Red Key Symbol on dash on attempted Emergency Start & Thoughts on Start/Stop effect on Main Battery Lifetime

Faults and Technical chat for the Mazda CX-3
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Vincent66
Posts: 12
Joined: Thu Dec 13, 2018 11:34 am
Location: UK

Post by Vincent66 »

The Cx3 (2016 Auto) is not my car so some of this info is indirect, and apologies for the quality. I thought it might be of interest though.

Event: Cx3 in pub car park for about 2 hours. Radio used while waiting for short time for other guest. Thought radio turned off when guest arrived(? - perhaps not?). Also thought car locked (perhaps accidentally not locked?)

On exiting the pub symptoms were:

1. The car would unlock/lock just fine with the fob (Aside: The fob battery has been recently changed with new one from Sainsburys a penknife and youTube)

2. The car would not start (Red key symbol on the dash)

3. You might think flat keyfob battery - so emergency entry and start procedure tried (take the physical emergency mechanical key out the fob to gain entry to the car, then (bit weird) press the back of the end of the fob (see youtube and/or the manual) against the starter button on the dash. Result - no start and Red key symbol on the dash. Manual just says call dealer (Really not helpful).

4. AA called and detected slightly low main 12V battery (the fob battery fine), recharged main battery, battery test etc. and car drove away fine. The AA report not good enough to provide any better info here.

5. Car still fine after 2 days (So operator error not turning off the radio, intermittent main battery fault, or main battery near end of lifetime)

So my only strange thought is poor design not shutting down the electronics earlier (e.g. radio use when engine off) to protect the car against flat main battery and failed start. (My ancient Mk4 Mondeo (with Mazda engine) would protect itself if you sit with engine off listening to the radio as I found after buying the car and testing/figuring out the radio). Also seems very poor not to have a better warning on the dash e.g. red battery symbol would help rather than red key symbol, and/or or message on the Nav pan.

The other concern is (from the AA) that the engine start/stop has a bad effect on main battery lifetime. In the case of this car though the driver generally attempts to disable the start/stop (as this car is rarely driven in rush hour slow start/stop traffic). Unsure then if the main battery on this 2016 car (about 45000 miles now) near end of lifetime (and believe if you ask whoever, they will just fit you a new main battery . . . )

Aside: (And please just ignore this rant here if it is disagreeable) With the driver I consider the default for the start stop of enabled is just downright dangerous. My own first experience (in this Auto Cx3) was it cutting out the engine just as I was releasing the handbrake to pull out from a T junction, so missed my opportunity. The driver may well then make a very bad call on the next pull out opportunity having been unnerved by this feature. Lesson learned. So fine to turn it on when in stop/start traffic but otherwise a crazy feature (just my opinion, I know others (probably more confident drivers) think different.)
Perhaps the feature works better in a manual transmission version of the car(?)
Future Mazda: AI will detect traffic in front as reason for the auto stop (vs T junction etc.) and do a much better job I hope. I think start stop much better idea in hybrids with better facility to get the car moving again (But hybrid general reliability may be unacceptable. I've had one drive of a mild hybrid and one total failure of that same car - not a Mazda though, and the dealer too embarrassed to give any explanation - they just towed it away. )

Many thanks for reading and any thoughts / education please - I may well be missing some obvious points.
2016 Cx3 2L Petrol Auto

Graeme67
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Joined: Wed Apr 14, 2021 8:37 am
Location: Sunderland UK

Post by Graeme67 »

Your car is a 2016 so battery probably needs changing, don't seem to last as long as they used to.. Low battery will cause weird things on the car. As for stop start, I switch it off, I don't like it and it kills batteries.
2017 CX 3 1.5 Diesel Sport Nav
Vincent66
Posts: 12
Joined: Thu Dec 13, 2018 11:34 am
Location: UK

Post by Vincent66 »

Graeme67 wrote: Fri Jul 29, 2022 1:44 pm Your car is a 2016 so battery probably needs changing, don't seem to last as long as they used to.. Low battery will cause weird things on the car. As for stop start, I switch it off, I don't like it and it kills batteries.
Many thanks Graeme for confirming the battery lifetime expectation.

According to the AA the Cx3 major breakdown/call-out causes are the battery and tyre issues.
2016 Cx3 2L Petrol Auto
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HouseSpider
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Post by HouseSpider »

Finally had to change the battery this week after 85k miles & 5.5 years old. I-stop had stopped working and I'd had a couple of weird issues with starting the car. Seems like new now & no more issues.
Sports Nav Auto Petrol 2017, 131bhp (chipped), Soul Red, Half Stone Leather, Safety Pack, Arm Rest, Auto Folding Mirror Kit, Detachable Tow Bar, HatchBag Boot Liner, Stebel Nautilus Compact horn. Space saver.
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jtonline
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Post by jtonline »

My battery is still the original 2015. In my experience, i-stop will not cause an EFB Start/Stop battery to have a shorter life than standard car batteries.

If you're coming to a stop at junctions or pedestrian crossings, for example, when you're not expecting to have to wait long before moving off again, you can stop the car without activating i-stop by not pressing so hard on the brake pedal.

The following notes are extracts from the 2016 Owner's Manual:

"If the driver's door is opened while the ignition is switched to ACC, a beep sound will be heard 6 times to notify the driver that the ignition has not been switched off. Left in this condition, the keyless entry system will not operate, the car cannot be locked, and the vehicle battery power will be depleted."

"To prevent the battery from being discharged, do not leave the audio system on for a long period of time when the engine is not running."

"Do not leave the ignition switched ON while the engine is not running. Doing so could result in the battery going dead. If the ignition is left in ACC (For automatic transaxle, the shift lever is in the P position, and the ignition is in ACC), the ignition switches off automatically after about 25 minutes."
Julian.
Sept. 2015 CX-3 Sport Nav, Dynamic Blue Mica, 1.5 Diesel, AWD, Automatic
http://www.jtonline.info
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hsdejong
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Post by hsdejong »

In my one and a half year old CX-3 I once had the ventilation and audio on for 2 hours without running the engine and was able to start and drive off without any problems.
It took a while for the I-Stop to function again, because the battery had to be sufficiently charged first.
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HouseSpider
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Location: New Forest

Post by HouseSpider »

A couple of weeks ago when having a windscreen chip repair the uv light used to cure the resin deleted the battery enough to cause starting issues.
The battery symbol would never blue out, even after a full reconditioning battery charge.
These were the final indicators that my battery had had it.
Sports Nav Auto Petrol 2017, 131bhp (chipped), Soul Red, Half Stone Leather, Safety Pack, Arm Rest, Auto Folding Mirror Kit, Detachable Tow Bar, HatchBag Boot Liner, Stebel Nautilus Compact horn. Space saver.
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