Battery not charging message but it is sometimes

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

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

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

EfiniMotorsport said:

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

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

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.

@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.

Burban22 said:

@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.

Click to expand...

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.

S33k3r said:

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.

Click to expand...

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.

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?

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.