Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Evaporative emission control
system / Circuit description
Toyota Corolla (E120): Circuit description
The vapor pressure sensor, vsv for canister closed valve (ccv), vsv for pressure switching valve are used to detect abnormalities in the evaporative emission control system.
The ecm decides whether there is an abnormality in the evaporative emission control system based on the vapor pressure sensor signal.
Dtcs p0441 and p0446 are recorded by the ecm when evaporative emissions leak from the components within the dotted line in fig. 1 Below, or when there is malfunction in both vsv for evap and vsv for pressure switching valve, or in the vapor pressure sensor itself.
Hint
: typical dtc output of each trouble part.
*1: Ecm may output some other dtcs combination.
*2: Refer to p0442 and p0456.
Monitor description
P0441
The ecm checks for a stuck closed malfunction in the vsv for evap by commanding it to open with the ccv closed. If a high negative pressure does not develop inthe fuel tank, the ecm determines that the vsv for evap remains closed. The ecm turns on the mil and a dtc is set.
The ecm checks for vsv for evap ”stuck open” fault by commanding both valves (vsv for evap and ccv) to close at a time when the fuel tank is at atmospheric pressure. If the fuel tank develops a high negative pressure at this early stage of the test, the ecm determines that the vsv for evap is stuck open.
The ecm will turn on the mil and a dtc is set.
P0446
If there is a malfunction detected in the vsv for evaporative emission (evap), the canister closed valve (ccv) and the vsv for bypass valve; the ecm will illuminate the mil and set a dtc.
This portion of the evap diagnosis checks the following evap system functions:
- 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 (lose vacuum), the ecm determines that the ccv is stuck closed. The ecm will turn on the mil and a dtc is set.
- vsv for pressure switching valve stuck closed.
The ecm checks for a vsv for pressure switching valve ”stuck closed” malfunction by commanding the vsv for pressure switching valve to close after an evap leak test. If the fuel tank pressure does not change, the ecm determines that the vsv for pressure switching valve is malfunctioning. The ecm will turn on the mil and a dtc is set.
- vsv for evap (purge line to intake manifold) stuck closed.
The ecm checks for a stuck closed malfunction in the vsv for evap by commanding it to open with the ccv closed. If a high negative pressure does not develop inthe fuel tank, the ecm determines that the vsv for evap remains closed. The ecm turns on the mil and a dtc is set.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
P0441
P0446
Monitor result (mode 06 data)
Refer for the detailed information on checking monitor status.
Wiring diagram
Other materials:
Cruise control
The vehicle can be driven at
a set speed even if the
accelerator pedal is not
depressed.
Use the cruise control only
on highways and expressways.
WARNING
■For safe use
Driving safely is solely the
responsibility of the driver.
Therefore, do not overly rely on
this system. The driver is solel ...
Circuit description
In the diagram below, when the engine is cranked, current flows from terminal
st2 of the ignition switch to
the starter relay coil and also current flows to terminal sta of the ecm (sta
signal).
When the sta signal and ne signal are input to the ecm, tr is turned on, current
flows to the c ...
RCTA function
■ Operation of the RCTA function
The RCTA function uses rear side radar sensors to detect vehicles
approaching from the right or left at the rear of the vehicle and alerts
the driver of the presence of such vehicles by flashing the outside
rear view mirror indicators and sounding a buzzer.
Appr ...