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Terminal 61 for BCM? Jump to Latest Rossafuss I've asked several times and nobody has given me an answer in another thread, so i figured id give this question a dedicated thread. WHERE is terminal 61 relating to the BCM? how do you troubleshoot it? is there a fuse related to it? Trouble code is 9055 on the BCM stating "The terminal 61 signal on the CAN bus is missing or faulty" Apparently terminal 61 is where the BCM detects alternator charging voltage, and that communication takes place over the can bus. Does anyone know how to troubleshoot this circuit? Any help is appreciated. 1 - 13 of 13 Posts

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts I've asked several times and nobody has given me an answer in another thread, so i figured id give this question a dedicated thread. WHERE is terminal 61 relating to the BCM? how do you troubleshoot it? is there a fuse related to it? Trouble code is 9055 on the BCM stating "The terminal 61 signal on the CAN bus is missing or faulty" Apparently terminal 61 is where the BCM detects alternator charging voltage, and that communication takes place over the can bus. Does anyone know how to troubleshoot this circuit? Any help is appreciated.

noetico

· Registered 2002 Mercedes ML320, Mercedes 190E 2.3L (sold), 2001 Mercedes c320(gone) Joined Feb 13, 2015 · 1,453 Posts Maybe check this post, don't know if its related directly to your issue, but the OP, got the same code. Searxh for: W211 Battery/Alternator problem Here'sa line from jookoo, the op: "I figured it out! The wire that goes from alternators B+ terminal to starter has a fuse in it that is exposed to the elements, mine was corroded and broke in to few pieces. So I fix that fuse and it started to work again. I didnt find that fuse in any diagrams, so if someone is having similiar problems its worth checking out." Maybe worth lookin at. Sent from my ZTE G720T using Tapatalk

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts That's reffering to the massive (150A+) 'fuse' that is inline between the starter and alternator. It sits on top of the bell housing. If that breaks, it physically breaks the connection between the battery and alternator and prevents charging. That's a helpful tips for anyone else that may have that problem, but That's not where my problem lies. I'm having a communication issue between the alternator and BCM. Most likely, a communication issue between the ECU and BCM.

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts REVELATION: terminal 61 for Bosch alternators has always reffered to the D+ or indicator light terminal. On older alternators, this D+ terminal is used to power the indicator light, AND was tied to the ignition switch. This was both the Exciter wire, as well as the 'sense' wire for the computer to see if the alternator is charging. On new computer controlled alternators, terminal 61 reffers to 'DFM', Or digital field monitor. It's the ECU & BCM's way of sensing load on the alternator. So it seems like the alternator is sending DFM to the ECU, and then the ECU is sending that signal over the can bus to the BCM. Somewhere along there I have an issue, and my guess is that it's right at the voltage regulator on the alternator.

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• 125400693_1531231656832.jpg 43.8 KB Views: 5,878

konigstiger

· Premium Member '71 Pinto Joined Jan 4, 2007 · 6,531 Posts Test BCM, relay, battery using SDS all fine, more than likely alternator.

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• Sensitive content, not recommended for those under 18 211_dual_battery_system.pdf 1.8 MB Views: 2,385

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phporterx

· Registered 2003 E320 Joined Feb 12, 2018 · 268 Posts Rossafuss, konigstiger et al are a regular cornucopia of information when it comes to the W211 chassis. I'm presently printing the information presented for inclusion into my W211 notebook. Thanks for taking the time to post this data for the rest of us. Ask and ye shall receive apparently works very well on this forum.

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts

konigstiger said: Test BCM, relay, battery using SDS all fine, more than likely alternator. Click to expand...

I already have. Alternator is new and I JUST replaced the regulator. The alternator is actually charging, I've confirmed that. Heres the related thread explaining my problem for anyone interested. http://www.benzworld.org/forums/showthread.php?t=2995841&goto=newpost#/topics/2995221?page=1 P

phporterx

· Registered 2003 E320 Joined Feb 12, 2018 · 268 Posts Since it's doubtful that the voltage regulator (VR) has any analog-to-digital conversion (ADC) internal circuitry, the field voltage signal is probably an analog signal of the voltage placed on the rotor for current/voltage control of the stator side. Based on your schematic diagram, this analog, field voltage signal (aka Terminal 61 or the DFM signal) is supplied to a high impedance input circuit located in driver-side, signal acquisition module (SAM) N10/1 located under the hood. You would think that you could use a DVM to measure the potential between ground and Terminal 2(?) of the N10/1 module to determine if the correct field voltage is being furnished to the ADC circuitry inside N10/1. It is this circuitry that probably digitizes the field voltage signal and places it on the CAN buss with suitable identification for use by other components (e.g., BCM). If you have a good DFM voltage signal at N10/1 then you have probably narrowed your search down to where the problem lies. It would be helpful to have hardware and software that could monitor the CAN buss so you could look at the data train and see if it matches what the input voltage is. However, I'm not sure that the MB SDS has that capability per se except for its ability to specifically tell you that the Terminal 61 voltage signal on the CAN buss has a problem which probably indicates that you have an N10/1 ADC circuit or termination problem if the DFM voltage signal present is good.

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts Remember, those JIMCO test bench pages I uploaded are for old school externally regulated alternators, on a different application. They are NOT for new computer controlled alternators. I have no reason to believe that the regulator is NOT capable of sending a digital signal to the SAM, especially since it needs to be able to send a digital signal to and from the BSS terminal. There is a printed circuit board in there. Since according to that diagram, the regulator connections are going to the driver's side SAM and NOT the ECU, that changes things a bit. How would I test those connections at the DR SAM? That module has no stored fault codes according to DAS. Are all those inputs fused? IE; could I use a test light to see if I'm getting any type of voltage from that circuit?

Rossafuss

· Registered 2005 E320 CDI *Over 500k Miles*, 2013 GLK250 Joined Oct 1, 2013 · 1,053 Posts I'm having a hard time deciphering the wiring diagram in WIS for the front driver's side SAM. Can someone with access to WIS that actually knows how to use it try and explain to me where the wires coming out of G2 are going?! ? It's a 2005 E320 CDI, 211026 P

phporterx

· Registered 2003 E320 Joined Feb 12, 2018 · 268 Posts You are running two threads on the forum and have already answered your question in the previous one. Fortunately, your show-and-tell presentation is quite informative for the rest of us forum members. I wonder why MB calls them signal acquisition modules (SAM)? Could it be because this is where analog signals are converted to their digital representations and then conditioned for placement on the CAN buss? Your theory that the alternator VR circuitry converts the DFM voltage to a digital CAN buss signal may not hold water if you examine what is required to generate a CAN buss data signal :0) and the number of wires required to make a CAN buss. Your other post said that you measured 13.3 VDC at N10/1 Connector B1 Terminal 2. That's an interesting CAN buss signal.

Ahish

· Registered Joined Jul 8, 2021 · 7 Posts

Rossafuss said: That's reffering to the massive (150A+) 'fuse' that is inline between the starter and alternator. It sits on top of the bell housing. If that breaks, it physically breaks the connection between the battery and alternator and prevents charging. That's a helpful tips for anyone else that may have that problem, but That's not where my problem lies. I'm having a communication issue between the alternator and BCM. Most likely, a communication issue between the ECU and BCM. Click to expand...

I think this is the problem I have... My car is not charging, do I have to remove the starter to get to this fuse?

Ahish

· Registered Joined Jul 8, 2021 · 7 Posts

noetico said: Maybe check this post, don't know if its related directly to your issue, but the OP, got the same code. Searxh for: W211 Battery/Alternator problem Here'sa line from jookoo, the op: "I figured it out! The wire that goes from alternators B+ terminal to starter has a fuse in it that is exposed to the elements, mine was corroded and broke in to few pieces. So I fix that fuse and it started to work again. I didnt find that fuse in any diagrams, so if someone is having similiar problems its worth checking out." Maybe worth lookin at. Sent from my ZTE G720T using Tapatalk Click to expand...

I can't find this fuse, do I have to remove the starter to get it? 1 - 13 of 13 Posts Insert Quotes Post Reply

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About this Discussion 12 Replies 5 Participants Last post: Ahish Jul 10, 2021 posts 7.9M members 751K Since 1999 BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more! Show Less Full Forum Listing Explore Our Forums W126 S,SE,SEC,SEL,SD,SDL Class R/C107 SL/SLC Class W163 M-Class W124 E,CE,D,TD Class W210 E-Class

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