Saturday, January 7, 2017

W211: The Most Ridiculous Battery Drain Problem Ever, 2003 E320, P.5 THE END

Figure I'll post up a closer here.

I believe we have success! Well, I know we have success lol Battery was shot from all the draining, but with a new battery the car hasn't needed a jump for the past couple days. No messages and draw is down to where it should be with the options the car is equipped with (roughly 20mA-30mA). Cars with the motion sensors will run anywhere under 70mA. 

A bit of a recap here: 

After SAM replacement, I was able to isolate draw location by removing the F81 power cable from the F33 pre-fuse box in the trunk next to the battery and getting an instant amp drop during testing, no other wire had the same effect. F81 feeds power to F34 driver side interior fuse box. This entire process was being initially thrown off by the fact that the system was fluctuating so greatly it was impossible to isolate. Rear SAM replacement came to be by isolating the CAN system connector by connector (first isolating IC/EZS, then go down the system) - I found the system would not fluctuate in draw with the rear SAM essentially removed from the CAN. Replaced and coded the SAM - no fluctuation. I removed the Teleaid from the car entirely with a MOST bypass cable, unplugging the module, and properly coding the AB/CGW/IC .... Now that everything in the car was working properly and had a steady amp draw, that was the first success.

So with installing the new SAM, making sure everything was coded properly, and NOT getting any ridiculous fluctuation, I went back and redid my quiescent drain testing to the isolated interior fuse box. [B]The problem? F023 - Passenger Seat Adjustment/Memory[/B] .... I got a good laugh out of it as I unplugged both seat modules in initial testing! DAS doesn't recognize amp consumers, though it does provide CAN test procedures to isolate major consumers. It's somewhat helpful, but you still need to get out your multimeter and have at it. This wasn't something that could have been found with a simple quiescent/parasitic drain test. A series of problems were cumulatively making this entire process more difficult than it should have been, but such is life. 

A few tips for those looking to find battery drain problems

- With the car in SLEEP (wait 6 minutes) and you're reinstalling a fuse it will take a few seconds for the car to re-enter that sleep state. Do NOT continue pulling fuses immediately after reinsertion as you will get false readings. Avoid removing the fuse for the central gateway in F34 fuse box as it will freeze consumers and maintain whatever draw was on the car. You can isolate CGW problems using CAN isolation.

- As with seemingly everyone else's battery drain problems on the forum - most problems can be found with simple quiescent drain testing. If that proves to not be successful, isolating systems via the X30 CAN connectors found throughout the car would be the next course of action. 

- Short of that, you can directly remove individual SAM power suppliers via the pre-fuse box in the trunk or the passenger footwell fuses. From there, it's very easy to direct your attention to specific locations/modules. 

In my case, after all that testing, the major consumer was the passenger seat module which is a VERY common failure on these cars. Coupled with SAM and coding problems, it sure was a fiasco. 

Thanks for reading!


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