Wife’s 2018 MB cla 250 intermittent starting issues

[Tonyv__]

I know an MB is the furthest thing from a GM truck. But you guys been good to me so I bring you my problems lol

wife’s car just started giving her trouble about a month ago. This only happens in the mornings occasional not everyday. She starts her car and the starter engages for a second then stops. Then she try’s again and the car starts. Today it got slightly worse with 2 failed starts and then a successful start. However when she gets going the car starts fine a few times until it decides it wants to be a pain a couple days later ..

To me this definitely sounds like a battery issue. The battery reads 11.92 volts after driving around.. Which I’m almost positive shows a dead battery. Did not get a chance to test while running to see the charging volts.. But why is the car starting at all if the battery is that dead?

my experience is with cars that still have keyed ignition. You crank the key. If the battery is dead. The starter clicks and nothing more. This car with push button ignition is giving an attempted crank.. so I’m confused. Whether it’s a sensor or maybe the 2nd auxiliary battery is jumping in? Or maybe I’m overthinking it and the battery is dying

I should add that it’s a 2018 with 20k miles

any input is greatly appreciated

 

[wjburken]

I would check your fuel pressure as well. It could be loosing pressure and needs a few start sequences to bring the pressure back up.

 

[Tonyv__]

I would check your fuel pressure as well. It could be loosing pressure and needs a few start sequences to bring the pressure back up.

Good idea. I’ll check that in the morning... I hate to just put a battery in it. Even the “basic” batteries are close to $200 for her car

 

[mb1500]

Go to any chain auto part store and they will load test the battery for free. No need to throw parts at it.

 

[ivin74]

Go to any chain auto part store and they will load test the battery for free. No need to throw parts at it.

X2, the battery to my suv showed 12.42 volts and sometimes it would start and sometimes it would not. Autozone did a load test and it failed. Since I installed the new battery I have had no more issues.

 

[grouch]

I know an MB is the furthest thing from a GM truck. But you guys been good to me so I bring you my problems lol

wife’s car just started giving her trouble about a month ago. This only happens in the mornings occasional not everyday. She starts her car and the starter engages for a second then stops. Then she try’s again and the car starts. Today it got slightly worse with 2 failed starts and then a successful start. However when she gets going the car starts fine a few times until it decides it wants to be a pain a couple days later ..

To me this definitely sounds like a battery issue. The battery reads 11.92 volts after driving around.. Which I’m almost positive shows a dead battery. Did not get a chance to test while running to see the charging volts.. But why is the car starting at all if the battery is that dead?

my experience is with cars that still have keyed ignition. You crank the key. If the battery is dead. The starter clicks and nothing more. This car with push button ignition is giving an attempted crank.. so I’m confused. Whether it’s a sensor or maybe the 2nd auxiliary battery is jumping in? Or maybe I’m overthinking it and the battery is dying

I should add that it’s a 2018 with 20k miles

any input is greatly appreciated

Where is your battery located? Trunk? This sounds like either a failing cell in the battery or an alternator that is heading south. I'd lean more towards the battery. I know about batteries for fancy cars. I had a BMW 528i that ended up needing a battery but I wanted to make SURE as not only was it a unique (and expensive) battery, it was a booger to replace since it was tucked into the right rear quarter in the trunk.

I would make sure the terminals are clean on the battery first. I'd also snag a cheap OBD II reader just to make sure there's not a code with the charging system. They are handy to have anyway.

I'll bet in the end, your 3 year old battery is just at the end of it's service life.

 

[Tonyv__]

Where is your battery located? Trunk? This sounds like either a failing cell in the battery or an alternator that is heading south. I'd lean more towards the battery. I know about batteries for fancy cars. I had a BMW 528i that ended up needing a battery but I wanted to make SURE as not only was it a unique (and expensive) battery, it was a booger to replace since it was tucked into the right rear quarter in the trunk.

I would make sure the terminals are clean on the battery first. I'd also snag a cheap OBD II reader just to make sure there's not a code with the charging system. They are handy to have anyway.

I'll bet in the end, your 3 year old battery is just at the end of it's service life.

luckily right in the engine bay. The battery isn’t too bad just has a plastic cover over the entire thing. I’ll run the obd tool. I didn’t think about that If the CEL isn’t on and I’ll check the alternator before I pull the trigger on the battery. Thanks

 

[FrankU]

$ 200. Isn't bad for a battery , but you may be in for a surprise on the price of a new one.

 

[Tonyv__]

Go to any chain auto part store and they will load test the battery for free. No need to throw parts at it.

I physically want to throw things at it..... I’m sure I’m just over thinking it. Never worked on an MB before this one. Was never interested in it either. But I couldn’t convince the wife to get an suv

 

[Tonyv__]

Took the battery to be tested today. They said it’s a good battery just currently charged at 50 percent... I checked her running voltage this morning before pulling the battery. It was 14.8v


Only thing that comes to mind is the wife has been working from home since Covid hit and drives her car once a week to the grocery store. Maybe twice. Starting to think that this is exactly why people buy battery tenders