Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: raps on May 18, 2013, 10:48:10 PM
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Hi everyone, been having a problem recently (last two weeks) with the alarm going off sporadically at night, never in the daytime, I'm sure the cars not being interfered with, anybody got any idea what the hell is causing it, it's driving the neighbours crazy!!, thanks.
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what jeep ?
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Is there a motion sensor inside the car, as part of the alarm?? Might be that it pickup lights of passing cars as movement
I had a similar issue on an aftermarket alarm years ago.. End up moving the motion sensors - problem sorted
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Some alarm systems also have an adjustable sensitivity function..I had this problem with a vehicle a while back..passing traffic would set it off! Wound it down a bit and problem solved.
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Thanks for the ideas, should have said the car is a 2003 Cherokee if that give's any clue
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Same as mine raps..not sure if they can be adjusted, so will check it out in the w/shop manual later today.
Assuming yours has the factory fitted jobby and not after market.
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Unit fubar, it's a plug in type and can easily be replaced.
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Common fault on the Cherokee is the interior ultrasonic sensors failing. I had mine replaced under warranty twice!
The short term option is to disable the ultrasonics, I think by pressing the remote arm key twice (or x3?) in quick succession (at least it was in my old 2005 model).
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Thanks again fella's, I will try all those options meanwhile, if anybody's got any other input, I would be very grateful!! :icon_winkle:
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silly q i know but is there anything inside hanging loose? be amazed how a car will wobble in the wind especially tall things like jeeps
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Ok, an update, this is a 2003 Cherokee LTD 2.5TD with the factory fitted alarm system. I have also just discovered that you cannot lock the rear (5th) door using the key alone, you have to lock all doors via the buttons on the key fob.
I tried the suggestion of pressing the lock button on the fob 3 times in quick sucssesion, that produced an answering beep from the system!, fixed it I thought, looking forward to a night of peace!!, and no dirty looks from the neighbours :icon_biggrin:. Alas, how fucking wrong can you be?, the bastard thing went of more times than ever!!, culminating in me leaving the alarm off and the back door unlocked just to get some peace and quiet!.
Incidently, this only happens after 10-11pm, never in the daytime, thanks again.
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Outta tha box thought :
You don't happen to have a amateur radio ham/shortwave chappie accross the road or in the neighbourhood perchance ?
Look for a mofo antenna array on nearby roofs. Those guys can pump out some serious interference.
Any other signal emitting devices you know of ?
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Most problems like this are voltage related and your car battery voltage might be dropping below the threshold which is simulating a door opening. Before you change anything just put a charger on your battery overnight for a week and see if the problem goes away.
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Hmmm, Dutch thats an interesting thought, as oddly enough one of my neighbours has had the same problem, just not as frequently, I will look into that. Cockney boy, good thinking but I've already tried, I've also changed the batteries in the key fob, don't know why!, just desperation I think.
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From the 2005 owners guide:
The Security Alarm System is designed to protect your vehicle; however, you can create conditions where the system will arm unexpectedly. If you remain in the vehicle and lock the doors with the transmitter, once the system is armed (after 16 seconds), when you pull the door handle to exit the alarm will sound. If this occurs, press the “Unlock” button on the remote keyless entry transmitter to disarm the system. You may also accidentally disarm the system by unlocking the driver’s door with the key and then locking it. The door will be locked but the Security Alarm will not arm.
From the Service Guide (2005):
INTRUSION ALARM
The intrusion alarm is an exclusive feature of the export premium version of the VTA, which is only available in certain markets where it is required. When the VTA is armed, a motion sensor in the Intrusion Transceiver Module (ITM) monitors the interior of the vehicle for movement. If motion is detected, the ITM sends an electronic message to the BCM over the PCI data bus to invoke the visual alarm feature, and sends an electronic message to the alarm siren in the engine compartment over a dedicated serial bus to invoke the audible alarm feature.
The motion detect feature of the ITM can be disabled by depressing the “Lock” button on the RKE transmitter three times within fifteen seconds during VTA arming, while the security indicator is still flashing rapidly. The VTA provides a single short siren “chirp” as an audible confirmation that the motion detect disable request has been received.
The ITM must be electronically enabled in order for the intrusion alarm to perform as designed. The logic in the ITM keeps its intrusion alarm function dormant until it is enabled using a diagnostic scan tool. The intrusion alarm function of the ITM is enabled on vehicles equipped with this option at the factory, but a service replacement ITM must be configured and enabled by the dealer using a diagnostic scan tool. Refer to the appropriate diagnostic information.
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Hi Ivan, well I followed your instructions to the letter and, at first all was well but last night the bloody thing went off twice again (lol) sodding thing! :017:
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Try a can of fly spray and empty the whole can in there..if you've got a moth in there that reacts to the outside lights..it will/can set it off. My workshop manual says the same as what others have posted, that's why I haven't come back sooner.
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the alarm unit is fucked, its under the os headlight somewhere.
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I bow to your better judgement daggie.
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I had it on a mates, he took it out, removed the rechargable batteries and put it back together, turned out to be a duff cell in it,
unlike mine on the grand, it got a ferking big screwdriver through it :011: then removed in the morning :icon_biggrin:
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Hi Daggie, so your saying, under the offside headlight an alarm unit with rechargeable batteries within it which are replaceable?. Is it obvious what it is by any chance?, thanks for the help.
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Unit fubar, it's a plug in type and can easily be replaced.
the alarm unit is fucked, its under the os headlight somewhere.
Indeed what I said :banghead: