Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Evaporative emission control
system pressure sensor / Monitor description
Toyota Corolla (E120): 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 0.5 V and 4.5 V according to the pressure level in the fuel tank.
When the pressure in the fuel tank is low, the output voltage of the vapor pressure sensor is low. When it is high, the output voltage is high.
For this dtc p0451, the ecm checks for a ”noisy” sensor or a ”stuck” sensor.
The ecm checks for the ”noisy” sensor by monitoring the fuel tank pressures when the vehicle is stationary and there should be little variation in the tank pressure. If the indicated pressure varies beyond specified limits, the ecm will illuminate the mil and a dtc is set.
The ecm checks for the ”stuck” sensor by monitoring the fuel tank pressure for an extended time period.
If the indicated pressure does not change over this period, the ecm will conclude that the fuel tank pressure sensor is malfunctioning. The ecm will illuminate the mil and a dtc is set.
P0452 and p0453
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 0.5 V and 4.5 V according to the pressure level in the fuel tank.
When the pressure in the fuel tank is low, the output voltage of the vapor pressure sensor is low. When it is high, the output voltage is high.
If the output voltage of the vapor pressure sensor is out of the normal range, the ecm will determine that there is a malfunction in the sensor or sensor circuit.
When pressure indicated by the vapor pressure sensor deviates below –3.999 Kpa (–30 mmhg) or above 1.999 Kpa (15 mmhg), the ecm interprets this as a malfunction in the vapor pressure sensor. The ecm will turn on the mil and a dtc will be set.
Monitor strategy
P0451
P0452 and p0453
Typical enabling conditions
P0451
P0452 and p0453
Typical malfunction thresholds
P0451
P0452 and p0453
Wiring diagram
Refer to dtc no. P0441
Other materials:
Hydraulic test
1. Perform hydraulic test
Measure the line pressure.
Notice:
Do the test at normal operation atf temperature 50 to 80 °c (122 to
176 °f).
The line pressure test should always be carried out in pairs. One
technician should observe
the conditions of wheels or wheel stopper outsi ...
Brake fluid
■ Checking fluid level
The brake fluid level should be between the “MAX” and “MIN” lines on the tank.
■ Adding fluid
Make sure to check the fluid type and prepare the necessary item.
1 Slide and lift up the rubber strip to partially remove it as shown.
2 Disconnect the ...
Outside temperature display
The temperature display shows temperatures within the range of -40°F (-40°C)
to 122°F (50°C).
► Type A
► Type B
► Type C
► Type D
■The outside temperature is displayed when
►Vehicles without a smart key system
The engine switch is in the “ON ...