Fault 49 high voltage

[jayc20xe]

Still getting this code on my Gsi Astra 2,5 motronic

49 Battery high voltage what could cause this fault???

Tried 2 batteries in it still comes up and I left the battery disconnected for the guts of a week

Thanks James

[gilly-06]

possibly the alternator over charging parhaps ??

[Andy K]

99% likely the alternator.

Does the light only come on at high RPM ? 3000+ ? Don't try this for too long if it is doing it else it can damage the whole car.

[Paul]

Check the charge rate at the battery.

[jayc20xe]

Only diagnostic light, will check the alternator have a spare as well, and test the voltage at the battery!

[Vinci]

Still in to the spaghetti mate? A short on D+ could also cause this (the thin wire on the alternator) Most likely it's the alternator itself. Check battery voltage while idling, anything higher than 14,5V is suspicious.

Does the battery check light work when put on ignition pos2? Does it go off while the engine is running?

[jayc20xe]

Battery light is working but goes off when car is running, Not sure the battery light Works for High voltage??

There is actually a loose blue wire I spotted on the alternator today not sure what it's there for! It comes from the positive side.

Will check the voltages tomorrow and see!

Yes I'm still loving spaghetti ;-) trying to get this check engine light off!

[Vinci]

That's the D+ mate (blue/white), strange, because that goes to the battery check light...

If that's hanging loose that's not good anyway!! If it comes from the alternator and is shorted to ground somewhere it might explain the fault. The more current is drawn on the D+ the more current goes to the battery...

[jayc20xe]

So I got some tests done today to see what could be happening! Thought I had found the problem looked at my alternator and there seemed to be no regulator on the back so change the alternator started it up and still a light on code 49

So tested the volts without load getting 13 volts and with lights heater on 12 volts!

Any other ideas??

James

[Vinci]

That's with the engine running or off?

[jayc20xe]

Running

[Vinci]

Looks like too low voltage then... How about that blue/white wire?? It's impossible for the battery check light to operate properly without this wire being connected....

[jayc20xe]

Yes it's ok connected up ok, the loose wire was the regulator wire basically there was a wire and no regulator looked like it had been ripped off.

[Vinci]

When the alternator has a firmly mounted and good condition earth wire from the body to the block and the B+ (thick red) makes good contact to the battery and the D+ (blue-white thin wire) gets a 3 to 5 watt load then the alternator should deliver. Period.

Try to measure if the earth and B+ are doing a good job first, then connect a probe wire to the D+ on the alternator and put a 5 watt bulb on the wire which connects to earth. Then measure the voltage on the battery and see if it rises on earthing the bulb.

If not then the battery is gone.... (considering you have already changed the alternator I exclude this as a possibility)