P0621 p0622 no alternator charge

[clrussell]

Lbz swap in my 01 truck. Almost all buttoned up other than the alternator isn't charging. I tried a new alternator for a 2001 and one for an 06 on it with both same codes.

I'm 99% sure that the wiring from the alternator to the ecm is factory lbz wiring.

Just seeing if anyone has any ideas? I'd like to get it going this weekend. I sent Ben an email asking for his input but it's the weekend and I don't expect an answer back until Monday.


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[Muff]

Blown fuse?

 

[clrussell]

Looking at the diagrams there isn't a fuse from ecm to alt on either wire.


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[02greysixer]

Only time I've had codes related to the alternator (don't remember if it was those exact ones or not) the pins on the alternator plug were spread way open and it wasn't making contact.

Don't know if it's possible or could cause your issue but maybe the ecm was flashed for dual alternators by mistake and that's causing a problem.

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[clrussell]

Only time I've had codes related to the alternator (don't remember if it was those exact ones or not) the pins on the alternator plug were spread way open and it wasn't making contact.

Don't know if it's possible or could cause your issue but maybe the ecm was flashed for dual alternators by mistake and that's causing a problem.

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I didn't think to check the pins at the alt.. I've checked everything else I can think of.

Hmm the dual alt flash is possible I guess, although ben did the base ecm tune himself and I figure he had one that's for a single alt.

Here's the codes and description provided by the solus

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[02greysixer]

I definitely had the F-terminal code. Staked the connector and it started charging fine.

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[clrussell]

I definitely had the F-terminal code. Staked the connector and it started charging fine.

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Might run into town later and give that a try. That'd be awesome if it fixed it. I've had this truck since March and havnt got to drive it more than out of the shop


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[clrussell]

Tightened up pins in the alt connector, no change


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[clrussell]

99% sure I need a ecm.. Both wires check good from ecm to alt plug.

Waiting to hear back from ben before I try finding one.


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[duratothemax]

Hey Corbin, Sorry I was away at a wedding all weekend, Ill send you an email iin a couple minutes

 

[clrussell]

Hey Corbin, Sorry I was away at a wedding all weekend, Ill send you an email iin a couple minutes

Thanks ben, I figured you were busy


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[duratothemax]

If you rev up the engine over 2000 rpm, does the voltage start to show charge? IE, does voltage then jump up over 14 volts?

Regardless of what the ECM is doing, even with the connector unplugged, I THINK the alternator should still self-excite once RPM goes above ~2000 or so.

 

[clrussell]

If you rev up the engine over 2000 rpm, does the voltage start to show charge? IE, does voltage then jump up over 14 volts?

Regardless of what the ECM is doing, even with the connector unplugged, I THINK the alternator should still self-excite once RPM goes above ~2000 or so.

I'll try after lunch. Dont think I've reved it that high yet.


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[clrussell]

Reved to 2500 and held a few sec.. Still no charge


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[duratothemax]

Run through the diagnostic steps that I emailed you...

I might be wrong on the fact that the Duramax alternators are self-exciting over a certain RPM (in which case, revving it wouldnt do anything)...Im looking that up now.

 

[clrussell]

Run through the diagnostic steps that I emailed you...

I might be wrong on the fact that the Duramax alternators are self-exciting over a certain RPM (in which case, revving it wouldnt do anything)...Im looking that up now.

I went through em.. Emailed you back


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[clrussell]

Update.

Finally installed my new ecm and got truck running after 30 min security relearn. Trying to flash the file in from ben that has to be in the truck in order for gauges to work properly.

A message pops up saying script failed mode not supported?

Alternator charges correctly now but the truck isn't driveable since it goes into reduced power or something after about 30 sec of run time.

Both ecms read correctly and the new ecm took a vin license like normal.

Thoughts ? I'm waiting to hear back from ben but just looking to see if I missed something that maybe I don't need to bug him for.


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