OBD Operation Summary for Fiesta - MotorCraftService.com

NVLD II Module OperationNVLD II module diagnostic operation is divided into three operational modes, which are entered depending on externalconditions.oooEngine On mode: The NVLD II module receives and responds to a communication request from the ECM.These requests are sent during engine run operation. On a key on event, a Wakeup-Request is sent toestablish communication between to NVLD II module and ECM.Diagnostic mode: At the end of a driving cycle (ECM powerlatch active), the NVLD II module receives aDiagnosis-Request to go into "diagnostic mode" and perform engine-off switch and temperature monitoring forvery small leak detection.Off mode: When diagnostic mode is finished or conditions for very small leak detection are not met, the NVLDII module receives a Sleep-Request and goes into "Off mode";Note: ∆T = difference between actual and maximum temperature valueIn diagnostic mode, after an initial delay time has elapsed, the temperature and switch position are checked every 10minutes and two separate conditions for small leak detection are determined by checking if the calibrated temperaturedifference between the actual temperature and the minimum temperature is met for at least 2 hours. If this occurs, acorresponding condition flag is set.ICONTINENTAL REVISED: SEPTEMBER 17, 2010 PAGE 19 OF 111