mihir_d

Hello All,

My beloved 2000 ML320 … at 231,000 miles....stalled a few times on the road over the last 3 weeks. A STAR diagnosis at the dealer confirms low voltage on Circuit 87. Dealer does not want to fix this car anymore, since they say, it is now too old, and electronics parts are starting to become unavailable through Mercedes for the W163 models.

I had it looked at by a specialist mechanic who specializes in German car electronics, and he says, the problem is with the fuse panel. I gave him the go ahead to replace the fuse panel, but we both soon discovered what the dealer had told us. The fuse panel is no longer available through Mercedes parts anymore.

He is hesitant to go down the salvage/used part route understandably.

Anyone out there, who knows other places to source hard to available parts?

I am fearing, this might be the end of road on my 19 years of this beautiful W163 ownership.
Mihir.

Plutoe

I don't believe your mechanics no parts story----whats the SAM's part number

Maj. Dundee

mihir, what was the code number that the mech. discovered?

After the eng. cuts off, how long does it take to restart the eng.?

mihir_d

Maj. Dundee,

The truck throws a handful of 'P' codes and a handful of 'C' codes..
My mechanic tells me, the 'P' codes are engine malfunction codes, the 'C' codes are chassis malfunction codes.

My specialist mechanic and dealer diagnosis both concur that P1747 & C1010 are the primary fault culprit codes among these..

There is fluctuating or low voltage in the car's electronics. The truck started stalling randomly..sometimes few hundred feet after ignition, sometimes, 7-10 miles after startup, sometimes just after starting and goes into full limp mode locking up transmission as well. Over the last 3 weeks, the problem got more aggressive..and last before I got it towed, it was then consistent...if I clear all the codes and start the engine, it immediately goes into limp mode with a prominent rough idle...no gas pedal effect, transmission locked out...CEL turns on right away.

These codes now appear more or less consistently.

C1010 - Terminal 87 under voltage
C1025 - CAN-Bus
C1202 - BAS Release Switch A1/7s1 plausibility
C1332 - BAS Solenoid Valve A7/7Y1

P1747 - Control Equipment EGS CAN Signal Error
P0446 - EVAP System Vent Control Circuit

Dealer wants to start off by replacing what they call "Main Wiring Harness" - I am presuming, they mean the main CAN Bus wiring and then troubleshoot further - they are saying, that the "Main Wiring Harness" is unavailable from Mercedes Parts as well. The passing winter season might have caused moisture damage somewhere on the main wiring harness.

My specialist mechanic did some detailed diagnosis and concurs, the CAN Bus wiring is fine....he is 100% sure, the fuse box panel is the primary culprit & he wants to repair 2 other wiring junctions in the car (don't know where they are, but he says, they need repair).

Having owned this truck for all these years, I believe in his version...the fuse box panel has been giving some minor irritating but livable issues since the last 5-6 years..(handful of randomly blowing fuses/relays especially in peak summer months - I got the cooling fan underneath replaced, but no help) , some incorrect after market wiring done by insurance mechanic to restore front fog lights a few years ago, after someone backed into my truck in 2015 and damaged the fog lights), the horn relay also keeps blowing, starter relay has blown a few times, fuel pump relay/fuse has blown a few times, turn signal relays have blown 1-2 times, ABS fuse blown 1-2 times etc. etc.

The last I heard from my mechanic this evening, he seems to have located a lightly used fuse panel in his parts network..and he wants to give it a try.

Plutoe, I have asked him to pull the SAM part no. - since truck is in his shop..after it had to be towed last week. Will share it as soon as I get a hold of it.
I called a few dealers in the area and am getting conflicting answers..some are saying, based on my VIN no, the fuse panel is most likely still available (as a special order item), some are saying they can confirm - no longer available..

I should add, the battery is 2.5 years old and repeated tests on the battery and alternator concur that they are quite healthy....alternator voltage & current output is steady and in spec......and so is battery voltage and current. Both my mechanic and dealer have ruled out battery & alternator as a possible cause.

Mihir.

Maj. Dundee

Tell this mech. to stop removing the fuse module. In all probability you are in limp home mode because your ESP control module is faulty, code C1010..

All of the codes descriptions you posted are generic ones and have incorrect descriptions. Open ESP PDF (scroll all pages and look for GREEN highlights) and you will see the correct descriptions, except for C1332 & P1747 which I cannot find.

Also what fuses were blowing the you speak of.

Please post your full vin #.

mihir_d

Thanks Maj. Dundee for the pointers....

Full VIN# is 4JGAB54E4YA196818

I will discuss with mechanic and keep you posted.

The fuse relay problem has been random. No specific pattern, so I am okay with his trying a new fuse panel to begin with. It might be the fuse panel and then possibly the ESP module as well..

Maj. Dundee

You didn't answer the question.............. Also what fuses were blowing the you speak of.

mihir_d

Oh...no fuses blown in the recent past.

Random fuses (mostly turn signal, window roll up/roll down, door lock related) used to blow a few years ago when I used to live in much hotter climate (Sacramento). After, I moved into more moderate temperatures, the problem of random fuses and even relays blowing has more or less gone away.

I was trying to make the point that the fusebox has had some history of erratic performance to it over the years, so replacing the fuse panel will not hurt.

I was on the phone with the mechanic today..and mentioned to him about the code descriptions that you referred me to. Yes, he concurs C1010 might be the root cause (Bad ESP module) of all the problems, but he emphasized that there are a lot of codes related to CAN Bus communications/low voltage being thrown as well.

Do you/anyone know, if the ESP module can simply be unplugged from the vehicle? Would that at least pull the truck out of limp mode? If we could do that test, we would know for sure, that the ESP module needs attention.

mihir_d

Maj. Dundee,

I happened to google this thread...with a focus on the C1010 code

https://www.benzworld.org/forums/w16...placement.html

Low voltage or voltage fluctuations to the ESP module will cause C1010.

As per this thread C1000 is the dreaded code that confirms, the ESP module is bad...

It seems, my mechanic must have tested and confirmed unstable voltage levels at a few points in the car to arrive at his fuse panel conclusion.

Maj. Dundee

OK, so let the mech. replace whatever he thinks is necessary and post back with results.

mihir_d

Maj Dundee,

Glad to report that my ML is back from the shop! Purring like a happy cat! The mech. was spot on. It was the fuse panel. After some sourcing in the parts network, he was able to locate a donor fuse panel from a W163 that had only 60,000 miles on it and was totaled. We tried our best to source a new fuse panel, but after this find, decided to go ahead with this after getting conflicting replies from various dealers on the new fuse panel availability. I am sure, if we had pursued it a bit further, we would have gotten to the bottom of it. Regardless, we were told, a new panel would run us $580 in part alone, much higher than what we found in the parts network.

I will share more technical information that I extracted from the mech. while taking delivery of the truck.

Besides, the codes I described previously, through initial testing and troubleshooting, the following additional codes had shown up..

C1314
C1202
C1332 - Err with AAM

P0560
P1580
P1605

I believe, the B codes are all CAN Bus related codes? (or maybe Engine codes, sorry, if I got the mappings wrong...I am just trying to copy over from mech. handwritten notes)
B1858 - Mech. did not document
B1040 - Mech. did not document
B1784 - CAN Bus err with passenger door lock
B1086 - CAN communication err with AAM
B1099 - CAN communication err with DAM
B1040 - Mech. did not document
B1041 - CAN Bus err with ESP
B1089 - CAN Bus err with ***

It seems, the alarming no. of CAN Bus errors made the mech. hone on to the fuse panel. Fuse panel seemed to be having comm. issues with a lot of systems in the truck. That is why, he probably insisted on swapping out the fuse panel first.
In his service report notes (see attached) he has mentioned performing repair on the wiring harness for main power supply. This is probably what the dealer meant when they said, they wanted to replace the "main wiring harness" to begin with..which also, they told me, was no longer available through Mercedes parts. That is why, dealer gave up on pursuing this any further.

For w163 owners in the San Francisco area, I certainly want to give a shout out to this gem of a mech. I was referred to him by my primary care mech. after he realized, the electrical problem was beyond him & the dealer did not want to deal with this except giving us a more in depth Circuit 87 low voltage diagnosis using STAR diagnostics, and that Bob at Tri-city Auto Electric specialized in this kind of work.

Bob spent a lot of time on troubleshooting all the electrical on the car and his total diagnostic and repair labor totaled a good $800 (and it cost us $300 in parts to source the donor fuse panel and wiring harness repair kit pieces), but I feel, his effort was worth every penny. Not only was he extremely detailed in his troubleshooting, but also confident on his diagnosis. He also backs his repair for up to 1 year/12,000 miles which I think is a very generous warranty for this kind of work.

mihir_d

I wanted to leave some more notes on this thread which might be helpful to other forum members..

Almost 10 years ago, back in 2010, the fuel gauge had started acting up...giving somewhat of an inaccurate reading.
There was a lot of discussion regarding it on various forums, and I could not get the fuel gauge restored in all these years having tried all possible things suggested

1. Reset the fuel pump/cluster fuses a few times.
2. Fuel pump/float assembly fully replaced in 2013....but fuel gauge kept acting up...
3. Have the dealer apply the latest software update for the cluster...there was a software update they could apply, but the gauge kept acting up...

Guess what, the fuel gauge has now restored to reading fuel level accurately in 1-2 days after the fuse panel was replaced.

The real culprit was the fuse panel..and it had started deteriorating possibly almost 9 years ago...

The random blowing of misc. fuses/relays in hot weather...was not related to cooling....it seems to be also a contribution of the fuse panel.
Horn would stop working 2-3 months of installing a new horn relay.....the relay would test out good, but replacing the relay would restore the horn....for another 2-3 months...
Fuse panel was possibly slightly overloading the horn and a bunch of other relays... Horn has suddenly restored with a 1 year old horn relay.

The fuse panel had started deteriorating long ago, but it was not throwing any precise failure in the car to be able to nail it. Finally, this spring, it had it...all the electronics in the car started shutting down...and voltages started to become unstable on all critical wiring.

That is when the car started suffering random stalls for a few weeks, until it finally would simply start into full limp mode. Engine wakes up to rough idle and transmission locks out.

In a nutshell, the fuse panel replacement has eliminated a whole bunch of pesky electrical issues that were plaguing the truck for some time...