2010 Chevy Suburban 1500 4wd.
5.3 Vortec.
Had system Check at dealer.
Started truck and let run to warm up, as I walked out to drive smelled
electrical burning smell, I got in the truck checked the basics and all
seemed fine, as I was driving Volt gauge was showing under 14 v, as
I drove it dropped even lower almost to, what I figure, 12v. When I
shut off the truck I waited short time and then re-started voltage back
up to over 14v. I figured that it was the battery just recovering, drove
it again and the voltage dropped as before. Sent to service at
dealership then checked and stated that the charging system was
working as designed?
Tech told me that the computer shuts the charging down when the
vehicle doesn't need it. Sounds like a story to me, and why the
electrical burning smell, something def cooked under the hood.
Question - does the system operate as he told me? Why would it
allow the voltage to drop down to almost 12v while running? Took
vehicle to my son's repair shop and tested voltage it was at 12.9
when I first got there and then went to 13.7 before dropping back to
12.5 a short time later.
5.3 Vortec.
Had system Check at dealer.
Started truck and let run to warm up, as I walked out to drive smelled
electrical burning smell, I got in the truck checked the basics and all
seemed fine, as I was driving Volt gauge was showing under 14 v, as
I drove it dropped even lower almost to, what I figure, 12v. When I
shut off the truck I waited short time and then re-started voltage back
up to over 14v. I figured that it was the battery just recovering, drove
it again and the voltage dropped as before. Sent to service at
dealership then checked and stated that the charging system was
working as designed?
Tech told me that the computer shuts the charging down when the
vehicle doesn't need it. Sounds like a story to me, and why the
electrical burning smell, something def cooked under the hood.
Question - does the system operate as he told me? Why would it
allow the voltage to drop down to almost 12v while running? Took
vehicle to my son's repair shop and tested voltage it was at 12.9
when I first got there and then went to 13.7 before dropping back to
12.5 a short time later.
Tech JK:
Yes, the GM Tech was correct. This charging system is called
"Electrical Power Management (EPM)". Basically a sensor on the
battery cable senses battery voltage / amperage and electrical load
while the truck is running. Then the Body Control Module(BCM)
determines how much alternator charging capacity is needed. The
BCM tells the Powertrain Computer (PCM) how much charging is
needed, then the PCM controls the voltage regulator for a controlled
output.
For example, when there is a heavy electrical load- rear defroster,
blower on high, headlights, at idle- the PCM will boost charging. This
system is designed to extend battery and alternator life.
Now, the burning smell does not seem related. If the truck is
absolutely new with very low miles, then some smells are normal. If
something has melted, I would assume the Tech would have spotted
that quite quickly.
Yes, the GM Tech was correct. This charging system is called
"Electrical Power Management (EPM)". Basically a sensor on the
battery cable senses battery voltage / amperage and electrical load
while the truck is running. Then the Body Control Module(BCM)
determines how much alternator charging capacity is needed. The
BCM tells the Powertrain Computer (PCM) how much charging is
needed, then the PCM controls the voltage regulator for a controlled
output.
For example, when there is a heavy electrical load- rear defroster,
blower on high, headlights, at idle- the PCM will boost charging. This
system is designed to extend battery and alternator life.
Now, the burning smell does not seem related. If the truck is
absolutely new with very low miles, then some smells are normal. If
something has melted, I would assume the Tech would have spotted
that quite quickly.
