remote keyless entry

try resetting your security system


https://www.2carpros.com/articles/how-to-reset-a-security-system

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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?

ya but you need a scanner tofix that if round off means to fix it

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?

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

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?

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

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?

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.

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

I have a 1997 Jeep Grand Cherokee 2.5 diesel right hand drive. The alarm fob will not unlock door nor disable alarm and allow car to start. I have put fresah batteries in fob and have confirmed that it is transmitting a signal. What next? Can I permanently disable the alarm if so how?

System can be disarmed by unlocking a front door, liftgate if not by remote keyless entry transmitter(fob)
check door jam wiring harness

You cannot dissable the alarm permanently but you can reset it. That vehicle comes equiped with a VTSS Module (Vehicle Theft Security System). Locate it under the dashboard, left side, just the place you put your left knee while sitting on the driver's seat. Underneeth, the module has three connectors. One of them is square shaped. No need to unplug any, jus locate a violet wire with a black stripe, pinch it for a fraction of a second with a sewing pinch connected to a good ground. That will instantly dissable the alarm. What you have just done is what the door key switch does every time you unlock the vehicle from the outside by using your key. If you need to always use this procedure for disarming the alarm, then there might be a faulty swich sending spurious signals to the VTSS. The switches to inspect are the four doors open switches, liftgate open switch and hood open switch (this last one is a mercury one located on the base of the lamp that lights the engine compartment when the hood is lifted, it hangs from under the hood). Instead of wanting to disable the alarm permanently you can not arm it. You do that by always locking the doors manulally either by sliding the locks or by using your key to lock the vehicle from the outside. Do all this without moving the door lock switch levers that are on each front door.

the the key remote has been squashed so its not working but have got another remote from another jeep will have to be reprogramed? the red light on the dash is still flashing , but dont no how to bypass the imobliser its a 1998 grand cherokee ltd so is the VTSS connected to the imobiliser not sure many thanks

I was haveing a problem with an electrical drain and I found that fuse #8 was causing the problem, so I pulled it out and it set the security.

How do I reset the security?

Close all doors, hood and trunk and use the key to lock and unlock the door to disarm the system.

the VTSS is arming as the light is flashing on the dash but with the squashed remote carnt disarm the jeep il try the violet wire 1st then get the engine started and sort a new remote out

I closed the doors and hood and unlocked the driver side door with the key and the security is disabled. Jeep starts fine.

Every time I disconnect the battery the security will set. It did not do that before. Not a big deal but seems abnormal. Any ideas, thanks

No, that is normal. It happens to us all the time when working on a vehicle.

I have a 1993 Jeep Grand Cherokee Laredo that is having "issues". I get in it to start it and it doesn't even turn over, then the lights start flashing and the interior security light starts blinking. I have to get out of the car, lock the door, unlock the door to disable the security, then try to start it again. I have to do this over, and over, and over, until finally the jeep starts. It almost acts as if there is a kill switch that is screwing up and preventing me from starting the car. The thing is, I had a mechanic friend of mine look at it and he says there is not a kill switch. What the heck is going on and how can I fix this cheaply...money is definitely an issue.

Once the battery is disconnected, the security would reset when reconnecting. The only way it will not set is wile reconnecting the battery, the ignition switch is turned to ON, which is not advisable as it can fry the engine computer if there are any current surge.

I was told the security system is at fault, and would need to be replace! Only choice is to do what you are doing and enter with key through passenger door.

Now it does not fire up right away. the security lights are NOT flashing so that side seems normal.

Need some expertise.
It takes 4 or 5 crank attempts before it starts. I can not hear any activity at power distribution box for the first few cranks.
Also there is no spark on initial crank.

In detail: The coil has positive feed in run position, but not any ground pulse from PCM (on first 5 cranks). Also the fuel injectors are the same way no grounding pulse(on first 5 cranks)

I suspect Ignition switch, PCM, ASD relay, or possibly crank sensor.

I appreciate your help, thanks!

If difficulty in starting is only after angine is stopped for a while, the most likely cause would be drop in fuel pressure.

If there is not sparks, you need to test if battery voltage is available at the ignition coil while cranking, if yes, it is not likely to be the ignition switch or ASD relay. The PCM is a likely cause but PCM seldoms fails and allow you to start.

The most likely cause would be the crank or cam sensor depending on what is missing, fuel or sparks.

Ok here is where I'm at. The Jeep will not start in the first ten cranks, or the first 2 min of trying roughly.

1 The fuel pump does not come on.
2 The coil has 12v cranking but no PCM pulse and "NO SPARK"
3 Injectors also have 12v cranking but no PCM ground pulse.
4 Security/theft activated when battery is disconnected.

The first three problems go away after a minuet of cranking or so.

i had mechanic put new computer in cause it would not start now it starts for 3 sec. then shuts off the dealership says i have to replace that same computer along with another one too but if i go to junkyard can i get the two computers from same jeep and switch them out with mine or how can i disable the security so it can drive without shutting off thank you chris

Do you have the factory anti-theft system on your Jeep? I don't know if a '93 model was already using the Chrysler electronics but if it is, and you do not have the factory anti-theft system, you MUST use a used Body Computer from another vehicle that also did not have it. If you have the anti-theft system, you can use any computer from the salvage yard, but from then on, that computer will only work on another car that also has the anti-theft system. DO NOT borrow a friend's Engine Computer or Body Computer if his car doesn't have the anti-theft system.

Both computers have anti-theft programming that can not be undone. If your car does not have the anti-theft system, you must find a used computer from a donor car that also did not have anti-theft, and that can be impossible to find out from the salvage yard since there's no easy way to tell unless the car was running when it was brought in. Even then, they might not have bothered to find out.

When you install either the Body Computer or the Engine Computer with anti-theft programming into your car without anti-theft, the new computer will teach it to the other one. A Body Computer will teach it to the Engine Computer or a replacement Engine Computer will teach it to the Body Computer. At that point the car will not start because both computers are waiting for the disarm signal that's never coming. Both computers will have to be replaced at the same time. If you just replace one of them, it will immediately learn the anti-theft programming from the other one as soon as the ignition switch is turned on.

If you buy a remanufactured Body Computer from the dealer, it will come without the anti-theft programming. It will work in any car as soon as it is installed and will self-program itself for anti-theft only if the system is on the car, when it learns it from the Engine Computer.

Presence of battery voltage at the ignition coil and injectors indicates the ASD relay is being energised and should also energise the fuel pump relay.

Which engine do you have?

I have the 5.2l

I found whats going on, When I turn the key to the run position, I leave it there for 15 seconds then I hear the fuel pump come on and then I crank and it starts.

there is a delay in the ignition. Not sure why

The fuel pump relay is being energised late.

Attach a test light to the ignition coil power supply wire and turn ignition on. Note if battery voltage is present then or delayed as well.

If it is present, check the fuel pump relay. It could be failing.

If battery voltage is also delayed, you have a fault with the PCM. Check for bad ground circuit connections.

could I have wiring diagram of fuel pump relay?

I will check again but I believe the COIL POWER was NOT delayed.

Note: Delay problem is only when car is cold in the morning.

If the ignition coil power is not delayed, then most probably you have a problem with the fuel pump relay.

It could be a failing relay or poor connectivity with its wiring. Ignition coil receives its power from the ASD which is energised togethter with fuel pump relay.

I did some more testing, and both the fuel and ASD relay are not getting ground from PCM in the first 15 seconds with key in run position, followed by the security light.

Starts and runs well, just a delay.

Trying to find the valet button now.

A factory security system won't have a valet button. As for your relays, that's pretty much the way they are supposed to work. When the key is cycled on, you get a 2 second prime and then the relays shut off until the computer sees a tach signal from the crank sensor and then it energizes the relays again.

I said Its 15-20sec="delay" in run position before fuel pump even comes on.

followed by security on the dash!

If the 15 seconds is very consistent, it could be a fault with the key/security system which is taking an abnormally long pause before disabling the security system and turning the ASD and fuel pump relay on.

Did you keep disconnecting the battery?

If the delay is inconsistent, you could be looking at a failing PCM.

Looks like it is NOT leaning towards the PCM, Because of the security light. The dealerships say the security modules often go bad. Is there any way to test the security module circuits, or disable it. There are two modules that are both on passenger side.

I would like to disable the security if I could.

Also do you have any diagrams of the security modules?

Attached are the anti-theft wiring schematics.