Never heard this one

2017 Kia 3.3 L. 65,000 miles. Stalls at low speeds (15mph) and restarts immediately. It happened twice. No codes.
I told son check for faults in harness by shaking and tugging , clean connections, check grounds & battery connections, clean TB & MAS.
I couldn’t get there with my test equipment to check fuel pressure, alternator, etc. so he took it to the Kia dealer. Kia dealer told him it was the battery.
I wasn’t there to hear how the engine cranked but he said it would start back immediately.
My question……I never heard of a battery causing a running car to stall and die like that. I hope the dealer is correct but is it possible? Your thoughts.

A bad crank sensor can cause that.


I thought same and told him since I think Kia uses Hall Effect crank sensor but the no code ( maybe the fault didn’t last long enough) had me stumped and I didn’t know if he should just gamble on a new one……but dealer, with more sophisticated equipment than I have “said bad battery.”

Read it again.

Especially about the Check Engine light.


Okay. Yes the part about not always showing a fault. I knew sometimes faults don’t last long enough (in milliseconds I guess ??) to show.

Personally I would have changed the crank sensor (I carry a spare) if it was my car doing that.

But really curious if anyone ever heard of a battery doing that as the dealer said?

If the voltage gets too low the car can stall. Hopefully they checked alternator output. I have a crank sensor in the trunk but they say it has to be synced with the computer on mine requiring a mechanic with a tech two.

Yes I’ve had vehicles stop and not start again, from dead batteries ( from a bad alternator) but to stall and restart immediately has me wondering.
I know bad diodes can cause excessive AC current and mess with sensors. But that’s easy to diagnose with a multimeter.

But if the battery voltage was so low that it caused the engine to die, it wouldn’t have enough charge to restart it .


As a follow up……80 miles of mixed suburban driving since trip to dealer and the new battery. No stalling.

Before dealer installed new battery it stalled and restarted immediately three different times at low speed.

Kia dealer said it was undersized ( amps) and weak battery.

First time I ever heard a battery could cause this.

The transistors in the car’s electronics won’t work reliably if their power supply (from the battery) is low. A faulty battery will show up as failures in myriad ways, varies car to car. A faulty battery is sort of like being low on gasoline, first thing to check for when car isn’t behaving properly. The reason a faulty crank sensor may not produce a diagnostic code is b/c it thinks the engine isn’t running when there is no crank signal, so since the engine isn’t running, no need to produce any codes. Crank sensor failure can be detected in some cases. If the computer notices there is no crank signal when the engine is supposed to be cranking (key in start), that might produce a code. Or if the computer notices there is a camshaft-rotating signal, but no crank signal, that might produce a crank sensor code.

I guess you don’t argue with success but I would still monitor the alternator to make sure it is keeping the battery up.

I really doubt it was the battery. Loose battery terminals would be more likely. Did you get to keep the old battery? If so put it back in to see.

I believe the engine is made to stay running with the battery Voltage all the way down to 7.2 Volts, which is the required minimum Voltage for the battery cranking Amps rating.

RV Tech Library - Battery Charge Voltage


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Three low speed ( around 15mph) stall and stops and three immediate start ups over more than one days time.

Dealer said they checked everything and the only thing was an underpowered ( lower amperage ratings than stock ) and also worn out.
( this was bought from a rental company a few years ago……what replacement battery they put in is a mystery )

Now over a hundred miles of suburban, picking up the kids, groceries, starting and stopping driving etc and no problem.

Like I originally said ………it’s a new one on me. Never heard of such a thing and still don’t quite believe it.

2017, it is due for a new battery. But the reason you may not have seen a CEL is that most DTC’s (diagnostic trouble codes) are two trip DTC’s. For the CEL to come on, the PCM would have to have seen the DTC on two successive trips. If he had a stall, then a trip with no stall and a stall on the third trip, the CEL would not have come on. It would have stored a pending DTC in the PCM that the dealer would have seen.

Faults like P1603; Engine stall or P1604; Startability Malfunction are not required to turn on the check engine light.

I can tell you with 100% certainty that any modern day gasoline engine will not run with a charging system at 7.2 volts. Or even 8.2 volts. Probably not 9.2 volts either.


My neighbor has a Sedona that had a similar problem, it was a weak ignition key cylinder. They were using a large key ring and it was causing the van to shut itself off. By any chance did you remove excess keys from your key ring while the van was being serviced?

No. No pounds of keys but I’ve seen that happen.

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It’s been my experience that when the car system voltage gets down into the 10s/11s for whatever reason issues start showing up and dying is one of them. My 87 Mercury would run until the mid 10s and then start stumbling.

In the old days someone could drive a carbureted, contact point distributor car across an entire large state on the battery alone; sans the lighting. A 12 volt car could run fine on 6 volts or less as many cut the voltage down anyway to conserve the points. Think; Chrysler ballast resistor or VW air cooled ign. coils.
Not so with fuel injection and electronic controls.

I was coming back from the TX Panhandle one evening in a Sunbeam Alpine and the alternator died 90 miles from the house. Drove that 90 miles with nothing but moonlight reflections on the roadway.