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Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8594
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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Mitsubishi Montero Limited: I have a 2001 mitsubishi montero

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I have a 2001 mitsubishi montero (limited), whenever the car is off and i open the driver side door there is a buzzer sound, BUT my key isn't in the ignition. Also, whenever i try to lock my car with the remote, it doesn't lock or make a sound that it's locked. So, I have to manually lock it with my key. How do i make the buzzing sound stop and my car to lock itself again?

There is a key detection switch in the steering column that tells the car is your key is inserted or not. There are two parts to this switch, a lever that is part of the lock cylinder that moves when a key is slid in, and the switch itself that is mounted on the lock housing that interacts with the lever on the lock cylinder.

When the key detection switch is activated (either by the key being inserted or malfunction), the key reminder buzzer will go off any time the door is opened whether the key is in or not (unless the key is turned to On). Additionally the keyless remote will not work at this time, as the system thinks the key is in the ignition and it does not want to accidentally lock the keys inside the car.

So at this point our likely suspects are the lock cylinder as the most likely, the detection switch on the lock housing second, and a wiring problem third.

So that being said, have any of the following things occurred recently?
Any change to the ignition or keys
Any repairs to upgrades that involved wiring/electrics
Any difficulty operating the ignition lock
Customer: replied 4 years ago.

No, I have not changed the ignition or key. I have not done any upgrades with wiring/electrics. The ignition seems fine, I'm still able to start the car with no problems.


Try running the key in and out of the cylinder quickly and firmly several times and see if the operation changes any.
Customer: replied 4 years ago.

What am I supposed to be looking for?

I'm sorry, what I meant by operational changes was if the reminder noise stops occurring after the key removal after vigorous insertion/removal.
Customer: replied 4 years ago.

No, the noise hasn't stopped


At this point we will need to do some column disassembly to diagnose any further; is this something you are comfortable with?
Customer: replied 4 years ago.

It depends on how difficult it is going to be

Well it isn't too difficult, but can seem a bit overwhelming if you haven't done this sort of work before.

What we want to do is remove the ignition cylinder to see if the chime stops indicating that the ignition cylinder detection lever is sticking.
To do this we will need to remove the covers from the steering column by unscrewing the philips screws holding the top and bottom halves together then unsnapping the top and bottom half apart from each other.

With the column covers off, inspect the ignition housing where the key goes in. About 2 inches back on the side facing you will be a small metal circle; this is the release button for the cylinder. Insert the key and turn it to On, then use a metal pick to depress the release button while pulling on the key to remove the cylinder.

Once this is done, we need to know if the key reminder noise is still occurring or if it stops.
Customer: replied 4 years ago.

I don't think I'm comfortable doing that, I'm sorry

That is OK, would you like me to provide the full check over so that you can provide it to someone to perform the inspections for you?
Customer: replied 4 years ago.

yes, that would be very helpful, thank you

No problem.

It will take a little bit to type it all out as well as pull a diagram I need to review briefly. I will post back as soon as I am done.
Customer: replied 4 years ago.


Thanks for your patience.

Again we are trying to determine what portion of the key detection system is malfunctioning to keep the key reminder on and wireless system disabled.
Because this system is nearly entirely located in the column, the column covers need to be removed by taking the philips screws out then popping the top and bottom halves apart, exposing the column.

With the column exposed, the first thing we need to do is make sure the ignition cylinder lever is not sticking. This is the lever on the cylinder that pushes out when a key is installed and touches the key detection switch in the lock housing.
Insert the key into the cylinder and turn it to On, then use a pick to depress the release button about two inches back on the lock housing while pulling on the key. The ignition cylinder will slide out and you will see the detection lever (similar picture shown below):

If you pull the ignition cylinder out and the noise silences, it is about a 95% chance the cylinder is at fault. Lubricating the lever may take care of it and is much cheaper than replacing the cylinder (due to the key programming).
The 5% chance is if the detection button that the lever touches was sticking and removal happened to free it.... not too likely though.

If the removal of the cylinder does NOT silence the reminder, then we need to go deeper. Look into the lock housing and identify the button that the lever touches. Use a pick to work it in and out several times and see if the reminder stops. If it does, the reminder switch on the lock housing is faulty and you will need to replace the lock housing.

If you are unable to determine if the lock housing detection switch is sticking, we will want to isolate the switch from the system. Locate the electrical connector for the detection switch just back from the housing, it will look like this:
Unplug this connector (do NOT unplug any other connectors!). The reminder will continue to go off.
Take a paper clip or short jumper wire and short pin 4 (Black wire) to pin 6 (Red with Blue stripe wire) together. If the reminder chime stops, your detection switch in the lock housing is bad and again the lock housing will need to be replaced.
If the reminder chime continues to sound, you will have a broken circuit for the key detection switch, either via broken wire or internal issue to the ETACS computer.

For what it is worth, the ignition cylinders are common to have the lever stick, though normally running the key in and out hard several times usually takes care of it.

Now if you find the cylinder is an issue, again you can usually lubricate it and be fine. If you opt to replace it, you can either get a bare cylinder and have a lock smith re-key it to match your old keys, or you can get an already assembled cylinder with new keys.... the problem here is that you will need to have the keys programmed, and you will have to replace/re-key the doors to match... a real pain going that route and very expensive.

If you find that the lock housing is at fault, it will take quite a bit of disassembly. The battery will need to be disconnected and the airbag removed, steering wheel and clock spring removed, and all combination switch parts removed.
With the lock housing now exposed, it will be a bit confusing as to how to remove it. Looking at the aluminum arch that goes over the top of the column you will see two broken off bolts. These are what hold the housing on, they are snap bolts (for security reasons) that break off the head on installation. You will need to use a die grinder to cut flat slots in the heads so a screw driver can be used to unscrew the bolts. The new lock housing will come with new snap bolts.

If you have any questions at all just let me know. I would be happy to elaborate if needed.
IF you feel the need to use one of the lower two negative ratings, please contact me first via the Reply/Continue Conversation link so that I may address your concerns.
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