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rickhantz

Code Alarm system in 1998 subaru keeps going off when not set

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The alarm will go off occasionally when not set on. Vibrations sometimes will do it --like on a ferry. Other times its sitting in my driveway at night.

I replaced my car battery, as it was getting old --that didn't help. 

Any ideas? I'd prefer to fix myself. At minimum, I want the keyless remote to keep working. It would be nice to get the alarm reliable again, but I'd settle for disabling just the alarm system or the sound.

 

I did find some data in my glove box. Security System Upgrade Legacy H7110AS600  and H7110AS400 Remote Keyless Entry System

It does say that there is a shock sensor. If I can find it, maybe there is an adjustment.

 

Next time it goes off, I'll see how many chirps so I can check what set it off.

 

1998 Subaru Legacy Outback Wagon

 

Left it in valet mode last night. Alarm went off two or three times during the night.

I'll see how easy it is to just disconnect the siren until I can fix the system.

Edited by rickhantz

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No chirps, so no sensors set it off. I suspect a weak solenoid that gets triggered by vibration. A replacement module will be tough to find/

I cut the wire to the alarm speaker.

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I had a similar issue with 99' Lincoln Continental, where it was triggering the alarm randomly (always at night) despite the alarm NOT actually having been set. 

 

In my case, I traced the issue to the hood's plunger-style sensor. Basically, car reacts the same as if someone opened the hood w/o opening the car door, etc.

 

Door ajar dummy lights are helpful if equipped, as you'll often get a message while driving. Hatches and trunks usually trigger a message in many cars. Hoods however, don't.

 

To avoid the alarm, try unhooking the hood sensor, and if equipped, hatch/trunk sensor if you are certain the doors have been ruled out. Either replace the sensor or leave that unhooked.

 

On cars like Saab, they had a separate alarm "box" (usually behind the fender) with a speaker inside and it had it's own battery source that was supposed to stay charged. When they failed to keep a charge, they'd trigger the alarm.

 

Unsure what Subaru uses, but hopefully that'll be helpful as the alarm in your case will most likely still trip, and could drain the car battery.

Edited by Bushwick

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There should be two 'boxes' under the drive's side dash. 1 for the keyless, and 1 for the alarm. They should be labeled and tucked up there somewhere as it's a dealer-installed option, AFAIK.

 

Anyway....I can't recall for sure it it exists, but there might be a 'sensitivity' adjustment on the alarm box?

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I would think if the alarm is in valet mode, no sensors would trip the alarm. The alarm goes off even if the doors are unlocked, and locked in valet mode.

 

I looked all over the hood, and didn't find a hood sensor. I'll look again this weekend.

 

The hatch in back turns on a light when opened. I suspect that the alarm is tied into that, same as the front doors.

 

If the speaker is disconnected, there should be little battery drain even if the alarm goes off --just the timer circuit.

 

The OEM/ODM for the system is Code Alarm, now owned by Audiovox.

Edited by rickhantz

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I'm just guessing at the hood (for Subaru) as it is something that can trigger an alarm on some cars. In my case, it was along the driver's side fender on I think an "L" bracket and had a long rubber boot on it, and was a simple 2 wire deal (open/closed circuit) and was thankfully easy to get at. Once disconnected, it quit acting up. Unfortunately on that car, it'd flash the lights AND honk the horn; I unhooked my horn 1st as that was more offensive at 1am than the flashing. What's funny is they went through all the effort to alarm the car (only driver's side even has a key hole) and yet they mounted the actual horn in such a way you can reach under the front bumper and disconnect it in 5 seconds flat w/o removing anything else.....

 

Had a 96' Mark VIII with a driver's side door (another plunger-style sensor) that did the same thing, but I'd get the "door ajar" warning while driving. That sensor however was a rpita to even get to as Ford decided to mount it in the door jam. WD-40 worked as a temp-fix.

 

You "might" have a secondary battery pack in the box with the speaker. On my 9-3, it looked like a shorter AA battery IIRC. 

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I had this same issue on my 98 obw. You are getting interference from other peoples key fabs. My neighbors ford key fob would set my car off. I replaced the alarm module located under dash driver side and never had the issue happen again. They are cheap on eBay and super easy to reprogram your fabs

Edited by msmithmmx

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