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Multiple erratic short circuit to positive errors after changing faulty rear battery
Hi and Merry Christmas,
I am new here, thanks for accepting and I allready have a complicated situation, maybee someone has an idea hiw to proceed...
I have a W221 2006 S500/M273 with 2 batteries.
Both batteries were changed about 3 years ago (original MB).
I recently had some fault messages on the display during driving (ESP etc.), then an engine light on (position sensor B6/4 code 0757 P0348) and low voltage. The rear battery failed so I changed it (original MB). The front starter battery still seemed OK.
Just to make sure I also checked the position sensor B6/4 (according to Xentry). Voltage on pin 1 and 3 was 12.04V and position testing B6/4 36.21 (all 4 position sensor within normal range).
After changing the rear battery I cleared all errors with Xentry and started the engine. Everything seemed OK. After starting again the engine light came on again.
Again "short circuit to positive" B6/4 error code 0757/P0348 now with a new error B6/6 Code 0765/P0393. After a while another error B11/4 Code 2066/P0118) Temperature sensor came up and the front fan now switches on permenantely.
When clearing the error codes they come back again immidiately on ignition and today with another additional sensor Code 0524/P2005.
The engine runs smoothly without any shaking or so.
Where do all those erratic "short circuit to positive" error messages might come from all of the sudden. Could the starter battery be defective as well and cause those ?
With it you can go through Tips cases to find what others at MB got to do to solve the issue.
Others have got to solve this before you.
thank you for your reply.
I have xentry and have gone through testing with voltmeter and checking testing ranges, which all are OK.
I dont have that multiple Mercedes connector kit to make further electrical tests, which is recommended in the last step by xentry.
As the error codes seem erratic and keep on adding without impairing the engine, I was hoping to get some tips where to continue looking or where it might come from.
Could the starter battery be defective as well to trigger those error codes due to bad voltage?
Another thread has the similar P2005 error that is one of mine recently popping up. They head for changing motor harness.
Last edited by Blackstonehd; Dec 25, 2025 at 10:31 AM.
loads of random engine sensor codes coming and going - would make me think its a cooked bosch ME9.7 engine ecu - they are junk and get cooked due to terrible location
if <100k miles might be other fun (mice or wiring stuff) >100 K cooked ECU should be on the list of possibles
Thanks for your reply, I have just over 100k miles....and was hoping that this is the last option....
propably will have the ME9.7 checked....
It probably is not the ECU if the engine runs ok.
A little while back I suddenly got multiple error codes from several control modules so thinking at it the codes suddenly from multiple modules does not make sense. They don’t just all fail at the same time.
What is common for the modules is the Central Gateway (CGW) or ZGW it is called in German.
my CGW had bad connection of the harness pins to the board. The pins are not soldered from the factory, they are just pushed in holes on the board.
You may be able to check if this is your problem by simply disconnecting/reconnecting the harness as this can move the pins a little bit and change the pins connection on the board.
I soldered my pins and all errors went away and have not come back. If I get an error now I know it is not the CGW.
My car is a 2012 model and the CGW is located inside the dash in the driver side end. It is a small about 4x4x1 size box but I don’t know if your car has it made this way, if it is and you find it bad you can always buy a new one that needs coding.
You have xentry so if you are member of the BenzNinja team he will code it for you.
A little while back I suddenly got multiple error codes from several control modules so thinking at it the codes suddenly from multiple modules does not make sense. They don’t just all fail at the same time.
What is common for the modules is the Central Gateway (CGW) or ZGW it is called in German.
my CGW had bad connection of the harness pins to the board. The pins are not soldered from the factory, they are just pushed in holes on the board.
You may be able to check if this is your problem by simply disconnecting/reconnecting the harness as this can move the pins a little bit and change the pins connection on the board.
I soldered my pins and all errors went away and have not come back. If I get an error now I know it is not the CGW.
My car is a 2012 model and the CGW is located inside the dash in the driver side end. It is a small about 4x4x1 size box but I don’t know if your car has it made this way, if it is and you find it bad you can always buy a new one that needs coding.
You have xentry so if you are member of the BenzNinja team he will code it for you.
Thanks!
That is interesting and would match the erratic faults. I just checked EPC and have a ZGW in my 2006 model A2219006702 and will check this next!
Thanks!
That is interesting and would match the erratic faults. I just checked EPC and have a ZGW in my 2006 model A2219006702 and will check this next!
that was not the original - thats a much later facelift part - what software has it got
from memory something ending in 221 420 1327 sounds right - ending 1427 is for later cars with other hardware for ultrasonic parking sensors and tyre pressure sensor gear and it won't behave correctly
that was not the original - thats a much later facelift part - what software has it got
from memory something ending in 221 420 1327 sounds right - ending 1427 is for later cars with other hardware for ultrasonic parking sensors and tyre pressure sensor gear and it won't behave correctly
That number is from the EPC for my car....but would this ZGW affect crank-shaft and engine temperature sensors?
In addition its a pain to use Xentry as the fan turns on permanently upon ignition due to fault P01118. Maybee I pull the fuse on that one
Last edited by Blackstonehd; Dec 26, 2025 at 04:41 AM.
engine codes I suspect is dying engine ECU - its very common
strange faults across the car and not the engine might be soggy canbus or maybe CGW being silly (merc are better at leaving the engiine to do engine stuff whilst the rest of the car confuses itself for fun)
they often play with later parts that can go on the earlier cars - still keen to know you CGW software part number.... the first thing one that new will need is flashing with the early software or it'll never make sense - might need to have VIN coded in or may never start - plus all the coding must be aligned to toys on the car - or half will never work / will work strangely / and will throw error noise everywhere - it is the main network hub for ALL systems on the car
engine codes I suspect is dying engine ECU - its very common
strange faults across the car and not the engine might be soggy canbus or maybe CGW being silly (merc are better at leaving the engiine to do engine stuff whilst the rest of the car confuses itself for fun)
they often play with later parts that can go on the earlier cars - still keen to know you CGW software part number.... the first thing one that new will need is flashing with the early software or it'll never make sense - might need to have VIN coded in or may never start - plus all the coding must be aligned to toys on the car - or half will never work / will work strangely / and will throw error noise everywhere - it is the main network hub for ALL systems on the car
enclosed is a picture of ECU data. I guess that is the next step. They have shops here that repair ECU (if possible) and will send it there to have a look.
I have a used ECU as well, they might be able to clone it if necessary....
quick scan - then press F8 you get a nice printable doc of all modules on the car with Part number, Hardware, Software versions and dates - delete the junk errors or printout will be twice as long and full of lies
I mentioned in the other thread how the cam sensors, coolant temp sensor, and one of the tumble flap sensors all have the Z7/44 Sensor Ground Connector Sleeve in common.
Thanks!
That is interesting and would match the erratic faults. I just checked EPC and have a ZGW in my 2006 model A2219006702 and will check this next!
This is the easiest thing to check if not for anything else to rule it out. If this is the issue, then everything else you spend your time and money and effort is wasted if you do those before checking for this magic little box called ZGW.
When I had the multiple module errors not one of them said anything was wrong with the ZGW itself.
- the fault codes seem erratic and came quickly within one day.
- They quickly come back after deleting the fault codes, especially the coolant temperature sensor P0118 (with a permanent running fan) allready starts upon ignition.
- all of them in the engine area within the same ground (as mentioned by TimC300)
- the engine runs smoothly and normal, temperature is shown as always.
Could a defective starter battery trigger those erratic codes upon starting, as the engine works normal after that. I do not have a special tool to check the battery more closely, from voltage its in the lower end of OK.
Could the i.e. ground be interrupted or impaired upon ignition due to defective starter battery and trigger those faults? I just want to rule out anything else before I cut through the harness.
ZGW seems more for everything else in the car than engine area? Could it still trigger fault codes there? It seems a pain to get to it (remove seat etc.)?
Last edited by Blackstonehd; Dec 27, 2025 at 03:24 AM.
I mentioned in the other thread how the cam sensors, coolant temp sensor, and one of the tumble flap sensors all have the Z7/44 Sensor Ground Connector Sleeve in common.
thanks for the detailed and valuable info!
So you recommend to get to that cable and check if it is worn/torn or has other issues? Wouldn't there be something noticeable in the engine or sensors running bad or so if a permanent ground problem was there? I am just a little hesitant to go into the harness but will do so if necessary.
I first thought of getting a new starter battery to rule out anything from there (as engine runs normal and sensors show normal ratings in xentry). But had a chance to check with a tester and it seems OK.
How about having the ECU checked at this point as well?
Last edited by Blackstonehd; Dec 27, 2025 at 05:23 AM.
This is the easiest thing to check if not for anything else to rule it out. If this is the issue, then everything else you spend your time and money and effort is wasted if you do those before checking for this magic little box called ZGW.
When I had the multiple module errors not one of them said anything was wrong with the ZGW itself.
Ok,
Did not realize the 2006 model ZGW is under floor below the seat so not that easy to get to and I do not know if it has the same push-pin issue as in my car's ZGW.
- the fault codes seem erratic and came quickly within one day.
- They quickly come back after deleting the fault codes, especially the coolant temperature sensor P0118 (with a permanent running fan) allready starts upon ignition.
- all of them in the engine area within the same ground (as mentioned by TimC300)
- the engine runs smoothly and normal, temperature is shown as always.
Could a defective starter battery trigger those erratic codes upon starting, as the engine works normal after that. I do not have a special tool to check the battery more closely, from voltage its in the lower end of OK.
Could the i.e. ground be interrupted or impaired upon ignition due to defective starter battery and trigger those faults? I just want to rule out anything else before I cut through the harness.
ZGW seems more for everything else in the car than engine area? Could it still trigger fault codes there? It seems a pain to get to it (remove seat etc.)?
CGW is beside the ODB2 port around ignition switch area - any other module below under carpets is something else - if wet soggy or muddled won't help
Starter battery starts the car and basically nothing else, box of trick above rear battery manages whats going on re charging / support in odd situations
Duff rear battery will often cause the whole car to get a muddle on
20 mins key on interior blower motor off, exterior lights off, is enough to kill and brand new fully charged 100 amp hr rear battery
based on toy count it can eat 37 amp with the key in run position..... and it can take a car 15 plus mins to get xentry to connect up and run fully quick scan with the key on
cooling fan running all the time is a network fault or cooling system based fault - not well documented and little know about the ins and out - but merc do it on purpose to signify something - or is it just to scare you in to paying a dealer to work on the car
CGW is beside the ODB2 port around ignition switch area - any other module below under carpets is something else - if wet soggy or muddled won't help
Starter battery starts the car and basically nothing else, box of trick above rear battery manages whats going on re charging / support in odd situations
Duff rear battery will often cause the whole car to get a muddle on
20 mins key on interior blower motor off, exterior lights off, is enough to kill and brand new fully charged 100 amp hr rear battery
based on toy count it can eat 37 amp with the key in run position..... and it can take a car 15 plus mins to get xentry to connect up and run fully quick scan with the key on
cooling fan running all the time is a network fault or cooling system based fault - not well documented and little know about the ins and out - but merc do it on purpose to signify something - or is it just to scare you in to paying a dealer to work on the car
cooling fan went on with P0118 B11/4 coolant temperature sensor fault and propably will stay on until solved.
so CGW is accessed from the side or under the dashboard?. I went with some part number to find out what it is, well what I found seems something else under the driver seat. Does anyone have a CGW part number so I can find the reference to my car?
for now I will check the ground Z7/44 as it is connected to all sensors with the short to plus fault. I might have pulled to hard on that ground cable when I changed the plug 64/4 recently and soldered it a bit for now.
my Nov built 2006 car has it where they all are from then on (above the throttle peddle) - don't see why the earlier cars has it else where (if they ever did)
my Nov built 2006 car has it where they all are from then on (above the throttle peddle) - don't see why the earlier cars has it else where (if they ever did)
Mine is not above throttle peddle, it is at far end in the dash. And my car is a 2012 model.
just worked out why you think its not above the throttle pedal - if you are LHD, your steering wheel is in the wrong place - which also means the pedals are in the wrong place
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