Golf Mk4 Alarm Problem

[dunfers]

Hi, stumbled on the site whilst trying to diagnose a fault with my Mk 4 Golf, looks like a really helpfull website.

Anyway, my problem:

The alarm on my Mk 4 Golf GTI wont stop going off !! Have had the car for about 6 months and had no real problem until now.

Symptoms:

The internal lights are staying on even though the car has been locked and all doors closed. Tried closing every door in the car: rear doors, passenger, drivers, bonnet and boot. Even made sure that the glovebox was locked. But the alarm (audible alarm and indicator lights flash) is going off regardless.

Interestingly when i had the car unlocked (alarm should be disabled?) and i opened the glovebox the alarm was triggered (????).

To stop the alarm from being triggered (it was sunday night after 6 and had been trying to fix for a couple of hours) i gave up and disabled the battery. This threw up a fresh problem when i reconnected to drive into work this morning: when i tried to shift into second gear the power was trying to cut out (bunny hopping) i could get round this by driving in 3rd.
At a junction i was in 1st, there was a crunch from under the bonnet, and 2nd was available again (???). Im now very concerned that i can do some serious damage.

Car booked in electrical specialist tomorrow, although a bit concerned about getting there !

Spec:

V reg Golf GTI (2.0) Mark IV roughly 60,000 miles, 5 door, no sunroof.

Any pointers at all would be greatly appreciated.

Thanks,

Paul

[Col]

What happens is....

The rear washer pipe splits where it goes into the motor and then procedes to wash the tailgate lock including the alarm microswitch, this then dies and sets off the alarm.

This is very common and accounts for most Golf alarm problems. Have you got any signs of wet around the tailgate area ?

Other then that, it's best to get the car diagnosed / read for faults. A faulty door lock module or the central convenience module could be faulty. The only way if the quick fix tailgate washer isn't the culprit (which should be easily identfiable) is to get it read for faults.

Good luck.

[dunfers]

No obvious signs of wetness around the tailgate area. Alarm seemed fine last night until about 8 in the evening, after not going off for about 4 hours. Was driving back home last night with the interior light flicking on and off randomly, so looks like a dodgy door sensor.

Is with the garage today, so will see what he comes up with.

Again this morning i was experiencing a loss of power and juddering when driving about 20..25 mph, after reconnecting the battery. Am i right to assume this is related to the alarm problem, seems too much of a coincidence to be a different fault.

Regards,

Paul

[Lex Luthor]

Again this morning i was experiencing a loss of power and juddering when driving about 20..25 mph, after reconnecting the battery. Am i right to assume this is related to the alarm problem, seems too much of a coincidence to be a different fault.

It is related to the battery disconnection.
It will be the throttle body that has lost its adaption. You can do an adaption via VAGCOM, some say turning the ignition on for 2 minutes will do it, or I think if you just drive it for a while it will relearn.
Might be on opportunity to clean the throttle body.

[dunfers]

Thanks for the reply Lex, handy to know. From the behaviour i was experiencing yesterday it seemed to sort itself out by the time I had reached work (5 miles drive).

Vag-Com seems like a handy tool so i have ordered a copy.

[dunfers]

Just off the phone to the garage. They are claiming that there is a fault in one of the Throttle Management sensors which is causing the juddering problem. When i put it to them that the TP just need realignment then they said they would check. Is it likely to be a dodgy sensor, or is the faulty reading being thrown because it needs re-alignment ?

I have only started seeing this throttle problem since i have disconnected the battery so i cant see it being a faulty sensor ?

[dunfers]

Sorry, TP should read TB in above.

[Lex Luthor]

Just off the phone to the garage. They are claiming that there is a fault in one of the Throttle Management sensors which is causing the juddering problem. When i put it to them that the TP just need realignment then they said they would check. Is it likely to be a dodgy sensor, or is the faulty reading being thrown because it needs re-alignment.

Is the garage saying that without seeing the car, or have they actually read fault codes ?
Probably just needs a clean where the butterfly seats.

[dunfers]

Got the car back from the garage. Bit of a waste of time as they havent fixed anything. They said that their software (Bosch, i think) would not give them access to the Central Locking or the Alarm modules of the ECM so they could not read the fault codes to diagnose the problem with the alarm. Im reluctant to take it to the VW dealership, but is looking increasingly likely.

Secondly, they said they found a fault with the Mass Air Flow sensor which is causing a loss of power. Though the sensor was not far enough gone to show a problem on the dash. They said it ran better with MAF disconnected (?) They also said that the MAF that was fitted was dated 1999, perhaps a second hand one, as the car is a V reg.

I was going to have a look at the sensor in the tailgate for signs of corrosion. The plastic panel on the inside of the boot is a pain to get off. Cant see it being easy to go back on either, i take it needs to come off though ?

[dunfers]

Got the plastic panel off in the end - couple of screws well hidden in the handle recesses ! Anyway, no obvious signs of water shorting the tailgate lock sensor - it all looks as new and dry as a bone. Weird.