Alternator trouble

[SCOOTA44]

Does anyone know what the charging rate should be? mine is charging at 13.5 volts. and im led to believe that the alternator is controlled by the ECU. if so could there be a problem with the ECU? or would it throw a code if it was that?

[METAL13]

13.5 volts from what i generally know is the normal output for an alternator as the battery is 12v and can take a little more input !

I don't think it is controlled by ECU.The alternator generates electricity from the drive belt spinning the alternator (engine needs to be running for drive belt to move)

But to be 100% sure just wait for a more technical person to reply

[Spillzee]

Does anyone know what the charging rate should be? mine is charging at 13.5 volts. and im led to believe that the alternator is controlled by the ECU. if so could there be a problem with the ECU? or would it throw a code if it was that?

Hey Scoot. 13.5 is ok. The alternator is equiped with a regulator internally. Will vary slightly depending on how much electrical equipment is drawing off the battery. If it the charge rate is too high or to low the ecu will detect a fault. What is the actual problem you are having. More info needed to be accurate.

[450HP/tonne]

Check battery charge first.

13.2 - 14.8V at 2000rpm with no electrical load.

10A or less no load.

30A or more with heater on HI and high beam lights on.

[SCOOTA44]

Does anyone know what the charging rate should be? mine is charging at 13.5 volts. and im led to believe that the alternator is controlled by the ECU. if so could there be a problem with the ECU? or would it throw a code if it was that?

Hey Scoot. 13.5 is ok. The alternator is equiped with a regulator internally. Will vary slightly depending on how much electrical equipment is drawing off the battery. If it the charge rate is too high or to low the ecu will detect a fault. What is the actual problem you are having. More info needed to be accurate.

I have been told by auto electrical that its not charging correctly 13.5 volts idling, and only 13.6 @ 3000 rpm, they say it should be 14.4 to 14.8 volts. everything seems to be working fine. being a taxi I have a lot more crap running (2way radio, scanner, tv, etc, so batteries only last 8 to 12 months anyway.

[SCOOTA44]

Check battery charge first.

13.2 - 14.8V at 2000rpm with no electrical load.

10A or less no load.

30A or more with heater on HI and high beam lights on.

Thats what i thought too, but was at the dealer for something else and they assured me that the alternator is working fine.

[01 VEY]

Check battery charge first.

13.2 - 14.8V at 2000rpm with no electrical load.

10A or less no load.

30A or more with heater on HI and high beam lights on.

Thats what i thought too, but was at the dealer for something else and they assured me that the alternator is working fine.

Hey Scoota44

I work for an importer/wholesaler and we pride ourselves on being the people auto electricians ask about things like this.

If you can get me the chassis number from the car I should be able to get the correct info for you. (Through a mate at a Toyota dealer)

Yes there are some late model vehicles in which the alternator is controlled by the E.C.U. or system computer or body control module.

If the alternator is a Denso unit there is a possibility that it is only designed to display the charge at low - mid 13's and will not show anything else until it is on the road. In this case the alternator sends a signal to the computer to let it know that all is normal or otherwise. Depending on the power demand at any given time the computer decides how much work the alternator needs to do.

This is(according to the EPA)to save the engine driving the alternator unnecessarily thereby saving horsepower - saving fuel - reducing emissions - and saving the planet. yup

If the alternator is a Bosch unit it is usual that it should charge at 14.6v which is what most of the late series Bosch alternators are set to. This can also apply to some Denso alternators.

Please remember that even though both these units have the same mounting points and the 4 pin plug may well be connected it can take as little as 4-5 seconds to either burn out the(wrong)alternator or in some cases there could be internal damage done to the E.C.U. Many of them have the pin configuration printed on the label.

Make sure that if you change the alternator that the wiring diagram on the label is identical. Some units can look identical but this can lead to disaster.

Keep us posted on the results of your problems if there are any.

[SCOOTA44]

Check battery charge first.

13.2 - 14.8V at 2000rpm with no electrical load.

10A or less no load.

30A or more with heater on HI and high beam lights on.

Thats what i thought too, but was at the dealer for something else and they assured me that the alternator is working fine.

Hey Scoota44

I work for an importer/wholesaler and we pride ourselves on being the people auto electricians ask about things like this.

If you can get me the chassis number from the car I should be able to get the correct info for you. (Through a mate at a Toyota dealer)

Yes there are some late model vehicles in which the alternator is controlled by the E.C.U. or system computer or body control module.

If the alternator is a Denso unit there is a possibility that it is only designed to display the charge at low - mid 13's and will not show anything else until it is on the road. In this case the alternator sends a signal to the computer to let it know that all is normal or otherwise. Depending on the power demand at any given time the computer decides how much work the alternator needs to do.

This is(according to the EPA)to save the engine driving the alternator unnecessarily thereby saving horsepower - saving fuel - reducing emissions - and saving the planet. yup

If the alternator is a Bosch unit it is usual that it should charge at 14.6v which is what most of the late series Bosch alternators are set to. This can also apply to some Denso alternators.

Please remember that even though both these units have the same mounting points and the 4 pin plug may well be connected it can take as little as 4-5 seconds to either burn out the(wrong)alternator or in some cases there could be internal damage done to the E.C.U. Many of them have the pin configuration printed on the label.

Make sure that if you change the alternator that the wiring diagram on the label is identical. Some units can look identical but this can lead to disaster.

Keep us posted on the results of your problems if there are any.

thanks for that, it seems to be ok, and the dealerhas assured me that its ok.