Looking at buying a 9n 2002 Polo (for my daughter).

It's got one recorded DTC fault code 17550

Load Calculation Cross Check Lower Limit Exceeded

which I have found

http://wiki.ross-tech.com/wiki/index.php/17550/P1142/004418

and one 17558.

O2 Control (Bank 2) Out of range

What could cause that?

It's 14 16v BBY engine which I fear is drive by wire.

Now got some freeze frame data. Engine load was very low 6.2% at time of fault.

Erasing the codes - and seeing if they recur.

For better or worse we bought it...

17550 DTC came back on the journey home.

at 65degC

1025 rpm

6mph

Engine load 8.2 %.

MAP 44kPA (0.44 bar)

ShortFt1 0%

LongFt1 -10.2%

Sys1 0L

I'm guessing a vacuum leak. Maybe the brake servo hose 6Q2612041AJ?

Brake servo hose was a tiny bit loose at the servo, but in reasonable condition, even at the one way valve.

Gave it a 1/8th turn on all the fittings and pushed them together, then used carb cleaner spray in the throttle body - when cold, the when idling, then when revved to 2500 - wow that throttle plate drive by wire operation is weird. I suppose the injection pulse lengths can control most fuel air needs at no load. So the cleaner spray managed to stall engine a few times. That gave some random misfire codes

Anyway, erased the codes. Restarted. No more EPC light on dashboard. No more codes after a short drive to reach temperature and upto 60mph.