[bob70]

My daughter has a 2016 Malibu that has a weird ignition switch problem. On more that one occasion the key will not come out of the ignition switch. When that happens, it's as though the electrical system is totally dead. No lights, no horn, nothing. When the hood release is pulled (with hood remaining closed) electrical power is restored, the key is once again removable and all returns to normal. This has happened three times exactly like that. I'm thinking it may have something to do with anti-theft system, but really don't have much of a clue. Has anyone seen this before, or have any ideas?

 

[1979Malibu]

The short answer is that you need to have the batteries tested. The one under the hood and the auxiliary in the trunk. One or both of them is in need of replacement.

When you pull the hood release, the ECU sees that and it disables the Auto-Start system. It's interesting to say this....the Auto-Start was what was not allowing it to start. If the system isn't seeing proper voltage...no start, lock key, etcetera.

 

[bob70]

Both primary and aux batteries are less than 6 months old. I know this is no proof they are both still good, but when the system is working there's no indication of weak batteries. I will check out that possibility, though. Thanks for your input.

 

[1979Malibu]

Ok. If you had the batteries replaced that recently, it "should" rule that out.

Are you getting the P305F Check Engine Code?

I would be looking at the connections in general, but the "battery fuse block" and "battery control module" are very suspect parts in this system when a problem like this occurs.

 

[1979Malibu]

Here's a short video to demonstrate looking for voltage drop. It should point you in the right direction.

 

[Eduramac]

Here's a short video to demonstrate looking for voltage drop. It should point you in the right direction.

Sounds like the engineers really got carried away with this system. Un real.

 

[bob70]

Many thanks to both 79 Malibu and Eduramac for the help. I haven't been able to get to further investigation in the last few days due to other commitments (work). I'll certainly follow your suggestions when opportunity allows and report back. Again, thanks much!!

 

[LATECH]

likely a underhood fusebox problem

 

[bob70]

I had a chance to make some checks last night. Primary battery reads 12.5 V. Aux battery in trunk reads 14 V, which seems a bit high, but I wouldn't think that would be an issue. I checked all voltages per the video above and everything checked out as it should. So, I haven't yet located the source of the problem. I ran across reference to an anti-theft module or relay and I'm wondering if that could be the problem. More research and investigation awaits.

 

[bob70]

LATECH, can you elaborate on what your thinking/what I should look for in the fusebox. Anything specific, or just general condition of terminal connections and fuses?

 

[LATECH]

likely wont see the problem
It is internal ,if it exists
It could also be a ground
Check all the connections under the hood.

Pro tip .....turn the key on verify power, tun on the headlights etc. Leave them on
Then go under the hood and start jiggling wires, like the battery cables, the power feed to the fuse box etc.
When the lights start flickering , you are close to the problem

 

[bob70]

likely wont see the problem
It is internal ,if it exists
It could also be a ground
Check all the connections under the hood.

Pro tip .....turn the key on verify power, tun on the headlights etc. Leave them on
Then go under the hood and start jiggling wires, like the battery cables, the power feed to the fuse box etc.
When the lights start flickering , you are close to the problem

Great suggestion, LATECH, I'll do that first chance I have.