I noticed my wife's 2011 GLK350 having a progressively weaker start over the past few months, and now that its "getting cold" here in Texas (55F) in the mornings, the car was have trouble turning over fast enough, but was still starting. I obtained a new Interstate battery (correct spec flooded not AGM) from COSCO last night, and returned the old for core charge at the same time. I decided to throw the new battery on the charger over night as I didn't trust Cosco to have actually been maintaining their battery stock. In the morning I dropped the battery in the car, secured the holder bar at the base of the battery, connected the leads securely and closed the hood. When I went to start the car there was nothing. I initially had the driver side door open so I could reach in and start it quick, the only message I got on the dash was "remove ignition key" reminder that you get when exiting the car. The radio / infotainment center did not turn on, nor the gauges nor any solenoid clicking action, although a very faint hum of some circuit getting energized I think. The radio will turn on manually, the seats move back and forward, but the windows do not move. Steering column does not feel locked. The key fob will lock, unlock, and panic button work (the flashers work in panic mode).

Tested battery voltage 12.75V on the posts. Also the same on the ground stud and positive flat terminal box. For good measure I swapped out the battery with my truck, which happened to be the same size, the behavior remains unchanged.

Ran codes on a cheap OBD2 reader, which yielded nothing.

I've been reading up on a lot of posts about the steering ESL and EIS issues, but I find it very coincidental that either of these devices would just stop working for the first time at the exact same time I had the battery out for 12 hours. I'm debating buying a better code reader to see if anything shows up.

Not really sure what the next best step is. Local repair shop is quoting $300 for diagnostics and $1,800 for ESL replacement if that turns out to be the issue (plus towing).

I work on all my cars, primarily Toyota and Nissan, and have tackled some decent sized mechanical jobs on those, but this is a new one for me.

Can anyone point me in the right direction?

Thanks

 

I’m sure this isn’t the cause but did you clean the terminals that are attached to the vehicle inside them where they clamp ? Because regular lead acid batteries release sulfuric acid that corrodes everything, and your battery If like my 13 is in a case, sealing in corrosive acid. FYI . AGM are superior in every way. Minimal gas so no corrosion . Won’t leak in an accident , last longer, take larger and more discharges , hold voltage longer and more. AGM I’m sure is recommended for your 11. AGM easily last 6-8 years . Wet clean with a post cleaner tool or rough sandpaper inside the cable terminal . Hopefully you get lucky.

If it’s not a daily driver there are places that rebuild the steering lock , I think it’s just Brushes for the motor but don’t know. there are ways to not spend a fortune if you don’t need it for awhile .

 

When a mechanic sold me a replacement battery for my 8yr old , and good AGM , I said I wanted the most power - amps. He put in an interstate wet cell. I went home and researched AGM vs Wet cell. The next day I went back and paid up, for the proper AGM by Interstate

 

Probably wasn't the best idea to leave the vehicle without any source of electricity overnight, and also not a good idea to choose a non-AGM battery. Your GLK's original battery was an AGM one for a reason (quite a few actually).

Also, when a battery's voltage shows 12.6v that's generally considered undercharged, so it seems your overnight charging didn't do a whole lot of good for a "new" battery.

I would suggest you take it back to the store and get the proper AGM one, install it and then hook up your trickle charger for overnight charging. Make sure you also lock the doors overnight, that way the car isn't actively searching for the key-fob signal and draining the battery further.

 

I agree with the superiority of AGM, that's what I run in my other vehicles. This GLK, which we more or less inherited came with a flooded lead-acid (certainly a replacement from OEM) with a date stamp of 11/2020, so it had been functioning adequately for 4 years. The battery from my FJ that I swapped in to check if it was a battery issue or not is in fact an AGM (X2Power) and as I mentioned starts the FJ without a hitch. I think that leaving the GLK without power overnight is the culprit, but I'm not sure what the solution is. I'm thinking some sort of reset is in order, but I called the local MB dealership service department and was told there is not such reset procedure in association with battery swap...

 

This seems to be a common problem:

 

Did you clean the cable TERMINALS ?

Right now I’m charging a friends old wet cell , it went to 14.65, it settled at 13.8. 12.75 is not what a New battery should read . New off a charger should be 13 or so

 

dukeoleary, excellent video. That emulator looks like a great solution to an ESL failure.

 

Backward compatibilty of AGM batteries seems not to be a problem, but forward compatbility of flooded cell batteries is. I installed an Optima redtop AGM in my '95 Jeep (so old it predates OBDII) 13 years ago, and it was continuing to perform reliably until I replaced it preventatively last week with another Optima redtop. Battery was disconnected for 3 days before I got around to installing the new one -- no problems. Oh for the good old days of simplicity!

 

You had a 13 yr old optima ??

 

Yep -- 13 years is probably exceptional. I had a yellow-top in my Lexus that died 3 weeks before its 3 year warranty expired, but it was replaced at no charge!

 

I think you always had a charge above 12 so it didn’t sulfate . That’s what kills batteries in 6 months . Low voltage. But I never heard of 13 years! 7-9 yes.

 

Our 2014 GLK 350 Base original battery is still there, with no signs of weakness yet (10+ years now).

I put a trickle charger on all our vehicles every two weeks (even the zero turn!). A maintenance procedure many folks avoid.

 

I just bought a harbor freight 7w , 33$ solar charger , as cheap as they are they should be factory standard equipment. Yes charging up is smart , mine is never fully charged . In fact I’m charging with a charger now .