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Lotus Service Notes
Section EMP Page 31 Evaporative Emission Control – Purge, Open / Closed Circuit P0444 P0445 P0446 P0447 P0448 P0451 P0452 P0453 P0444 Evaporative Emission System Purge Control Valve Circuit Open P0445 Evaporative Emission System Purge Control Valve Circuit Closed P0446 Evaporative Emission System Vent Control Circuit P0447 Evaporative Emission System Vent Control Circuit Open P0448 Evaporative Emission System Vent Control Circuit Closed P0451 Evaporative Emission System Pressure Sensor/Switch Range/Performance P0452 Evaporative Emission System Pressure Sensor/Switch Low P0453 Evaporative Emission System Pressure Sensor/Switch High Description When the engine is running the ECU continuously monitors the feedback signals from the evaporative emission components. The feedback signal should be low when the turned ON and high when turned Off. The following codes will be set if the above conditions are not met. P0444, P0445, P0447, P0448, P0452, P0453 P0446 This code can be caused by the canister closure valve (CCV) being either stuck closed or open. CCV stuck open: A CCV is stuck open then there will be minimal tank depression when the leak test is performed. Addition check will be performed when the vehicle is being driven before the code is set. CCV stuck closed: Detection of a stuck closed CCV is implemented by detecting an excessively low tank pressure during normal purge. Detection of this fault will disable further purging Additional checks for stuck CCV closed: • Vehicle not stationary • Load between 30 – 35% • Purge Value >= 75% Monitor: Until leak check is completed. P0451 This code is set when the ECU detects abnormalities in the fuel tank vapour pressure sensor signal. The ECU analyses the filtered and unfiltered pressure signal at idle after a de-slosh period to determine if there is any difference, a big difference indicates as fault. The ECU also monitors the signal on gear changes to see if there is any pressure rise as a result of the fuel sloshing around. Disable Criteria: P0500 – Wheel speed sensor fault Monitor: Until leak check is completed Notes: The MIL will be illuminated if the fault is present for 2 consecutive trips. |