I have a brand new Honda Vezel (Japanese market only). It has this fanciful but useless and nuisance feature that shuts down the engine when I come to a stop and automatically restarts the engine once the foot is off the brake pedal. As a result, the air-conditioning compressor is driven from an another power source in addition to the serpentine belt from the engine. The AC is not as cool when the engine is not running. I think the thermostat is auto increased by a few degrees, maybe to save battery. Anyway, the engine will come on, even if foot is on the brakes, after a minute or so, presumably because the battery cannot take it anymore.

(I manually switch off this feature every time I start on a new journey.)

I now have a problem with the AC. The compressor runs for about 10 seconds and then cut off, at the usual thermostat setting of 26°C. I have to set it to more than 5°C down to achieve the previous cooling environment (ie before I discovered this problem).

I suspect the compressor may be operating in the mode when the engine is auto shut-off, ie the setting is compensated by n degrees. I want to do some investigations. How do I trigger an auto-engine shut down situation with the hood open and no one is in the driver's seat?

  • 2
    Welcome to the site. It sounds like your AC is cutting out because the system is either under-pressurized or over-pressurized. Could you confirm that your high-side and low-side refrigerant pressures are within spec?
    – Zaid
    Oct 7 '15 at 8:09
  • 2
    If this is a brand new car, why aren't you taking it back to the dealership to have it fixed? If you mess around with it, you could be voiding your warranty ... at least I'm assuming they have warranties in the Japanese market? Oct 7 '15 at 10:35
  • 1
    Just curious, why do you consider this 'useless'?
    – JDT
    Oct 7 '15 at 14:40
  • @JDT It kicks in, ie shut down, at inappropriate times. It is unable to tell whether I will be stopping for 2 seconds or 1 minute. When I pause to make a turn, it can shut down. I can't imagine the shortened battery life and the amount of lead and energy needed to make a new battery. There is now the increased complexity in the AC system.
    – Old Geezer
    Oct 8 '15 at 1:40
  • Oh, it's an automatic transmission. My bad for living in a country where manual transmission is still the norm and thinking that applies everywhere:) I've been told the batteries are specifically designed to incorporate start/stop systems by the way, but YMMV.
    – JDT
    Oct 8 '15 at 8:21

To answer the question in the title

There are ways to fool the car into thinking that the car is in 'D' and the brakes are on (activating the brake switch, for instance).

However, given the fact that the car is supposed to be in motion prior to auto-shutoff, unless the car is jacked up and all four wheels are off the ground it is an adventure fraught with peril.

I'd recommend the following options:

  • have a second person sit in the driver's seat and hold the brake pedal while you investigate around the engine bay with the bonnet open.

  • mount a miniature camera like a GoPro with additional lighting in the engine bay to allow you to monitor the internals while you drive around in various conditions. The video footage can then be analyzed later.

As for the AC...

There are a host of things that could be wrong. Possible culprits could be:

  • improper high-side, low-side pressures
  • fan(s) not working so heat is not getting rejected out
  • lack of air flow through the radiator due to blockage/clogging
  • faulty pressure sensor signal
  • I like the GoPro idea. Good one. Jan 16 '16 at 15:47

As it's a brand new car, I would be inclined to contact the dealership and have them confirm that the system is working correctly or rectify the fault at their cost.

I have a car with stop-start and find it quite brilliant. It's added at least 5 MPG to my commute.

  • 2
    +1, but now where's the fun in handing it over to the dealership? ;)
    – Zaid
    Oct 7 '15 at 8:03
  • I imported the car myself, so no dealership to fall back on.
    – Old Geezer
    Oct 8 '15 at 1:34
  • Your local Honda agent will be able to honor the Honda warranty. I'd speak with their head office first but just because a vehicle is out of area does not void their responsibility to you as the new owner. Oct 8 '15 at 9:28

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