Battery not charging message but it is sometimes

[EfiniMotorsport]

After finally getting my 04 Denali back up and running it was fine for a few weeks and now I'm getting a battery not charging message. I put a new interstate battery in when I did the transmission a month ago. I went to take it out 2 weeks ago and when I started got the battery not charging message. Checked the battery with the truck running and it was under 11.5v. I got a used DC power engineering 270a alternator from work and had it tested at autozone and it passed. When I installed the alternator I was still getting the message even when the voltage gauge was showing 14v and meter was showing 14.5v. I tried restarting the truck a few times and sometimes the alternator wasn't charging at first but would start charging if I disconnected the 4 pin plug then plugged it back in. I don't want to just throw a new alternator at it until I confirm that's the issue. I know these trucks can have issues with the cluster as well. Anyone have any suggestions on testing?

 

[Doubeleive]

After finally getting my 04 Denali back up and running it was fine for a few weeks and now I'm getting a battery not charging message. I put a new interstate battery in when I did the transmission a month ago. I went to take it out 2 weeks ago and when I started got the battery not charging message. Checked the battery with the truck running and it was under 11.5v. I got a used DC power engineering 270a alternator from work and had it tested at autozone and it passed. When I installed the alternator I was still getting the message even when the voltage gauge was showing 14v and meter was showing 14.5v. I tried restarting the truck a few times and sometimes the alternator wasn't charging at first but would start charging if I disconnected the 4 pin plug then plugged it back in. I don't want to just throw a new alternator at it until I confirm that's the issue. I know these trucks can have issues with the cluster as well. Anyone have any suggestions on testing?

first thing to do is clean the battery cable connections and grounds, even if they "look ok" use a wire brush, unbolt them and scrub both sides at battery, alternator, block, frame or anywhere else you can reach or access.
then see what happens.

 

[EfiniMotorsport]

I wired wheeled everything. I also made a new cable from the alternator to the power distribution point.

 

[Doubeleive]

@rockola1971 any idea's with the 4 pin?

if worse comes to worse you can just run a 12v exciter to it and make it work

 

[EfiniMotorsport]

I checked voltage on the brown wire in the 4 pin plug (there's 3 wires in it, center of the 3 is brown) and it's 10.5v which from what I can find it's supposed to be. It goes through a bulb to drop voltage

 

[Doubeleive]

I don't know a whole lot about the 4 pin systems other than you can make it work with a voltage feed if you have to, but otherwise it should have at least 13.4v pretty much anytime the engine is running, it's not like the newer 2 pin rvc regulated systems.
have you looked at the pcm harness and fuses?
there is also a off chance that it could just be a funky alternator I have had problems with those aftermarket (off-brand) alternators with intermittent operation. so I bought a mechman and no further issue's

 

[EfiniMotorsport]

The DC power isn't an off brand. I called them and they said there's usually a harness that runs a wire from the + terminal to the left pin on the 4 pin plug. I'll give that a shot and see. They did say if the regulator went they can fix it for about $50. Much cheaper than even a stock replacement.

 

[Doubeleive]

The DC power isn't an off brand. I called them and they said there's usually a harness that runs a wire from the + terminal to the left pin on the 4 pin plug. I'll give that a shot and see. They did say if the regulator went they can fix it for about $50. Much cheaper than even a stock replacement.

wasn't familiar with the name, looks like they use the same press fit diodes as mechman and the newer style oem.

 

[EfiniMotorsport]

For the price they better do it right. They also use a billet front cover which looks good

 

[Doubeleive]

For the price they better do it right. They also use a billet front cover which looks good

Ya that's about what I paid for my mechman, they are pricey

 

[rockola1971]

From what I found the 04 model should only have 2 wires going to the alternator Pins B and C then of course the BAT terminal as well. You can see in the schematic what B and C go to. What is the purpose or need for the bulb to drop voltage on the 3rd wire? Brown according the schematic should goto your PCM and that is essentially the signal to the voltmeter. So what is your extra wires hooked too and which terminal is sre they coming from? A or D? @Doubeleive @EfiniMotorsport

 

[EfiniMotorsport]

When looking at the alternator from the front the left 3 pins have wires. The second pin from the left is the brown wire.

 

[EfiniMotorsport]

I'll have to see what the other 2 wire colors are when I get home. I don't remember what the production month is or if it would be different on the 03

 

[rockola1971]

I'll have to see what the other 2 wire colors are when I get home. I don't remember what the production month is or if it would be different on the 03

Where is "03" coming from? Your first post states your vehicle is a 04.

 

[EfiniMotorsport]

I don't know if it's an early 04 that has something held over from 03, wiring wise. The alternator has a 4 pin 3 wire plug.

 

[Burban22]

@EfiniMotorsport
Did you ever get this resolved? My 03 burb just gave me the battery not charging on startup today but went away after a minute of driving.

All my grounds are clean, new negative cable. Positive cable is clean.

If it happens again, guess I’ll change the alternator? It may be the original at 170k.

 

[S33k3r]

@EfiniMotorsport
Did you ever get this resolved? My 03 burb just gave me the battery not charging on startup today but went away after a minute of driving.

All my grounds are clean, new negative cable. Positive cable is clean.

If it happens again, guess I’ll change the alternator? It may be the original at 170k.

When you say the positive cable is clean, do you mean each end of it, or were you able to check the entire cable? Those cables have been known to rust through, under the insulation.

 

[Burban22]

When you say the positive cable is clean, do you mean each end of it, or were you able to check the entire cable? Those cables have been known to rust through, under the insulation.

The old negative cable had a ton of corrosion under it and I replaced that over a year ago with a new one. First time I’ve seen the battery not charging message. I’ll take another look at the positive cable and report back.

 

[Burban22]

Positive cable looks fine under the boot where it connects to battery all the way to the red battery box / jump terminal. After that it disappears behind power steering pump under engine to the starter.

The thin pos wire to alternator also looks fine. The battery cables were tight to the posts but I removed them, no corrosion and reattached.

Starts fine and if I turn on lights, AC and fan on max the volt gauge barely drops below 14 and no messages.

If the message happens again I’ll probably just throw in another alternator unless there’s an easy way to check if the brushes in the alt are almost worn out?

 

[Burban22]

Also have code P1637

CIRCUIT DESCRIPTION
The powertrain control module (PCM) uses the generator turn on signal circuit to control the generator. A high side driver within the PCM allows the PCM to turn the generator ON and OFF. When Generator operation is desired, the PCM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the PCM, the voltage regulator controls generator output independently of the PCM. Under certain operating conditions, the PCM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit. The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the PCM to set the DTC.

CONDITIONS FOR RUNNING THE DTC


The ignition is on.
System voltage between 9.0 and 18.0 volts .
CONDITIONS FOR SETTING THE DTC


An improper voltage level has been detected on the generator L-terminal circuit.
The above conditions are present for at least 30 seconds .
ACTION TAKEN WHEN THE DTC SETS
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

CONDITIONS FOR CLEARING THE MIL/DTC


The DTC becomes history when the conditions for setting the DTC are no longer present.
The history DTC clears after 40 malfunction free warm-up cycles.
The PCM receives a clear code command from the scan tool.