Battery light stays on

willbur

01 nissan almera 1.8 auto saloon , has new battery giving 12.7 volts, alternator is fine giving 14.4 volts at idle speed all cinections are in good nick so has anyone idea why the battery/charging light is staying on ,thanks for any help you can give

swhyte027

When the car is running and you connect the meter to the battery is it giving 13 volts or more.if yes then ur altenator is perfect.and my advice would be go get a battery.but before you do make sure to check all the connections and earths.

Mar4ix

i think , if battery light on, it means car using battery as main electrical supply, cos some problems with alternator. if you check battery, while engine running, it should be 14.4... same as alternator., also could be some problems with reley, but i dont know about nissan reley much..

willbur

THE battery is a new one and is working fine ,some one said it might be mass air flow metre giving faulty voltage to the ecu, what di you think

Mar4ix

willbur wrote: »

THE battery is a new one and is working fine ,some one said it might be mass air flow metre giving faulty voltage to the ecu, what di you think

never heard that air flow meter would have any influence in to car electricity. airflow meter gives signal to ecu about how much air goes in to inlet manifold, and it adjust fuel injector to give proper quantity of fuel.

i told you, would you check terminals on battery while engine is working ... it should be 14.4.

car using battery just to start car, all rest electricity car get from alternator.

simpliest test for alternator, start car, and disconnect battery terminals, if engine stops, means problems with alternator..... or could be relay.... which switch over car using from battery(while starting) to alternator (when car started) , or loose connection somewhere.

Nissan doctor

willbur wrote: »

01 nissan almera 1.8 auto saloon , has new battery giving 12.7 volts, alternator is fine giving 14.4 volts at idle speed all cinections are in good nick so has anyone idea why the battery/charging light is staying on ,thanks for any help you can give

How are you measuring the battery power? With the battery connected and the engine running the battery should be reading 14.4V if that is what the alternator is giving.

If the battery is only giving 12.7 when the engine is running but the alternator is giving 14.4 then you have a broken wire between the alternator and battery.

Mar4ix

willbur wrote: »

THE battery is a new one and is working fine ,some one said it might be mass air flow metre giving faulty voltage to the ecu, what di you think

Nissan doctor wrote: »

How are you measuring the battery power? With the battery connected and the engine running the battery should be reading 14.4V if that is what the alternator is giving.

If the battery is only giving 12.7 when the engine is running but the alternator is giving 14.4 then you have a broken wire between the alternator and battery.

Agree... just wondering, who told him about airflow meter... must be good lad, who looking for some easy cash ... :pac:
have you any idea how could be connected - aiflow meter and battery on dash? mine head cant fit it toghether... might 01 almeras has something "special" .. :pac: :P

willbur

thanks everone,
I checked the battery while it was disconnected and got 12.7 volts then checked the battery terminals again with the engine running and the battery connected and got 14.4 volts, I allso did the screwdriver test at the side of the alternator which was magnetic, in relation to the m,a,f, sensor , I read a tread on another site ,where if the sensor sends wrongs signals to the p,c,u, it can cause the battery light to stay on , I will post a link to this site later

willbur

this is the site http://www.rx8club.com/showthread.php?t=179662

this is the tread from a user

Make sure that your connection to the Mass Airflow sensor is still hooked up. If the MAF isn't reporting any voltage to the PCM it will trigger a battery light and a check engine light. The car will still idle as it will assume there is 8 grams of air incoming and apply the appropriate amount of fuel.
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could this be happing to my car , i ckecked and i here that m,a,s, go faulty on almeras alot and they cost aalot to fix

Mar4ix

just to find exact cause of that light is - connect to diagnostic system. you can buy your own for 30 ish quid from ebay, and use free software to read fault, or go to garage find out problem - usually 50 quid.
if you near blanch, i have nissan obd II scan(that one from ebay) , would look your car. 5 min to read that fault.