Unusual plip locking failure

DaveW · Unread post by **DaveW** » 14 Nov 2010, 21:38

Yesterday I unlocked the car with the plip and drove the short distance to home but when I used the plip to lock up there was no response from the car.
I checked the plip battery and that showed the correct 3V. so I then tried the spare plip - still no go (battery in that was OK also).

The courtesy lights fade down as normal and the 'lights left on' and 'key in ignition' alarms also work OK when a door is opened so it would seem that the Body computer has not died completely but there is a fault in the RF receiver.

Has anyone encountered this fault and been able to effect a repair?

Car is a Mk. II as per my signature.

Dave.

Toby_HDi · Unread post by **Toby_HDi** » 14 Nov 2010, 22:25

Try re-synchronising the keyfobs.

Key in ignition, switch ignition on and press a button on the keyfob.

DaveW · Unread post by **DaveW** » 15 Nov 2010, 00:27

I tried that but no success.

Dave

Unread post by **citroenxm** » 15 Nov 2010, 10:12

Switches on the Key Fob Board are surface mounted, with little solder...

BOTH of mine were broken on the Lock button but ok on the unlock.. ive managed to re solder them back on in work with a fine tip iorn...

Remove the bottom of the fob and take the board out and check the switches... this be my bet....

Paul

wheeler · Unread post by **wheeler** » 15 Nov 2010, 11:27

CPH (body computer) equiped cars have a habit of randomly loosing their coding for the plips & the only solution is to reprogram them with diagnostic gear like Lexia, you also need the cars 4 digit security code to do this.

DaveW · Unread post by **DaveW** » 15 Nov 2010, 11:41

Paul,

I did quite a bit of surgery on the plips for my MK I so I know that aspect can be an issue.
I will give the board a once over but It seems too coincidental that both plips should cease functioning at the same time. The reserve plip was working fine a couple of months ago and since then it has sat, undisturbed, in a drawer. Neither plip will lock or unlock the car.

Dave.

DaveW · Unread post by **DaveW** » 15 Nov 2010, 11:49

Wheeler,

Hmmmm..... Sounds like that could involve a dollop of cash. Any idea of how much?
Are there any diagnostic checks an amateur electronics bod can do to confirm that might be the problem?

Dave.

Unread post by **CitroJim** » 15 Nov 2010, 12:18

DaveW wrote:Are there any diagnostic checks an amateur electronics bod can do to confirm that might be the problem?

As the plips work in the 432MHz region, a quick test can be carried out by finding a local radio amateur enthusiast who has a receiver that will tune across the 70cm band and ask him/her to listen for a signal from the plip. It'll sound (at a guess) a bit like a mobile phone sounds when placed to near the wireless and it makes that motorboating sort of sound as the mobile does an announcement broadcast.

In the absence of a local radio ham, one of those cheap scanning receivers might do the job...

DaveW · Unread post by **DaveW** » 15 Nov 2010, 12:50

Jim,

Thanks for that. Knowing the frequency, I may be able to knock something up to do the job when I get the time.
At the moment the key works in the passenger door but there seems to be an obstruction in the drivers door lock stopping the key from entering more than about 1 Cm - the metal 'shutter' is not visible either. Is it possible to strip down the front (key) end of these locks?

Dave.

DaveW · Unread post by **DaveW** » 15 Nov 2010, 15:40

Update,

Today I drove to the local metropolis to do some shopping. I got out of the car and, without thinking, automatically pressed the plip ..... the locks operated !! I locked and unlocked the car a few times and everything worked without hesitation.

Drove home parked the car in the same spot as usual .. plip did not work.
Drove 100 yards up the village ... plip worked fine.
Drove back to the same parking spot but with the car pointing the opposite way .... plip worked.
Turned the car around and parked in the same spot .. plip did not work.

Now all of this may just be coincidental and the cause might just be an oxidised pin on a connector giving intermittent contact, but I will ask the neighbours if they have recently installed any wireless equipment - it's a very narrow road with most of the houses built onto each other.
I plan to check/clean the connectors on the Body computer anyway so is it necessary to remove the glove box to get to the Bc or can this be reached by removing the lower carpet/card trim?

Dave.

Unread post by **myglaren** » 15 Nov 2010, 16:22

There are a couple of spots at work where my remote won't work - nearby microwave aerials are considered to be responsible.

Unread post by **CitroJim** » 15 Nov 2010, 16:32

Again Dave, a local radio amateur might be able to help you out - it certainly seems you have a strong RF field around your way at around 430MHz. It's a small band any number of control devices can use, not just plips...

Odd that whatever it is is radiating constantly and enough to overcome your plip receiver...