CAN removal with bad consequence - PeachParts Mercedes-Benz Forum

dhillman · #1 08-25-2014, 09:18 AM

Hello friends, last post was in 2009. I guess my S430 is getting old, so I am in need of assistance to diagnose the new problems I am facing. This is a 2001, 220170 S430 Mercedes Benz. Everything started about a week ago, when I tried to start the car, it crancked but never started, after many attempts, until I needed to go to my job. This happened early in the morning with an ambient temperature of 85 degrees. Next day in the afternoon, I tried, same thing, crancked fast but did not start. I then close the car with the remote, re-open it and after several attempts, it did start. I use the car for a week, Behaving as usual, and again it did the same thing next morning, but it had never started ever since.

I tried to read the codes, with the quick test, and there were many fault codes. The engine electrical test, were: Mass air flow, right and left oxygen sensors. I suspected in the CAN, so I removed the ECU, and big mistake. The car now with the CAN in place and everything re-attached, there is no crancking at all. When the key is in the run position, the big engine fan turns on. All the information in the cluster is on and ok, the steering wheel position itself, and the shift can be move to D when the brake pedal is pressed.

I seems like the ECU is not recognized. The computer was never opened. Just removed from the plugs, and re-attached.

Any ideas, please advice, I have the DAS and the laptop with the interconnector to read the fauts.

Thank you in advance.

Darrel

Zulfiqar · #2 08-25-2014, 10:24 AM

This sounds like a main power relay block failure. I know of it on the older cars thats in the big apparatus box.

The engine fan running is a sign of that.

dhillman · #3 08-25-2014, 01:37 PM

Thank you. Can you give me more information even for the old models? Maybe I can trace the relay in my car. Well that still be the case even though everyting inside the car is working, like close asistm the radio the cluster windows trunk etc?

Thank you again.

Darrel

Zulfiqar · #4 08-26-2014, 11:08 AM

on the w210 and other models there is a relay called the K40, its actually a big brick with multiple relays and fuses on it. It controls the power distribution to various items. When that goes a bit south the ECU does not switch on.

The ECU not being switched on is signalled by the electric engine fan running at full speed as soon as the key is put to run.

on the W210 the K40 is housed in the big box that holds the ECU, TCU and ABSCU. Its the most forward of the items.

ILUVMILS · #5 08-26-2014, 12:04 PM

The running fan is telling you that the engine control module is off-line. Dis-connect it and look closely to make sure you didn't crush a pin.

dhillman · #6 08-26-2014, 02:08 PM

Thank you again. I did check de N3/10 for pin damage, but I couldn't see any. I will remove the K40 which I found it in the service manual, and inspect everywhere for blown fuse and also have seen corroded solder in other posts. I hope I can fix the starting problem. I read that if the fuel filter is clogged the ME-SFI will not deliver fuel to the injectors, to prevent accident at intersections, therefore cranck but no start. Is that true.

Thank you very much, I have work to do tonight.

Darrel

dhillman · #7 08-27-2014, 04:40 AM

I just charge the battery, it went up from 9.95V to 12.48V as per the Fluke meter and 13.1V as per DAS. Again same message, "communication error with the control unit". It seems like N3/10 is fried. I also tested the battery with my Snap-on instrument, and it tested good at 12.48V and 698 CCA AFTER Charging. Can I open the ECU to inspect it visually? Any thoughts are welcome.

Darrel

vince · #8 08-27-2014, 09:44 AM

I have disconnected the modules in the electronics box many times and never "fried" the ECU. In fact, you must remove those modules to do many jobs such as replacing the A/C evaporator, so disconnecting them should not clause an issue. I'm with the suggestions that the K40 has failed.

dhillman · #9 08-27-2014, 10:15 AM

Thank you Vince. By the look of K40, It looks expensive. Is that part also programmed to the VIN number? I saw there is a CHIP inside the K40.

Thank you again for letting me know that indeed this controllers are removable without consequences.

Darrel

Zulfiqar · #10 08-27-2014, 10:41 AM

the K-40 is not locked to the car but its important that the correct part no. is sourced.

dhillman · #11 08-27-2014, 11:47 AM

Thank you Zulficar. Can you tell me where I can get information of how and why the Fan is on when the ECU is off-line? I'll get the wiring diagram of the K40 and identify the STARTER relay to see if it gets activated. I will post an image of the K40 pc board tonight. So the question is K40 or ECU is my problem???

Thanks again for the information, Darrel

vince · #12 08-27-2014, 01:52 PM

Darrel. I did some digging in the EPC and can't come up with a part # for a K40 relay for your car. It doesn't seem to show up in Group 54.40 (the fuse and relay cabinet on the driver's side) which is where it is in the 210 chassis. FYI, one for a 210 E-Class retails for about $120. Perhaps you tell me where you located it so I can do some more digging in the EPC.

Your other question was answered by Zulfiqar.

Zulfiqar · #13 08-28-2014, 10:33 AM

a member called Dr Bert had the exact same issue on his W210 and the dealers said it was a dead ECU because their diagnostic equipment showed communication error. His car's electric fans were also blowing with Key on.

His remedy was a new K40 relay which powered up the ECU and started the car perfectly on first crank.

ILUVMILS · #14 08-28-2014, 12:05 PM

The W220 doesn't use the same K40 as in other models so don't waste any time looking for it. What you need to do is verify power and ground to the ECU. If power AND ground are good the ECU is toast. If not, diagnose accordingly. You'll need the correct wiring diagram to make life simpler.

dhillman · #15 08-28-2014, 01:31 PM

Thank you very much all of you. This is embarrassing, I apologize , but when I went last night to remove and re-inspect the ECU, I noticed that one of the plugs with the lever was not in all the way. It was lock in place but the engagement was not pushing the plug all the way down when the lever was lock. So I plug everything back, and now I am at step 1. I do have crancking, although slow but does not start. I plugged the DAS and read the ME-SFI and, L5 is not sending information.
So with this new information I decided to buy a new battery, to replace the slow one after charging, and buy the cranckshaft position sensor. I already bought both and I am ready to work on the car tonight. I hope I can solve the no starting problem.

Now I have a new question. The service manual states that if L5 is replace with a new one, it has to be confirmed or something with the DAS software. What do I have to do after replacement? Can someone guide me with the software.

Please reply. I hope my mistakes help others prevent to get into this nightmare.

Darrrel