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Problem with Motor Control Unit

7K views 14 replies 9 participants last post by  atc98092 
#1 · (Edited)
I had an unfortunate issue with my Niro today. As I was driving, on the infotainment screen a message came up about a problem with the Motor Control Unit. The HEV warning light on the instrument panel came on, the check engine light came on. So I pulled over, turned the car off and put the hazard lights on while waiting for a tow truck. Then the hazard lights stopped working. Long story short, my car is at the dealership where they say they will need to hear back from Kia about whether they want any additional tests run before they can determine exactly what is wrong. Does anyone happen to know what the motor control unit actually is and what it does, and also would replacing that part be covered under any of the vehicle's warranties?
 
#3 ·
Well, I heard back from the dealership and they didn't mention anything about the Motor Control Unit and instead said I need a whole new engine. They said there was no harmonic balancer in the engine at all, and that a bolt came off the crankshaft and flew through the engine causing it to lose all the oil. Now this really doesn't make any sense to me because 1) if all that happened, I assume I should've heard some nasty sounds coming from the engine before I shut the car off, and 2) even if the car was never turned on at all, the hazard lights should still work. The fact that they stopped working seems to me to point to some sort of electrical problem. At this point I'm not only more confused than ever but also worried that replacing the engine isn't going to actually fix whatever was wrong.
 
#4 ·
You have reason to be concerned!!
I have never heard of a harmonic balancer coming off a car...ever
There would certainly be some major noise and vibration if that were to happen.
You should also have noticed oil puddle under the car as well, if oil left engine as they state.
Yes, you are also correct that the hazard lights should work regardless of engine condition.
I assume, this is a Kia dealership - regardless, it is time to take it to a better Kia dealership...run, don't walk!
 
#5 ·
You should look at the car's engine and ask them to point all this out to you.As Techy said major damage like this should be obvious. A few years ago I was driving for an airport shuttle service and the Sprinter van I had threw a rod. I never experienced anything like that, it was a big deal. You could see the inside of the engine through the hole it made.
 
#6 ·
It's been the '70s since I've grenaded an engine, but I still remember it was quite obvious when the rod came through the block. Smoke, noise, and lots of dripping fluids on the ground. Kinda hard to miss...
 
#7 ·
Yeah, major mechanical failures are not normally subtle. I lost a driveshaft in my truck on the highway one time and it sounded like I ran over a drum kit.

Having said that I suppose it's possible a flying bolt could have pierced the oil pan without massive amounts of noise. Could it have tossed the balancer? Maybe, that means losing the drive belt as well. I think that just runs the HSG so that might not be immediately noticeable.

6748


I'm skeptical but I find it hard to believe even the dealer would mistake a blown fuse for a blown motor. I could be wrong though.
 
#8 ·
Everyone who's replied, I really appreciate it. What makes the dealership's explanation of what went wrong so suspicious to me is that up until I shut the car off there was no sound out of the ordinary, no unusual vibrations and no smoke or anything like that. None of what they said explains the hazard lights suddenly no longer functioning as I was stopped on the side of the road. If anything besides a loss of battery power would cause hazard lights to stop working, I have to believe that would be considered a serious safety issue. When I noticed they weren't blinking anymore, just for the heck of it I put my foot on the brake and pressed the button to start the car again and absolutely nothing happened, as if the car was totally dead electrically.

As for why the dealership would make the claims they did if that weren't actually what was wrong, I have no idea. When asked over the phone about the message on the infotainment screen about the Motor Control Unit (something that as far as I've been able to deduce is a part that is associated with the car's electric motor and not the gasoline engine) and the hazard lights no longer working, the dealership guy only offered some vague statement about all those things being connected. I hate to venture into tinfoil hat territory, but the one thing I can be certain of is that I'm having serious doubts about the truthfulness of their statements.
 
#11 ·
Go with your gut - I think you are absolutely correct.
I assume whatever is done to rectify the problem is covered under warranty but regardless, I would not feel good leaving my car with a dealer that does not appear to be trustworthy.
I agree with you when you question whether a new engine will solve your issue....won't unless they repair the electrical issue as well.
I would find it hard to believe that the dealer can get approval for a new engine under warranty with the "line of garbage" they gave you
 
#10 ·
Maybe about ten minutes or so. The tow truck got there after a while, but I then had to wait for a taxi to get myself to the dealership where the car was being taken. I believe I spent more time sitting on the side of the road with the hazard lights not functional than working.
 
#12 · (Edited)
Wouldn't it be very easy to confirm - quick trip to the dealer and a look at the bottom of the engine when vehicle is up on a hoist?

"my car is at the dealership where they say they will need to hear back from Kia about whether they want any additional tests run before they can determine exactly what is wrong."

What sort of additional test needed to be run if the engine was obviously damaged and damage could be visually seen?

Engine codes can be called up and in some cases have time stamps so they can be sorted through thus giving a history of current and past problems.

Maybe time to have a face to face meeting with the service advisor where you both view the vehicle and he can point out the problems-you can visually confirm- then have a sit down to discuss warranty coverage- their ability to make the repair in a timely manner and rental car options
 
#15 ·
The gas engine in the HEV/PHEV is started using the traction battery. There is no "starter" battery. The 12v battery is basically used to "boot" the car at startup and run things like the lights and accessories. The traction battery is used to start the ICE and run things like the A/C compressor and power steering system.
 
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