"Something else that hasn't changed is vendor's annoying, no,
make that pathological mania for secrecy. Another gadget you can
get is one to read and decipher the trouble codes emitted by your
vehicle's engine. These have just a tiny bit of storage, so if you
don't capture the information quickly it's lost, which makes
diagnosing a transient problem ever so much fun. Auto manufacturers
hate these and try to keep their codes as Big Important
Sekkrits."