Toyota Celica 2005 Repair Manual page 701

DI−502
CCV
Pressure Switching Valve
Closed
EVAP VSV
Cold Start
ECT/IAT nearly the same temp.
MONITOR DESCRIPTION
P0441
The ECM checks for a stuck closed malfunction in the EVAP VSV by commanding it to open with the CCV
closed. If a high negative pressure does not develop in the fuel tank, the ECM determines that the EVAP
VSV remains closed. The ECM turns on the MIL and a DTC is set.
The ECM checks for EVAP VSV "stuck open" fault by commanding both valves (EVAP VSV and CCV) to
close at a time when the fuel tank is at atmospheric pressure. If the fuel tank develops a high negative pres-
sure at this early stage of the test, the ECM determines that the EVAP VSV is stuck open.
The ECM will turn on the MIL and a DTC will be set.
P0446
If there is a malfunction detected in the evaporative emission (EVAP) VSV, the canister closed valve (CCV)
and the bypass valve, the ECM will illuminate the MIL and set a DTC.
This portion of the EVAP diagnosis checks the following EVAP system functions:
(a) CCV stuck closed.
The ECM checks for a CCV "stuck closed" malfunction by commanding the CCV to open after an EVAP
leak test. If the fuel tank pressure does not rise (no vacuum generated), the ECM determines that the
CCV is stuck closed. The ECM will turn on the MIL and a DTC will be set.
(b) Pressure switching valve stuck closed.
The ECM checks for a pressure switching valve "stuck closed" malfunction by commanding the pres-
sure switching valve to close after an EVAP leak test. If the fuel tank pressure does not change, the
ECM determines that the pressure switching valve is malfunctioning. The ECM will turn on the MIL and
a DTC will be set.
(c) EVAP VSV (Purge line to intake manifold) stuck closed.
The ECM checks for a stuck closed malfunction in the EVAP VSV by commanding it to open with the
CCV closed. If a high negative pressure does not develop in the fuel tank, the ECM determines that
the EVAP VSV remains closed. The ECM turns on the MIL and a DTC is set.
2005 CELICA (RM1131U)
DIAGNOSTICS − ENGINE (2ZZ−GE)
Open
Closed
Open
Closed
Open
P0441
Negative
Pressure
Introduction
700
Open
Closed
P0442, P0456 P0446
Tank & Canister Pressure Switching
Leak Check Valve, CCV Testing
Closed
A19285