Toyota Corolla Repair Manual: Circuit description
The vapor pressure sensor and the vsv for the canister closed valve (ccv) 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.
Dtc p0442 or p0456 is recorded by the ecm when evaporative emissions leak from the components within the dotted line in fig. 1 Below, or when the vapor pressure sensor malfunctions.
Hint
: typical dtc output of each trouble part.
*1: Ecm may output some other dtcs combination.
*2: Refer to dtc p0441 and p0446
Monitor description
The evaporative emission system consists of the vapor pressure sensor, the canister close valve (ccv), the vsv for pressure switching valve and the vsv for evap (purge vsv), those are used to detect malfunction in the system by ecm.
This test will run once per driving cycle when the ecm detects stable vapor pressure in the fuel tank. While the vehicle is being driven on rough or winding roads, the movement of the fuel in the tank will cause unstable fuel tank vapor pressures and the diagnostic test will not executed.
The ecm performs the following steps:
- the ccv is closed. (Shutting the system)
- the fuel tank pressure stability is checked. The diagnostic is disabled if the pressure change is more than specified value.
- the vsv for evap is opened. This introduces a negative pressure from the intake manifold to the fuel tank.
- the vsv for evap is closed and the negative pressure is sealed in the fuel tank.
- the ecm monitors the increase in fuel tank pressure for:
- rapid increase in the internal pressure i.E. A large leak: 0.040 Or more
- pressure rise just above normal
If the ecm detects either of above conditions, it will interpret this as a leak in the evap system. The ecm will illuminate the mil (2–trip detection logic) and set a dtc.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Monitor result (mode 06 data)
Refer for detailed information on checking monitor status.
Evaporative emission control
system leak detected
Dtc p0442 evaporative emission control
system leak detected (small leak)
Dtc p0456 evaporative emission control
system leak detected (very small
leak) ...
Inspection procedure
Hand–held tester:
1 Check fuel tank cap assy(check that fuel tank cap is toyota
genuine parts)
2 Check that fuel tank cap is correctly installed
3 Inspect fuel tank cap assy
4 Check f ...
Other materials:
How to register a Bluetooth® device
1 Display the “Bluetooth* Setup” screen. *: Bluetooth is a registered trademark
of Bluetooth SIG, Inc.
2 Select “Add”.
3 When this screen is displayed, search for the device name displayed on this
screen on the screen of your Bluetooth® device.
For details about operating the Bluetooth® devic ...
Receiving a call
When a call is received, the following screen is displayed together with a
sound.
To answer the phone
Press the switch on the steering
wheel or select .
To refuse a call
Press the switch on the steering
wheel or select .
To adjust the incoming call volume
Turn the “PWR/VOL” knob. You ...
Monitor description
Dtc p0451, p0452 or p0453 is recorded by the ecm when the vapor pressure
sensor malfunctions.
P0451
The ecm senses pressure in the fuel tank using the vapor pressure sensor. The
ecm supplies the sensor
with a regulated 5 v reference–voltage and the sensor returns a signal voltage
between ...