Weakness in transponder - alarm system

[Ardent]

Any thoughts or suggestions on this.

Had a drive came home parked on drive.

Got out closed doors  and pressed the lock button on the key. Car did not lock. Tried again no. Light red light comes on, on the key. Took apart had the multi meter on the battery 3.22v. Seems heathly enough there.

Put back together. Tried again took a couple of attempts then locked. At which point I thought oh bugger, what if it now won't unlock.  Took a few presses but it did. Phew!

So what are the things in play here.
The batt in the key seems fine.
Is the transponder in the key failing?
Is the receiver failing?
How to test, which, what and how.

No issues with starting.

Thoughts 

[Carolyn]

Any thoughts or suggestions on this.

Had a drive came home parked on drive.

Got out closed doors  and pressed the lock button on the key. Car did not lock. Tried again no. Light red light comes on, on the key. Took apart had the multi meter on the battery 3.22v. Seems heathly enough there.

Put back together. Tried again took a couple of attempts then locked. At which point I thought oh bugger, what if it now won't unlock.  Took a few presses but it did. Phew!

So what are the things in play here.
The batt in the key seems fine.
Is the transponder in the key failing?
Is the receiver failing?
How to test, which, what and how.

No issues with starting.

Thoughts 

Just try a new battery.   Apart from the meter reading it has all the symptoms of a struggling battery.

[rusty0273]

Any thoughts or suggestions on this.

Had a drive came home parked on drive.

Got out closed doors  and pressed the lock button on the key. Car did not lock. Tried again no. Light red light comes on, on the key. Took apart had the multi meter on the battery 3.22v. Seems heathly enough there.

Put back together. Tried again took a couple of attempts then locked. At which point I thought oh bugger, what if it now won't unlock.  Took a few presses but it did. Phew!

So what are the things in play here.
The batt in the key seems fine.
Is the transponder in the key failing?
Is the receiver failing?
How to test, which, what and how.

No issues with starting.

Thoughts 

Tried holding the key against your head  Never actually tried it but apparently it works. The other factor is temp if the key battery was particularly cold. If you take it and rub it in your hand a for a few second to warm it up, can be enough.

[bobo83]

Any thoughts or suggestions on this.

Had a drive came home parked on drive.

Got out closed doors  and pressed the lock button on the key. Car did not lock. Tried again no. Light red light comes on, on the key. Took apart had the multi meter on the battery 3.22v. Seems heathly enough there.

Put back together. Tried again took a couple of attempts then locked. At which point I thought oh bugger, what if it now won't unlock.  Took a few presses but it did. Phew!

So what are the things in play here.
The batt in the key seems fine.
Is the transponder in the key failing?
Is the receiver failing?
How to test, which, what and how.

No issues with starting.

Thoughts 

I sometimes have similar issues when trying to unlock the car. I am pressing the button hard enough but the car just does not react. Takes quite a few tries to unlock the car. The battery is a few months old and is a Toyota replacement.

To test the car key, I was thinking to use a spectrum analyser: press the button and check whether any message is broadcast on the right frequency. If the key works, have no good idea on how to test the car receiver.

Does anyone know what device in the car is responsible for the communication with the key ? And its location ?

[fawtytoo]

Is that the only remote key you have?

[moredun]

I would go with Carolyn's advice

95% battery, voltage might be ok, but no power (amps) to power the device   

[Ardent]

Tried holding the key against your head  Never actually tried it but apparently it works. The other factor is temp if the key battery was particularly cold. If you take it and rub it in your hand a for a few second to warm it up, can be enough.

I do the head trick with the more modern lozenger shaped fobs, but normally when distance is involved. Does work as well, which i find amusing.
Should have been warm enough but fair point and leans to weak battery.

[Ardent]

Does anyone know what device in the car is responsible for the communication with the key ? And its location ?

If it's where I think. It's the box you can see if you remove the tunnel just pokes down a bit. Sits above the gear/brake cables.

[Ardent]

Is that the only remote key you have?

I'm not sure now. This is the only one I've used. Think I have another not sure if it's a blipper though.

[Ardent]

Going with the batt option 1st.

[fawtytoo]

I'm not sure now. This is the only one I've used. Think I have another not sure if it's a blipper though.

I was just thinking that if you need to replace it, you'll have to go to Mr T if it's the only remote key you have. To program one yourself you need a working key (I don't know if the valet key will do the job).

[paulj]

If still a problem after you've changed batteries etc, is this a new problem?  If so have you also got a new wireless doorbell or camera?  Our alarms are old enough to be working on a frequency that got handed over for that sort of kit.  If that was the case you would only see the problem on the driveway and not when out and about.

[Ardent]

I was just thinking that if you need to replace it, you'll have to go to Mr T if it's the only remote key you have. To program one yourself you need a working key (I don't know if the valet key will do the job).

If i have got one, I can't find it. 
Not where I expected it very. Oops.

[Ardent]

If still a problem after you've changed batteries etc, is this a new problem?  If so have you also got a new wireless doorbell or camera?  Our alarms are old enough to be working on a frequency that got handed over for that sort of kit.  If that was the case you would only see the problem on the driveway and not when out and about.

Good shout.

[boor]

Weak car battery or more likely micro switch in the remote.

[Ardent]

Weak car battery or more likely micro switch in the remote.

Confident not the first. Fear the latter.
But still to change fob battery. Job for weekend.