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Discussion Starter #1
Would really appreciate if someone could give me some insight. Do I need to buy a voltage regulator or Alternator? I could really use a lot of patience and explanation from someone very knowledgeable. Profusely thanking you in advance :bow:

2011 328i. It went down to 13.6 and up to 15.2 while I was checking through insturment cluster. Stays at ~15. Dashboard lit up and if I start driving, the airbag light goes on too. Attached pics. Are modules turning off to protect the systems?

Also, at one time, the fuel gauge showed empty and wouldn't move.
Speedometer stayed at zero initially and jumped up to 15 when the car reached that speed.

Battery is brand new. And car starts right up.

SES light also on.

Other codes:

CDA7......Status reverse gear 3B0>not currently detected: no signal

2FE5.......?
2FE4.......?

581A...... DSC error: Can left FRONT wheel speed> Not currently detected: Invalid signal: Warning lamp on

581C......DSC error: Can left REAR wheel speed> Not currently detected: Invalid signal: Warning lamp on

5DF4......Electrical system voltage drops below 9 volts>not currently detected

5DF7......System voltage>18 Volts> not currently detected: Warning lamp on

5DB1.....Speed sensor input Extrapolation Back left> not currently detected: Warning lamp on

5DB6.....Direction sensing the rear left>not currently detected

5DB3.....Speed sensor input rear left starting detection V-Compare>not currently detected: Warning lamp on
 

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02/2012 X5 35d M57Y CPO 99K miles NOKIAN WR G3 12K miles
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Is the alternator producing voltage, doing its job? Yes. Is the 'voltage regulator' regulating voltage, doing its job? Yes.

The issue is that the voltages that you see are not what you expect. Do you expect to see proper voltages?

The ECU commands alternator output from moment to moment and it is doing much more than just charging the battery, for instance.

See the third wire to the alternator from the DME?

https://www.newtis.info/tisv2/a/en/...rnator/intelligent-battery-sensor-ibs/aeTiAe0
 

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3/2007 328xi E91
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...2011 328i...Dashboard lit up and if I start driving, the airbag light goes on too...Battery is brand new. And car starts right up...codes:
...
5DF4......Electrical system voltage drops below 9 volts>not currently detected
5DF7......System voltage>18 Volts> not currently detected: Warning lamp on
I would NOT drive the car until you change the voltage regulator (~$50 part cost if DIY).
I would check the Freeze Frame Data related to ALL the faults you read, but particularly the two listed above related to excessively LOW voltage, and excessively HIGH voltage (EXTREMELY high at >18V -- THAT will damage battery & electronic modules in short order). That "Over-voltage" is what is causing the light show on your instrument cluster. Make sure you do NOT have battery acid boiled from the battery corroding things in the battery well.

To better understand what the sequence of events has been, and to ensure proper diagnosis & proper part replacement, I would want to know:
1) at WHAT mileage/km those two faults were set (LOW V & HIGH V)? Freeze Frame Data shows that.
2) at what mileage the battery was replaced? If battery was "registered," that mileage is recorded in DME & INPA can read that mileage, and
3) your current mileage?
4) why was it necessary to recently replace the battery -- symptoms & tests before replacement?
5) when the battery was replaced, was the replacement (a) the same Type (AGM v. LA), and (b) the same Ah (Amp-hour) rating as the old battery, and if not, were the proper coding changes made in the DME Power Management module?

Here is the TIS procedure for Voltage Regulator Replacement:
https://www.newtis.info/tisv2/a/en/...ne-electrical-system/12-32-controller/HwWK2Fi

Please let us know the outcome,
George
 

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Discussion Starter #4
I would NOT drive the car until you change the voltage regulator (~$50 part cost if DIY).
I would check the Freeze Frame Data related to ALL the faults you read, but particularly the two listed above related to excessively LOW voltage, and excessively HIGH voltage (EXTREMELY high at >18V -- THAT will damage battery & electronic modules in short order. That "Over-voltage" is what is causing the light show on your instrument cluster. Make sure you do NOT have battery acid boiled from the battery corroding things in the battery well.

To better understand what the sequence of events has been, and to ensure proper diagnosis & proper part replacement, I would want to know:
1) at WHAT mileage/km those two faults were set (LOW V & HIGH V)? Freeze Frame Data shows that.

The mileage I have no idea. I just bought the car. have been driving it in town. The cluster lit up perhaps 20 miles ago. For the previous 100 miles, not a hickup.
This was all of a sudden when I pulled off the ramp and took an exit. I have roughly driven it about 110 miles since I bought it.


2) at what mileage the battery was replaced? If battery was "registered," that mileage is recorded in DME & INPA can read that mileage, and

Battery is not even 24 hours old. Have driven it perhaps 10 miles. Mileage replaced was approximately 88585. It currently has 88594.

3) your current mileage?

88594

4) why was it necessary to recently replace the battery -- symptoms & tests before replacement?

It already had a dead battery when I bought the car so I knew I would need to replace it. But I had charged the battery and drove 100 miles in a couple of days without a hickup and all of a sudden, all the lights came on. Before that, nothing. Changed battery, registered it, and these lights remained lit. Cleared the codes but came back on immediately.


5) when the battery was replaced, was the replacement (a) the same Type (AGM v. LA), and (b) the same Ah (Amp-hour) rating as the old battery, and if not, were the proper coding changes made in the DME Power Management module?

Yes same type. Lead Acid. 94R

Please let us know the outcome,
George
Thank you for the detailed reply. Here are your answers in red. Also, I'm thinking that all this must be recent. As after charging the old battery, car did fine for at least 100 miles in city and little highway driving. Than after these lights came on, I replaced the battery, registered it, erased codes, but these lights came back on. Both of the left speed sensors went out at the same time. For the last 100 miles, everything was great. Had a huge smile on my face. Now very very tense.
 

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Discussion Starter #5
Also, could my original bad battery have caused my voltage regulator to die?
 

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Also, could my original bad battery have caused my voltage regulator to die?
Probably not. The opposite is more likely the case. I agree you should replace the voltage regulator. I replaced the one on my M3 after it behaved similarly to yours
 

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Discussion Starter #7 (Edited)
Probably not. The opposite is more likely the case. I agree you should replace the voltage regulator. I replaced the one on my M3 after it behaved similarly to yours
Thank you for your reply. Were your voltage levels similar too? And did you get all these lights too? Did you DIY and was it easy if so?
Regards
 

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...after charging the old battery, car did fine for at least 100 miles in city and little highway driving. Than after these lights came on, I replaced the battery, registered it, erased codes, but these lights came back on. Both of the left speed sensors went out at the same time. For the last 100 miles, everything was great. Had a huge smile on my face. Now very very tense.
I don't know what you have available to read codes, but when a Fault Code is saved in DME memory (or Fault in memory of most other modules) the mileage/km existing at that moment is ALSO saved in "Fault Details" or "Freeze Frame Data." While clearing codes to see if they recur is proper procedure, one SHOULD RECORD the Fault Details or Freeze Frame Data BEFORE clearing the codes, as that data usually is LOST when the code is cleared. In the case of certain faults saved in the DME, you MAY still have a "Historyspeicher" or Memory History even after the code is cleared.

I'm just being picky, trying to make sure we have ALL the data the car's electronic system is still able to give us, so we don't miss something in the diagnosis. If it were MY car, I would want to know WHEN the system voltage was GREATER than 18V! But then, if you just bought the car and do NOT know the history of the alternator & voltage regulator, that is somewhat academic, and we really need to focus on what you are able to observe and measure NOW.

Your monitoring on the instrument cluster using Hidden Menu 9.00 suggests greater than normal voltage, at whatever point & conditions those photos were taken. If the 15.1V shown, or 15.2V reported was at idle, I would want to know how much higher it gets at 2k to 3k RPM. If your scan tool has the ability to log a Parameter (System Voltage) as you drive, you might go around the block a few times (don't go far in case it goes >>15.2V).

I don't pretend to have experience with hundreds of BMWs and my 328xi has never had a voltage issue, so here is what Bentley says (p. 121-17; p. 248 of pdf):
"The regulated voltage (engine running, battery charged, accessories and lights OFF) is usually between 13.2 and 14.5, depending on temperature and operating conditions. If the voltage is higher than 14.8, the voltage regulator is most likely faulty."​

The short answer is, IF (1) there was a fault code in memory that says System Voltage was greater than 18V at some point before you cleared that code, AND (2) you have NO indication that the voltage regulator was ever replaced after that code was set, AND (3) you are now seeing abnormal random warning lights (light-show) on your instrument cluster, AND (4) you are reading System Voltage in excess of 15.0 V using Hidden Menu 9.00 with engine running:

I would change the Voltage Regulator.

Here are examples of options for my 2007 328xi E91 with 180 Amp Alternator (I would personally go with the Bosch option), but make sure you know (1) make of your alternator (Bosch, Valeo, etc.) and correct BMW part# for YOUR car:
https://www.autohausaz.com/catalog/k/bmw/2007/1433811-328xi_n52_e909192/voltage regulator?s=r&page=1

Auto DIY 101: Don't be tense! It's NOT like operating on a family member (so don't give your car a name ;-). Realize you will likely spend $200 to $500 per year on parts & supplies (oil changes, etc.) to properly maintain your car (and a number of hours of your own time), and don't sweat $50 and less than an hour time. :rofl:

Now, if the $50 Voltage Regulator doesn't fix things, and you have to spend nearly $500 for a reman alternator, THAT may be a heartburn-producer, but the issue you describe suggests the problem is in the Regulator or control circuit. :)

Please keep us posted,
George
 

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Would really appreciate if someone could give me some insight. Do I need to buy a voltage regulator or Alternator? I could really use a lot of patience and explanation from someone very knowledgeable. Profusely thanking you in advance :bow:

2011 328i. It went down to 13.6 and up to 15.2 while I was checking through insturment cluster. Stays at ~15. Dashboard lit up and if I start driving, the airbag light goes on too. Attached pics. Are modules turning off to protect the systems?

Also, at one time, the fuel gauge showed empty and wouldn't move.
Speedometer stayed at zero initially and jumped up to 15 when the car reached that speed.

Battery is brand new. And car starts right up.

SES light also on.

Other codes:

CDA7......Status reverse gear 3B0>not currently detected: no signal

2FE5.......?
2FE4.......?

581A...... DSC error: Can left FRONT wheel speed> Not currently detected: Invalid signal: Warning lamp on

581C......DSC error: Can left REAR wheel speed> Not currently detected: Invalid signal: Warning lamp on

5DF4......Electrical system voltage drops below 9 volts>not currently detected

5DF7......System voltage>18 Volts> not currently detected: Warning lamp on

5DB1.....Speed sensor input Extrapolation Back left> not currently detected: Warning lamp on

5DB6.....Direction sensing the rear left>not currently detected

5DB3.....Speed sensor input rear left starting detection V-Compare>not currently detected: Warning lamp on
These are all stored codes. The hint is "not currently detected". At one time you had them but they are not currently active. Clear the codes and run a charging system diagnosis.

What were you doing when "((It went down to 13.6 and up to 15.2) normal)) while I was checking through insturment cluster"? Were you checking for codes using the instrument cluster readout?
 

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Discussion Starter #10
I don't know what you have available to read codes, but when a Fault Code is saved in DME memory (or Fault in memory of most other modules) the mileage/km existing at that moment is ALSO saved in "Fault Details" or "Freeze Frame Data." While clearing codes to see if they recur is proper procedure, one SHOULD RECORD the Fault Details or Freeze Frame Data BEFORE clearing the codes, as that data usually is LOST when the code is cleared. In the case of certain faults saved in the DME, you MAY still have a "Historyspeicher" or Memory History even after the code is cleared.

Hi, The scanner was from a mechanic I know. He has the latest Mac tools scanner. This is not a BMW mechanic, just a generic mechanic. I'm going to go ahead and order the voltage regulator. Realoem shows it to be Bosch. The mechanic did reset all the modules or at least that's what I understood. He said something like this will be back to the day it left the factory with nothing stored??? But after I replace the regulator, I will check to see if there is something in the memory. Thank you for letting me know about recording the codes. I'll certainly remember that for the next time.

I'm just being picky, trying to make sure we have ALL the data the car's electronic system is still able to give us, so we don't miss something in the diagnosis.

Thank you so very much in taking the timeout to explain everything in such great detail. And thank you for all the help and knowledge. I am very appreciative.

If it were MY car, I would want to know WHEN the system voltage was GREATER than 18V! But then, if you just bought the car and do NOT know the history of the alternator & voltage regulator, that is somewhat academic, and we really need to focus on what you are able to observe and measure NOW.

Your monitoring on the instrument cluster using Hidden Menu 9.00 suggests greater than normal voltage, at whatever point & conditions those photos were taken. If the 15.1V shown, or 15.2V reported was at idle, I would want to know how much higher it gets at 2k to 3k RPM. If your scan tool has the ability to log a Parameter (System Voltage) as you drive, you might go around the block a few times (don't go far in case it goes >>15.2V).

At idle it was 5.1, about 2 minutes after ideling. Once it went to 5.2 but dropped back to 5.1. It remained constant at about 5.1 during 2-3k rpm. I didn't have the car on for very long as I was afraid that I would destroy something. I just saw some Youtube videos of guys experiencing these problem and driving so it makes me feel better that my computers may not have been compromised. I have driven about 10 miles or so with these symptoms. While at 5.1, I turned on the heater, turned on the lights and radio, and it remained between 5.0-5.1. As soon as I turned these accessories off, that is when the reading dropped to 3.6 for a second and then went back up to 5.0-5.1. I didn't give it another change to go above that and turned it off.

I don't pretend to have experience with hundreds of BMWs and my 328xi has never had a voltage issue, so here is what Bentley says (p. 121-17; p. 248 of pdf):
"The regulated voltage (engine running, battery charged, accessories and lights OFF) is usually between 13.2 and 14.5, depending on temperature and operating conditions. If the voltage is higher than 14.8, the voltage regulator is most likely faulty."

Oh wow, this helps me out a lot. Thank you so much for this. Now I know what it should be.

The short answer is, IF (1) there was a fault code in memory that says System Voltage was greater than 18V at some point before you cleared that code, AND (2) you have NO indication that the voltage regulator was ever replaced after that code was set, AND (3) you are now seeing abnormal random warning lights (light-show) on your instrument cluster, AND (4) you are reading System Voltage in excess of 15.0 V using Hidden Menu 9.00 with engine running:

Yes. You know, that 18V could have happened night before last when the car did this. I want to kick myself for not thinking about trying to find out exactly when it happened. Most likely I think it may have happened under my few days of ownership as I have driven in city and highway approximately 100 miles in both city speeds and highways speeds and there was no malfunction. Now, it is every time I start the car since it occurred 2 nights ago.

I would change the Voltage Regulator.

I will take your advice.

Here are examples of options for my 2007 328xi E91 with 180 Amp Alternator (I would personally go with the Bosch option), but make sure you know (1) make of your alternator (Bosch, Valeo, etc.) and correct BMW part# for YOUR car:
https://www.autohausaz.com/catalog/k/bmw/2007/1433811-328xi_n52_e909192/voltage regulator?s=r&page=1

I was thinking about buying it from FcpEuro because of their lifetime warranty.
Also, if realoem is showing Bosch after putting in the VIN, is it safe to assume that I do have a Bosch?


Auto DIY 101: Don't be tense! It's NOT like operating on a family member (so don't give your car a name ;-). Realize you will likely spend $200 to $500 per year on parts & supplies (oil changes, etc.) to properly maintain your car (and a number of hours of your own time), and don't sweat $50 and less than an hour time. :rofl:

:thumbup:

Now, if the $50 Voltage Regulator doesn't fix things, and you have to spend nearly $500 for a reman alternator, THAT may be a heartburn-producer, but the issue you describe suggests the problem is in the Regulator or control circuit. :)

What is the control circuit?

Please keep us posted,
George
George, your replies and help and your taking the time out to explain these things are nothing short of amazing. I have no words to express my gratitude. :bow:
 

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Discussion Starter #11
These are all stored codes. The hint is "not currently detected". At one time you had them but they are not currently active. Clear the codes and run a charging system diagnosis.

Thank you for this..!! :thumbup:

What were you doing when "((It went down to 13.6 and up to 15.2) normal)) while I was checking through insturment cluster"? Were you checking for codes using the instrument cluster readout?
^^^ No, I was only checking for voltage regulator using option menu 9.

Here is a more detailed explanation:

At idle it was 5.1, about 2 minutes after idling. Once it went to 5.2 but dropped back to 5.1. It remained constant at about 5.1 during 2-3k rpm. I didn't have the car on for very long as I was afraid that I would destroy something. While at 5.1, I turned on the heater, turned on the lights and radio, and it remained between 5.0-5.1. As soon as I turned these accessories off, that is when the reading dropped to 3.6 for a second and then went back up to 5.0-5.1 (with absolutely no load. Just idling) I didn't give it another change to go above that and turned it off.
 

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^^^ No, I was only checking for voltage regulator using option menu 9.

Here is a more detailed explanation:

At idle it was 5.1, about 2 minutes after idling. Once it went to 5.2 but dropped back to 5.1. It remained constant at about 5.1 during 2-3k rpm. I didn't have the car on for very long as I was afraid that I would destroy something. While at 5.1, I turned on the heater, turned on the lights and radio, and it remained between 5.0-5.1. As soon as I turned these accessories off, that is when the reading dropped to 3.6 for a second and then went back up to 5.0-5.1 (with absolutely no load. Just idling) I didn't give it another change to go above that and turned it off.
This helps A LOT.

As Doug said: "The ECU commands alternator output from moment to moment and it is doing much more than just charging the battery, for instance." In this scenario, the regulator is used as a 'fail safe' device. It's job is to keep the system @16V max IF the DME should screw up. Question: Do you hear the alt. trying to charge?

Because you have a recorded +18V error, my thoughts are the regulator is fried and is keeping the output low. Good thing is they are relatively inexpensive (for a BMW) and easily replaced with the alternator in place. The bad ***8230;. If the alt. is bad, you have a spare regulator laying about. If I were doing the job, I'd remove the alt., check for thrown solider, overheated components and decide from there.

I can't stress enough, before doing any electrical repair (especially when disconnecting the battery) make sure the car is fully 'asleep'. And never, NEVER, NEVER disconnect the battery with the car running.
 

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Discussion Starter #13
Is the alternator producing voltage, doing its job? Yes. Is the 'voltage regulator' regulating voltage, doing its job? Yes.

The issue is that the voltages that you see are not what you expect. Do you expect to see proper voltages?

The ECU commands alternator output from moment to moment and it is doing much more than just charging the battery, for instance.

See the third wire to the alternator from the DME?

https://www.newtis.info/tisv2/a/en/...rnator/intelligent-battery-sensor-ibs/aeTiAe0
Thank you for this. However, I don't understand what I have highlighted in your post.
Regards
 

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This helps A LOT.

As Doug said: "The ECU commands alternator output from moment to moment and it is doing much more than just charging the battery, for instance." In this scenario, the regulator is used as a 'fail safe' device. It's job is to keep the system @16V max IF the DME should screw up. Question: Do you hear the alt. trying to charge?

I'm sorry, I don't know what to listen for. I am not very knowledgeable at all about electric things.

Because you have a recorded +18V error, my thoughts are the regulator is fried and is keeping the output low.

This is what I was thinking. This is why in my OP I mention/asked whether the regulator is shutting off the systems. You think that could be the case here? (As soon as I start driving the car and it reaches about 10-15 mph, the airbag light comes on too and remains on until I turn off the car. However, when I start the car again, all the lights in the pics I posted in the OP come on except the airbag light, which remains off until the car starts to get going again).

Good thing is they are relatively inexpensive (for a BMW) and easily replaced with the alternator in place.

WOW..! I can change the voltage regulator without taking the alternator off??
:thumbup: I've search numerous youtube videos but haven't come across a DIY for it sadly.
If you happen to know of one posted somewhere I would really appreciate if you could point me in the right direction. :bow:


The bad ….. If the alt. is bad, you have a spare regulator laying about. If I were doing the job, I'd remove the alt., check for thrown solider, overheated components and decide from there.

I can't stress enough, before doing any electrical repair (especially when disconnecting the battery) make sure the car is fully 'asleep'. And never, NEVER, NEVER disconnect the battery with the car running.

Thank you for this advice. So I disconnect the negative terminal and how long do I have to wait after that?
Thank you so much for taking the time out to help me. Sir, I really appreciate it. :)
 

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Alternators under load have a distinctive sound. It's something you'll have to train your ear to hear.

I've done it 'on car' but I have a bit more experience than most. Basically it's remove rear cover (hold a magnet pick up tool by the screws and nuts to catch them when you drop them), take out the regulator and replace. Just don't force the regulator in. It's the same as George's instructions but you're standing on your head and working from the side. Sometimes a mirror helps.

BEFORE removing the battery cable, the car should be asleep. This ensures that all the sensitive electronic stuff is turned off incase a reverse voltage spike should happen when the cable is removed. I had an instructor who's favorite saying was "Google (search) is your friend'.
 

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Alternators under load have a distinctive sound. It's something you'll have to train your ear to hear.

I've done it 'on car' but I have a bit more experience than most. Basically it's remove rear cover (hold a magnet pick up tool by the screws and nuts to catch them when you drop them), take out the regulator and replace. Just don't force the regulator in. It's the same as George's instructions but you're standing on your head and working from the side. Sometimes a mirror helps.

BEFORE removing the battery cable, the car should be asleep. This ensures that all the sensitive electronic stuff is turned off incase a reverse voltage spike should happen when the cable is removed. I had an instructor who's favorite saying was "Google (search) is your friend'.
Thank you.
 

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Discussion Starter #17
One other thing I forgot to mention. Before the battery was replaced, the old one required jump start and the car would start easily, quickly. Upon reaching the destination, if I shut the engine and immediately started the car, it would crank, however, if I shut it again and immediately tried to start again, it would not and would require a jump again. I then replaced the battery.
 
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