[mfinkbiner]

I have 2006 RTS with 46000 miles. I'm the second owner and have had it for about 18 months. Carfax says it has never been wrecked. It has the stock factory alarm, as far as I know. When it's been locked I can see lights blinking on the stereo and on the drivers side door.

A couple of times over the last year the alarm has sounded without any cause I can see. The one time I was there, I tried to turn it off by turning the engine on, opening and closing the doors, etc. but it just shut off by itself after a couple of minutes.

Yesterday after driving 150 miles I stopped for gas and left it unlocked while shut down. It started OK and I drove across the street to a restaurant, shut down and locked with the fob. After dinner I unlocked using the fob, got in, started the truck and the alarm sounded. I tried locking and unlocking the doors with the door switch, no change. Drove to the far end of the parking lot, still sounding the alarm. Started looking through the owners manual, no real info.

Alarm shut off, I re-started, it sounded again. I found the horn fuse and pulled it - blessed silence. But that controls the brake lights, too. I re-started with the fuse out, and reinstalled the fuse with the engine running. The brake lights work, and no alarm sound. No blinking lights either.

Drove home with the ABS and Stability Assist lights glowing on the dashboard.

When I shut off in the driveway, the alarm sounded. Popped the hood, pulled the fuse, and noticed the lights were flashing. Don't believe that was happening at the restaurant, but wouldn't swear to it. Unloaded the truck from my trip, several times opening and closing doors. Tried locking and unlocking. When I opened a door the interior and exterior lights would flash for a few minutes.

They eventually shut off. This morning I unlocked with the fob got in and started. The fuse is still out, so I don't know if the alarm would have sounded, but no interior or exterior lights flashed when I shut down.

I have been reading online and can't find a way to just disable the alarm while I work out the issue. The dealer is a fair distance away (small town north Idaho). I might check with the local auto electrical specialist who has a good reputation.

So -

- I read there is a TSB about software problems in the security system control unit.
- Some folks believe the hood latch is a common problem
- I haven't been able to find instructions on how to disable the alarm so I can drive it while figuring this out.

Any suggestions?

 

[AlexRTS]

Sounds like you have a bad case of electrical gremlins!

I read there is a TSB about software problems in the security system control unit.

I have not seen anything about this personally nor have I had issues with my 2006.

Some folks believe the hood latch is a common problem

The hood latch sensor can prevent the alarm from engaging (you'll notice the horn won't honk if you press lock twice on your key fob). I don't know for sure if the hood latch sensor is a trigger for the alarm.

You stated that the alarm sounds when starting the engine. This is kind of strange, because under normal circumstances that would disable the alarm.

You could potentially have:
- an electrical short in one of the triggering sensors
- a faulty connection between the MICU and one of the triggering sensors
- a bad sensor
- a malfunctioning MICU

If you've got the "know how" for electrical diagnostics, perhaps you can check some of this out yourself. Wiring Codes Here

If you're like me, aside from finding a mechanically broken sensor, a disconnected wire or an obvious short - you'll likely require professional assistance. With the exception of diagnosing the MICU, any reputable repair shop that specializes in electronics would be good in my book. Even better if you can take it to a mobile electronics store... one that sells and installs remote starts and the like.

Also, just for sh*ts and giggles - have your battery tested. If it checks out low just replace it. You'll need to replace it anyway and there's a slim chance that it may solve your problems. Hondas and this vehicle in particular seem to be more sensitive to low voltages than others.

Keep us updated and good luck solving this issue

 

[boobai]

+1 on start with the battery

 

[mfinkbiner]

Thanks for the suggestions. Yes, it kept alarming while the engine was running until it timed out, and then started again when I turned the key to re-start.

The TSB I referred to was mentioned at the end of this thread, but I didn't see a Honda ID -

http://honda-tech.com/showthread.php?t=2794870

Accessory Security System Triggers Unexpectedly
(Supersedes 05-010, dated April 15, 2005, to update the information marked with the black bar)
SYMPTOM
The accessory security system triggers unexpectedly
(the horn sounds and the parking lights flash)
PROBABLE CAUSE
A software problem in the security system control unit
(control unit).
CORRECTIVE ACTION
Replace the control unit and the security system
microphone.
>>>>>>>>>>>>

Don't know if it would apply in my case.

After your thoughts about low voltage, I took an analog multimeter out and checked. The battery after sitting all night is showing 12.5 v measured across the terminals. Starting the engine (with the horn fuse still out) brought no flashing lights and a voltage of 14 - 14.1

The VSA and ABS icons on the dash weren't lit any more, so I put the horn fuse in while it was still running. No change. I shut down and re-started. No alarm, the dash icons lit and then went out as normal.

So - perhaps the issue has to do with heat buildup? It's mid-60s today and the truck is in the shade, plus it's only been run for a few minutes since last night.

Will talk to my mechanic tomorrow.

No way you know of to disconnect the alarm system so I don't have to worry about it going off unexpectedly until this is resolved?

 

[Ourfarm09]

The battery voltage reading looks good, but a least have it load tested.

 

[mfinkbiner]

Talked to the dealer this morning. The service tech said this wasn't a known problem, and that the alarm doesn't save any codes to tell you what caused the alarm, so if it isn't going off at the time they can't tell what the problem is.

He's not aware of any TSB on the alarm system, but didn't check for one.

He also said this is the procedure to turn off the alarm. Turn off the car if it's running, then use the key in the driver's side door lock cylinder on the outside to manually unlock and lock the door. That should turn the alarm system off.

At this point I guess I'll have to wait for it to happen again and see if that works.

I'll also arrange to have the electrical system load tested.

Oh the joy of intermittent electrical issues!

 

[AlexRTS]

The battery voltage reading looks good, but a least have it load tested.

+1 on this.


The service bulletin you refer to appears to be from a 2003-2005 Accord (2003–05 Accord DX and LX With Accessory Security System). Here's a link to the TSB.

It's referring to an accessory security system -- an "upgrade" from the standard factory system. I don't recall there being such an accessory available on the Ridgeline, but if you have some sort of aftermarket alarm installed, you might experience the same types of issues. Perhaps bringing your truck in to a mobile electronics shop would be a good investment of your time.

Additionally, the TSB states the alarm may trigger unexpectedly when "you open the door, or when you insert the key into the ignition switch, or while driving"
Has your alarm triggered when you inserted the key into the ignition, or does it not trigger until you actually start the engine? This could be a crucial bit of information in diagnosing your issue. Electrical gremlins when starting your engine (i.e., putting the electrical system under the heaviest load it will ever encounter) seem to point towards a bad ground or bad connections.

You may want to also check your ground cable. I had a bad ground and it did some pretty funky stuff. If you're curious, here's what a "good ground" and a "bad ground" look like on an oscilloscope. These were taken before and after replacing the ground cable - each while starting the engine. If you think your problem could potentially be more widespread than just your alarm system, you may want to look here.



BEFORE

AFTER

 

[mfinkbiner]

I have an appointment at the electrical specialist place on Tuesday to load test the battery/charger system. They will also look for ground issues - good suggestion.

Thinking back I believe the alarm started going off when I turned the ignition on, but it also went off when I shut down in the driveway. The lights flashing also occurred when I opened a door after the truck had been shut down for awhile.

I drove to work and the grocery store yesterday with no issues, but short distances so nothing warmed up completely, if heat is part of the problem.

My other vehicle is an '87 Vanagon Westfalia camper, and I have fought lots of grounding issues there with the Digifant ignition system. Hoped a newer rig would get me out of that! :act002:

Thanks for the help, I'll let you know what happens.

 

[AlexRTS]

Has this issue been resolved?

 

[larryr]

the RFID piece in the keyfob might be bad - the car reads it and if it is not a match to the stored info the alarm will go off.

New keyfob and the dealer programming it in might be the fix. Might be possible to move the cut key part to the new keyfob or if you have the tag for the key the dealer can cut a new one ( they can look it up via the VIN number too).

 

[mfinkbiner]

Electrical Specialists looked at the car and were unable to reproduce the problem. It hasn't misbehaved since the trip back from Seattle.

They did find a fair bit of corrosion on the positive terminal of the battery. It looked clean on the outside, but when they took it apart found the corrosion. They felt that is a possible cause, because it can cause a voltage drop when the circumstances are right, which could cause the alarm to go off.

We'll have to see what happens now. If if never misbehaves again I'll be happy, but I'm glad I know where the horn fuse is!

Thanks for your suggestions. At this point all I can do is wait and see.