Charge System Fault won't go away no matter what I try
08-01-2009, 03:19 PM
#1
6th Gear
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Charge System Fault won't go away no matter what I try
Charge System Fault message on DIC. I have changed the battery, alternator,starter,cleaned all the grounds, new cables from battery to alternator and starter. I still get this messagae. 1999 C5 Convertible Please advise.
08-01-2009, 03:55 PM
#3
Le Mans Master
mine broke down yesterday, with the same thing on dash. It was due to the crankshaft position sensor.
Last edited by winters97gt; 08-01-2009 at 04:01 PM.
08-01-2009, 06:10 PM
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Burning Brakes
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http://forums.corvetteforum.com/c5-g...lp-please.html
Additional info on the alternator itself –
http://forums.corvetteforum.com/show....php?t=1517493
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Last edited by timemender; 08-01-2009 at 06:13 PM.
08-01-2009, 07:16 PM
#5
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My volts on the guage reades anywhere from 13.4 volts to 12.0 volts when I get the messsage on the DIC. I do not have an original alternator installed, but I will get an original an install it and see what happens. When I get the messsage it is only the volts drop for a moment then come back up to normal.
08-01-2009, 11:09 PM
#6
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
This is Bills (ET) reply and explanation of the C5 alternation operation:
QUOTE "
You have the wrong alternator in your car....If you had a credible dealer, they would have told you this.... Problem is they don't realize that your new alternator is not communicating with your old PCM... I'm guessing that you now have an alternator that puts out more than 110 amps.. You PCM is expecting to see a full duty charge of 110 amps>
The alternator is very specific to the PCM...
GM's upgraded alternator is a poor fix... while it is functioning fine... the PCM thinks it isnt...
The only way to Fix this problem for sure is to have the original alternator rebuilt..But it just cant be a 110 amp GM alternator it has to have the specific part number GM 10246634 because of the specific switching found in this alternator, that talks with the PCM
Good Luck and I apologize for the poor service found at your dealership.
Bill aka ET
I've posted this many times, and you may find it of some insight.
The PCM monitors the alternator through the red and grey wires The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.
The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.
The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.
When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.
The L and F terminals are the red and grey
I hope this helps...
--------------------------------------------------------------------------------
Last edited by Evil-Twin; 10-24-2006 at 09:20 PM.
Its an excellent explanation!
Here is a schematic of the C5 Charging System:
Before you start spending more money, get a digital volt meter and do some testing.
The RED wire on the back of the alternator on the BATT terminal is the output terminal. Read it to ground while the engine is running. Then read the battery positive terminal to ground.
BOTH readings should be the same. Your alternator output goes to the starter solenoid and then the battery. That connection is frequently defective and requires cleaning and tightening. Read the positive battery terminal on the battery to the BATT terminal on the alternator.
That voltage should be ZERO. If you see a reading, theres your voltage drop. There should be ZERO voltage drop on that circuit.
Compare the DIC and IPC Volt meter reading to what you see at the battery terminals. They should be close.
NOTE the ground connections!!! CHECK THEM!!! They MUST be clean and tight!!!
Bill
QUOTE "
You have the wrong alternator in your car....If you had a credible dealer, they would have told you this.... Problem is they don't realize that your new alternator is not communicating with your old PCM... I'm guessing that you now have an alternator that puts out more than 110 amps.. You PCM is expecting to see a full duty charge of 110 amps>
The alternator is very specific to the PCM...
GM's upgraded alternator is a poor fix... while it is functioning fine... the PCM thinks it isnt...
The only way to Fix this problem for sure is to have the original alternator rebuilt..But it just cant be a 110 amp GM alternator it has to have the specific part number GM 10246634 because of the specific switching found in this alternator, that talks with the PCM
Good Luck and I apologize for the poor service found at your dealership.
Bill aka ET
I've posted this many times, and you may find it of some insight.
The PCM monitors the alternator through the red and grey wires The L-terminal circuit from the generator is a discrete circuit (a discrete circuit has no splices and only one source and destination) into the PCM. The PCM applies ignition voltage to the generator L-terminal circuit. A small amount of current flows from this circuit through the generator windings to ground to create a magnetic field which starts the generator process. When the generator is at operating speed and producing voltage, a solid state switch for the L-terminal circuit in the generator opens and the PCM detects that the initial startup current flow has stopped.
The PCM expects to detect low voltage on the L-terminal circuit prior to the generator rotating at operating speed and conversely expects the circuit to be at ignition voltage potential when the generator is operational. When the PCM detects a fault (circuit shorted to ground, or circuit shorted to voltage), the Driver Information Center will display Charging System Fault.
The generator has an input to the PCM called the F Terminal to indicate the percentage of total capacity that the generator is producing. This signal is detected by the PCM as a duty cycle from the generator and displayed on the scan tool as a percentage. The PCM can monitor the generators output under all conditions to determine if it is functioning normally.
When there is low demand from the electrical system on the generator, a low duty cycle percentage will be displayed. As more accessory load is placed on the generator, the duty cycle output detected by the PCM will approach 100 percent. A normally functioning generating system will never reach 100 percent as indicated on the scan tool.
The L and F terminals are the red and grey
I hope this helps...
--------------------------------------------------------------------------------
Last edited by Evil-Twin; 10-24-2006 at 09:20 PM.
Its an excellent explanation!
Here is a schematic of the C5 Charging System:
Before you start spending more money, get a digital volt meter and do some testing.
The RED wire on the back of the alternator on the BATT terminal is the output terminal. Read it to ground while the engine is running. Then read the battery positive terminal to ground.
BOTH readings should be the same. Your alternator output goes to the starter solenoid and then the battery. That connection is frequently defective and requires cleaning and tightening. Read the positive battery terminal on the battery to the BATT terminal on the alternator.
That voltage should be ZERO. If you see a reading, theres your voltage drop. There should be ZERO voltage drop on that circuit.
Compare the DIC and IPC Volt meter reading to what you see at the battery terminals. They should be close.
NOTE the ground connections!!! CHECK THEM!!! They MUST be clean and tight!!!
Bill
Last edited by Bill Curlee; 08-01-2009 at 11:22 PM.
