Simply, a guy i work with has this displayed on his digital tachograph
“fault 13”
Now’ this guy is a bit of a nob to put it mildly and he’s in the deepest winnie the ■■■ at the minuite cos of alot of things but , me and another driver reckon he has done something to the digital taco. Deliberately tampering with it so as he can blame it for his em’‘’‘’’ shortcomings.
As far as i know it isn’t recording the mileage at all and the current time is hours off.
anyone shed any light on this fault 
Oooh thats a bad un!
13 Unauthorised change of motion sensor
Alex
Sorry for the double post but just found the full list as originally posted by “GeeBee” (very kindly)
EVENT CODES
General events;
00 No further details
01 Insertion of non valid card
02 Card conflict
03 Time overlap
04 Driving without an appropriate card
05 Card inserted whilst driving
06 Last card session not correctly closed
07 Overspeeding
08 Power supply interruption
09 Motion data errorVehicle Unit related security breach attempt events;
10 No further details
11 Motion sensor authentication failure
12 Tachograph card authentication failure
13 Unauthorised change of motion sensor
14 card data input integrity error
15 Stored user data integrity error
16 Internal data transfer error
17 Unauthorised case opening
18 Hardware sabotageSensor related security breach attempt events;
20 No further details
21 Authentication error
22 Stored data integrity error
23 Internal data transfer error
24 Unauthorised case opening
25 Hardware sabotageRecording equipment faults;
30 No further details
31 VU internal fault
32 Printer fault
33 Display fault
34 Downloading fault
35 Sensor fault
Card faults;40 No further details
Manufacturer specific;
80 Upwards
Reason for event / fault record;
00 One of the 10 most recent (or last) events or faults
01 The longest event for the last 10 days of occurrence
02 One of the 5 longest events over the last 365 days
03 The last event for one of the last 10 days of occurrence
04 The most serious event for one of the last 10 days of occurrence
05 One of the 5 most serious events over the last 365 days
06 The first event or fault having occurred after the last calibration
07 An active / on-going event or fault
80 onwards Manufacturer specific
ellies dad:
Simply, a guy i work with has this displayed on his digital tachograph
“fault 13”
Now’ this guy is a bit of a nob to put it mildly and he’s in the deepest winnie the ■■■ at the minuite cos of alot of things but , me and another driver reckon he has done something to the digital taco. Deliberately tampering with it so as he can blame it for his em’‘’‘’’ shortcomings.
As far as i know it isn’t recording the mileage at all and the current time is hours off.
anyone shed any light on this fault
Now this sounds a bit familiar…might be worth checking for the placing of a strong magnet close to the gearbox or so I am led to believe although I have never done it myself. But alegedly this scrambles the electronic signal \aand does daft things to the tacho .
Thanks lads, 
something tells me your both bang on the money.
Scarab:
Oooh thats a bad un!13 Unauthorised change of motion sensor
Alex
That what happens if you’ve had too many Immodiums?! 
Thats the last Immodium joke from me, i promise! 
Hammer,
I’m a tad worried, you seem to have a fixation with my bottom!
quite understandable of course, but none the less its still disturbing.
However, I might make it a monthly thing with them pills, I’ve never been so regular in my life, I even set the Tacho clock by it this morning!
vague attempt to keep this thread on topic
Mind you, it was a bit worrying when you climb into a lorry and the Tacho clock is SEVEN and a half hours out!
Alex
In get a code 13 fault several times a day, it comes up “Internal Fault 13” just after starting the engine if I don’t wait a moment between switching the ignition on and starting the engine. Most of our DAF’s seem to do this.