MB SLK R170 not cranks, how to figure it out

How to check why it doesn't crank. I forgot to mention these on video: thick wire on pulse module connector A pin 1 is 12V from battery and B2 is 12V from ignition switch when power is on.

[@Jgarage5]

Literally the best guy on youtube about the r170. You and Clint Hightower.

[@TestAccount-s4b]

I’m a car newbie, trying to follow your video. When I plug the probe connecter from the reader in to the purple wire (2:30) and crank I get 0v. I get that when testing the other wires too. I have the negative probe on the negative battery terminal.

[@zJanneKz]

0 V everywhere? Your multimeter is on DC voltage position?

[@TestAccount-s4b]

@@zJanneKz yes 0v everywhere and it’s set to DC yes.

[@tallerdefab]

Thanks a lot ! You safe me a lot of work. now my Slk work's again !!!

[@rubenguzman1825]

Hey man thanks for your video I was able to turn my SLK 230 engine on for the first time

[@LaurentMONFORT]

thin I have 10 volts without having shifted a gear!!! on the Red wire and black line....help!!

[@zJanneKz]

On red and black where?

[@LaurentMONFORT]

Yessssss

[@LaurentMONFORT]

@@zJanneKz yesss

[@yoderleus]

the PCM does not ground the red/blk wire on pin2 connector A... those that mean i have a bad driver from the PCM?

[@zJanneKz]

If you have automatic transmission, check if transmission control module tells to ECM that gear selector is on P or N, see 7:30->

[@marketingexpertjourney2024]

@@zJanneKz Hey buddy. I have the same issue here - no GND on pin2 connector A, but I have a manual transmission with no clutch switch (do not need clutch down to start). Any ideas?

[@zJanneKz]

@@marketingexpertjourney2024 Unfortunately I can't help as my wiring diagram covers automatic only. What happens if you try grounding that wire?

[@LaurentMONFORT]

hello, after (I think) a change of gearbox plate by me on 722.6 of my slk R170... Impossible to read ECM etc..er I'm lost... can you help me please????

[@zJanneKz]

Check first if you have power ECU. Middle relay in K40 relay box delivers power to fuses F2 and F3 and one of them (I can't remember which one) goes to ECU. Turn ignition on and check if 12 V on F2&3. If not, most likely K40 needs repairing/replacing. Notice also that cooler fan starts blowing on full speed when ECU has no power.

[@LaurentMONFORT]

@@zJanneKz Hello...my two Relay run..but non accès at ECM...Thank you si much

[@LaurentMONFORT]

Hello Janne Karppanen, one other idea ???

[@mr.masters4015]

I have no volts from starter point on relay does this mean bad relay?

[@zJanneKz]

Do you have 12 V on pin that I check at 3:40-5:15 and it goes near 0 V when you try to crank? And pin A1 that comes from battery has 12 V? If both yes, then relay points are bad.

[@LaurentMONFORT]

HELLO, do you have the cable shema for my slk R170....Please and thank you for your video!!!

[@zJanneKz]

I have for 99 USA version but it mostly matches to my EU version.

[@lincolnvlogs8965]

GREAT VIDEOS. I HAVE A SIMILAR PROBLEM BUT MORE SO THAN YOURS. MY CAR IS EVEN THE SAME COLOR AS YOURS, HOWEVER, I HAVE 1. NO LIGHTS ON THE DASH AT ANY TIME....ONLY THE BUZZER. 2. NO START 3. NO CRANK. I CHECK THE RELAYS/WIRES YOU SUGGESTED....GROUNDS ARE GOOD TOO. NOW I HAVE DISCOVERED THE "CRASH SEPARATOR RELAY" AND IT DOES APPEAR THE CAR WAS INVOLVED IN A SMALL ACCIDENT ON THE PASSENGER SIDE OF THE CAR WHERE THIS CRAZY CRASH RELAY IS LOCATED ALONG WITH THE BATTERY. I DID ORDER A REPLACEMENT BECAUSE THEY CANNOT BE REUSED....BUT IT DOES LOOK LIKE SOMEONE RE-ROUTED SOME WIRES. I AM HOPING THIS WILL BRING LIFE BACK TO THIS DEAD CAR (168K MILES) OR WILL BE BACK TO MORE DIAGNOSTICS. WILL LET YOU KNOW. THANKS

[@zJanneKz]

I guess you are talking about alternator cut-out relay. I can't understand why such thing is used on some models, just doesn't make any sense. Have you checked if K40 relay box fuses F2 and F3 have 12 V when ignition is turned on? If not, ECU has no power. Cooling fan should start blowing when ignition is on if ECU is not operational.

[@lincolnvlogs8965]

@@zJanneKz Thanks for the reply. Yes, the cut or "crash separation relay" for I believe only '97 and '98 models was designed to prevent continuous power after a rollover crash. Now a different system is in place. Another effect was that my battery would not charge more than 11 volts. I will install the replacement relay to see the effect if any. Prior to this discovery, i did remove my ECU with the idea of having it refurbished in light of the fact that all of my systems are down, to the point I cannot even run a scan. However, interestingly as you mentioned, yes my coolong fan comes on when I attempt to turn on my engine with key. Thanks for your input. Will update.

[@lincolnvlogs8965]

@@zJanneKz I will chk the k40/f2/f3 as well. Thanks again

[@zJanneKz]

@@lincolnvlogs8965 You can bypass that relay by moving both cables under same nut. If charging then works, this relay is faulty. Weird thing in relay is that it only disconnects alternator and all other electric systems still have power.

[@zJanneKz]

@@lincolnvlogs8965 K40 is common problem in R170. Usually it has cracked solder joints but also relay can fail like in mine see kzbin.info/www/bejne/lXuqdHmnaZeHjc0 Video has English texting.

[@PaWu92]

Thanks Janne for this video, this is exactly what we discussed few days ago, unfortunately I had no chance to check this yet. Are you going to make some more videos about this issue?

[@zJanneKz]

I'm afraid not, out of ideas what else to check.

[@PaWu92]

@@zJanneKz Janne thanks for reply. BTW, I bought spare ECU with Immobiliser and key same serial number etc. Do i have to program it after replaced or it will work and self adopted?

[@zJanneKz]

@@PaWu92 It should work by simply plugging in.

[@PaWu92]

Janne, I have 0v on pin F when crank, the rest is showing V as on the video, what this means? Btw, this 12v you powered to crank was from car battery or separate supply?

[@zJanneKz]

@PaWu92 Check that 12 V comes to pin A1, it comes from battery and should always have 12 V. If not, check main fuses beside battery. B2 brings 12 V from ignition switch when power is on. I took power from car battery to F1 when tested starter.

[@PaWu92]

@@zJanneKz A1 it has 12v always, but 0v on Pin F, and also when i sent 12v from battery no cranking... I am completely confused now.

[@zJanneKz]

@@PaWu92 How about pin B2, do you get 12V there when ignition is on? From B2 power goes to relay coil and other end of coil comes out from A2 so you should also have 12V on A2 when not cranking. If both have 12V and ECU grounds A2 when cranking but nothing on F, your starter relay (alias pulse module) is broken. Wire from F goes to starter solenoid so if nothing happens when giving 12V to that wire, your starter has failed, wire is broken or engine ground to battery negative is missing.

[@PaWu92]

@@zJanneKz Very helpful informations, I will double check this once again but i am sure nothing is going out of F pin, it was pure 0v, everything else was ok. I will also double check this crank as i have sent 12v from car battery bit nothing has happened... Thank you for your support, I will update soon so maybe this will be helpful for other people too.

[@PaWu92]

@@zJanneKz Hi Janne, I just checked everything once again same as u did on the video and pin F has 0v, the rest showing 12v as per your video, also when sent 12v from car battery car is cranking, is this means pulse module is faulty? Or there is something else what can cause 0v on F pin? Thanks in advance

[@samipaldani253]

oma 230 vm 98 alko nyt temppuilemaan kun oli seisomassa ulkona muutaman kovemman pakkaspäivän ja sitten kun lauhtu nollan tienoille niin lähdin ajamaan ja toimi ensin ok mutta sitten lämmettyä alko nykimään ja meinas hyytyä....lopulta oli sitten pakko jättää auto kaupan pihaan. sain sitten kylmänä sen ajettua takas kotipihaan mutta lämmetessä taas alko hyytymään. parina seuraavana päivänä ei sitten pysyny käynnissä ollenkaan vaan sammu heti starttauksen jälkeen (kylmänä)...tänään kuiteskin sitten lähti taas pyörimään ja nyt näyttäs toimivan...en taida vielä kuiteskaan uskaltaa lähtee ajamaan. vikavaloja ei ole syttynyt ja ei ole testeriä että onko jotain koodia jättäny. k40 releboksi tähän on vaihdettu viime vuonna

[@zJanneKz]

Kannattaisi hommata vaikka ebaysta 38pin to obd adapteri ja siihen perään bluetooth obd-lukija. Sitten on helppo puhelimesta seurata, näyttääkö moottorin ja imuilman lämmöt, MAF ja lambda-arvot yms oikeilta, vai piiputtaako joku anturi. Jos on Android-puhelin, niin Car Scanner ELM OBD2 on tosi hyvä softa tuohon hommaan.

[@samipaldani253]

@@zJanneKz pitänee varmaan hommata mutta nyt ei ole temppuillut enää niin olisko sitten keleistä ollu kiinni...löin tankkiin varuilta kuiteskin jäänestoa ja kävin tankkaamassa...varmuuden vuoksi on uusi ilmamassamittari tulossa kun aikasemmin oli myös semmosia oireita että isolla vaihteella kaasu pohjaan matalilla kierroksilla meinas hyytyä....bensansuodatin pitäs varmaan vaihtaa mutta odottelen parempia kelejä tolle kun ulkona sen joutusin kuiteskin vaihtamaan

[@zJanneKz]

@@samipaldani253 Jäänestosta ei ole hyötyä, sitä kun on jo valmiiksi 95:sessa 10 % ja 98:ssa 5 %.

[@samipaldani253]

kävin nyt ajamassa viimeinkin ja ei nykiny normaalissa ajossa mutta kun kakkosella tarjos vähän kaasua niin noin 4000 kierroksessa hyyty eli yli ton ei päässy....paikallaan seistessä yli 4k antaa polkea kierroksia....olisko sitten bensansuodatin/pumppu syynä....uuden maffin laitoin tänään paikalleen muttei sillä ollu vaikutusta.

[@zJanneKz]

@@samipaldani253 Ei sen pitäisi paikallaan ollessa kiertää yli 4500 rpm, siinä on jonkinlainen rajoitin. Siihen kun saisi vikakoodinlukijan kiinni ajon ajaksi, mistä näkisi maf- ja lambda-arvot. Jos maf-arvo nousee tasaisesti kaasua lisätessä ja lambda pyytää paljon seoksen rikastusta, niin on bensasta pulaa. Itse käytän Android-puhelimessa Car Scanner ELM OBD2 -softaa, mistä näkee näppärästi kaikki arvot. Bensanpainetta ei suoraan näe, siellä ei taida olla sille anturia.

[@germanhb4222]

Thank you

[@matilotelephones3557]

Thank you, Janne

[@darrentucker1]

Fantastic! Thank you

[@john2693]

😮😮😮😮😮😮😢😢😮😮

[@flycatchful]

The ECU is the problem so replace it and get done with it. I watched numerous videos on this problem and it all goes back to a defective ECU.

[@zJanneKz]

My car starts fine.

[@tallerdefab]

In my case I only need to clean the connectors on my Ecu. No replacement. no wasting money !

[@john2693]

😮😮😮😮😮😮😢😢😮😮