Chrysler: 1995 concord not charging battery

On Mon, 6 Oct 2003, Joust wrote:
 

Well, let's start from the start, here, before we go condemning the
voltage regulator.

First, check for codes. There are diagnostic flash codes for the charging
system.

To check the computer codes:

With the engine off, switch the ignition key on-off-on-off-on,
leaving it "ON". Do not
go to "start", just "on" during this procedure.

Watch the "Check Engine" or "Power Loss" light. It will turn on, then go
off, then will begin to flash-out any trouble codes that have been stored.
For instance, if it flashes:

flash <pause> flash flash
<long pause>
flash flash flash <pause> flash flash flash flash flash
<long pause>
flash flash flash flash flash <pause> flash flash flash flash flash

Then you have a 12 (one flash followed by two) a 35 (three and five) and a
55 (five and five). 55 means "end of codes" or, if by itself, "No codes
stored. Check the codes and report what you find.

Are you quite sure you're seeing "40VDC" and not 40mVDC on your meter? If
you truly had 40V at the alternator output, you'd be broasting batteries
and popping bulbs and computer components all over the car.

What else could it be other than the SBEC (you said "PCM")? Could be a
wiring fault, could be a faulty original alternator replaced by a
typically garbageful "remanufactured" alternator.

And in the end, if you run through all the tests and find the voltage
regulation function in the SBEC has failed, you have several options for a
cost-reduced fix: You can get a used SBEC with a quick search on
www.car-part.com . Or, if you're reasonably electrically knowledgeable and
have some basic electrical repair tools, you can install an external
voltage regulator rather easily. On a '95 you must also install a resistor
across the original field wires to fool the SBEC into not setting a
charging system fault code and tripping the Check Engine light, but this
is a minor additional effort.

Go do some diagnosis; if installing an external regulator becomes
necessary, instructions will be forthcoming.

DS

"Daniel J. Stern" wrote: 

I had the same reaction to the 40VDC reading. Follow Daniel's advice,
but I'd be interesteed to know what voltage you measure at the battery
with the engine off (IOW, if it's not in the 12V range, then the meter
is not reading what you think it is.

Do you maybe have a grounding problem?

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")


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HI,

Thanks for the detailed reply. I'm sure it will be very helpful and much
appreciated.

So I double checked my voltage reading. It is indeed 40v DC but t is at the
alternator lug. NOT the battery. This should be before the regulator and I
expect it to be high. This would be consistent of a unregulated dc source
with no load I'm sure. Could be wrong though, I'm not the expert.

I took it for a spin until the engine light came on.

Stopped and did your procedure.

The code that flashed is 124755


Any ideas?

Wiring looks good.

I put a second ground jumper on to be sure.

Thanks

Barry

"Daniel J. Stern" <umich> wrote in message
news:engin.umich.edu... 

In article <mCygb.2762$bellglobal.com>,
"Joust" <joust!@sympatico.ca> wrote:
 

Code 47: Charging voltage low.
 

Measure the voltage -at- the battery with the engine running.
Voltage drop the alternator output to battery wire.

Sounds like there's an open circuit between the alternator
output and the battery.

On Tue, 7 Oct 2003 08:48:06 -0400, "Joust" <joust!@sympatico.ca>
wrote:
 
from the Shop manual:

12 - Battery Disconnect - Direct battery input to PCM was disconnected
within the last 50 Key-on cycles.

47 - Charging System Voltage Too Low - Battery voltage sense input
below target charging during engine operation. Also, no significant
change detected in battery voltage during active test of generator
output.

55 - End of codes

Looks like you are having an open circuit from the Alternator.


 

Joust wrote:
 

No, this leaves you with a broken connection between the alternator B+
terminal and the rest of the electrical system. The PCM is obviously
telling the alternator "charge" or you wouldn't see 40 volts there. What
is not happening is current flowing from the alternator to the battery.

this alternator does NOT have an internal regulator.
for some god awful reason of design ingenuity the designers decided to put
the regulator circuit inside the Power train control module.

I'm off to trace the wires and connections to the PCM.

"Neil Nelson" <net> wrote in message
news:news.prodigy.com... 
the 
I 
source 

On Tue, 7 Oct 2003, Joust wrote:
 

Listen to what people who know are telling you: There is an open between
alternator B+ and battery +!

DS