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M13 Auxiliary Heating Water Circulation Pump issue
Hi guys,
I have the following fault stored and current "Component M13 (Heating Water Circulation Pump) has an overload or short circuit or the wire to the component has an open circuit or a short circuit." The fault code is stored Front SAM module and the code is 9041.
I'm using Autel AP200 scanner. My car is Mercedes W221.186 Facelift 2010.
What I did:
1. I replaced the auxiliary water circulation pump M13 with a new unit.
2. I've checked the ground wiring and it's OK.
3. The positive wire is not checked due to difficulties accessing the wire, however all wiring looks in very good shape. I didn't have enough time to locate MR8 connector on the front SAM module.
The pump is not running at all. The live data regarding the pump status changes from On to Off two three times and the fault appears. When I search the fault code (9041), I can't find this code to be standard DTC code and that confuses me.
Additional faults that I have are:
Air Conditioning Module Fault Code 9395 A31/1m1 (Circulation pump)
Fault Code 9001 Control module 'N93 (Central Gateway (CGW/ZGW) control module)' is faulty.
Electronic Parking Brake Event 5821 No CAN message is received from the control module 'Engine Control Module’
Any suggestions or relevant experience will help me.
Thanks guys.
Best Regards,
Nick
Last edited by nikolay_zhelev; Nov 8, 2024 at 12:47 PM.
.... not much fun or good ideas from me I'm afraid...
we have one guy with an older car where his heating has gone walkabout for a year, and he too changed an electrical circulation pump... I thought it did nothing other than operate coolant flow after the key has come out to help warn the cabin in very cold climates (if the REST button is pressed). But he reports back this pump is meant to run ALL the time and was an utter nightmare to change. It still didn't fix his issue.
Park brake fun is not unusual and not likely related to the rest of the issues... except its claiming the engine ECU is linked - the set up of these cars is quite strange and Merc in general like to confuse the AC operation with the engine cooling and indeed meddle with engine operation too... Which makes me wonder if the Engine ECU is broken (its quite common on these to die due to heat / gunk ingress due to interesting wiring looms, oil leaks and terrible location...)
To start with I'd charge batteries and do a battery reset - disconnect for at least 20 mins (sunroof and windows will need the anti-trap reset) the CGW on these does like to lose the plot and at times the battery off for a period makes it forget lots of lies, and its confusion, till the car and its canbus systems wake up normal - Don't bother with ANY diagnostics without a power external supply connected (good battery charger connected at worst). Whilst MANY like to run the engine whilst doing diagnostics - you are not meant to - and on this model certain systems will not behave / allow you to correctly interact with them with the engine running. Its is hit an miss which bits don't care and which complain, due to the multiple can bus systems and so many dim modules
Dear BOTUS, thank you for your time to review my issue and reply.
A quick update on the fault isolation:
Since I replaced the pump itself and the problem is still present, I assume that might be a wiring issue, so I started troubleshooting the wiring.
According to the attached photo, the wiring is very simple. The pump M13 has a 2 pin connector, for my model there is intermittent connection below the windshield identified as X73/2 and from that point from pin No 2 there is one direct line to ground (W3/2) and from pin No 1 there is direct line to Pin No 5 on MR8 connector on Front SAM module N10/1.
What I managed to check is:
There is continuity between Pin No 2 on X73/2 connector to Ground (Measured resistance 5 Ohms)
There is continuity between Pin No 1 on X73/2 connector and Pin No 5 on MR8 connector (Measured resistance 6 Ohms).
What I couldn't check due to very difficult access in my opinion and experience is:
Continuity between M13 connector and X73/2. The problem might be there, but I don't have good access to disconnect M13 connector from the pump and also I don't know how to unscrew the X73/2 connector.
If you have any practical experience or photos showing how to undo those connectors that would help me a lot.
If the wiring is OK, the issue might be in the SAM module. I was wondering, can anyone show me what is the schematic behind MR8 connector inside the SAM module? There should be some sort of relay and fuse, but I couldn't locate them.
I'm attaching photos from the problematic points.
Best Regards,
Nick M13 connector in the red square
trying to reach the item in the big red square in your pic ?
that must be simple to pop apart but u just can't reach ? does the connector "clip" in place by just being forced over that threaded stud - if so ease apart the leg on the thread and it should just pull off so you can pull it apart
On the pump M13 - yes, trying to reach the connector in the red square. The problem is that ABS lines are on the way and the access is with one finger only (my middle finger).
Regarding X73/2 - it looks like a solid connector, but I'll try to pull it out of the metal stud and inspect it.
Last edited by nikolay_zhelev; Nov 9, 2024 at 11:15 AM.
I replaced all the hoses and heater valve near the pump. Should have gone ahead and done this also, but I thought it was a throwaway that only ran when needed when the car was off.
In my opinion other than the convenience function that gives you that pump, once the engine is stopped and the pump is running, it cools down the engine gradually preventing hot spots.
Last edited by nikolay_zhelev; Nov 9, 2024 at 11:10 AM.
the pump appears to be located via a rubber band (you can just see it in your picture) ... people often fail to see the benefits of using lube - I suspect copious silicon lube will help it slide off, then maybe you can wrestle to a location were you can reach the essential bit - you can also see the locking tab for the connector here
Update from today. After 4 hours of efforts to unplug the M13 connector, I did it. My recommendation to other dealing with the same defect is to use steel O-Ring removal tool to in order to lift the connector lock and while lifted to push the connector out. Sounds simple, but it took me quite a lot of time to find the proper tool.
After removal of M13 connector, I managed to remove the X73/2 connector also. I would like to clarify that it's not necessary to remove the bracket holding the connector. See photos for more details.
I did continuity check and the results are:
Pin 1 X73/2 to M13 connector - full continuity (6 ohms resistance)
Pin 2 X73/2 to M13 connector - full continuity (6 ohms resistance)
I did inspect both sides for any damaged pins/sockets but everything looks fine. Now I'm lost.
Having performed all troubleshooting that came on my mind I have not idea what else to do now. If you have any suggestions feel free to share.
what age car pre March 2007 ? ...if so did you try to disconnect the battery for 20 mins and and wipe fault codes afterwards - then see ?
we discovered by accident they made the first 20,000 cars with a software fault that meant the pump NEVER runs using the REST button - like all car software dealers NEVER bother with most updates outside the engine management stuff
those early cars had 4 software updates trying to resolve... they kept getting stuck with a looping canbus bug that locked up the logic
if you search I found they left the code comments in one update whilst trying to help the other guy with no heat
don't get too excited he had the update and still couldn't get heat - but I guess better to have it than not - the update is to the heater button logic
have you physically tried the pump yet - usually if Merc diagnostic carries the info to tell you whats broken - it was one of the elements where they used their designed to fail philosophy and the component is dead - nice earner for dealerships - part of the criminal set up of you scratch my back, that Germans so love
$250 diagnostics
$200 for the part
$200 labour
to do a ten minute job - all in a few hundred in profit to share around to both parties - only problem this one can't be reached so easily - so likely this was the next level up - last 10 years then scrap the car by deliberately destroying the engine
what age car pre March 2007 ? ...if so did you try to disconnect the battery for 20 mins and and wipe fault codes afterwards - then see ?
we discovered by accident they made the first 20,000 cars with a software fault that meant the pump NEVER runs using the REST button - like all car software dealers NEVER bother with most updates outside the engine management stuff
those early cars had 4 software updates trying to resolve... they kept getting stuck with a looping canbus bug that locked up the logic
if you search I found they left the code comments in one update whilst trying to help the other guy with no heat
don't get too excited he had the update and still couldn't get heat - but I guess better to have it than not - the update is to the heater button logic
Hi BOTUS,
Thanks for the suggestions. My car is year 2010. Is there any way to send me the bulletins to review them?
Disconnect Black/Yellow Cable from Position 5 in FSAM MR8 connector, apply a positive potential and listen carefully if the pump starts, this is very easy and will reveal all requested answers.
Also Fault Code 9001 Control module 'N93 could be important, as on w221 all the requests for fault codes in any electronic modules are being broadcasted through CGW. So any Fault codes could be misinterpret by the defective CGW software.
This fault code can be caused by a primitive solution to install a CAN filter that helps the EZS to not synchronize with the cluster usually in a KM manipulation experience.
Anyhow, using Autel for any SW repairs is very risky especially for the CGW. Also, in most of the cases if the KKM manipulation was the cause for CGW SW corruption, once repair it...the last greater value of km will be updated into the cluster.
Actually now I remember I have fault message relater to the pump responsible for the rear heating (A31/1m1) fault code 9395. The fault states short circuit to battery or open circuit.
Having said that there is bulletin regarding software update sorting out the issue with the pumps, both faults might be related.
Btw, I disassembled the remove pump M13. It’s brushless motor type pump, very good design. Once I have 12V source I’ll test the remove pump to see if it’s working.
Disconnect Black/Yellow Cable from Position 5 in FSAM MR8 connector, apply a positive potential and listen carefully if the pump starts, this is very easy and will reveal all requested answers.
Also Fault Code 9001 Control module 'N93 could be important, as on w221 all the requests for fault codes in any electronic modules are being broadcasted through CGW. So any Fault codes could be misinterpret by the defective CGW software.
This fault code can be caused by a primitive solution to install a CAN filter that helps the EZS to not synchronize with the cluster usually in a KM manipulation experience.
Anyhow, using Autel for any SW repairs is very risky especially for the CGW. Also, in most of the cases if the KKM manipulation was the cause for CGW SW corruption, once repair it...the last greater value of km will be updated into the cluster.
Yes, I’m almost sure I have CAN filter. Any idea where to look for this filter? I would like to remove it
Actually now I remember I have fault message relater to the pump responsible for the rear heating (A31/1m1) fault code 9395. The fault states short circuit to battery or open circuit.
Having said that there is bulletin regarding software update sorting out the issue with the pumps, both faults might be related.
Btw, I disassembled the remove pump M13. It’s brushless motor type pump, very good design. Once I have 12V source I’ll test the remove pump to see if it’s working.
Now I’m very curious to see the bulletin content.
I think they run independent of the front one
the rear not working is usually leaking by and rust build up locking up the pump motor
konigstiger posts them look at the top under stickies
P-B-83.10/108 JAN08 Water leakage into the passenger compartment may cause erroneous blower and A/C operation. CL (216) caused by blocked drain holes on the right and/or left sidewalls. S-Class (221) due to body tolerances, the left rear or right rear wheelhouse may leak. Moisture can penetrate the rocker panel on one and/or both sides. If the4 drain grommets do not open when moisture enters the rocker panel, moisture can enter the passenger compartment. The result of which is that control units, electrical connectors, and lines become damp. Have your dealer check your VIN in VMI to determine if your vehicle is involved in Service Campaigns 2008010002 and/or 2006020007 if not, then this DTB will apply.
S-B-46.30/21a FEB08 Grinding or gushing noises heard from the area of the steering system/power steering pump may be in the A/C compressor drive. Noise is present at both idle and higher engine speeds, can be heard whether the steering wheel is stationary or moving, and frequency increases with the engine speed.
P-B-83.75/113 MAR08 - VIN A092227 to A119911. If the REST Button is nonfunctional, the Upper Control Panel (UCP) may have incorrect software installed. UCP will be flashed with latest available software.
For the aft pump - you are right. As it’s brushed motor it’s prompt to wear and seize.
Thanks for digging up the bulletins. I’ve checked and my VIN is outside of the quoted range for the REST function. Anyway I’ll check the current software version and once I have proper access to OEM diagnostic software will follow up.
Thank you very much for all comments and suggestions. I hope this topic will be helpful to others as well.
it wasn't the only VIN numbers impacted
221 442 1323 - I think original SW mess
221 442 2023 - first attempt to resolve there were two or three fix it docs - not sure why I can't see in that stickie list any more
221 442 2623 - last attempt for pre face lift cars and the one in P-B-83.75/113 MAR08
221 902 1102 - alleged current for most of the early cars too
If your vehicle is equipped with the rear HVAC option, there is another heater valve in the front right wheel well, located forward of the passenger door. Easy to access by removing the wheel well liner. I had the same issue with my 2010 S550 4Matic and found the issue was the duo-valve. The motor had worn out/seized. Took 90 mins to replace the duo-valve and have not had an issue or related error code since.
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