Mechanics

REMOTE KEYLESS ENTRY

1997 Jeep Grand Cherokee • 4.0L 6 cylinder 4WD Automatic • 100,000 miles

I'm asking on my father's behalf
The jeep is currently off the road. Awaiting mechanical repair (front anti roll bar bushes) and had developed a serious prob. Battery went flat due to standing so was fully recharged and locked/unlocked & started np's on Wed, but today (Fri) keyless entry and starting was not possible? New batteries in remote fob but still not unlock/lock and so no start due to immobilizer. Is there any way to test remote functionality as it has no visible indicators, no little red led lights on it nor is there a clear led (like on a tv remote that pokes out the front)?
I have tried to re-sync the remote but as it appears dead I have no way to check if it is synching?
I've seen the remote fobs on ebay if I buy one do I simply sync the New one or does it have to go the dealers? I don't have local dealer anymore
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Magmushroom
January 31, 2014.




Try resetting your security system look online how to do it if no manual

Hmac300
Jan 31, 2014.
Cheers, will have a look on web, manuals are useless only tells u how it operates and how to re-sync the remote fob. As far as I can tell without a working fob there's no way round ff alarm and immobiliser?

Tiny
Magmushroom
Jan 31, 2014.
Ya but you need a scanner tofix that if round off means to fix it
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Hmac300
Jan 31, 2014.
Not round off? The alarm is ff (factory fit) and the remote fob unlock has to be pressed in order to signal the immobiliser u intend to start the vehicle and as it appears the fob is not working (as I can't test it) the jeep won't start and I can't see a way of switching the alarm Or immobiliser off. If it is the fob at fault can I simply buy another and sync it or does it need a scan tool to sync it?

Tiny
Magmushroom
Jan 31, 2014.
Some need to be scanned to reset it if you have another one and it will start the car then you can just get another one and set it up like that otherwise it has to be programmed with a scanner. Most auto parts in u.S. Can test the key fob. So it may be an imobilizser problem which will require a scanner to fix it

Hmac300
Jan 31, 2014.
Can't understand how one day it's fine nxt nothing?
Btw we are in the UK and only have 1 fob, so to buy one only to have to find someone to program it, if there was leds in there I could check it but the no visual indicator to show when a button has been pressed? The old batteries appear ok good voltage etc, but New ones were put in as a precaution? My Vauxhall has similar system but a little black chip inside if lost needs expensive reprogrammed key but I'd have thought there would be a way to switch off the alarm/immobiliser without a fob? What are u supposed to do if your fob dies miles from home?
Idk it just looks like a standard 2 button alarm fob and on a 97 model I wouldn't have thought it would need reprogramming the a new fob bit no one seems to have a definitive answer to that Q?

Tiny
Magmushroom
Jan 31, 2014.
Normally if the key fob dies it'sno big deal the car will still start that is why I think there is something wrong with system or another problem

Hmac300
Jan 31, 2014.
As far as I can make out from the owners manual, (Haynes workshop manual doesn't mention alarm, etc.) The car can be locked/unlocked in various ways but the only way to start the car is to press unlock on the remote fob and turn key within 20 Or 30 secs if u don't press unlock on remote the immobiliser stays on and the car won't start. The owners manual says there is no way round it? I really don't understand the logic behind that as I said in my previous post what if your far from anywhere and the fob fails your stuck. It's all well and good resetting everything but it won't turn it off. I'd have thought there would be a way to start the vehicle in those circumstances. My remote fob for my car has a transponder chip inside that doesn't require any power if my fob don't work to unlock my car I just use the key and it'll still run if chip is present. Loose the chip and it's expensive. Rovers are similar so why are jeeps so diff?
Idk what to do with it?

Tiny
Magmushroom
Jan 31, 2014.
This is how it works if you unlock the door with a key it should disarm it.

Vehicles equipped with Vehicle Theft Security System (VTSS) are protected from vehicle theft and unauthorized entry. VTSS system monitors vehicle doors, liftgate and ignition system. If an attempt is made to enter or operate vehicle without proper disarming of system, vehicle horn will sound, headlights, taillights and parking lights will flash, and engine will be prevented from running.
VTSS system arms when ignition key is removed from ignition switch, headlights are off and doors are locked using power door lock switch. Alternatively a remote keyless entry transmitter can be used to arm system. A security light on panel will flash for 15 seconds to indicate system is arming. At the end of 15 seconds, if no door or tailgate is opened, system is armed.
If alarm is triggered, horn will sound for 3 minutes, and lights will flash for an additional 15 minutes. If horn sounds 3 times when either front door is unlocked, vehicle has been tampered with (tamper alert). If doors are locked manually or with key, system will not arm (manual override). If an unauthorized entry does occur, VTSS system signals Powertrain Control Module (PCM) to prevent vehicle from being driven. PCM reduces injector pulse width to zero, causing a start and stall condition.
System can be disarmed with the keyless entry transmitter, or by using key to enter vehicle. In both instances, if alarm was activated, vehicle alarm will be terminated. If battery is disconnected and reconnected, alarm will be activated and it will be necessary to disarm system.

I have no further suggestions.

Hmac300
Jan 31, 2014.
Thanks. Will have to check in drivers door I think he has a prob with the external door lock but I'll sort that and hopefully he can start it but I still don't know why it suddenly gave up the ghost. I know that model has a wiring prob associated with drivers door and it has been raining more than usual?But still thanks again ppl

Tiny
Magmushroom
Jan 31, 2014.

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