Muddz

Hello,

I have a 1995 ZJ Limited (4.0L) where I swapped out a leaking oem plastic sides radiator for a new all aluminum aftermarket.

New radiator works well, however during and after the swap the OEM (factory installed) passive security system started to every once in a while go into power up mode (same as when the battery is disconnected and then re-connected).

Chrysler's passive security system isn't the same as the oem security system with an immobilizer. When the battery is disconnected and then reconnected the passive security system shuts off or restricts fuel output from the fuel injectors so no one can take off with your Jeep. At the same time it honks the horn and flashes the headlights.

There is also a "Diagnostic" mode which is a little different than power up mode after a battery disconnect. In diagnostic mode you can test the monitored security sensors such as door locks, power door locks, hood, tail-gate, ignition, etc. that all are working as expected.

The ZJ Limited keeps going into a "power up mode" (same or similar to when one disconnects then reconnects the battery).

To come out of "power up" or "diagnostic" modes one needs to turn the ign. key to on then off then reset the security with the key fob using power unlock from the keyfob.

I haven't yet figured out what's causing the power up mode to activate, honking the horn and flashing the headlamps.

Perhaps some sort of 12 volt hot wire from the battery connected to the passive security system board and or sec. system relay? Causing the passive sec. system to detect a false battery disconnection?

Muddz

I suppose some will say to just disable the alarm, which there are suppose to be different methods.

However I'm next a main road with lots of traffic, and next to the ocean with tourists throughout the year. The OEM passive security system does help prevent break-ins, car and parts theft, etc. Cars potentially can be stripped in the matter of mins. So I like having at least the oem passive security system which would help to a degree deter theft and break-ins.

I don't really want to try to disable the OEM and install an aftermarket system.

I think the problem may be the sensor that monitors the engine bay hood, but am uncertain how it operates.