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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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I cannot unlock my car with my key? it sets off the alarm i

Customer Question

i cannot unlock my car with my key? it sets off the alarm i tried programming the system to he default mode but it cont to go off im down to only 1 functinal key fob now i would appreciate your help.
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.


Can you clarify exactly what is occurring with the vehicle in relation to the key, the fob, and unlocking the door?

For example is it that when you unlock the door with your key the alarm still goes off when you open the door (indicating a likely bad key detection switch), but when you use the remote fob it operates normally?

Customer: replied 1 year ago.
the fob works perfectly i cannot unlock the doors with my key when i do the alarm goes off ive been on the progammer for 2 hours attempting to set the default A so i can use the fob or key it still alarms everytime i unlock the car with the key and it cont to alarm until i click the fob
Customer: replied 1 year ago.
when i try to program this to default A i also dont get a beep like its already set to default
Expert:  Doug replied 1 year ago.

No problem.
There is no configuration or setting for this. What is happening is the disarm signal on the key detection switch is not reaching the ETACS to turn the alarm off. Since the fob uses a wireless signal to disarm and that is working, we know the ETACS is doing its job, it just isn't getting the manual key signal. This is unrelated to the answer-back settings etc.

Customer: replied 1 year ago.
i fix this how ????
Expert:  Doug replied 1 year ago.

What needs to be done here is to determine if either the key detection switch is failed or the wiring between it and the ETACS is failed. The reason for mentioning the latter is that it is VERY common to see the wiring in the drivers door fail where it passes in between the door and the chassis from years of repeated opening/closing. To say it happens a lot would be a huge understatement.
Are you comfortable with some moderate disassembly?

Customer: replied 1 year ago.
Expert:  Doug replied 1 year ago.


What we want to do is get the door panel off again to access the inside. I would strongly recommend removing the door glass as well since the access behind the door panel is tight with it in (it is just two 10mm bolts, then lower the regulator and lift the glass up, rear end first).
With the door off, first do a visual inspection of the key detection switch. It is mounted to the back side of the lock cylinder if it has not fallen off. If it has fallen off, you need a new switch (they just have thin plastic clips holding them on that break off).
If the switch is intact, carefully pry it off the lock cylinder being careful not to break the plastic clips holding it on. Looking at the inside of it you will see a raised rib that engages the lock cylinder, gently turn it either direction twice each way and see if the locks cycle.
If they cycle both directions, then the wiring is good in the door and likely the switch is just failed (doesn't turn far enough to engage when using the key operation).
If the locks do not cycle both directions, unplug the switch. Looking at the three wire harness you have a black wire and two "other" colored wires.... usually a red/green and a green/black, but 2004 had a few oddballs. Never the less, with the connector unplugged, short between the black wire and one of the other two wires twice and see if the locks cycle, then between the black and the other wire twice and see if the locks cycle.

If the locks cycle normally this way, then the switch is bad.

If the locks still do not cycle in either or both directions, then the wiring in the door is your most likely suspect. To address this you will need to remove the door speaker, then unplug the door harness connector in the foot well and pass the entire harness/grommets through the chassis and into the door, then pull the connector out through the speaker hole. You can then trim down the rubber grommet to inspect the wiring for fractures inside the grommet.