Diagnostics in Beeston

Reading the code is the easy half. A code names a circuit, not a culprit. The failure you are trying to avoid is paying for the part the code named, driving away, and having the same light come back a fortnight later, because the named part was fine and something upstream of it was not: a corroded connector, a bad earth, a loom chafed through where it crosses the engine mount.

Tracing that means testing the circuit rather than swapping the part, which takes longer and is why a code-read-and-replace quote is cheaper. The board outside calls it Crypton tuning and engine management diagnostics, which is the older name for the same work and still the right one, because it is about how the engine is running rather than what the computer says about it.

Bring it in and describe what it is doing, when it does it, and whether it is cold or warm at the time. Those three answers narrow it more than the code does.