Alarm/anti Theft Trouble

[pakman123]

Hello!

So recently I've been having some alarm/anti theft trouble.

If I unlock the car with remote or key, it opens the doors but wont disarm the alarm. This means that if I unlock the doors and open the door, the alarm goes off. However I found that if I lock the car and then leave it alone for a couple of hours, it will unlock and disarm like normal when I get back.

It only does this if I lock and then unlock the car back to back or within like 15-30 minutes.

My temporary fix this far has been to simply disconnect and reconnect the battery again. It starts just like normal after that. Obviously I can't go on like this forever though.

This all seems to weird to me, so I thought I'd ask you people instead.

Any ideas?

 

[wmburns]

It might be helpful for you to mention the model year of the Mustang in question. There are different PATS systems through the model years.

But if asking for an educated guess, how about the driver's key in lock switch isn't working. There's a switch inside the door lock that sends a signal when the key is actually used to unlock the door. It's a simple on/off switch. If this were my car I would start by using WD40 on the switch around the door key lock.

 

[pakman123]

My bad, It's a 2000.

But if it were the switch you are talking about, wouldn't it still be working using the remote? As of now, the key nor the remote works. They both unlock, but wont disarm the alarm/anti-theft.

The weirdest part as I said is that non of this happens if I just wait for a couple of hours before unlocking the car. It only happens if I unlock the car within 1-40 minutes or so after locking the car.

 

[wmburns]

How about a loose battery cable or bad battery? If there is any interruption in power the PCM "thinks" this is a break in attempt. You need to stop disconnecting the battery.

Are you positive this car does not have an after market alarm?

Or maybe try reprogramming PATS. Here's some information on an affordable Windows based ODB2 scanner. This ODB2 scanner could also be used to monitor various PIDS like, door ajar, theft-detected. Information that might make short work of this problem.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

 

[pakman123]

Battery cables are fully secure and cleaned, and the battery is pretty new and showing good health. I'm not a 100% positive it doesn't have an after market alarm.

Could I use the OBD2 tool to fully disable the PATS?

 

[wmburns]

Did you read all the way through the links provided?

IF your car has an after market alarm THEN disabling PATS isn't going to fix the problem.

Does the cluster gauges sweep all the way across at key on? If so that means that the PCM/cluster experienced a power failure.

 

[pakman123]

Cluster gauges does not sweep.

 

[Neuron]

The aftermarket alarms can do some weird things. I have seen a lot of complaints about them and also a lot of trouble to remove. On mine I cannot reprogram a new remote even though the car goes through the proper sequence according to the shop manual and all of the online info. Still can't figure out why the aftermarket alarm with the PATS, I was told it was a way for the dealer to make money, although the salesman said it was a insurance requirement.