Subaru Legacy Shock Sensor - removal and manual adjustment

So I bought the Rallitek Legacy GT Ltd wagon, knowing that it had the factory alarm, but not knowing that it also had the accessory shock sensor on it. I don't know if they even knew it was on it! There was no sticker on it stating that there was a shock sensor on it (or at least I don't know where the sticker lives).

Anyway, here are the instructions on how to remove it and adjust it. I'm not too sure if I've adjusted mine to my liking. I gave my tires a medium-light kick and whacked the B-pillar but it didn't chirp. I did this around 8:30pm so I didn't want to wake my daughter who was already asleep. I'll give it another go tomorrow during the day. Oh, and if you want to, click the images below to see a larger picture.

Tools needed:

a) a 10mm wrench

b) a small flat-head screw driver - I used one of those small "precision" screw drivers.

So on to the instructions!

1) Move the front passenger seat all the way forward. Gotta love power seats for this.

2) Open the rear passenger door, bend down and have a look under the seat. On the horizontal bar that spans the base of the seat, you should see a little tab, and a 10mm bolt holding the shock sensor to the seat. If all you see is the mounting tab and no black box, then you don't have the shock sensor.

Start by unplugging the sensor from its harness. It's a little tight in there - luckily my asian hands fit without much effort under the Japanese car seat. Feel around for the little spring-tab that keeps the plug locked in place. Press the tab and wiggle it out. It shouldn't come out with any force.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0325.jpg

Then use the 10mm wrench to unbolt the shock sensor from the mounting tab.

When you pull it out of the car, this is what you get:

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0302.JPG

Some more pics of the unit:

Hmmm, molded in Mexico, made in Japan. Good 'ole NAFTA at work! Here's the part number for everyone to see.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0307.jpg

Here you can see how the mounting bracket snaps to the case of the unit. In the previous image, you see the two other mounting positions of the unit.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0308.jpg

Here is the face where you plug the unit into the alarm harness found underneath the seat. This plate is what you pop open to remove the actual shock sensor circuitry. There are two outer locking tabs that secure the face to the body of the shock sensor. Gently pop the locking tabs one at a time. Once that is done, gently push the screw driver into the "little dimples" you see here above and below the white plug harness. The cover should come off with very little effort.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0305.jpg

Once the face comes out, simply slide out the circuit board from the case. In this photo, you can see the manual adjustment potentiometer. On mine, it was pre-marked with the knotch of the potentiometer at the blue mark seen below, so it's an easy line-up job to get the shock sensor back to stock. It doesn't look lined-up in the photo I took, but it was pretty well much lined up with the blue mark before I mucked about with it. The blue mark was pretty close to the middle of the range of sweep of the potentiometer.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0309.jpg

So according to odie1, turning the potentiometer to the right increases sensitivity. Turning the knob to the left decreases the shock sensor's sensitivity.

I turned my knob just past the "bottom right black dot." Like I said before, I'm not too sure if I like this setting or not. I didn't really get a chance to see how much of a whack I needed to give my car before it chirped. Drumming my fingers on the shock sensor when it was plugged back in did cause the car to chirp though.

Anyway, to put things back together simply slide the circuitry back into the box, clip the cover back on, go back to the car and secure the sensor back onto the bracket using the 10mm bolt and plug it back in! Voila! You've now adjusted the shock sensor!

A few caveats:

When I took my shock sensor out to open it up, I armed my car. After the 30 second delay, my alarm went off! Any guesses why? Well since there was no shock sensor plugged into the alarm it triggered itself to let me know something was wrong. I just hit the "unlock" button on the alarm fob and it shut right up. Don't be surprised if the alarm does go off when you arm it and the shock sensor is unplugged.

If you've unplugged your shock sensor and arm your car, and the alarm does NOT go off after 30 seconds, then it looks like your alarm's shock sensor setting was not enabled!! There's nothing you can do about it (if you've got a MY05 at least) other than to go to the dealership and get them to enable the shock sensor. While you're at the dealership, you might as well get them to adjust the shock sensor setting with the Subaru Select tool!

I snapped some other photos of the unit while it was out. Here's the "top" side of the unit. Notice that the impact unit itself is by Alpine, made in Korea.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0312.jpg

Here's the bottom of the circuitry for everyone to oogle at.

http://photos.yungfamily.ca/albums/userpics/Darren/shock%20sensor/thumb_IMG_0322.jpg

Enjoy everyone! Oh, and of course like with any mod or wrenching done on your car, you do so at your own risk or reward!

If someone really wants to make the adjustment easy access, simply drill a hole in the plastic where the potentiometer lives! Then you don't need to open up the case to adjust it - only a screw driver to turn the knob.

LaterZ!

Darren!!

There's an alarm without the shock sensor? I thought the shock sensor enabled the alarm?

There is an alarm that is armed when you lock the car with the remote key fob. When the corner lights flash after locking the car, that is a signal the the alarm is armed. The alarm will sound if anyone opens the hood, trunk or any doors while it is armed. An easy way to test it is to open a window, lock the car so that the alarm turns on, reach through the window, unlock the car and open the door. The two flashes of the corner lights when you unlock signals that the alarm is disarmed. This feature is in all the Legacies, not just ones with the shock sensor.

Edit: After looking at the manual again, it says that the alarm goes into a 30 second standby mode right after you lock the car (as referenced by the OP as well) so that the doors, hood or trunk can still be opened within 30 seconds of arming and the alarm will not go off. If you really want to test it I guess you'll have to wait 30 seconds after locking the car before opening a door.

Edit: After looking at the manual again, it says that the alarm goes into a 30 second standby mode right after you lock the car (as referenced by the OP as well) so that the doors, hood or trunk can still be opened within 30 seconds of arming and the alarm will not go off. If you really want to test it I guess you'll have to wait 30 seconds after locking the car before opening a door.

Yes, it does initially go into a 30 second stand-by mode. If you watch the flashing "security" signal on the instrument cluster, you'll notice that once you arm the vehicle, it flashes quickly to identify that it is in "stand-by" mode. Once it has gone through those 30 seconds, it resumes a slower flash telling you the alarm is now armed and activated.

sebberry - in my readings here on LGT.com and elsewhere, the shock sensor is an optional accessory that the buyer can purchase. Like I said in my intial post, I was pleasantly surprised to see that it came with the shock sensor. If the alarm does not have the optional shock sensor, it can only be triggered when one of the doors is opened. The shock sensor provides another trigger zone - say if the window is broken.

A few years ago, my sister's Accord was broken into - the driver's side window was smashed. The alarm didn't go off because it didn't have a shock sensor - only the keyless entry basic alarm. The thief stole the pocket change from the car by reaching through the broken window.

The very next day, my old car was broken into as well, however my alarm did go off. The vandal broke the passenger side rear window of my RS coupe which triggered the shock sensor. Nothing else was damaged or stolen in my car because the alarm scared them off.

LaterZ!

Darren!!

If you've unplugged your shock sensor and arm your car, and the alarm does NOT go off after 30 seconds, then it looks like your alarm's shock sensor setting was not enabled!! There's nothing you can do about it (if you've got a MY05 at least) other than to go to the dealership and get them to enable the shock sensor. While you're at the dealership, you might as well get them to adjust the shock sensor setting with the Subaru Select tool!

You can enable I think. There was an old thread and it stated the following:

Activating and Deactivating the alarm.

'Valet mode' is the same as deactivated

Activate or Deactivate/set Valet the alarm.

1. Sit in the driver's seat and shut all doors and rear gate etc

2. Cycle the ignition switch from LOCK to ON three times within 10 seconds, leave it in the ON position.

3. Within 10 seconds open and close the driver's door.

4. The current setting (on or off) will be displayed in the odometer/trip meter screen. It will say 'AL on' or 'AL off'

4. Within 10 seconds operate the driver's door locking switch as follows:

To deactivate, or set 'valet' mode:

Move the door panel power lock switch to the unlock position (toward the rear) three times. The odometer/trip meter screen will display 'AL OF'

To activate:

Move the door panel power lock switch to the lock position (toward the front) three times. The odometer/trip meter screen will display 'AL ON'.

When the setting has been changed, a buzzer will sound and the odometer/trip meter screen will display the new setting.

These steps only activate/deactivate the alarm, not the shock sensor itself. That option must be activated by the Subaru select tool, or, if you have the navigation system, I believe you can activate the shock sensor and adjust its sensitivity with it.

LaterZ!

Darren!!

How much is a shock sensor from subaru? It was on my list of parts to buy, but considering that somebody stuck some winterfresh gum to my front bumper the other day while I was at work, i'd like to get a shock sensor and turn up the sensitivity all the way.

Also, are the non-navigation shock sensors different from the ones you adjust with the nav system?

I don't think the shock sensor would detect someone sticking gum on your car.

As for the sensor itself, I believe it is the same sensor and that you can adjust its sensitivity through the NAV unit. I don't own a Spec-B nor a NAVI unit so I can't give you a 100% sure answer. I just remember reading it somewhere. As for turning on the shock sensor feature within the alarm, again, I'm not sure if you can do that using the NAV unit.

Sensor unit costs somewhere between $70-$100.

LaterZ!

Darren!!

Ok, I know this is a Legacy forum, but I'm at a loss. I bought a used '06 Outback SE wagon, that has what I believe to be an aftermarket security upgrade installed. I'm not sure if it's particularly a shock sensor, but it has an extra key fob that is required to be pressed in order for the car to start. I'm guessing that's an immobilizer of some sort?

Ideally, I'd like a second fob to go with the second set of keys, but the dealer doesn't know when it was installed or how to obtain a second one. So, I'm trying to figure out how difficult it would be to remove the system myself, as the dealer has no idea what it is. And, I don't feel like paying $90/hr to have them determine what it is, and remove it

Anyone have any idea what it might it might be with this information? The fob is a simple little circular one with a grey open lock button and a little red LED that lights when pressed.

Must. Not. Feed. Troll.

Seriously, though, I figured as good a place to ask as any.

If the alarm does not have the optional shock sensor, it can only be triggered when one of the doors is opened. The shock sensor provides another trigger zone - say if the window is broken.

i have this sensor and the broken window from a flying brick didnt set it off... sooo this mod is timely. i will give this a whirl tomorrow, thanks for the post!!

the dealer has confirmed that it is enabled, just need to up the sensitivity.