Big Mistake? Can it be Fixed?

[Music] foreign [Music] hi everybody and welcome back to a new episode of diagnose Dan today we'll be working on a 2019 Mercedes-Benz A-Class and this car is a crank no start now that's not the only problem with this car but we'll get to that later now this is a real bizarre story now according to the previous owner but I do think we need to take the story with a pinch of salt this car suddenly became a crank no start about a year ago since then it has been to several shops but in the last year nobody has been able to fix this car a few days ago the customer called our company and you know what one of our sale guys picks up the phone and gets into a conversation the customer tells the sales guy that is really fed up with this car and he'd rather sell it now before I knew it our company bought this car without ever seeing it now yesterday this car was towed into our shop and it's a lemon it's low on coolant every warning light that's available is on it doesn't move it doesn't crank it doesn't start so no pressure but let's see if we can diagnose this car together [Music] now in all fairness we didn't pay a lot of money for this car what we paid for the car the car is probably worth in parts now the car is probably worth 10 000 more if it was perfect now it's far from perfect but if we can get it to crank and run and move again which it hasn't done in the last 12 months it's probably worth five thousand more than what we've paid for it now if we make it perfect we can potentially make ten thousand more but in this video let's focus on at least getting it to crank start and move again as you can see the car was towed into my diagnostic Bay and the customer told us that about a year ago out of the blue this car became a crank no start now I don't fully buy that story because why for instance is there no coolant in the reservoir now in all fairness we don't know what the other workshops have been doing but what he has been speaking the truth about is that this car hasn't been going anywhere in many many months it has been sitting and collecting dust now let's start out by confirming the complaint and let's try to crank this car over now let's start out by reconnecting the battery terminal and let's see if we can crank this car over which would be a miracle because it hasn't been cranking over or starting for the past 12 months but hey you know what maybe get lucky for Once In Our Lifetime this is the key by the way and right away we're getting a parking brake mail function so I'm pushing the brake let's start to crank the car let's try to start it but as you can see the car is not responding so that's customer complaint confirmed now I quickly hooked up a battery maintainer because the battery voltage was getting low in the meanwhile I took a full scan of the vehicle and there are many many fault codes stored and I was kind of expecting this [Music] now we got to start somewhere and I saw fault code in the electronic ignition lock and it says the buffer battery of the electronic ignition lock has a mil function now I'm not sure if this would cause a crank no start but it's probably pretty easy to fix so in the next step we're gonna take a look at that auxiliary battery now another fault code I saw in the Sam module is also quite interesting first of all coolant level sensor has a mill function we already know that the coolant level is low but the other fault code really one circuit 15 has a milk function the actuator doesn't close that's rather interesting because circuit 15 is ignition on now the relay for ignition on is not closing or the computer thinks it's not closing but that could definitely cause a crank no start so in the next step let's first take a look at that auxiliary battery and after that let's take a closer look at that terminal 15 relay now let's go into the ignition lock and let's select power supply now when we select power supply we can see that the main power supply the main battery is 14 volts because we're hooked up to a battery maintainer but the voltage for the additional battery is 0.3 volts and that's no good now let's take a closer look at the vehicle itself and it actually comes up with a warning message for the backup battery in the instrument cluster now it is in Dutch but you can see that it says hold on this is for the parking brake and now it says backup battery mail function what will you do hold on don't start talking to me now the backup battery is underneath the center console so let's take a closer look at that back up battery now getting access to the auxiliary battery is pretty easy just pop off the cover of this armrest underneath there are three screws unscrew them and there are two more screws at the back and then you can lift up the center console and gently put it to a side to get access to that auxiliary battery I gently put the center console to the side and underneath there we got pretty good access to that additional battery or auxiliary battery or backup battery or parking Paul battery whatever you want to call it it's in its own little tray um there are two clips holding it down and positive and a negative so let's get it out and let's see if that battery is any good now this is the original battery we just got out of the vehicle it's a 12 volt 1.2 amp battery and this is a non-good battery we've got laying around the shop non-original but also 12 volt 1.2 amps now let's test the original battery and you can see it has only got 0.25.26 of a volt and let's test the known good and it has got a healthy 12.8 volts so let's install the new battery now this tiny battery goes by a lot of names it's called additional battery backup battery auxiliary battery but according to official Mercedes-Benz service data this battery is called a parking Paul battery or at least on this model now what this little battery is responsible for is when the main battery loses power this tiny battery is still capable of engaging the parking Paul of the automatic transmission and that got me thinking when the car is not in park of course it won't start so could this tiny battery be responsible for our crank no start I guess we're gonna find out in a minute but before we do that let's find out and do a little test if this tiny battery is responsible for engaging that parking Pole as you can see the tiny battery is not installed and as you can see the car is in park right now right there now let's see what happens when we disconnect the main battery there we go and you can see we can still roll away the vehicle which makes sense because there is no power source to put the car in park now let's install the parking fault battery and let's see if we disconnect the main battery if it then goes into park right now the parking pole battery is installed the car is still in neutral as you can see now let's see what happens when we disconnect the main battery let's disconnect it there we go Let's Pretend We're trying to start the vehicle and you hear it click and now we can no longer roll away the vehicle and the vehicle is in park now let's reconnect the main battery and it's shoot indicate that the car is in park and as you can see it does I installed the new auxiliary battery and by the way we no longer have got a message for the auxiliary battery in the instrument cluster this is the old one I put everything back together so the moment the truth does this car now crank has this tiny battery resulted in a crank no start that nobody has been able to solve over the last 12 months for us it would be fantastic Moment of Truth but unfortunately hold on we still have got a crank no start this video was made possible by ddtsb the world's biggest automotive aftermarket bulletin supplier if you got a workshop in Europe ddtsv is a must-have simply enter the license plate number or the VIN number and the system will automatically select the vehicle for you then enter a fault code or a symptom and the system will search through thousands of non-fixes for the most likely solution if it doesn't come up with a solution you've just wasted 30 seconds if it does come up with a solution you've saved yourself hours of searching for the problem for only 365 Euros a year or one Euro a day it's an absolute no-brainer for a professional Workshop if you want more information please visit diagnosedan.com unfortunately that tiny auxiliary battery didn't solve our issue it did solve a issue but not the crank no start we're trying to solve today so let's focus on the next fault in the list which is the Fault Code b212172 relay one circuit 15 as a male function the actuator does not close now I took a look at Mercedes-Benz service data and that relay one for terminal 15 is actually located in the fuse box under the hood so let's take a closer look at that relay foreign I took a look at a wiring diagram and this is actually relay one for terminal 15 and this relay is basically responsible for powering up a lot of stuff under the hood when the ignition is turned on now I also saw that right next to it is the starter motor relay and I was thinking has anybody checked the starter motor what if we just got a bad starter motor now before we get too deep into that I want to quickly check if the starter motor functions at all and we can very easily do that by removing this relay and providing power to the starter motor ourselves now as you can hear there's nothing wrong with the starter motor itself so let's continue with our initial plan and take a closer look at that terminal 15 relay now since we've got a fault code for the Relay net closing we could simply have a bad relay so let's start with testing the relay first now I'm gonna test the relay using my relay tester now some of you might say you can just swap around the relay or test it in other ways and I agree but I prefer this method because this tool is going to test the relay 10 times it's going to open and close it 10 times look for the values and when it's a good relay a green LED lights up now I'd rather test than guess and since it's so easy we're going to use this tool so let's push the button it's gonna go through a test cycle and if the relay is good a green LED will light up and the green LED does light up so there's nothing wrong with this relay now this is a four pin relay and a four pin relay needs two power sources one for the control side and one for the load side so on two of these four pins we need to have a power source so not on this one not on this one there's a power source here and a power source there so we do have got two power sources at the relay so nothing wrong with the power source now in the next step we need to find out when we turn on the ignition the relay is actually being commanded to close now I took a little look at the little schematic on the side of the relay and I found out that this pin should provide a grant to the relay when the ignition is being turned on this is a ground side switched relay so I hooked up my test light and when this pin is provided with a power you can see or sorry with a ground you can see that my test light lights up now let's put it in the control wire for the relay and let's turn on the ignition and see if our test light lights up now I'm going into the car while you guys take a look at the test light now go into the car right now and I'm turning on the ignition right now attempting to start the car and I'm looking through the window but it looks like our test light is not lighting up so it definitely looks like we got a control issue now this is a four pin relay and this pin and that pin are power sources and the other pin is the control wire now the final pin is the pin the power needs to be switched to when we close the relay now to see if we're on the right track I want to see if we provide this pin with a power ourselves if the car will then crank or start up just to see if we are on the right path if it doesn't we've got more problems now I'm going to use the Power Probe to power up this wire and I like to use the Power Probe by the way you can see the wires powered up I like to use the Power Probe since it's safe to use and it has got a fuse inside now let's power up the pin that the relay is supposed to power up when the relay closes now let's go inside the car and let's see if it does more than it did before now I've got the key right here now let's hit the start button and it actually starts oh fires up for the first time in 12 months after 12 months this car started and it ran again and it actually sounded pretty decent but we're not out of the woods yet why is that really not being energized now to find out I've printed out some service data and a wiring diagram so let's take a closer look so I printed out a wiring diagram for a relay but unfortunately the relay we are looking for is exactly on the edge of the paper so I'm gonna split it and we're going to focus on this piece of paper now this is the control side of our relay and it's getting its power from a common power source now the control side is being controlled through this wire from a module that's called n10 now it's being controlled through a red and pink wire over here so in the next step we need to find out what module and 10 is where it's located and we need to find that red with pink wire now the red with pink wire was actually quite easy to locate as it is right there you can see it's a red wire with a pink stripe that goes directly to the pin of that relay now if we wiggle that wire we can actually see the pin wiggling right there so that was easy enough now we need to find out where the buyer is going to what module is responsible for uh controlling it and where is the module located I found out that module n10 is actually the front Sam control module a body control module that supposedly lives somewhere underneath the carpet right there I'm gonna dig it up and once I got access to it we're going to take our testing from there I had to remove this trim I had to fold back the carpet and I had to unscrew this panel and when you do you can fold it back and then you get pretty good access to the back of the fuse box and and 10 module or the front Sam module right here now when I took a closer look I could actually see a red wire with a pink stripe right there in a big white connector now I'm going to take a look at a wiring diagram to make sure that's our wire and when we made sure that there's a wire we're going to take our testing from there now I took a little bit of wiring diagram and I confirmed that the wire I pointed out is actually the wire we are looking for it's on that big white connector on pin 31. now I took that connector apart and actually deep pinned the red with pink wire from that connector what we can do right now is we can manually energize the relay now if we ground this wire and the relay doesn't close we probably have a broken wire if we ground this wire and the relay that's close then somehow this module is not controlling that relay I connected a crocodile clip to that control wire as you can see and I hooked that up to my Power Probe what we can do now is manually energize that relay while we're attempting to start the car now let me take a closer look at this Power Probe we can see is receiving a power when we disconnect this wire the red LED goes out and that means the only place the power can come from is through this wire all the way through the relay from the power side of the relay so basically this means our entire wire Integrity is is good there's nothing wrong with the wiring now if we do provide it with the ground and we're very quiet we can actually hear the relay click I don't know if you guys are picking this up now this basically means that our wiring is good and I have no doubt when we provide this relay with a ground the car will start up right now we're providing the relay with the ground so the relay closes let's try to start the car and sure enough the car fires right up [Applause] now off camera I did a lot of measuring I measured Powers grounds I took the connectors apart checked the wires checked pin drag but I can actually not find the reason why this module wouldn't control that relay now not a fun fact when we started this diagnosis there was actually a fault code stored for the Relay not closing that fault code was stored inside this control module so this control module is complaining about the relay not closing but it is responsible for closing the relay itself and that makes me believe there's actually something wrong with this module so I'm gonna call the shot we're going to order a new sign module now once you disconnected all the connectors you can actually very easily click out the Sam module and it can very easily be removed now quick update on the Mercedes after I called it a bad module yesterday I went online and ordered a new module from Mercedes-Benz within the hour they replied to me and sent me a message and they told me that the part number I ordered is no longer available that number is now superseded not only is the number superseded but the price also changed the price went from 266 Euro 16 which I think is a fair price two 172 Euros 63 I got a 14 discount so I paid 148 Euro 46 before taxes now normally it's the other way around now not only did it become a lot cheaper but it also came in this morning so I'm super excited very good service from Mercedes-Benz let's plug it into the car and see what happens now I plugged in the new module that's the old unit now I still need to program it although I think we can do that later I think it should work without programming although we might get some fault codes now moment of truth let's hit the start button all your hand it fires right up now let's release the parking brake and let's put it in reverse and for the first time in a year this car is moving again now we still got some warning lights and some fault codes but I still need to program the module and we will see after programming what remains now if there's something interesting I will also film it and take you on that Journey now we had a 10 000 Euro budget and so far we spend about 200 on the module and the batteries are not a bad outcome now I opened the old module to see if I could see something but I see absolutely nothing no water damage no loose contacts no loose solder joints so I don't know what went wrong with this one now I really hope you enjoyed this video if you did please subscribe to my channel and when you hit the little bell you will get a notification each time I upload a new video and remember diagnose then fix it again see you next time guys [Music] foreign

Channel: DiagnoseDan

Views: 57,771

Keywords: Mercedes, Fix, Broken, a class, sam module, topdon, South main auto, pine hollow auto diagnostics, rainmanray, die autodoktoren, scantool, garage, workshop, diagnostics, snapon, fordtech, topdon phoenix max, ddtsb, w177, scotty kilmer, faultcodes, diagnosedan, ed china, wheeler dealers, watch, scannerdanner, engine, mistake, money, repair, educate, tools, relay, scanner, programming, solve, toolbox, mechanic, best, investment, car, vehicle, problem, electrician, gearbox, wheels, exhaust, petrol, restore, restauration, fixed

Id: PU8gvd9y0mU

Length: 23min 18sec (1398 seconds)

Published: Tue Jun 27 2023