ECM will not let the alternator charge the battery

The ECM is located under the dash on the passengers side here is a diagram.

Check out the diagrams (below).

Please let us know if you need anything else to get the problem fixed.

Cheers

Good afternoon,

I attached a guide for you to view. You will need a voltmeter to test the voltage at the battery. It needs to be 14 to 14.5 volts.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

I attached a wiring diagram for you to view. Check the black/red wire for power all the time.

As far as the PCM controls, yes, it does turn the regulator on and off.

Roy

Generator Warning Light
1. Verify that the battery is fully charged.
Charge if necessary.

2. Verify that the drive belt deflection/tension is correct.
Adjust if necessary.

3. Turn the ignition switch on and verify that the generator warning light comes on.
If not, inspect generator warning light, wiring harnesses between the battery, generator warning light, and PCM terminal 98. When the generator warning light and the wiring harnesses are okay, replace the PCM.

4. Verify that the generator warning light goes out after the engine is started.
If rot, inspect if any of the following DTCs are displayed: P0112, P0113, P1631, P1633, P1634.

Generator

Voltage
1. Verify that the battery is fully charged.
Charge if necessary.

2. Verify that the drive belt deflection/tension is correct.
Adjust if necessary.

3. Turn off all electrical loads.
4. Turn the ignition switch to start the engine and verify that the generator rotates smoothly without any noise while the engine is running.

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Standard Voltage
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5. Measure the voltage at the terminals shown in the table.
If not as specified, repair or replace the generator as necessary.

Current
1. Verify that the battery is fully charged.
Charge if necessary.

2. Verify that the drive belt deflection/tension is correct.
Adjust if necessary.

3. Disconnect the negative battery cable.
4. Connect an ammeter, capable of reading 120 A or above, between generator terminal B and the wiring harness.
5. Connect the negative battery cable.
6. Turn off all electrical loads.
7. Start the engine and increase the engine speed to 2,000 - 2,500 rpm.
8. Turn the following electrical loads on and verify that the current reading increases.
1. Headlights
2. Blower motor
3. Rear window defroster
If generator terminal B current will not increase, repair or replace the generator as necessary.

NOTE: Current required for generating power varies with electrical loads applied.