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Good Morning all! A month or so ago I had my first experience with the "Alternator Fault Battery Not Charging" message. Ive been playing with it off and on, trying to get through it. I've also read more posts on forums and explored the internet more than I care to admit. Currently I am aware of how finicky the charging systems can be in these cars, the BEM codes and voltage regulator issues. I do not have a way to read codes or get data on my own. Here is what I have so far.
Had the car for about 15 months. I usually only drive the car periodically in the summer, its more of a winter car. Still, its not used much in the winter. If I would listen to the radio with the car off, I would get a message saying that the batter was getting low and I needed to start the car. Based on this, I figured I was getting close to a bad alternator or battery, but I have it on a battery tender over the winter, so I wasnt too worried about it. The first time the "Alternator Fault...
message came up was when the fiance was driving the car home from work. She made it home and I noticed that the front pulley had some significant wobble to it. Went to my locat Napa and bought a remanufactured alternator and installed. It is a Bosch, but it doesnt have a bosch voltage regulator on it. The voltage regulator part number is a direct replacement for the correct Bosch part number based on the manufacturers information online. Ive been of the mindset that when your alternator goes, it usally take the battery with it, so when I still wasnt getting good voltage readings after the new alternator, I replace the battery as well with an Interstate Battery unit that meets or exceeds the factory one. It was the original battery in a 12 year old car, so didnt seem that hard to believe, In hindsight, it probably didnt need to be replaced.
Thats all Ive done for parts. Since then, I still have the same problem: Intermittent charging. I took it to a parts store and had them pull the codes. The CEL was on already, but thats for an intake leak that I havent looked into. Nothing else. For two weeks, every time we drove it, we checked the voltage and clamped the alternator output as well as the exciter wire with a multimeter. At one point it died on her on the way home from work. When the alternator wasnt charging, the amps on the exciter wire and the output would be zero and the voltage would drop as we the car ran, which seems correct. When it would charge, voltage would be good and there would be 1 to 2.5 amps on the exciter (dont know about accuracy on that) and 20 to 90 amps on the alternator output. It was still very hit or miss, though. Disconnecting the battery overnight seemed to give us a better chance of it charging the next startup, battery tender/charger overnight seemed to make it worse. We never did see the "Alternator Failure" message again over this time, but I always got it to charge or charged it so it wouldnt drop below ~11.5 volts with the car running.
Since I was getting nowhere, so I took it to a mechanic in town and paid my 150 bucks to have the diagnostics read. He cleared the underlying codes, which there was 45 of. Started it up, checked it and it was charging. I had explained to them what had been happening, so I asked them to check it a couple times again over the course of the day and change one number on the BEM serial number so that would be taken care of. They did so and it was charging all three times they said they checked it. They said thats about all they could do and if there was any other issues, I would have to take it to a dealer. He didnt give me the print out of the codes. We made it about a day and 100 miles and the warning came back. We kept checking it over the next week, but not putting it on a tender/charger to see how long it would last. Make it about a week or so and it died on her again. Message came up and within about two blocks it was dead. Took it back to the mechanic and he wouldnt touch it. We went on vacation, left it in the garage and I havent checked it since.
Im not 100% on how the charging system system works with the BEM, but seems pretty straight forward. Computer controls the alternator output based on battery age, capactiy, charge, and how much load is on the electrical system, etc. To me it seems like the fault here is with the computer, since the alternator is capable of charging and will do so when the computer tells it to by supplying current on the exciter wire. I know everything is better with codes and live data, but I want to get some insight on what Ive done and where to go next before I spend any more money. Wether it be on a VAG-comm or taking it to the dealer, where Im sure I will get chastised for non-factory alternator and battery, or a new $130 voltage regulator, new $350 alternator, new $$$ BEM module or whatever else could be wrong.. Finding out that its true that Audi parts are expensive, this car can be a pain and you definitely have to do your research before you touch anything.
You can't do any real diagnosis of the charging system without an appropriate tool. VCDS and OBDeleven will let you read the DTCs (codes) and monitor charging system measuring values from the J533. You kind of need this stuff to make any legitimate conclusions.
If it was still on the original battery, it must have been an AGM. AGMs, if maintained (ie, kept in a reasonable state of charge), can last well over 10 years. A flooded battery is good to make it to 5.
"and bought a remanufactured alternator" and you have a MY09. I need more hands to count these kinds of posts. Did you make absolutely sure you got the alternator with the voltage regulator for the CAEB engine and not the BWT engine?
What do you mean exciter wire? That's not how the voltage regulator on the CAEB alternator works. It's a LIN bus comms line, shared with the J367 BEM on the negative battery post. The LIN master is the J533.
You can't do any real diagnosis of the charging system without an appropriate tool. VCDS and OBDeleven will let you read the DTCs (codes) and monitor charging system measuring values from the J533. You kind of need this stuff to make any legitimate conclusions.
If it was still on the original battery, it must have been an AGM. AGMs, if maintained (ie, kept in a reasonable state of charge), can last well over 10 years. A flooded battery is good to make it to 5.
"and bought a remanufactured alternator" and you have a MY09. I need more hands to count these kinds of posts. Did you make absolutely sure you got the alternator with the voltage regulator for the CAEB engine and not the BWT engine?
What do you mean exciter wire? That's not how the voltage regulator on the CAEB alternator works. It's a LIN bus comms line, shared with the J367 BEM on the negative battery post. The LIN master is the J533.
I've triple checked the parts numbers. The alternator is correct and the voltage regulator cross-checked with the correct Bosch number that parts stores, the internet and forums said was correct for MY and engine. I will check again just to make sure.
I agree on the battery, I shouldnt have replaced it. Just another self inflicted variable.
So my terminology might be off on the wire from the module, but doesnt it have to supply some kind of amperage or voltage input to control the alternators output? I guess my point was that there is changes in the comm line that seem to correlate with changes in the output of the amperage from the alternator. It also proof that the alternator should be good because it is some of the time.
So next step is getting a VCDS or OBDeleven so I can get some codes and data. What am I looking for when I get it hooked up? I'm new to this, but willing to learn. My experience consists of pulling CEL codes and using that to do research and come to a conclusion on parts.
If you're sure it's a BR14-C-L voltage regulator and not the BR14-H or BR14-MO, then yeah, you need a tool so you can query the measuring blocks in address 19 (CAN Gateway) and see what the car electronics are actually doing. Blocks 1, 14-16, 18-20, 21-23, and 26. Each measuring block has four values within it. What process you use to query that information will depend on which tool you select. If you have a Windows laptop, VCDS is the superior tool (https://store.ross-tech.com/shop/vchv2_ent/). But if you don't have a portable Windows device, you'd have to add that to your budget.
OBDeleven does not run on Windows; it targets the more current day mobile platforms of Android and iOS. So you probably have something you can run it on. It's not as good, but good enough for many who are primarily looking at the price tag and the platform requirements. https://obdeleven.com/en/products-pa...&id_currency=3 There are basically three purchase options, the next gen device alone (all you need for this purpose), the next gen starter pack (which adds 100 credits for $12 more), and the next gen pro pack. The pro license is necessary to match VCDS functionality, but is not necessary to read codes and live data, which is your concern here. I myself would have only considered the pro pack, but since they changed it this month from a perpetual $30 license to a $30/year annual subscription, no thanks.
On the subject of credits, i.e., should you get the starter pack or the plain device and build up "free" credits, this is the best write up of the credit concept that I've seen so far - https://www.audiworld.com/forums/aud.../#post25602895 But it's not all sunshine and joy with these "apps" - https://forum.obdeleven.com/thread/1...set-app-notice So notice it's 10 credits for the oil change message reset and 10 more credits for the service interval reset. The thing I find funny is anyone can reset the oil change message through the CAR menu.
On to voltage regulator tech. You're thinking old school about the voltage regulator, ie external regulation. Around 2004, LIN bus managed internal regulation was achieved. That's what our vehicles use. https://www.testmyalternator.com/en/...technical.html
I will look at those two. Any suggestions on units that will cover Audi and GM so I dont have to buy two? Or is that looking for trouble?
Here is the information I found on the voltage regulator. I've attached pics. If I remember right, the F00M133259 that was original has been replaced by the 144-151 or 197. As I go back and look, I'm not so sure that that is correct, so I'm digging into it again. Here is the cross reference info. This is the voltage regulator that is on the remanufactured unit. This is the best shot I have of the original voltage regulator.
When I search the F00M133259 in the Regitar catalog, I get a different unit. I also get indication on the internet that this belongs to a Valeo alternator, not a Bosch.
Original alternator, marked as it should be for a B8.0 CAEB engine. 06H 903 016 L (being Audi OE, it's going to have an Audi part number marked, not the Bosch OEM part number) with type BR14-C-L voltage regulator.
The Bosch OEM model number for that alternator is AL0891N for new and AL0891X for reman - https://www.boschautoparts.com/en/au...partId=AL0891N
You can see in the pic, voltage regulator type BR14-C-L, with a part number that looks like F 00M 144 197. If you look in your screen shot of those third party regulators, only one refers to LIN, and it's the one that says it replaces the part number from the Bosch pic. So it would appear your rebuilt alternator (I wouldn't call it a Bosch AL0891X reman as it's not using all Bosch parts) is using a Mobiletron produced voltage regulator. Clearly a Chinese company, but there's no reason to presume it's worthless immediately. Best that can be told, you have physical product that should work. You'll need the diagnostic tool to determine anything more.
As for the diagnostic tool, if you're going close to $1k or more for a multi-platform tool, I imagine there are. But in the sub $500, there's only two tools worth hooking up to your VAG (Volkswagen Automotive Group) vehicle, mentioned previously. Neither operate on GM products. My uncle was having engine issues with his MB diesel. We picked up the Foxwell NT644Pro as he has seven different brands of vehicles under his oversight. The one task it needed to do, it couldn't even do, read the codes from the engine in the MB. And Foxwell support? Beyond useless. Had he not waited so long after receiving it to actually try using it, he would have returned it. An expensive paperweight.
Ok, finally got a unit from Ross-Tech. While I was screwing around with that decision, I used a scan tool at Advanced that said the alternator wasnt charging correctly but the battery was good. For whatever that is worth. Those scan tools they use actually do quite a bit more than they lead on.
Anyway, hooked up the VCDS and logged those points from above. Think I did it correctly.
Sunday,18,July,2021,07:58:15:20230
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 21.3.0.0 (x64) HEX-V2 CB: 0.4544.4
Data version: 20210226 DS325.0 www.Ross-Tech.com
Address 19: CAN Gateway (8T0 907 468 M)
07:58:09 Group 016: Power Supply (Generator)
Not OK Generator Type
Generator Vendor
Generator Size
Generator Control
07:58:09 Group 018: Power Supply (Battery)
11.800 V Battery Voltage
-27.4 A Battery Current
30.0°C Battery Temp. (Estimate)
29.0°C Battery Temp. (Ambience)
07:58:09 Group 019: Power Supply (Battery)
42.0 % Battery State of Charge (SOC)
90.0 % Battery State (as shown in MMI)
80.0 % Battery Aging (derived fr. Load)
126.0 % Battery Aging (derived fr. Output)
07:59:14 Group 020: Power Supply (Battery)
4.2 mOhm Internal Battery Resistance (actual)
2.4 mOhm Internal Battery Resistance (stan.)
19 Ah Battery Capacity (actual/available)
12.10 V Quiescent Voltage
07:59:14 Group 021: Power Supply
Stage 2 Idle Speed Increase
Inactive Fresh Air Blower Reduction
StatCurStg 0 Quiescent Current Stage (actual)
Yes Auxiliary Heating activatable
07:59:14 Group 022: Power Supply (Battery)
0.13 Battery Input
-3.62 Quiescent Current Average
9976 Ah Total Energy Balance
304 Ah Total Energy Throughput
Sunday,18,July,2021,08:00:00:20230
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 21.3.0.0 (x64) HEX-V2 CB: 0.4544.4
Data version: 20210226 DS325.0 www.Ross-Tech.com
Mileage: 290370km-180427mi Repair Order:
Address 19: CAN Gateway (8T0 907 468 M)
07:59:55 Group 001: Power Supply
11.50 V Voltage (Terminal 15)
11.40 V Voltage (Terminal 30)
Sunday,18,July,2021,08:01:15:20230
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 21.3.0.0 (x64) HEX-V2 CB: 0.4544.4
Data version: 20210226 DS325.0 www.Ross-Tech.com
Mileage: 290370km-180427mi Repair Order:
Address 19: CAN Gateway (8T0 907 468 M)
08:01:12 Group 001: Power Supply
11.60 V Voltage (Terminal 15)
11.40 V Voltage (Terminal 30)
08:02:07 Group 018: Power Supply (Battery)
11.700 V Battery Voltage
-27.5 A Battery Current
30.0°C Battery Temp. (Estimate)
29.0°C Battery Temp. (Ambience)
08:02:07 Group 019: Power Supply (Battery)
40.0 % Battery State of Charge (SOC)
90.0 % Battery State (as shown in MMI)
80.0 % Battery Aging (derived fr. Load)
126.0 % Battery Aging (derived fr. Output)
08:02:07 Group 020: Power Supply (Battery)
4.2 mOhm Internal Battery Resistance (actual)
2.4 mOhm Internal Battery Resistance (stan.)
18 Ah Battery Capacity (actual/available)
12.10 V Quiescent Voltage
08:02:35 Group 021: Power Supply
Stage 2 Idle Speed Increase
Stage 1 Fresh Air Blower Reduction
StatCurStg 0 Quiescent Current Stage (actual)
Yes Auxiliary Heating activatable
08:02:35 Group 022: Power Supply (Battery)
0.18 Battery Input
-5.16 Quiescent Current Average
9974 Ah Total Energy Balance
306 Ah Total Energy Throughput
08:02:35 Group 023: Quiescent Current Test
Invalid Quiescent Current Test Result
Invalid Quiescent Current Test Status
06-26-2021, 05:18 AM
Alternator Fault Battery Not Charging Woes
