP (which indicates you're approaching a junction / sharp bend). And the engine off won't activate if the car is doing an active dpf regeneration.
 
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WarwickBoy

Registered User
Interesting, thank you ZippyToo. I’ll try and get the conditions right to experience this. I’ve seen the “consider lifting off green icon on the dashboard” but never had accelerator pedal vibration “suggestion” he mentions. Does the S4 TDI have that feature?
 

cuke2u

Registered User
From my manual:
Screenshot_20200307-091436_Adobe Acrobat.jpg
 

Zippytoo

Registered User
Have to admit that my coasting and start/stop had stopped for a few months. With lockdown I've done a little less mileage and to begin with I had not noticed but in hindsight it must have been a good 3 months since stop/start and coasting had not worked. So, I applied some google science and, lo and behold, worked out that it was the REAR seat settings on the aircon (set on LO I think by rear seat family members sometime ago) that was the reason. Sorted now, with start stop and engine off working as it used to. But worth checking if you have the same issue!
 

Frankiejr26

A4 40 TFSI BE ordered 29th June
Is this for all mild hybrids or just those with the Driver Assistance pack?


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cuke2u

Registered User
I think manual shifts don't....
 

HMG1K

Registered User
Easy, take your foot off the accelerator at low speed, under 10mph, and the car will use all its stored battery energy without having to touch the pedals.

Keep in mind you'll have to have driven a bit to have stored up energy in the battery. Works a treat on my B9.5 A5 Sportback
 

cuke2u

Registered User
Checking my settings as described in the manual I don’t have the coasting option available.


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With newer cars the option might have been removed. Your's is a stronic, yes?
 

Frankiejr26

A4 40 TFSI BE ordered 29th June
With newer cars the option might have been removed. Your's is a stronic, yes?

Yeah it’s stronic. So yesterday I noticed it coasting (showed D with no number). So I think they have removed the option to disable/amend it.


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HMG1K

Registered User
Isn't it just, for the A4 and A5 I know about, just the B9.5 models that have mild hybrid tech we are chatting about?
 

cuke2u

Registered User
Nope, as mine is a mild hybrid. It depends upon the system used and even start stop systems with regenerative braking are described as mild hybrids. The systems are now more advanced of course.
 
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