Volvo Key Fob Problem

Factual Questions
1

We have two Volvos, a 2004 S80 sedan and a 2007 XC70. My question concerns the S80, which my wife drives.

Last week I took that car out to gas it up for an upcoming trip that Mrs. P was making. After getting back into the car, I started it, and immediately got the ‘Trunk lid open’ message on the dashboard. Thinking that I’d accidentally pushed the trunk release button on the fob whilst turning the key, I got out, re-latched the trunk, and went on to my next stop.

After loading the cat food, I again started the car, and again got the ‘Trunk open’ message. Hmm… So I got out, closed the trunk again, got back into the car, and turned the ignition off.

Starting the car again, this time being very careful to not touch any of the buttons, and again get the ‘trunk open’ message. Okay, something’s wrong with my fob.

I mention it to the Mrs., and her reply was, “Yours, too?” Seems she’s been noticing the same thing.

Yesterday she had to take the car in for an oil change, and she mentioned it to the people at the service desk. Their reply was that the fob had probably been “…dropped a few times too many.”

WTF? I don’t drive her car that much; my set of keys for that car usually sit in the kitchen basket, and besides, neither of us ‘drop the keys’ too much. I can’t understand why BOTH keyfobs suddenly go bad, and I don’t buy the ‘dropped’ theory, especially since the service department’s solution is to replace the keyfobs, at a cost of $300(!) each.

So for now she’s just going to accept the exercise of starting the car and re-latching the trunk, but I’m wondering if anyone (Rick, maybe? :)) has any ideas or advice.

2

Have you changed the batteries in the keyfobs recently?
I imagine the car will advise when the voltage drops but maybe they are just above the threshold.

3

I intend to try replacing the batteries as soon as the car (and the Mrs) return on Wednesday.

I could understand it being a battery (or fob) problem if it only affected one key fob; happening on both makes me think ‘underlying electrical problem’.

But thanks.

4

It is more likely to be the receiver/decoder module but if both batteries are the same age they could be dieing.

It may not work with your S80 but one method of curing problems like this on mine (Citroën C5) is to wait for 15 minutes after stopping the engine, disconnect the battery and short the terminals, first through a resistor ( lightbulb) then a direct short after a few minute, leave the leads shorted for a while or leave the battery disconnected overnight then re-connect.
Sometimes it works, other times not but it is a cheap fix if it does. The only downside is having to reset the auto-wipers, lights, windows etc.

5

No doubt Rick will be along soon with the definitive answer, but I’m also doubting it’s the fobs. I’d suspect that the remote release mechanism is getting triggered by the startup routine, perhaps by a trickle of extra voltage in a reset signal somewhere.

6

::: Scratches head:::
Trunk open message? Only time I have seen that is when I did leave the damn trunk open.Over the next few weeks I will be working with several of the engineers from the US Volvo headquarters, so I will ask around.
Do you have the other fob that came with the car? Try using that and see what happens. If everything is normal with that fob, try new batteries in the first remote.
Do me one favor. The next time this happens, leave the car running, and go out and just press down on the trunk and see if A) it latches, and B) Does the message go away. If the answers to both are yes, the trunk was in fact open. If A= no, and B = yes, then I would suspect the trunk latch, or its adjustment. If the answer to both is no, then just turn off the ignition, pull the key out, re-insert and start the engine. If the trunk open message goes out at that point, it isn’t the fob.

7

Thanks for stopping by, Rick.

Yes, the trunk itself opens (well, unlatches, the lid doesn’t physically raise) and it happens with both key fobs.

As I said in my OP, I put the key in the ignition and turn it. The engine starts, the message appears. I get out and find the trunk unlatched. I push the lid down, it relatches and the message goes away. All is fine until the next time I start the car, then the whole rigmarole begins anew.

This happens with both key fobs. I know I’m not accidentally pushing the button on the fob as I turn it, since the S80’s fob is identical to the XC70’s, and I’m not unlatching my tailgate every time I start that car.

She’ll have the car back home on Wednesday; I will replace the batteries in both fobs then and report back.

I just wasn’t satisfied with the dealer’s idea that the fob was ‘dropped once too often’.

Thanks again for the attention and for anything you can find out.

8

Oh, sure. Fob this question off on Rick. :smiley:

9

OK, so the trunk is actually unlatched when you get the message. This would tend to point to the remote(s). It is odd that both would fail in exactly the same manner at the same time, unless it is in fact the batteries.
Anyway here are two of the answers I have received so far
“My first question: “Was the trunk REALLY unlatched?” If yes-go to the remote, If no-go to the circuit.”
and from an instructor buddy of mine
“I have not heard of this in regards to our key fobs but the techs may be changing them and not saying anything to me when they come to training.
I have had this stuck switch phenomena on several other electronics though. Some plastic changes shape as it ages. I had to take a radar detector apart and trim the underside of the opening for the mute button a few months ago. The case had changed shape enough to depress the button and it would not be making noise (not good!).
I have Creative Personal Media Center (gizmo that you loads movies, pictures, MP3 music into) that wouldn’t come on unless I removed the battery and then wouldn’t go off unless I did the same. The failure ocuured after it had been sitting in cabinet in my house for a year unused. I figured out that the switch on it did not have the “click” feel when you pushed it although it was depressing a few mm’s. Took it apart and trimmed the underside of the case where the button fits and it is fine now.
I vote for key fob plastic contortion as the cause.”
My suggestion is change the batteries and let’s go from there.
Oh and DSYoung everybody else does, why should the OP be any different? :smiley:

10

So the wife and the car came home the other night, and she told me that every single time she started the car, the trunk unlatched.

I went out with both key fobs and started the car. With her key fob, the car started, and the trunk remained latched. Huh. Tried it with my key fob. Same thing. The trunk remained latched.

Okay, now the damned car is just effing with me.

This morning, she went out to a meeting. Returning home she reported that on two out of three starts, the trunk was fine, but the third time it unlatched. :confused:

Okay, so I get a couple of new button cells for the fobs (2032, if you’re interested). I again go out to the car, and, before replacing any batteries, I start the car.

Starts fine, no trunk unlatch. Just for the heck of it, while the key is in the ignition, and with the car running, I press the trunk button on the key fob. It won’t unlatch. I try the trunk button on the other key fob, same thing. The trunk won’t unlatch while the car is running.

I turn the car off, but leave the key in the ignition. The trunk still won’t unlatch, with either keyfob, while the key is in the ignition. I remove the key, press the button, and the trunk unlatches. (I assume this is a safety issue, so one doesn’t accidentally unlatch the trunk at highway speeds.)

I should note here that this model Volvo has no other trunk release than the key fob; i.e., there’s no release in the interior of the car.

So now I’m totally at sea. I’ll hang on to the fresh batteries, and wait to see if the problem reappears, then replace them. If fresh batteries don’t eventually solve the problem, then I think we’ll bank the $600 that two new key fobs will cost, and just use the valet key for driving, and the keyfobs for locking and unlocking the vehicle.

Thanks to all who replied, especially Rick, whom I consider to be the Volvo guru around here.

11

I don’t know if this helps or not, but, once in awhile the electric door locks will appear to go haywire in my Jeep. The locks will cycle intermittently as I drive. This is the signal that it is, once again, time to disassemble the fob and resolder the switches. Seems that over time and repeated use, the solder fractures.

12

I would expect the trunk switch not to operate while the key is in the ignition, that is the way it is designed.

Since you have the batteries, I would go ahead and swap them to see what happens.

13

Is there REALLY a Volvo that doesn’t have a manual trunk release in the interior compartment??

14

With the exception of the convertible, none New model Volvo sedans (S40, S60, S80) have inside trunk releases.
Since there is a release on the key fob, and on the trunk itself, most people don’t see this an issue.

15

As of this morning, the trunk is unlatching itself every time the key is turned. So I replace the battery in the fob, and try it.

Still happens. Trunk unlatches.

But now the light bulb goes on over my head. I take the valet key (which, to this point, had never been tried), put that in the ignition, and start the car.

The trunk unlatches!

I was all set to buy into the ‘bad key fob’ idea, but this changes things, and sends me back to my ‘underlying electrical problem’ idea.

At any rate, back to the service department again…

16

Good, thank you for trying the valet key. I agree that the failure is in the car. Let me get my hands on a wiring diagram and look for some likely failure points.
[Arnold]I’ll be back[/Arnold]

17

I sent your post with some comments to one of my technicans (he has wiring diagrams, I don’t have these at home) here is his comments. Note my comments are inside the :

Note: His 2 cents is worth somewhere north of $100 per hour. :smiley:

If I was going to take a SWAG on this problem, I would have the technician swap the replay on the REM that controls the trunk motor with another of the same part number. See if the problem either goes away, or moves to a different circuit. Relays sometimes get funky when they get old, and it might be triggering off the noise in the circuit as the car starts.
I hope this helps. If you need further info feel free to IM me or send an e mail.

18

I was having problems with the fob on my 960 wagon. I tried replacing the batteries but couldn’t get through the reprogramming steps in the manual.

So I said fuck it. I turn the key when I need to open the door. Do the same for the hatch.

Works like a charm.

19

FYI 960 programming instructions (from memory)
Get into car, and close the doors
Quickly turn the ignition key off and on 5 times. The last time leave it on.
Press button on fob
Remove key and test.

sunacres The newer cars are designed to have the remote used. The driver’s door keyway for instance is hidden under a piece of plastic trim. The passenger’s door does not even have a keyway.

20

Thank you, Rick. And thank you freaking genius technician, too. I will print out this thread for when we take the car in.

Rick, if I read your comments correctly regarding the UEM: You say that “…rather than pulling the batteries, just get the remotes at least 50 feet away and that will eliminate them”, this means I should try starting the car with the valet key, while the remotes are out of range? Or should I try starting the car with the keyfob, but with its battery removed?

Maybe I’ll just do all the above.

Thanks again.