Stop/start c3 aircross

Faults and Technical chat for the Citroen Aircross
Jwepjb
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Post by Jwepjb » Thu Jul 21, 2022 3:24 pm

My car stop/start was working ok, but just lately it’s not stopping. The green light flashes on the dash but car continues to run.
Any comments

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Juan Sheet
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Post by Juan Sheet » Thu Jul 21, 2022 3:32 pm

It's because the conditions for the Stop Start to work have not been met. This can be related to battery charge, outside temperature, interior climate control requirements of the passengers on the system, the frequency of previous Stop Start actions, the coolant temperature etc, etc.

In most cases it is the battery below a certain threshold, but can be due to the other circumstances I've mentioned.

I had my car battery replaced under warranty after a year as the Stop Start never worked at all. The dealer will need the vehicle overnight to properly test it and measure the charge before they will replace the battery under warranty though (if you still have a warranty and the car is under 2 years old).
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Mothy
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Post by Mothy » Thu Jul 21, 2022 5:39 pm

My start/stop has worked 3 times.
1. When I bought it.
2. Once after the first service having complained it did not work.
3. Once after the second service. Same as above.

My previous car a cactus it always worked.

I believe there are many other cars out there which don’t work either. It must be a different design to what the cactus uses.
Roly Alcock, Upton Upon Severn, Citroen C3 Aircross 1.2L Flair 6 Speed, colour coded to match the dog.

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Juan Sheet
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Post by Juan Sheet » Thu Jul 21, 2022 11:15 pm

There are several designs, but due to cost saving measures the later vehicles tend to have a main battery only and don't use the older 'ultra-capacitor' system with a secondary energy accumulator and regenerative braking. So when the main battery dips in voltage, Stop & Start won't work.

Depending on the Euro Standard of your vehicle, the battery (as measured by the battery charge status unit) has to be at the following percentage to operate the Stop Start system:

Euro 5: 76%
Euro 6: 78%
Euro 6.2: 80%

When mine was tested for the second time (I had to leave it with them for a few days, it was at or just under the 80% and mine is Euro 6.2. So it was changed under warranty.
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Juan Sheet
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Post by Juan Sheet » Thu Jul 21, 2022 11:18 pm

The ring volume can be separately adjusted in the settings menu, but is should be one or the other that is causing the issue I suspect.
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Daveg
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Post by Daveg » Sat Jul 23, 2022 2:11 pm

Noted below is my understanding of the factors which will inhibit the stop/start function. This was obtained from the web and was relevant to the Vauxhall Crossland which is mechanically similar to the Aircross.

I suggest you obtain a cigarette lighter battery voltage tester (cost you a fiver on ebay) and monitor the voltage.
With the engine running and with battery and charging system in good order the voltage will drop to around 13.2v / 13.4v.
Note that whilst my dealer told me that a charging voltage of up to 15.5v was ok, Bosch & Exide stated in correspondence I had with them that for an AGM battery the maximum charging voltage must not exceed 14.8v.

Regards Dave

Note referred to:-
1 The bonnet is open.
2 The driver's seat belt is not closed.
3 The driver's door is open.
4 The driver's seat is not occupied.
5 The stop/start system is manually locked.
6 The battery is less than 75% charged or there is a malfunctioning battery sensor.
7 Reverse gear is engaged.
8 Brake system vacuum too low
9 The battery temperature sensor reports less -5°C (23°F) or more than 60°C (140°F).
10 The ambient temperature is below -5°C (23°F) or above 35°C (95°F).
11 If, when the automatic climate control is switched on, the difference between the temperature air conditioning system set by the driver and the temperature in the passenger compartment is more than 4°C (39°F) or if the defrosting is set to maximum.
12 If condensate has formed in the vehicle.
13 The engine coolant temperature sensor reports less than 10°C or more than 100°C.
14 The diesel temperature sensor reports less than 60°C (140°F) or more than 100°C (212°F).
15 The oil temperature automatic transmission sensor reports less than 0°C or more than 118°C.
16 The diesel particulate filter is regenerating.
17 The temperature sensor in front of the turbocharger measured more than 670°C (1,238°F).
18 The speed at which the vehicle was last stopped is less than 3 km/h.
19 At altitudes above 2 000 m (6,562 ft). 20 When either the anti-lock braking system, the electronic stability program or the traction control is switched on.
21 When a collision has been detected (to prevent the engine from restarting after automatically switching off in the event of an accident).
22 A malfunction of a sensor or a system fault is detected.
23 An impact has been detected or the impact detection is inoperable.
24 There is a malfunction of the stop/start system.
25 There is a malfunction of the vacuum sensor.
26 There is a malfunction of the clutch sensor.
27 There is a malfunction of the brake pedal sensor.
28 There is a malfunction of the idle switch. 29 There is a malfunction of the reverse gear switch.
30 There is a malfunction in energy management.

end of note

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Juan Sheet
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Post by Juan Sheet » Sat Jul 23, 2022 2:20 pm

Worth pointing out that AGM batteries are generally not fitted to the later vehicles including the C3 Aircross, which use Enhanced Flooded Batteries.

I didn't put all the specific C3 Aircross Stop / Start conditions up as in 99% of the cases it will be the main battery that is below the threshold.
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Daveg
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Post by Daveg » Sat Jul 23, 2022 3:07 pm

Thanks Juan, I was unaware of the change of battery type.
In my correspondence with Bosch & Exide the stated maximum charging for a flooded battery was 14.4V.
Out of interest is there any way I can determine my battery type without removing the battery cover - my vehicle is a late 2021 C3 Aircross Shine plus
automatic?
Thanks
Dave

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Juan Sheet
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Post by Juan Sheet » Sat Jul 23, 2022 3:09 pm

Hi Dave, no worries, just PM me with your VIN and I'll let you know.
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Juan Sheet
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Post by Juan Sheet » Sun Jul 24, 2022 11:54 am

Hi Dave, as per my PM, here is the parts photo regarding not showing you battery as even fitted!

The battery type is generally shown at (1):

C3AC Battery.PNG

In your case it's not listed. So you may have one of the Accumulator types instead. A simple check would confirm though. Sorry I couldn't help you on that one.

You probably have this:

C3AC Acc.PNG

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