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03 Protege 5MT 2.0L Battery light at high RPMs

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2003 Protege DX 5MT
Hello all-

My battery light comes on when hitting higher rpms (accelerating onto highway etc.). I do not have a Tach so I do not know specifically what RPM. The pedal is pretty much on the floor and it mainly happens in 1st thru 3rd gear, sometimes 4th.

What I have tried so far;

2 TWO "rebuilt" new alternators (DBElectrical believe).
Grounding kit (Negative battery cable to engine block, to IM, to alternator)
LED headlights (lower amperage)
New Everstart MAXX battery
New Alternator Belt & AC Belt
New battery terminal connections

Any Protege gurus have an idea?
I do have a nice voltmeter as well I can test stuff with..

Thanks in advance!
 
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pcb

The Diagram Dude
:
2002 MP5
Our alternator is regulated by the ECU.
Check the connector #2 that plugs into the alternator to make sure the connections are clean and tight.
Try to inspect the two wires to make sure they aren't broken between the alternator and ECU.
You may have an intermittent bad connection.








Check to see if you have any of these codes.







You may have a faulty ECU.

I remember one guy that went through four alternators before he got one that worked but I don't remember exactly how they failed.

Try to get a voltage reading while the battery light is on.

Maybe add a ground wire from your grounding kit to the metal case of the ECU.

And check your belt tension.
 

pcb

The Diagram Dude
:
2002 MP5
The book says to check for codes P0112 and P0113.

I don't get what the IAT (input air temperature sensor) has to do with the battery light ?
 
:
2003 Protege DX 5MT
I was going through the comments on Amazon for the alternator I bought and several people say it tends to fail ~ 5000 rpm. The reason I got two alternators is I contacted the company with my battery light problems and they sent me a new one on warranty - 1 year.

I will check those wires & connections today and I will see if auto parts store will lend me obd2 scanner but I doubt it with all the Corona stuff going on.
 

pcb

The Diagram Dude
:
2002 MP5
It could very well be just the alternator.
It has happened before with others that have had multiple alternators failing.
It sucks because you assume that it's a new part so you start looking elsewhere for the source of the problem.

The codes P1631- P1634 do not light the CEL but should be stored in the ECU memory.

If others on Amazon have noticed the exact same problem with the alternator as you're having, then I would be inclined to blame the alternator.
They probably aren't rebuilding the alternators properly so a replacement is going to have the same issue.

 

pcb

The Diagram Dude
:
2002 MP5
If it were me, I'd get a new alternator.
Rebuilds can be problematic.





I think you should consider the PowerBastards. Lol

Brand new and 200 Amps to toss around.

Then you can install a kick ass stereo!!





$385 bucks, free shipping.

 
:
2003 Protege DX 5MT
I can get a new one with a lifetime warranty from advance auto for around $200 USD. And if I have to return or warranty it there is a store about every 7-10 miles around here.

Meanwhile,

I have inspected all connections (good), did voltage drop tests on connections (+) and (-) from battery to alternator (good), and voltage tests. At idle it is putting out 14.4-14.5 volts (which I call high) but when I turned everything on (high beam lights, heat, defrost, dome lights, blinkers, etc.) and revved motor pretty good I was hitting almost 17.5-17.9 volts!! THIS IS A 2 WEEK OLD ALTERNATOR. These DBElectrical alternators are trash!

I borrowed a pretty nice Bosch scanner from Oreilly's Auto Parts and it gave me a pending code of P0660 "Intake Manifold Tuning Valve , Control Circuit Open Bank 1"...

After some research, the code seems to have to do with the VTCS solenoid. And this makes perfect sense because I have a swapped computer from a Protege MP3 in my car, which will not recognize the VTCS system. Some threads say it could be the VICS system as well.

Does anyone know for certain what P0660 is? My service manual does not want to open on my computer right now
 

pcb

The Diagram Dude
:
2002 MP5




That 18 Volts you were pushing could have smoked your solenoid...

They go bad for a lot of us.
They're close to twenty years old.
 

pcb

The Diagram Dude
:
2002 MP5
There are separate codes for the VTCS.

The solenoids can fail intermittently, that may be why it's a pending code.

I got a code for my PRC solenoid valve about a year ago.
I put 12V to it and it clicked. Then again two more times and it clicked??

So I touched the 12V to it about 15 times really fast then it stopped clicking.

There's a bunch of solenoid valves on our car and most of them are the same solenoid.

A lot of people have had to replace one of the valves.

They're quite cheap at rock auto.

They have different names but it is the same valve...











I was wondering if your ECU had a code registered for the alternator?

I'm thinking the battery light might come on the instant the voltage peaks but it may need to be on for 5 continuous seconds to register a code.
 
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Did the problem show up after your swapped ECUs ? IIRC, 1999-up Mazda products use the ECU as part of the voltage regulating circuit. In the past, every time I had a battery light at high RPM it was due to bad brushes in the generator. -yes, alternators ARE generators.

The VTCS error code is a red herring.
 

pcb

The Diagram Dude
:
2002 MP5
... -yes, alternators ARE generators.
They both generate electricity but they are different.





The cars of yesteryear used to have generators and they were real workhorses but all of their output power traveled through the brushes and the brushes would wear out quickly.

Alternators only have the power to energize the spinning electromagnet running through the brushes so the brushes last much longer.
 

pcb

The Diagram Dude
:
2002 MP5
The VTCS error code is a red herring.
That could be.
Maybe clear the code and see if it comes back or it will probably clear itself in time if it was an erroneous code.

A lot of people here on the forum have had to replace their VICS solenoid valve.
They crap out over time.

The VTCS solenoid valve only clicks on when you first start your cold car.
The VICS solenoid valve is clicking on and off all the time while you're driving (above a certain rpm) and gets a lot more use than the VTCS valve.
 
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pcb

The Diagram Dude
:
2002 MP5
... I have a swapped computer from a Protege MP3 in my car, which will not recognize the VTCS system. Some threads say it could be the VICS system as well...

Actually, your VTCS solenoid valve isn't being used anyway.
You could just swap the solenoids if it's still on your car.

But, as mentioned, the code could have been caused by the 17.9 volts and your solenoid valve may be fine.
 
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2003 Protege DX 5MT
I only got a P0660 code. I grabbed about three of those sensors at the junk yard today and tested them for resistance before choosing the ones I wanted. Three Protoges there, and it looked like all three cars VICS side solenoids were toast (Zero resistance). So I got 3 VTCS solenoids that tested good with resistance.

And yes I had this problem on stock ECU.

I took the alternator that isn’t in my car and got it bench tested today. The machine couldn’t have been spinning more than 2000 rpm and it says 15.8 volts. Seems high to me. Bench test attached.
F5EFD0D0-58F4-4488-934B-7250FD27F0FC.jpeg
 

pcb

The Diagram Dude
:
2002 MP5
Yeah, they all say "PASS" but that sounds wrong to me.

You'll eventually cook your battery especially if it goes all the way to 17.9 Volts at higher RPMs. Not to mention blowing your headlights and other bulbs and circuits as well as a whole bunch of erroneous CEL codes.

I don't think the volts should go past about 14.5 Volts
 

pcb

The Diagram Dude
:
2002 MP5
... So I got 3 VTCS solenoids that tested good with resistance.
I use a 9 V battery to test solenoids.

A solenoid can have the proper resistance but still be seized and if the solenoid is shorted inside (0 ohms) your not going to blow anything up.
(I shorted the wires and couldn't even get a spark.)





I took a dead battery apart and used the clips from it to clip the wires onto the battery.

If the solenoid clicks with 9 V applied, it's going to work with 12 V (or 17.9 volts in your case. Lol)

Positive and Negative wires don't matter with a solenoid so you don't have to worry about polarity.
 
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2003 Protege DX 5MT
I read about the 9v trick in another thread, tried it, and it didn’t seem to work. The 9v battery was good tested that as well. I put my junkyard solenoid in, revved the engine and the VICS actuator arm moved. I reset my ECU for twenty minutes, got a scanner, NO CODES now, nothing pending.

The battery light still goes off under load and high rpm. I will update when I get paid and get a new alternator.
 
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2003 Protege DX 5MT
I got a new alternator, installed and tested it with every single button I could turn on from the inside, high beams, heated defrost, and no battery light at high RPMs.

It's nice having a real alternator, DBElectrical (for our cars) are junk. They are making them produce more voltage it seems. The one that was in my car bench tested at 16V, and I bench tested the Advance Auto Parts (CARQUEST) alternator at 14V.

I bet my car hasn't had VICS since I got it a year and a half ago, so thats fixed too.

Thanks everyone for the help.
 
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