Auto Stop / Start Quit Working

2017 HSE Dynamic with 8,500 miles

The Auto Stop/Start function quit working a few weeks ago. I recharged the battery (disconnected everything from the battery posts first) then used a slow 5 amp charge which fixed the problem. A week later it quit again so I recharged again but that didn’t fix it.

Very little electrical load this time of year – AC off, HVAC fan speed at 3, headlamps off, HVAC and electric defrosts off, seat HVAC off, recirculation set to auto, stereo usually on, and no accessories plugged in.

No other triggers are active; Not in Dynamic mode, not in Sport mode, in 2WD, paddle shifters not being used, seatbelts fastened, ambient temp 45-65F, all fuses good, drivetrain at normal operating temp, etc.

ASS (an appropriate acronym I'm starting to think) has a significant impact on my gas mileage. My average is 27.1 with it, 25.2 without so I'd like to get it functioning again. Any ideas?

If the ambient air temperature is less than 5c then stop start will not work until the engine is fully warmed up. I appreciate yours is a gasoline engine and not a diesel like the majority of European owners have but I’m sure that the same is true. On my diesel V6 RRS I have to have driven around 15 miles before the ASS will work on a cold frosty morning, it was the same in my 2 Evoques. So if the black ice warning snowflake is showing on the dash you won’t get stop start without doing a longer trip. BTW you would be better to run with the Climate control set to Auto and 21/22 setting (maybe US cars have Farenheight markings) not for your comfort but for two reasons - the Climate Control also dehumidifies the interior and stops windows fogging up and also that then prevents condensation in the hidden parts of the car where damp damage of electronics in Land Rover vehicles is a well know issue when they get older. Today’s AC systems are pretty efficient and don’t sap power like they used too as the compressor only runs when it needs to.

Sorry, should have posted this long ago. Back in September Land Rover diagnosed my battery as defective and replaced it under warranty at 15k miles. Battery management system and all other electronics were good. The Auto-Stop-Start system worked immediately after battery replacement and is still going strong at 24k miles. MPG over those 24k miles is 27.3 including the 1,500 miles while A.S.S wasn't working and MPG fell to 21.

(10-02-2018 10:21pm)JustinDOzone Wrote:  2017 HSE Dynamic with 8,500 miles

The Auto Stop/Start function quit working a few weeks ago. I recharged the battery (disconnected everything from the battery posts first) then used a slow 5 amp charge which fixed the problem. A week later it quit again so I recharged again but that didn’t fix it.

Very little electrical load this time of year – AC off, HVAC fan speed at 3, headlamps off, HVAC and electric defrosts off, seat HVAC off, recirculation set to auto, stereo usually on, and no accessories plugged in.

No other triggers are active; Not in Dynamic mode, not in Sport mode, in 2WD, paddle shifters not being used, seatbelts fastened, ambient temp 45-65F, all fuses good, drivetrain at normal operating temp, etc.

ASS (an appropriate acronym I'm starting to think) has a significant impact on my gas mileage. My average is 27.1 with it, 25.2 without so I'd like to get it functioning again. Any ideas?

Quote MPG over those 24k miles is 27.3 including the 1,500 miles while A.S.S wasn't working and MPG fell to 21. Quote.

You obviously do mostly urban driving then, stop/start and smart charging shorten the life of the battery, stop/start`s involvement is the thousands of extra starts, smart charging never fully charges the battery under engine power, on short journeys you get little regeneration therefor the battery stays undercharged for extended periods.