I popped a code for my fuel pressure regulator solenoid valve a few years ago, so I removed it and applied 12V directly to the solenoid, and it clicked!
WTF?? Did it again and it clicked and again, and it clicked.
Then I tapped the 12V to it really fast about a dozen times, then it stopped...
Replace your fuel pump relay.
They have been known to stick after a full heat soak.
Use dielectric grease on the contacts when you plug in the new one.
It helps to dissipate heat.
My fuel pump relay is working but the contacts on the backside look half cooked.
Make sure that you use a JIS screwdriver on the screws, or you'll most likely strip them.
https://mazdas247.com/forum/t/installed-new-ignition-switch-today-protege5.123877018/#post-6757664
https://mazdas247.com/forum/t/psa-know-your-screws-jis-vs-phillips-iac-valve-etc.123862298/
On the 2.0 liter engine, you can remove the oil cap to see if the cams are turning while the engine is cranking. If the cams aren't turning, then your timing belt is broken.
The 1.8 liter engine may be similar?
Keep in mind that when the battery is disconnected, the IAC needs to relearn how to idle the car.
It takes about 100 miles if driving
https://mazdas247.com/forum/t/p5-rough-idle-help.123871922/#post-6687160
Your IAC may need to be cleaned or replaced.
These are the two valves i12drivemyMP5 is referring to.
I think everyone here on this forum has had to replace one or both of those valves.
These are the choices at Rockauto.
The $13.37 one is all you need.
The other ones that have the same design are the same thing.
I don't remember what pictures I posted, but these are two of the codes I talked about.
This is a link to the service manual in case you don't have it.
https://www.floptical.net/mazda/
The engine codes are in the engine chapter of the manual.
Yes it can.
The regulator for our car is in the ECU so if there is a poor connection somewhere, it can create a Voltage drop so the ECU isn't getting an accurate reading of the actual voltage at the battery or alternator.
Yeah, sorry I lost all my pictures a few years ago.
The battery light...