2001 6.0 PCM, alternator output voltage huge swings 14.4-16.5v

[GrannySShifting]

After logging it I noticed the L terminal shows fluctuating 5% to 90% up and down too. This is the 4 pin plug, that Im only used to seeing it be ON or OFF. Any ideas, I dont see a setting in HPTuner that can change anything about that?

[GrannySShifting]

thought i had one with L Terminal on log but must not have saved, you can see Control Voltage swinging just like it does though

[GrannySShifting]

thought i had one with L Terminal on log but must not have saved, you can see Control Voltage swinging just like it does though

[blindsquirrel]

I can't find the max voltage spec in the service manual, but, I don't think the PCM can make it do more than what the regulator is set for, which should be 14.4-14.6. If it's more than that it's a bad regulator. P1637/P1638 diagnostics might give you some things to investigate.

[GrannySShifting]

I can't find the max voltage spec in the service manual, but, I don't think the PCM can make it do more than what the regulator is set for, which should be 14.4-14.6. If it's more than that it's a bad regulator. P1637/P1638 diagnostics might give you some things to investigate.

If I unplug it it all stops

[TheMechanic]

If I unplug it it all stops

If you unplug it, it will stop charging. Unless you have the internal regulated alternator that only requires an ignition tap. https://www.dirtydingo.com/shop/page...path=4&pID=108