Alternator help
10-06-2012, 07:25 PM
#1
Racer
Thread Starter
Member Since: Oct 2005
Location: Vancouver BC
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
Alternator help
2003 C5 A4
I'm no mechanic, but looks like I need a new alternator.
Getting DIC codes
P1637
C1236
B2282
B2283
Battery dead.
After recharge - voltage across battery is less than 10V with car running.
Can someone confirm that this does sound like the alternator?
Is this a DIY job?
I've replaced alternators on older cars - very simple. Just wondering if there is anything I need to watch for on replacing the alternator on a C5.
Any issues with getting a replacement at the auto stores?
My car came with a 110Amp alternator according to the Option Code.
Why is the local parts store telling me that they show a 150 amp as standard.
Will it cause any issues going to a higher amp alt?
Gary
I'm no mechanic, but looks like I need a new alternator.
Getting DIC codes
P1637
C1236
B2282
B2283
Battery dead.
After recharge - voltage across battery is less than 10V with car running.
Can someone confirm that this does sound like the alternator?
Is this a DIY job?
I've replaced alternators on older cars - very simple. Just wondering if there is anything I need to watch for on replacing the alternator on a C5.
Any issues with getting a replacement at the auto stores?
My car came with a 110Amp alternator according to the Option Code.
Why is the local parts store telling me that they show a 150 amp as standard.
Will it cause any issues going to a higher amp alt?
Gary
Last edited by driver68; 10-06-2012 at 07:43 PM.
10-06-2012, 07:30 PM
#2
Race Director
Member Since: May 2003
Location: Iowa
Posts: 13,995
Received 2,706 Likes
on
1,668 Posts
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'-'17-‘18-'19-'20-'21-'22-
'23-'24
10 volts while running, yep, your alternator is not working. Advance Auto or Autozone will check the alt for free to confirm 
10-06-2012, 11:30 PM
#3
Team Owner
10-07-2012, 01:20 AM
#5
Racer
Thread Starter
Member Since: Oct 2005
Location: Vancouver BC
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
Anyone run into any issues with remanufactured alt's?
This is my daily driver, so don't want to be without it for more than a couple of days. I think the GM dealers around here are going to want an arm & a leg for a new Delco. Reman (Bosch) is going to be half the price of new where I live, and time is really important, so I can't order one off of ebay (I see them for $330 for the 110 amp).
10-07-2012, 01:40 AM
#6
These aren't as simple as the old 1-wire alternators. The PCM controls the field windings on the C5.
If you are the mechanical type, you may want to get the alternator tested for free, before turning this into a project.
If you're more electrically oriented, you may want to ensure that both of the red wires (the large cable and pin D) have good continuity back to the starter. Both are protected by fusible links, so you may want to do a voltage drop test. The grey wire is the field, and you should see a PWM signal from the PCM there. The other red wire, pin B, is the alternator enable signal, which also comes from the PCM.
Oh, and don't forget to have a look at the grounds: battery to chassis and chassis to engine.
If you are the mechanical type, you may want to get the alternator tested for free, before turning this into a project.
If you're more electrically oriented, you may want to ensure that both of the red wires (the large cable and pin D) have good continuity back to the starter. Both are protected by fusible links, so you may want to do a voltage drop test. The grey wire is the field, and you should see a PWM signal from the PCM there. The other red wire, pin B, is the alternator enable signal, which also comes from the PCM.
Oh, and don't forget to have a look at the grounds: battery to chassis and chassis to engine.
10-07-2012, 01:54 AM
#7
Racer
Thread Starter
Member Since: Oct 2005
Location: Vancouver BC
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
These aren't as simple as the old 1-wire alternators. The PCM controls the field windings on the C5.
If you are the mechanical type, you may want to get the alternator tested for free, before turning this into a project.
If you're more electrically oriented, you may want to ensure that both of the red wires (the large cable and pin D) have good continuity back to the starter. Both are protected by fusible links, so you may want to do a voltage drop test. The grey wire is the field, and you should see a PWM signal from the PCM there. The other red wire, pin B, is the alternator enable signal, which also comes from the PCM.
Oh, and don't forget to have a look at the grounds: battery to chassis and chassis to engine.
If you are the mechanical type, you may want to get the alternator tested for free, before turning this into a project.
If you're more electrically oriented, you may want to ensure that both of the red wires (the large cable and pin D) have good continuity back to the starter. Both are protected by fusible links, so you may want to do a voltage drop test. The grey wire is the field, and you should see a PWM signal from the PCM there. The other red wire, pin B, is the alternator enable signal, which also comes from the PCM.
Oh, and don't forget to have a look at the grounds: battery to chassis and chassis to engine.
10-07-2012, 02:35 AM
#8
Team Owner
Member Since: Jan 2007
Location: cookeville tennessee
Posts: 28,846
Received 1,762 Likes
on
1,529 Posts
Get it checked out now befor your car will not start when it get under 10 amps it will not start up your elec pump in the gas tank.
Robert
10-07-2012, 03:15 AM
#9
Instructor
I was having the same issues. My voltage would start out at 13.6 then drop to 13.1 after idling for more then 20 minutes. Under WOT it would dip down to 11.7-9. Battery was good, grounds are clean, starter bolts nice and tight. Went ahead and pulled the plug on a new unit from GMPARTSHOUSE for $430. Takes 10 days to deliver, so you might want to order sooner rather than later. While the cars down, I sent off the PCM to ECS for a mail order tune to accommodate my new LTH and Vararam. Also picked up some new OEM wires, TR55 plugs, and a 160 t-stat. Figured if its going to be down, might as well get some little things done.
10-08-2012, 12:50 PM
#10
Racer
Thread Starter
Member Since: Oct 2005
Location: Vancouver BC
Posts: 324
Likes: 0
Received 0 Likes
on
0 Posts
I'm going to have my alternator rebuilt, but one more question.
With the car running, shouldn't the alternator be producing 14+ volts at the red terminal on the alternator? It shows 12.1 volts now. Would this be another confirmation that it is likely the alternator?
I did check all the connections at the starter and everything is tight there.
With the car running, shouldn't the alternator be producing 14+ volts at the red terminal on the alternator? It shows 12.1 volts now. Would this be another confirmation that it is likely the alternator?
I did check all the connections at the starter and everything is tight there.
10-08-2012, 12:59 PM
#11
Race Director
Member Since: May 2003
Location: Iowa
Posts: 13,995
Received 2,706 Likes
on
1,668 Posts
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'-'17-‘18-'19-'20-'21-'22-
'23-'24
I'm going to have my alternator rebuilt, but one more question.
With the car running, shouldn't the alternator be producing 14+ volts at the red terminal on the alternator? It shows 12.1 volts now. Would this be another confirmation that it is likely the alternator?
I did check all the connections at the starter and everything is tight there.
With the car running, shouldn't the alternator be producing 14+ volts at the red terminal on the alternator? It shows 12.1 volts now. Would this be another confirmation that it is likely the alternator?
I did check all the connections at the starter and everything is tight there.