Lotus 2004 Eleven Service Notes page 174

Lotus Service Notes
Evaporative Emission Control – Purge, Open / Closed Circuit
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.
Section EMP
P0444
P0445
P0446
P0447
P0448
P0451
P0452
P0453
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