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MG MGF Technical - Can the bonnet cause the superlock not to work


I really hope you guys can help as my F is making me unpopular !!! My F will not superlock and the alarm going off constantly. I can lock the car once but it doesn't flash the indicators - so I guess it thinks one of the doors is open. I have done the test below - which seems to work okay. The dash light illuminates for all openings except the bonnet, (front). The light works okay in the bonnet when it is opened but the test suggests there is a fault there. I've got no idea what to do now. If this a red herring - what else can I check.

Alarm system test

The alarm system can be tested by following the procedure described below:

1. Ensure doors, bonnet and boot lid are closed.
2. Sit in the drivers seat and close the door.

NOTE: The next three actions must be carried out within 2 seconds.

3. Depress the driverís door sill button.
4. Switch the ignition on, off and on again.
5. Raise the driverís door sill button.

If the test mode has been entered correctly, the horns will give a short beep and the engine immobilisation buzzer will sound.

Opening either door, the bonnet or the boot lid, or operating the driverís door sill button, will cause the alarm LED to illuminate for approximately one second. If the LED does not illuminate, there is a system fault.

The volumetric sensor can also be tested while in test mode. To test the volumetric sensor, press the unlock button on the remote handset several times. The alarm LED will illuminate for approximately 1 second each time movement is detected in the vehicle.

The test mode is cancelled by switching the ignition OFF.

Also, FYI...

If a door, bonnet or boot lid is open when the vehicle is locked, the alarm ECU withholds the indicator lamp flash and continuously illuminates the alarm LED to indicate that the system is not fully armed. However, perimetric protection will be armed for those doors/ bonnet/ boot lid that are closed and engine immobilisation will be set, but volumetric protection will not be armed. If the open door/ bonnet/ boot lid is subsequently closed, the alarm ECU flashes the direction indicator lamps and proceeds to flash the alarm LED to indicate that the system is now fully armed.

Taken from MGF manual.

I had this same problem a couple of years ago. it turned out that one of the door locks had become faulty. Once I replaced it (a reasonable DIY job) all went back to normal.


If replacing a door lock doesn't work, take a close look at wiring loom wher eit flexes on going into bootlid. This is a well-known source of a variety of faults.

Do you think the bonnet is just a red herring then. How do I determin which door lock is at fault. I had the drivers side done a few years ago when it completed jammed.

I have noticed that there are two horns on the F. Which one relates to the alarm if I disconnect it, (to get some sleep !!!).

Hi, having similar problems myself.

Booking it into the garage to to have the system looked at by testbook within the next couple of days. Both horn activate with the alarm so you will need to disconnect them both. Will publish the results of the testing so it may help. I will investegate the boot wiring tonight.

PT Greenwood

The alarm will sound when the light comes on, so perhaps it's more of a case of the light not switching off when the bonnet is closed? Have you checked the push switch which is activated when the bonnet closes?
Mark Clayton

Switch in bonnet works fine.

Is the superlock a seperate componant to the alarm. Still can't get it to superlock. I've had to disconnect the horn before the neighbours beat me up !!!

How do I get to the ECU to check that, (2000 model).

This thread was discussed between 01/01/2007 and 03/01/2007

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