Thread: Security light on

You may or may not know .. but battery condition is vital on a D2(compared to a D1, at least) to minimise security system issues.

I think this is common on all modern vehicles too tho .. my neighbours had the same issue with a small Mazda they own .. car sat a long time during lockdown, wouldn't unlock, then 'super locked itself' in their driveway.

At least in a D2 you can manually open the door with key, even it if may result in loud sounds from a blaring horn! ... with the Mazda, you don't get this luxury!

Before you examine the wonderland of security electrickery, be sure your battery is in very good to brand new condition, and not losing any charge .. then, if you still have issues investigate security system issues.

How old are the fob batteries? Been a while but I recall the light staying is a low fob voltage warning.

Originally Posted by AK83

You may or may not know .. but battery condition is vital on a D2(compared to a D1, at least) to minimise security system issues.

I think this is common on all modern vehicles too tho .. my neighbours had the same issue with a small Mazda they own .. car sat a long time during lockdown, wouldn't unlock, then 'super locked itself' in their driveway.

At least in a D2 you can manually open the door with key, even it if may result in loud sounds from a blaring horn! ... with the Mazda, you don't get this luxury!

Before you examine the wonderland of security electrickery, be sure your battery is in very good to brand new condition, and not losing any charge .. then, if you still have issues investigate security system issues.

Batt is brand new.

The "wonderland of security electrickery" is pretty scary.

Originally Posted by alien

How old are the fob batteries? Been a while but I recall the light staying is a low fob voltage warning.

Keys were new 2 years ago, but I'll change the batteries anyway.

The red LED will just flash when the battery in the fob is low if that's the setting in the BCU. If the LED stays on solid means the vehicle is immobilised and if you can override that with an unlock command the problem is with the passive immobiliser which should be disabled when you turn ignition on. If this happens with both fobs and they are D2 fobs not Rover 75 ones(which are the same from outside) then the problem is with the passive remobilisation exciter coil which doesnt react to the fob but unlocking with fob remobilises the vehicle for 30 seconds

Passive coil
The passive coil is located around the ignition key barrel. When the BCU detects that the ignition key has been turned
to the crank position, the vehicle's immobilisation system is activated and a signal is sent to the passive coil at a
frequency of 125 kHz. The magnetic field generated in the coil is induced in the remote transmitter to trigger a remobilisation
signal
.... The BCU controls the passive remobilisation exciter coil (located around the ignition barrel) to generate a magneticfield which causes the handset to transmit a remobilisation signal. The BCU receives the signal and allows the vehicle
to be started. If a valid signal from the handset is not received within one minute of the ignition being switched to
position II, the BCU stops the passive coil from generating the magnetic field.