Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Vehicle speed sensor ”a” / Circuit description
Toyota Corolla (E120): Circuit description
The vehicle equipped with abs detects a vehicle speed using the stability control ecu and wheel speed sensor. This sensor monitors a wheel rotation speed and sends the signal to the ecu.
The stability control ecu converts these wheel speed signals into a 4–pulse signal and outputs it to the ecm via the combination meter.
The ecm determines the vehicle speed based on the frequency of these pulse signals.
In the vehicle without abs, the no. 1 Vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the ecm. The ecm determines the vehicle speed based on the frequency of these pulse signal.
W/ abs:
W/o abs:
Monitor description
Equipped with abs:
the ecm assumes that the vehicle is driven when the rpm of the transmission counter gear indicates more than 300 rpm and it has been over 30 seconds since the park/neutral position switch was turned off. If there is no signal from the vehicle speed sensor with these conditions satisfied, the ecm concludes that there is a fault in the vehicle speed sensor. The ecm will turn on the mil and a dtc is set.
Not equipped with abs:
the ecm assumes that the vehicle is driven when the park/neutral position switch is off and it has been over 4 seconds since the actual vehicle speed was 9 km/h or more.
If there is no signal from the vehicle speed sensor with these conditions satisfied, the ecm concludes that there is a fault in the vehicle speed sensor. The ecm will turn on the mil and a dtc is set.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Wiring diagram
Other materials:
Replacement
1. Remove proportioning valve assy
Using sst, disconnect the 5 brake tubes from the proportioning
valve assy.
Sst 09023–00100
Remove the 2 bolts and proportioning valve assy from the
body.
2. Install proportioning valve assy
Install the proportioning valve assy w ...
If the vehicle becomes stuck
Carry out the following procedures if the tires spin or the vehicle becomes
stuck in mud, dirt or snow:
1 Stop the engine. Set the parking brake and shift the shift lever to P (automatic
transmission or continuously variable transmission) or N (manual transmission).
2 Remove the mud, snow or s ...
Circuit description
The shift solenoid valve sl is turned ”on” and ”off” by signals from the ecm
in order to control the hydraulic
pressure operation, the lock–up relay valve, which then the controls operation
of the lock–up clutch.
Fail safe function:
if the ecm detects a malfunction, it turns the ...