Hi, lately I've been noticing that the Start-Stop warning light on the speedo comes on while I'm driving, and it's happening more often, but not all the time.

Could the auxiliary battery need replacing? I replaced the main battery over a year ago. The Start-Stop battery is original.

Thanks
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Jaguar: Grace, Pace, and Space - Sir William Lyons
Current: '15 XF (X250) Portfolio AWD 3.0 (it's aubergine)
Past B: '08 S-Type 4.2 "Satin Edition" (250.06 whp / 259.67 torque)
Past A: '05 X-Type 3.0/AWD Jaguar Racing Green

 

Usually the Stop/Start battery is dead much earlier than the main battery. I assume Stop/Start does not work?
Can you measure the voltage on the batteries? If under 12V you want to replace it.
Chris

 

>I assume Stop/Start does not work?
Actually it's intermittent, sometimes when I start the car Stop/Start works fine (I can switch it off and on). However, more frequently it has stopped working soon after starting the car. At that point the warning light comes on in the information panel between the tach and the speedo.
I'll take it to my regular mechanic and see if he can test the battery.
Thanks
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You dreamed of a big star -
He played a mean guitar -
He loved to drive his Jaguar...

So welcome to the machine

 

Replaced the AUX battery and all's good, now.
However, the only place to get one was the dealer and the thing cost $266USD...
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Current Hers: '13 Lexus ES350
Current Mine: '15 Jaguar XF (X250) Portfolio AWD
Jaguar - making mechanics out of customers since 1935