C5X7 2.0td anti theft fault dash watching

[aerodynamica]

Hm, I'm getting a "electronic anti theft fault" when I turn on the ignition. Car still starts.

Fault code I found was 04BA that seems to be different things when searched.

Possible the key fob?

[aerodynamica]

Car still starts and this has happened several times. Is something about to die!?

[aerodynamica]

Here's the fault as shown on the old type lexia 3

What do you suppose it means by 'type of event' disappearance

[GiveMeABreak]

Quite possibly Graeme!

This can be a non-characterised fault with the BSI - but in this case it is referring to the Electronic Immobiliser.

Fault Code:	F4BA
Description of Fault:	Electronic immobiliser fault: Not characterised. Key not authenticated after 1 or 2 seconds. At least one of the following conditions must be fulfilled: - Key in the ignition switch and identified: Ignition off - Ignition on
Conditions for Fault to clear:	The key is authenticated by the built-in systems interface
Downgrade Modes whilst Fault is active:	-
Symptoms:	Possible display of the message "electronic immobiliser faulty" Starting problem
Suspect Areas:	Built-in systems interface Switch module at the steering wheel Transponder aerial Key transponder Body CAN

[wheeler]

Cant really see it being a key fault if it's still starting ok but do you have another key to try just to rule it out? Does the remote still work as expected?
Next step is a BSI reset i would think.

[aerodynamica]

No spare key I'll do the reset. There may be trouble ahead

[aerodynamica]

Quite possibly Graeme!

This can be a non-characterised fault with the BSI - but in this case it is referring to the Electronic Immobiliser.

Fault Code:	F4BA
Description of Fault:	Electronic immobiliser fault: Not characterised. Key not authenticated after 1 or 2 seconds. At least one of the following conditions must be fulfilled: - Key in the ignition switch and identified: Ignition off - Ignition on
Conditions for Fault to clear:	The key is authenticated by the built-in systems interface
Downgrade Modes whilst Fault is active:	-
Symptoms:	Possible display of the message "electronic immobiliser faulty" Starting problem
Suspect Areas:	Built-in systems interface Switch module at the steering wheel Transponder aerial Key transponder Body CAN

I wonder if I disable the alarm via the button it might prevent any immobiliser issue?

[GiveMeABreak]

That's a separate system Graeme. This is concerning the signal from the key fob to the transponder aerial in the Comms unit under the steering wheel, that then starts the authentication to the BSI, Engine ECU and back again and concerns the starting of the vehicle.

Do you have your spare fob, and is this still happening when you use that one?

[aerodynamica]

Afraid I have no spare fob. Anything I should do?

[aerodynamica]

I've been quite lucky so far though, the C5 have been working very hard during a house move and renovation. Carried a lot of heavy loads, gravel, bricks etc. We went on a holiday trip last week Glasgow- Stoke on trent - alton towers - Glasgow. All good although this same fault appeared occasionally.

[GiveMeABreak]

Has the fob been dropped recently? I'm just thinking if that being the case it may have damaged the internals.

I'd certainly consider getting a spare at this point if you don't have one.

[aerodynamica]

Hi Marc, the only thing with the key fob was that I replaced the key and casing last year and swapped over the internals.

Is it a rigmarole (and a bank balance destroyer) to get a duplicate key?

[GiveMeABreak]

A new official one where the combination is specified on order and cut is part: 649073, £198.11
A Raw, uncut key fob is part: 6490A3, £168.42

These provide the same original OEM key cut to your key code for less - £121.20 inc. VAT:

https://www.car-keys-online.com/oem-rem ... 90-a3.html

[aerodynamica]

Thanks Marc, I've just been enquiring with a local keys place and see what they come up with.

[aerodynamica]

Well I have a new key. At first it looked as though the new key was not going to program to the car and I thought we were in trouble.. but it programmed and the old key was erased and reprogrammed. The car unlocks etc and starts on all keys and the message seems to not have reappeared. I'm tentatively saying it's fixed. Possibly the existing key was dropped or something in the past few weeks and had a minor problem. He did have a look at the board in the fob but said it looked clean and that all the solders appeared good. So who knows.
Thanks for the help all