P2503-00

[Xitztyler]

Wow. Are you sure you should be doing this yourself?

Cars haven't had external voltage regulators since the late 60's, early 70's.
Voltage regulators were built into the alternator when car manufacturers stopped using generators, back in the 60's.
Some new cars don't even have regulators built into the alternator anymore. A lot of modern cars are now regulated through the ECM.

That's what I meant there regulated through ecm. Well I already did it, I put the salvaged alternator in.

 

[yrwei52]

so while vehicle running new battery reading 12.22 volts.
Reading 12.5 with vehicle off.

So your charging system is still having problems. You should get about 14V+ with engine running.

You may have a bad connection somewhere? Can you reinstall the original alternator back and check the voltage? Or just get a new battery and see.

 

[Xitztyler]

I have a new battery in there after I changed alternator, I might put original alternator back in and see what happens

 

[Xitztyler]

So come to find out, the salvaged alternator I purchased was no good as well as the original alternator. Problem solved! It was the alternator! Thanks guys for everything!

 

[wlong01]

So come to find out, the salvaged alternator I purchased was no good as well as the original alternator. Problem solved! It was the alternator! Thanks guys for everything!

Great to hear. Good Luck. 2016 is the best year. Make sure the recalls have been done, there were 3, 2 if you don't have the LED headlights.

 

[madar]

So, getting back to your first post....leaving your car in accessory mode ruined the alternator??

 

[Xitztyler]

So, getting back to your first post....leaving your car in accessory mode ruined the alternator??

Yes sir, I think the battery was so low the ECU was telling the alternator to put out a little too much voltage at once, the alternator starts when you start your car, also it takes a bit too turn the car over, even though we have starters. So in the long run I think it ended up burning "shot" out the alternator. As we know Mazda electrical system is complex and also can be troubling.

 

[yrwei52]

So, getting back to your first post....leaving your car in accessory mode ruined the alternator??

To me that’s almost impossible to happen as the ECM would turn off every accessary after about 30 minutes.

 

[yrwei52]

So come to find out, the salvaged alternator I purchased was no good as well as the original alternator. Problem solved! It was the alternator! Thanks guys for everything!

Thanks for the update. So did you bring both original and used alternators to an auto parts store and tested them out, and turned out both were bad? Did you get another used alternator from the salvage yard, or did you get a refurbished alternator from an auto parts store?

 

[Xitztyler]

I got an alternator at o Reilly, going to return salvaged alternator Monday and throw out the orignal, the auto store used a bench test for both alternators, said there bad

 

[yrwei52]

I got an alternator at o Reilly, going to return salvaged alternator Monday and throw out the orignal, the auto store used a bench test for both alternators, said there bad

OK. Usually auto parts store wants the old alternator back so that they can remanufacture it and resell it again. Was there a core charger when you purchased the alternator at O’Reilly, and you may need to take the old alternator back to get the core charge refund?

 

[Jmaz]

I got an alternator at o Reilly, going to return salvaged alternator Monday and throw out the orignal, the auto store used a bench test for both alternators, said there bad

Yes, check your receipt for a "core charge" which is refundable when you return the old alternator. It could be a nice chunk of change. Same thing goes for starter motors usually. Glad to hear you got it fixed.

 

[wlong01]

To me that’s almost impossible to happen as the ECM would turn off every accessary after about 30 minutes.

Doesn't turn the interior lights off if you turn them on with the overhead switch.

 

[Xitztyler]

Doesn't turn the interior lights off if you turn them on with the overhead switch.

My whole dash as well as infocenter was lit up whole time too

 

[yrwei52]

Doesn't turn the interior lights off if you turn them on with the overhead switch.

Yeh, you sure can turn the interior lights on independently without leaving the ignition in the accessary mode. But the OP said only he left the car in the accessary mode, didn’t say he left any of the interior lights on.

 

[yrwei52]

My whole dash as well as infocenter was lit up whole time too

Are your saying you left the parking lights on over night? If you leave the audio system on in the accessary mode, the infotainment system will be turned off by the ECM after about 30 minutes. The parking lights、dash lights、infotainment screen light、and the interior lights aren’t controlled by the timer of the accessary mode. Those lights have nothing to do with accessory mode.

 

[Xitztyler]

Yeh, you sure can turn the interior lights on independently without leaving the ignition in the accessary mode. But the OP said only he left the car in the accessary mode, didn’t say he left any of the interior lights on.

Yeah my car is setup so the interior lights don't turn on at all ex. Open doors, closed doors, vehicle shut-off. You need to manually hit the light for them to turn on.

 

[yrwei52]

Yeah my car is setup so the interior lights don't turn on at all ex. Open doors, closed doors, vehicle shut-off. You need to manually hit the light for them to turn on.

So based on what we’ve seen here, I believe leaving the car in the accessary mode has nothing to do with your failed alternator. You didn’t leave anything major on over night hence your battery was still strong enough to start the engine in the morning. With 120K miles on your 2016.5 CX-5 the alternator could fail although it’s rare. Your alternator just happened to fail over night, hence you got red “battery” warning light and the P2503-00 CEL both indicating charging system failure after you started the car. A new battery isn’t necessary for your problem.

 

[Xitztyler]

Ironic

So based on what we’ve seen here, I believe leaving the car in the accessary mode has nothing to do with your failed alternator. You didn’t leave anything major on over night hence your battery was still strong enough to start the engine in the morning. With 120K miles on your 2016.5 CX-5 the alternator could fail although it’s rare. Your alternator just happened to fail over night, hence you got red “battery” warning light and the P2503-00 CEL both indicating charging system failure after you started the car. A new battery ins’t necessary for your problem.

ironic how when I left accesory mode on alternator failed Idk seems to me like there's sort of a link.
EDIT: I will also say I was idling my car a lot at night for the heat. I was sleeping in the Mazda this winter.

 

[Conrad 16.5]

Ironic

ironic how when I left accesory mode on alternator failed Idk seems to me like there's sort of a link.
EDIT: I will also say I was idling my car a lot at night for the heat. I was sleeping in the Mazda this winter.

I couldn't stay away...

Ironic? I believe that you mean coincidence, don't you?

You were sleeping in your CX and letting it idle for long periods? Like, how long of a time?

Yikes!!!