Alternator fault message when first switched on

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clivesP38

clivesP38

Active Member
Posts
179
When I put the ignition on I get an 'alternator fault' message briefley. Have checked the battery and the charge goes up to over 14 volts so it would seem the alternator is working. I have looked and the alternator looks new. Does the computer need to be told a new alternator has been fitted or does it need a diagnostics tool to reset it? I have had the RR about a week so don't know if the alternator has been changed for sure.
 
if it claims alt fault and the alternator is charging it is normally a corroded BCEM plug
 
I had the same a couple of years ago. The alternator was on it's way out. Same message but as I drove everything dimmed in a couple of miles. Was putting out 14.4V the next day after I recharged the battery then the same thing happened. Warranty kicked in and new alternator fitted however could just have been the brushes worn which is repairable.
 
clivesP38 said:
When I put the ignition on I get an 'alternator fault' message briefley. Have checked the battery and the charge goes up to over 14 volts so it would seem the alternator is working. I have looked and the alternator looks new. Does the computer need to be told a new alternator has been fitted or does it need a diagnostics tool to reset it? I have had the RR about a week so don't know if the alternator has been changed for sure.
Click to expand...


Alternator fault usually means just that, no voltage reversal has been detected on the D+ line when the engine is running. Can also, as fanatic said, be corroded connections at the BECM or at the alternator itself.
 
Thank you all fo r the input, I will check the connection shortley. Being new to the range rover can you tell me where to find the BCEM?
 
After fitting a new battery I am still having problems! After measuring the battery power this morning (12.2v!!) and starting up the RR it went up to 14.2v...mmm, so then I put it under load by putting the lights and heater on. No change untill I revved it up then it dropped off to 12.2v, i.e. no charge to the battery. So the dash message IS right! New alternator needed? or can it be repaired?
 
clivesP38 said:
After fitting a new battery I am still having problems! After measuring the battery power this morning (12.2v!!) and starting up the RR it went up to 14.2v...mmm, so then I put it under load by putting the lights and heater on. No change untill I revved it up then it dropped off to 12.2v, i.e. no charge to the battery. So the dash message IS right! New alternator needed? or can it be repaired?
Click to expand...

New control unit and brushes can rejuvenate them depending on how much wear there is on commutator. Normally it would need facing up and undercutting for best fix.
 
Sounds like it would be just as cheap to put a new/reconditioned one on Wammers? I see Rimmer Brothers has some well priced aftermarket ones but they are three types listed, 100amp, 120amp and 150amp, do I take it the 4.6 hse auto takes the biggest one?
 
clivesP38 said:
Sounds like it would be just as cheap to put a new/reconditioned one on Wammers? I see Rimmer Brothers has some well priced aftermarket ones but they are three types listed, 100amp, 120amp and 150amp, do I take it the 4.6 hse auto takes the biggest one?
Click to expand...

Cost depends on whether you can do it yourself or not. Think 4.6 after 99 had 150 amp. You will have to look at the part number on the alternator. Vin number should tell you. Don't look cheap to me to be honest. But i get them trade.
 
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Ok that you for your time and advice Wammers, I'll give Rimmers a ring and see how much one will cost!
 
wammers said:
New control unit and brushes can rejuvenate them depending on how much wear there is on commutator. Normally it would need facing up and undercutting for best fix.
Click to expand...

Alternators have slip rings not commutators Tony, so no undercutting needed or possible. They only need facing if badly worn. Be aware, an alternator fault can sometimes be shorted/open windings.
 
The alternator failed to charged when I put it under load (lights and heater on) so needed replacement. Have replaced and tested and now works ok, battery charging correctly. I still get the alternator fault message, does it need 'clearing' or could there be another problem?
 
Datatek said:
Alternators have slip rings not commutators Tony, so no undercutting needed or possible. They only need facing if badly worn. Be aware, an alternator fault can sometimes be shorted/open windings.
Click to expand...

Yep another condor moment. :):)
 
Last edited:
Does anybody know if the 'alternator fault' message needs 'clearing' or should clear it self after fitting a new alternator?
 
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