jeep_tuner001

Hi guys,after trouble-shooting i recently changed my ecu in my 94 grand cherokee jeep limited 4.0 because it won't start at all. After it started , i thought everything was ok but unfortunately the oem alarm started to act up. I made sure that the ecu # of my old matches the new ecu. is it possible for me to bypass the oem/factory alarm? Any inputs are welcome.TIA guys

Willys55

ecu has nothing to do with the alarm, did you try putting your key into the driver door lock and lock and unlock the car.....this should deactivate the alarm,.

ol"blue

I'm not much on electrical, but when I replaced the battery on my '97 it acted up. I used the power lock button to lock it and closed the door. Then I used the key to open the drivers door and all was fine. The alarm and the key-less fob then worked as intended.

OverlandZJ

Yeah it does, you need to match the ECU part#'s dependant on whether Security is installed on the vehicle or not.

But i'm betting he didnt deactivate with a key.

jeep_tuner001

guys , did all that, to the extent of bypassing the alarm with the yellow/purple (-) wire on the black plug under the driver's side kick panel and grounding it. unfortunately when i get to start it and drive it around the block , the security indicator in the instrument panel keeps on blinking, no radio and no a/c blower, and even the door open display in my console has no display..any inputs guys,will be greatly appreciated. this is my daily driver and really need to get it running asap

ol"blue

I'm at a loss here. Maybe seed will shed some light on this when he logs on. He's the ZJ guru.

Willys55

I think this might help.
The BCM controls the security system, not the ECM.........
Got this off of ALLDATA.com.....................
Reset Procedure

When the armed VTSS senses that the battery has been disconnected and reconnected, it enters its power-up mode. In the power-up mode the alarm system remains armed following a battery failure or disconnect. If the VTSS was armed prior to a battery disconnect or failure, the system will have to be actively or passively disarmed following a battery reconnection.

The power-up mode will also apply if the battery goes dead while the system is armed and battery jump-starting is attempted. The engine no-run feature will prevent the engine from starting until the alarm system has been actively or passively disarmed.

Passive disarming of the Vehicle Theft Security System (VTSS) occurs when the vehicle is unlocked using the key to unlock either front door or the liftgate. Active disarming of the VTSS occurs when the vehicle is unlocked by depressing the Unlock button of the Remote Keyless Entry (RKE) transmitter.

Once the alarm has been activated (horn sounding, lights flashing, and the engine no-run feature), either disarming method will deactivate the alarm.

Depressing the Panic button (if equipped) on the RKE transmitter will also disarm the VTSS, but the horn will sound and the lights will flash for about three minutes as part of the Panic feature. The horn and lights can be stopped by pressing any of the RKE transmitter's buttons or driving the vehicle above 15 mph

seed

Did you ground the correct end of the yellow/purple trace wire?

jeep_tuner001

Hi seed, i grounded the yellow/ purple after which the water temperature gauge needle went up and thats the only yellow/purple wire that i saw, is it the only yellow/purple wire or did i miss something? hoping for your soonest reply guys....TIA

seed

I was asking if that,after you cut the wire, you capped the end that goes to the door and grounded the other,otherwise i don't think it will work.

I do not know if there are any other purple with yellow tracer but it does sound like you may have cut the wrong wire.

Is your alarm still going off? could be one of the door or hood sensors,also a failing battery can cause alarm issues.

jeep_tuner001

seed, after battery reconnection, i disabled the alarm via passive disarming (key unlock driver side door), after which it started instantly no blinking security etc.. after driving for 15 minutes around the block , my jeep just stopped and won't start again even if i disconnect the battery and reset the alarm. I towed my jeep to my house, still won't start....Even did what you told me to bypass the oem alarm re. yellow/purple cutting it and grounding the other end, but still won't start. I am really at a lost here......

jeep_tuner001

guys, any inputs will be greatly appreciated..

seed

Does it crank or do nothing?

jeep_tuner001

it just cranks

seed

ok,do you have spark and fuel?