I have a mazda 6 2003 I made a mistake by removing the battery while it was on so now I changed the ecm I change the alternator 4 times and the battery is new and the battery light shows and the alternator still not charging what could it be

Have the fuel trims been checked? These (short term fuel trim - STFT and long term fuel trim - LTFT) can be checked with an OBDII tool, and can provide a lot of information about what may be happening. If you have a vacuum leak, for instance, the O2 sensors will report a lean condition to the ECM and it will add fuel to the engine to try to correct. You will see this in the fuel trim numbers.

So, yes, the ECM can cause the misfire, BUT if so, it's because something is not right in the engine. Have a qualified technician evaluate ALL parameters and determine what may be wrong. You've spent a lot of money on parts (O2 sensors, coils, plugs, wires, PCV valve and hose, alternator), and have invested a lot of your time. It's very possible that none, or only a couple, of those parts needed to be replaced. Invest in the expertise of a trained technician.

use a scan tool to reset the ECM program as the battery removal may have corrupted the CPU program for all that you mention
if you changed the fob key battery ,it may be necessary to reprogram the key to the immobilizer.

No, not the ECM. Replace the alternator. The ECM fields/grounds the alternator to work. The ECM monitors the voltage and sets the light if voltage is to low or to high. Since it puts out 16+ volts the ECM is still working. The regulator in the alternator is bad.

Was it a 'new' alternator? Either way its NFG, you need to swap with a known good one, sorry.

You may want to try changing the coil pack rubber boots. Especially if your have recently had an alternator failure or battery failure. The coil packs themselves are probably good but I've changed my boots at least 4 times now. I have a 2000 Mirage DE with 198,000 miles. Runs great.

you might want to get a scan to see why the engine light is on. it would be unusual to burn the fusible links, but that's about all that could stop the alternator from charging. The links are along the wires from the battery to the alternator.

First begin by writing down your radio code if it has some anti-theft code.
2. Then open the hood and remove the negative terminal of the battery. Tuck the battery negative terminal aside so it won't flip back.
3. Unplug the alternator's generator connector, and the generator wire bolted to its body.
4. Locate the alternator adjuster and loosen its bolt/tensioner. Loosen the alternator pivot bolt at its base.
5. Push the alternator sideways until the belt slackens to maximum . Take out its belt.
6. Remove the pivot and tensioner bolts.
7. Take out the alternator.

Important: Battery must be fully charged before installing new alternator.

Reverse this procedure to install the new alternator.

az alts arnt the best. the volt reg in the ecm. you need to have it tested

Mazda Mpv 2000 I also have the same problem, the alternater is testing good- 14.12Amp, so what is the problem the battery light will not go off.

I have a 2001 Mazda Tribute. To change the alternator; the factory procedure at the dealership says to drop the sub-frame from under the front of the vehicle. Then everything is accessable. The tech at the dealership told me how they do it: (Its not easy!!) 1. Remove the right front tire 2. Remove dust pan from right front 3. Remove the brake caliper and caliper bracket 4. Remove the 2 bolts from the half shaft support bracket 5. Remove the half shaft axle assembly 6. Remove the serpentine belt 7. Remove the 3 bolts holding the alternator in place 8. Remove the 3 bolts holding the alternator mounting bracket 9. Remove the alternator mounting bracket 10. Remove the electrical connection on the alternator 11. Remove the alternator by turning the alternator until it will come out of the opening 12. Repeat process in reverse for installation. I did this twice in two weeks because of a bad alternator. The studs that are spot welded on the half shaft bracket will try to keep you from being able to remove the alternator. The left stud on the bracket popped out, when we were removing the alternator and it seemed to make it easier to get the alternator out. I just put a lock washer on the back side of the stud when I mounted the half shaft and it worked fine. Good luck