Come on Pete, What do you really expect from a £50 DIY code reader , I cannot believe you are even wasting time on this.....

just for future reference

all petrol engines after 2001 had to be EOBD compliant.

all diesel engines after 2003 had to be EOBD complaint.

the Structure of the DTC is Standard and cannot have any deviation .

B Body
C Chassis
P Power-train
U Network (UART)

Generic (normally P0xxx) The definition for the code is defined in the EOBD / OBDII standard and will be the same for all manufacturers.

Manufacturer-specific (normally P1xxx) Where manufacturers feel that a code is not available within the generic list, they can add their own codes. The definitions for these are set by the manufacturer.

The third character defines the specific system or sub-system within the car where the problem is located

P01xx Fuel and Air Metering
P02xx Fuel and Air Metering (injector circuit malfunction only)
P03xx Ignition System or Misfire
P04xx Auxiliary Emission Control System
P05xx Vehicle Speed Control and Idle Control System
P06xx Computer Output Circuits
P07xx Transmission
p08xx Transmission

So if P0800 is the actual code then it must be Transmission related error , just like Mark has already stated.

But very high probability it is duff info from cheap scan tool...

HTH

Darren..