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Warning lights after replacing 12v battery

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The 12v battery died on my 2004 Hybrid, I had it replaced by the AA. One restarting - brake, VSC, and red car with exclamation lights came on - initially the engine died! But on restarting all is well with driving the car but the warning lights remain. Any advice?




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I can advise you of my experiences over the last two winters. First one the 12v battery died over Xmas / New year as I hadn't kept using the vehicle- changed the 12v and car started but the headlight dash symbol was illuminated even though HL not switched on but removing key and starting again solved this- have had this a couple of times since after disconnecting the 12v and going through removing key and restarting solved it.


Last winter we had covid and couldn't use the van for some weeks and the 12v was dead . Changed the 12v battery after the last experience but had the same errors as you. Turned out after checking with Techstream there was an issue with the HV battery- 2 units were down. Had to have the battery professionally fixed by Mark at Hybrid Services Torquay.

He did suggest to check if the HV was an issue to run the engine (at idle) and see if it cycled normally between the petrol and the HV battery - in other words after so long the petrol would switch off and then switch on again when the HV needed boosting again. N.BDon't have the aircon, heater or other electric drains on when you do this. You might also look at the hybrid display on the HD unit and see if the charging of the bars seemed ok or a bit odd. Mine would go to 4bars then to one.


Another issue could be the hybrid inverter cooling pump- mine went faulty some weeks after having the HV repaired and gave the same dash errors- you can check by running the engine from cold and remove the Hybrid filler cap (to the right of the radiator) and see if the fluid is moving- if it isn't then may be the pump- if it is don't run the engine for any period of time as the inverter may overheat.


Also disconnecting the neg terminal on the 12v for 20 mins will reset the faults but if there is an actual fault they will usually re appear after about 20 mins of running the engine.

I am no expert- this is all through experience- still learning. Cheers.

Edited by PaulE
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On 10/6/2023 at 5:32 PM, Andy Hawes said:

Any advice?

Get hold of a JOBD reader (e.g. Ancel JP700). Use it to clear DTCs then see if the fault re-appears.

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