vettes4fun

Can a 04-05 alternator work on a 97-03 they have different part numbers. The 97-03 have a bracket on the back that bolts to the back of the alt and to the head and is a 110 amp and the 04-05 doe's not use one and is 150 amp I think. I bought a Alternator from Chromeco 5 weeks ago and he sold me on for a 04-05 now I'm having trouble with it and he will no return my calls or emails and his phone now as been disconnected.

Evil-Twin

No you can not use it... you need a 97 to 00 Y body 110 amp Valeo French made alternator... no others will work...you can not use an F body 110 amp, you cant use any Gm alternator...it is very specific for a C5... your PCM expects to see 110 amps at full duty cycle.. anything more will throw codes... Gm offers a 140 amp Valeo made in Mexico but you need to have it installed at the dealers and they have to reflash your PCM.. it is about a 500 dollar deal... you can have your original 97 rebuilt, or find a used 97 to 00 as long it is an original Valeo made in France with 110 amps..
your car whether an MN6 or an A4 takes the same alternator.
the only part number for your car is 10246634... you can not cross reference it without taking it to the dealer for a PCM reflash.
IN 2001 they went to a clutch pulley for A4 cars...no clutch on an MN6.

2KFRC5

The correct generator part# is 10316182. This supercedes the old generator part # of 10246634

flynbya2

This is exactly why I inquired about purchasing your old one

Send it out and have it chromed, or find a backup first,so you won't be without one in case it doesn't work when you get it back......then you won't be without one

All this info came directly from Evil Twin.He definately knows his stuff

Evil-Twin

Ive already said this cross reference is for a new version 140 amp.. it requires a PCM re flash it will not bolt right in and work without throwing charging system fault codes. The PCM uses a discreet circuit to communicate with the alternator. When the PCM see a full duty cycle is wants to see 110 amps not 140 amps...

here is how this communications link works.. Ive posted this hundreds of time when I did this write up:

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 ( 110 amps- not 140 amps )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

Rich Z

When you say "no others will work", what exactly do you mean by this? If you put in an incorrect alternator what sort of failures can you expect?

The reason I am asking is because Saturday I put an Autolite alternator (ATRA2301162 A2301-16-2 AUTOLITE ALTERNATOR) into my 2002 Z06 and after test driving it for about an hour on Saturday and close to 5 hours on Sunday, it appears to be working just fine. So is it not "just fine" and I am just not aware of what to look for to determine that?

Thanks.

Evil-Twin

If auto lite used an exact replacement, sure it will work... but many re manufacturers use a cross reference chart.. I have seen it hundreds of times in the field... the communications link in the alternator has to communicate with the link in the discreet circuit of the alternator... the PCM algorithms are written for a 110 amp alternator, and the PCM expects to see this...if the communications is not exact, it could drain your battery, cause a charging system fault, over charge your battery, and cause it to heat up and explode.. If you are seeing nothing unusual like high amps, or low amps, or no charging system fault, then you are ok.... Ive seen retailers offer a clutch driven alternator for an MN6 car, which is totally wrong...they just want your money, and if it remotely fits the requirements they give it to you, and then when it fails they say electrical parts are not returnable..There have been hundreds of people here tell of their problems with the GM replacement ( 140 amp replacement for the 110 amp original) or a re manufactured alternator here.. many have heeded what Ive said, and bought the right thing...Your car is now old enough for them to understand the system and what it takes to bring it into spec... several years ago they stopped making the correct alternator and used an upgraded alternator... it took GM two years to correct the problem with a PCM reflash... Many horror stories here in the past for early 97-00 alternators..
Your origianl stock alternator is worth much gold . I hope you kept it...but probobly turned it in for 25 dollar core... Many people would have given you 100 dollars for it Not working because they are no longer available..

Rich Z

Actually I still have the original (assuming it is original, since I've only had the car for 7 months). I would only get a $20 core charge for it. I'm thinking of perhaps getting it rebuilt, if I can find someone reliable and knowledgeable to do that. If I could find a shop that would chrome or polish it as well at the same time, well that would be the ticket, I think.

Of course, the wife will probably kick my butt for even THINKING of having a spare alternator laying around in my work room. But even though that Autolite has a life time warranty, I'm betting the car would be down for at least a week until a replacement could be shipped to me. Not a chance there will be one locally available.

Thanks for the help.

Oh, one question, however..... You made a comment
Is the voltage reading on the DIC an indicator of an actual amperage flow? I do have an ammeter in the workroom somewhere, but not sure it would help in this situation. So how do I actuall monitor the amperage coming from the alternator if the voltage reading on the DIC is not doing that? Sorry if this is a dumb question. Been a long time since my basic electric theory classes......

Bill Curlee

Rich

It requires special equipment to fully test the C5 alternator. The gage's on the dash and in the drivers information center DIC only show voltage. To get a current reading you going to need to install an amp meter in series with the alternator and it will need to be capable of showing 0-150 amps if your going to conduct a full current capability test. Not something the run of the mill C5 owner has in his tool box. The dealer uses the GM TECH II. I would assume that a reputable automotive electrical repair facility/shop would have something capable of testing your alternator/charging system.

If your not seeing charging system faults or DTC codes, the PCM must be happy. Not saying that it working 100%, just saying that it's making the PCM happy. Look in the yellow pages under the Automotive section and look for auto electric. It should list shops that repair starters and alternators. Just call them and ask them if they have the correct equipment to work on and test your alternator.

Please let us know how you make out.

Bill C

SFVetteman

If you have a 2002, then I would not expect any problems as it came originally with the higher amp alternator. This problem only exists with the '97-'00 years that had the 110 amp alternator.

2KFRC5

E-T, I missed your original write-up. Thanks for reposting the details. Your expertise is appreciated.

When I posted the new #, I was going by Fred Beans site. It listed the # as for the years '97-'00.

I'll most surely correct my personal parts list for my '00.

Rich Z

Not busting your chops or anything, but are you CERTAIN about this? Every listing I checked looking for an alternator showed that for a 2002 Z06 the alternator output was rated at 110 amps.

SFVetteman

Sorry about that :o I based my statement based on ET's info instead of checking my own parts info.

The 10246634 alternator (110 amp) was used in all '97-'00 and '01-'02 6-speed cars including the Z06.

The '01-'02 A4 cars used the 10315182 alternator, which may be a 120 amp with a clutch pulley but I'm not certain.

The 10353440 is the 145 amp alternator that I believe came out in '03 but I'm not certain. It is the only alternator available from GM now.

Hope this clears things up and I'm sorry for any confusion that I caused

HIGHRPM

I have installed the new GM 145 amp unit...made in Mexico...I get an intermittent "charging system failure" on the DIC. It always lasts about 8-10 seconds, then everything goes back to normal. There is no pattern to it.... sometimes it doesn't show for days....sometimes 3 or more times in an hour. My battery seems to stay fully charged.... have about 600 miles on the new alternator. My question is if I take the car to a dealer for a PCM reflash will this overwrite my existing 2-bar SD tune?, or just make the correction to the charging algorythms?

Bill Curlee

YES!!!!!!! Your new tune will be G O N E !!!!!!!!!!!!!!!!!! If you dont have a copy and a way to up-load it. your screwed!

BC

RED99

Anyway of telling if you have the correct updated o.s. already on a early model C5? I am 99% sure mine has the correct o.s. already because after I bought my car, I took it to the dealer and paid them $100 to upgrade my PCM to the newest updates, and I remember him telling me that the o.s. has been changed and not just updated, I think twice. And I seem to remember that he told me that I have the newest o.s. for my 99' now. But I would like to double check to see.