IMPORTANT:
Disconnecting the vehicle battery will cancel the fault memories
of control
units. Consequently, before disconnecting the car's battery, always
interrogate the fault memories. Investigate stored faults and, once any
faults have been remedied, cancel the fault memory.
Control unit
The N54 and N52KP meet ULEV II requirements for 2007. There are not many
changes to the emission
systems on these engines. The N54 engine has 2 underbody catalysts in addition
to the "near engine" catalysts
already in use from the N52.
The N51 engine, however, is a SULEV II compliant engine which