Hi, I've been reading some other posts on this forum, like "2005 e320 CDI error code P0683 after replacing glow plug controller". However my situation is a little different. I've been out of town for 11 days and nothing has touched my car in that time period. There was nothing wrong before I left the car sitting on my driveway. After I returned, first thing after starting the engine: glow plug and service lights illuminated on the dashboard, plus the big red battery "visit service" circle. A check with generic OBD scanner tool revealed 2 stored P0683 codes, nothing else. I drove the car for a little while to make sure the battery gets some charge, then tried resetting the code and it popped up right back after a few seconds. I don't have access to MB star tool, but got a Midtronics battery tester which showed the main battery is getting weak (it has put out 650A EN vs 850A EN rating). Turned around by MB strealership and got hold of new battery, swapped the old one out, but still no dice - same error. I've been reading around that either glow plug control unit or the associated relay may be a culprit. I've looked up the control unit on EPC, P/N 6481530279 and at $250 online it's darn expensive for a "consumable" part. So I was wondering where is the associated relay module is located as I could not find it anywhere on EPC. I have two questions -
1. Is there a relay in addition to glow time output stage unit?
and
2. Has anyone experienced a similar problem in the context I had described and what would be the recommendations?
My next step was to replace the aux battery, although the Midtronics says its' current CCA is on par (even exceeds a little) with claimed rating (170A EN) contrary to the main battery. But I want to hold on till I hear something back from this thread.
For the money, yes-replace it. You have certainly gotten your money's worth out of it if it is over ten years old, so you will end up doing it sooner or later anyway. Plus, these cars are very sensitive as to electronic matters, and it won't be the first time we have seen strange messages/activity coming from a weak aux battery.
It's a lot cheaper than starting to throw other parts at it.
So I was returning home from work last night shortly after I posted this thread and guess what! Miraculously, the glow plug light and the big red battery banner never came on! The check engine light was still on though. I drove back home without any issues. I borrowed a slightly more advanced version of Autel from my neighbor, did a full scan and reset all module stored codes. The check engine light went away and so far didn't come back. I didn't have to replace the aux battery yet. I plan on doing that anyway, following this thread's advice.
Now I only got the pesky "BRAKES visit workshop" banner, and the SBC module turns around with C2131 code. I know my pads and rotors are due, so I will replace them first thing in the nearest time and then see if it will take care of the C2131 error.
Thanks for the tip, I suspected that. I'll procure the new reservoir so as to replace it along with the new brakes. I know it's a different topic, but has anyone attempted to bleed the brakes without the pressurized bleeder as per MB WIS document?
Since this thread was filed a lot of water has flown away. I realized that I had never responded to this thread. So, yes, in the end, I sorted it all out as 3 separate issues.
I had invested in Xentry DAS multiplexer and virtual machine and some other equipment, which all adds up quickly in cost. It took a while to learn all that and get used to clunky convoluted user interface, but it all paid off.
The Xentry has revealed a massive number of stored low voltage codes. After replacing both batteries and resetting all codes with DAS I don't see them anymore.
I have swapped out the glow plugs with equivalent Beru part numbers and the old glow plugs were definitely due, but not totally done. This and new batteries took care of p0683 plus the other 2 goofy communication codes.
I have replaced the SBC reservoir. This took care of C2131. See this thread here -
P0683 indicates a communication fault between glow plug controller and ECU/front SAM.(cant remember which.) 99.9% of the time this is caused from a bad controller. ONLY the OEM controller will work for our cdi's, no aftermarket controllers will work. start there.
Red battery light can mean 2 different things. battery light BEFORE starting means SBC battery or main battery issue, red battery light shortly after STARTING usually indicates a charging issue.
You should look at the date code on the battery, not just the output.
From my limited knowlege, the voltage regs can be flacky above 100k miles. Could easily be the problem but it could be the battery controller too. The aux battery really doesn't see a drain unless the main is low. if it's showing 12.8-13.2 volts when you measure it after sitting- your good. My aux is getting weak- it's 6 year old dealer battery. On very cold days, it would give a warning for about 30 minutes. Right now, not an issue as it's 105 F today.
Hey fellas, just got back from a two week vacation and the car started right up no problem but what was surprising there was nothing wrong with it, no check engine or glow plug light. Drove about 5 miles and when i got back home glow light came on and check engine light with the same three codes p0683, u0155 and u0423. Today when started the car my dash went dead after maybe 30 seconds and all conveniences went dead like ac windows wipers radio signals maybe more but thats all i can remember lol. Same thing had happened before i left for vacation so i remembered that just recycling the ignition would restore power again to all conveniences but only for a few moments while the car is running and longer with the ignition on and engine off. When i check the voltage with car running is 13.7 - 14 volts. Im a little stumped. Would the auxiliary battery cause all this?
Hey man thanks for getting back to us with the results. I guess i mights have to change my batteries as well because sometimes the car starts and all its fine then sometimes it acts up and all functions go off lol
The batteries cost was not too bad, even from the dealer. So, I highly recommend replacing them both, especially if they had never been replaced before... My midtronics MDX-700HD battery tester said "OK battery, recharge" rather than "replace battery", even after recharging. The small one even had more than 80% useful CCA capacity in it. They are all AGM batteries, so they hold charge well. However, just a slight drop in voltage as it turns may cause some grief. To avoid issues, make sure you do them one at a time. The glow plugs are very easy to replace, took me like an hour for the whole thing. Good luck!
Update. i went in to check the main battery in the trunk and found water around the battery and the control module was wet, i'm beginning to think this might be causing all my issues. So first i have to figure out where the water is coming in from fix it then see what happens, ill keep you guys updated on my findings
Little update, i found the leak in trunk was caused by the trunk rubber seal so i siliconed that and i think its working as i didn't see any water in there. The only code now is the 0683 but i'm going to give it a little time for the trunk and everything in there to dry well and if the code remains i will get the new glow plug controller.
On a side note i wanted to mention that when my car has been off over night or more than e few hours when i start the car the glow plug light comes on with the ignition then it goes off, after the engine starts it stays off but then it comes on in 10 minutes. Also the check engine light is always on with the same 0683 code, I should add that the engine starts fine without any shudders or elongated cranking.
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