EMISSION CONTROL - K SERIES KV6 (page 6 of 7)

EMISSION CONTROL - K SERIES KV6

17-3-10 DESCRIPTION AND OPERATION

A check for minor leaks is only conducted after every 14th major leak check or after refuelling is detected.

At the end of the leak check the ECM stops the air pump and opens the change-over valve.

If the fuel filler cap is opened or refuelling is detected during the leak check, by a sudden drop in the current draw or 
rise in fuel level, the leak check is aborted.

If a leak is detected during the check, the ECM stores an appropriate fault code in memory. If a leak is detected on 
two consecutive checks, the ECM illuminates the MIL on the next drive cycle.

The duration of the leak check is between 40 and 270 seconds, depending on results and the level of fuel in the tank.

A leak test can be invoked using TestBook/T4, which overrides the baseline conditions requirement.

Leak Check Sequence

A = Pump motor current; B = Time

X = Current draw for tight system; Y =  Current draw for minor leak; Z =  Current draw for major leak

1 Pump motor energised: Air directed through reference orifice to atmosphere, to establish reference current.
2 Reference current.
3 Change-over valve energised: Air directed through EVAP canister into fuel tank.
4 Major leak check completed: If current is above stored value, no major leak present; if current is below stored 

value, major leak present.

5 Minor leak check completed, with no minor leak detected, when current exceeds reference value.
6 Minor leak check completed, with minor leak detected, when current stabilises at or below reference current.