Hi Sean,

P2339 should clear as soon as the injector calibration factor for No 4 Cylinder (forget injector no. it is not relavent) has been entered correctly It does not have to be the right no as long as it is a valid one.

You do not have to clear the DTC the ECU clears it as soon as the above is carried out. If the code does not clear you or your equipment is doing something wrong.

Once the code is clear even if the engine is still running dog rough it will not reflag this code until it has covered some miles, (100 miles?) in order for the ECU to determine the knock threshold on that cylinder.

IMHO You need to sort out P2339 before going any further.

HTH

Mike