sos warning on dash ? related to lead acid battery condition

[Van substitute]

Hello Everyone

I have recently been getting the SOS warning system light on the dashboard. My lead acid battery is original ( now 6 plus years old) I wondered if this might be the cause ? any views. Also as this battery does not crank the car to start are there any other indications of when this might need to be replaced before the inevitable "oh hell "day when nothing happens when you try to start up the car and you are stuck.

[Bristol_Crosstar]

You just need to check the battery voltage using a voltmeter or tester (cheap ones available on Amazon if you don't have one)

[Lord Voltermore]

You can buy voltmeters  that plug into the cigarette lighter socket  giving a constant voltage display . But they can be a bit of a worry meter.   I used one on my 2021  car before it was 3 years and even then it often read below 12v if the car had been unused for a few days   But it still  always powered up the car.

We dont seem to get as many complaints about flat 12v batteries since Honda changed battery brand to Panasonic/Yuasa in about 2023.

The battery is comparatively small. 6 years old may be pushing your luck.

[Van substitute]

Thanks Lord Voltermore . I do have a voltmeter and like you I have noticed that it often says around 12 v ( and has done for ages )which for a cranking battery would suggest its not great BUT this doesn't have that work to do so unless anyone knows the actual voltage that it won't power up the car its still a bit of guesswork.
I only linked the two issues because one day the sos warning came on. I usually do relatively short journeys however when I drove 100 plus miles in a day shortly afterwards the green light on the sos button came back on and the warnings stopped for a few days and then went back to coming on again once i drove more routinely.

[Lord Voltermore]

Even when my 2021 car was only  year or two old the voltage sometimes only read about 11.5 volts  if the car had sat unused for more than a few days. Which is below what is considered normal for a 12v lead acid battery even  in a fairly low state of charge. And borderline on possible long term damage to the battery (It raised to a healthy 14+ volts charging voltage when the car was powered up.)

 I probably should have got the battery replaced under warranty, but never bothered    Perhaps I was too confident that my small 12v powerbank jump starter pack would get me out of trouble if necessary.  The car never failed to power up and it never got any worse. 

I never noticed any problem with the e-call sos system when the voltage was below 12v, but maybe the call system is the first to fail if voltage drops too low.   (Sorry,until now I thought you meant the battery warning indicator light had come on)

I'd be inclined to get the 12v battery condition checked by a battery specialist. They check more than just voltage. 

Check out this previous post on 12v battery problems , which includes some suggestions of cheaper options than from a Honda dealership

https://clubjazz.org/forum/index.php?topic=18298.75

[Wonder]

Hi, I still have the original battery from 2020 (I don’t know the brand)—should I be worried? I’ve never had any issues (hopefully I’m not jinxing myself!). Maybe it’s because the car is kept in a garage? In any case, I also have low mileage—25,000 km.

(Sorry for any mistakes; I used Google Translate.)

[coldstart]

I don't quite get the "SOS" warning part...

I've searched the manual quite extensively and still came up short.
Should it concern the "e-call-emergency-system" please do keep in mind that this can only work if the car is in reach of a 2G or 3G cellular network!
As these presently are phased out in more on more regions (including Switzerland!) I'm wondering, why I don't get "SOS" messages on the dash.

It would be extremely helpful if you would upload a photo of the message!

[Van substitute]

Hi cold start I have attached the main display dashboard showing the warning as you requested.

[coldstart]

Thank you for the photo! - Although I'm still quite puzzled by it (as it doesn't show up in the manual).
What does the the "SOS" button in the ceiling look like? (e.b. is it "green"?)

And I'm very disappointed about your Honda dealership!
As this is a preprogrammed warning sign, at least Honda should know what causes it to appear!
(probably they just are too lazy to do their work properly and escalate this - hey: It's an orange warning sign with the ominous "SOS" - in my book that should them get "interested".

[5thcivic]

It's obviously the eCall system so are the leds in the roof correct as described in the manual pages 387/8? has anybody pushed the button and not cancelled the call? If it signals a fault in the system, failure to connect to phone signal etc, it's frankly amazing that a dealer cannot diagnose it.

[Steve_M]

With the ignition, press and hold the SOS cancel button for 5 to 10 seconds, it will then complete a diagnostic check and a voice will read out any issues.

[Van substitute]

Thanks for all the responses to this issue from everyone. I have done some internet digging and found the answer. In essence there are two power sources for the e call emergency call system. The 12 volt battery in the engine bay and another back up battery behind the central console. If either (or both) are too low in voltage the sort of problems I described in my original post are characteristic. I have copied and pasted the search replies below which tell the full story and my observation that the problem went away after an extended drive is actually mentioned.

 Does the honda jazz hybrid have a small backup battery for the emergency call system in the roof lining ?

Yes, the Honda Jazz Hybrid features a small, dedicated backup battery for its emergency call (eCall) system, but it is not located in the roof lining.
While the physical "SOS" button and its indicator light are mounted in the overhead console near the roof lining, the actual electronic control module housing the backup battery is located behind the vehicle's dashboard panels.

System Details & Lifespan

• Purpose: The backup battery ensures that the eCall system can still transmit your GPS coordinates and establish a call to emergency services if a serious collision completely cuts off power from the car's primary 12-volt battery.
• Lifespan: Honda states that this backup battery is designed to operate for at least 3 years.
• Low Battery Warning: If the backup battery's charge drops too low or its internal resistance breaks down, the eCall indicator light on your ceiling console will blink red to alert you that it needs replacement.
• Replacement: Honda does not sell this internal battery for direct consumer purchase, and it must be replaced by a qualified technician or dealer.

1. The Direct Fixes

• Drive the vehicle continuously: The eCall backup battery automatically recharges via the main powertrain while the car's power system is turned ON. If the car has been sitting or only used for very short trips, driving it for an extended period (typically 1 to 2 hours) should top up the battery and change the indicator light back to green.
• Check the main 12V battery: On the Honda Jazz, a weak or failing main 12V starter battery often stops the eCall backup battery from maintaining its charge, resulting in false or persistent alerts. Having a dealer test or change your primary 12V battery may solve the issue.
• Dealer Battery Replacement: If the backup battery has entirely degraded from age, it can enter a "locked state" where it will no longer accept a charge. It must be physically replaced, and a technician will need to use Honda diagnostics to clear the locked error code.

For anyone interested the cost of the back up battery is £85 on eBay and double or more from other parts suppliers even if a DIY fix was viable ( although not recommend naturally )