[Normal Diagnosis]

WARNING: This page is about a different variant/trim than selected.

Fig 1: Natural Vacuum Leakage Detection Normal Diagnosis Graph (1 Of 2)

Courtesy of KIA MOTORS AMERICA, INC.

Fig 2: Natural Vacuum Leakage Detection Normal Diagnosis Graph (2 Of 2)

Courtesy of KIA MOTORS AMERICA, INC.

Reading information (READ_INI & INI)
Ready to start diagnosis with initialization. Diagnosis starts with driver's request of vehicle start (key position at start)

When the process starts, ECM reads the NVLD information & failures which are saved during vehicle key OFF period.

The valid air temperature sensing range is -40°C to 120°C. An "out of range" is reported, if the measured temperature is out of this range. After requesting, the memorized values from the NVLD are read. The following information is acquired from the NVLD module; air temperature 6C deviation for at least 2 hour during soaking, checking NVLD switch closed during soaking, air temperature sensor plausibility/electrical failure check, which is detected during soaking, pressure switch electrical failure check during soaking, and reset failures due to power loss
Reading information (SW_VERSION)
NVLD sends the 8 bit software version value when the ECM performs a request.
Reading Air temperature (TAM_SWI_DIAG/READ_TAM)
When ECM requests NVLD Air temperature, the measured temperature value is sent to HCU as an 8-bit value.

In case an "out of range" error, maximum or minimum values are received. During the period, whenever ECM requests NVLD pressure switch electrical checking, NVLD returns the current and actual values for the electrical switch error. For the values are red from the NVLD, it is possible to return more than one electrical error at the same time, as all errors could have occurred during engine on phase.
Small leakage diagnosis (SMALL_LEAK_DIAG)
To check small leak, ECM requests the saved information from NVLD. During soaking, the resolution of switch closed time is 10min. This means, a maximum time of 2.5h (15 * 10min) can be counted. The switch closed time is reported to the ECM.
WAIT
Delay time to wait for the next process
Large leakage diagnosis (COMPLETE_DIAG)
At this process, ECM checks large leak with checking switch position. During large leak diagnosis, ECM requests switch position information which includes the current switch position and the switch position transition, which has been monitored since engine run.
PCSV plausibility diagnosis (CPS_CHK)
When Large leak error is detected or switch is closed at the beginning of engine start, canister purge valve (PCSV) stuck diagnosis is performed with opening PCSV.
STOP
When all of diagnosis are finished, ECM requests STOP mode. During the period, whenever ECM requests NVLD pressure switch electrical checking, NVLD returns the current and actual values for the electrical switch error until end of driving cycle.
ERROR
When any error is detected so EVAP monitoring can not be proceeded, ERROR status is performed.
OFF
When engine is off with key-off, ECM request STOP status. NVLD is reactivated with a wake-up call at next driving cycle (key position at start). During the period, NVLD checks its timer function and reports error message if any problem is detected.
SLEEP
If the key OFF monitoring conditions to detect small leak are not satisfied, ECM requests Sleep status. During the status, no calculations are done in NVLD during the key OFF period.