Toyota RAV4 Service Manual: Brake switch "A" / "B" correlation
Description
The stop light switch is a duplex system that transmits two signals: stp and
st1-. These two signals are
used by the ecm to monitor whether or not the brake system is working properly.
If the signals, which
indicate the brake pedal is being depressed and released, are detected
simultaneously, the ecm
interprets this as a malfunction in the stop light switch and sets the dtc.
Hint:
The normal conditions are as shown in the table below. The signals can be
read using the intelligent
tester.
Wiring diagram
Inspection procedure
Hint:
- Read freeze frame data using the intelligent tester. Freeze frame data
records the engine condition
when malfunctions are detected. When troubleshooting, freeze frame data can
help determine if the
vehicle was moving or stationary, if the engine was warmed up or not, if the
air-fuel ratio was lean or
rich, and other data from the time the malfunction occurred.
- Stp signal conditions can be checked using the intelligent tester.
- Connect the intelligent tester to the dlc3.
- Turn the ignition switch on.
- Turn the tester on.
- Select the following menu items: diagnosis / enhanced obd ii / data list
/ primary /
stop light sw.
- Check the stp signal when the brake pedal is depressed and released.
- Check stop light switch assembly (terminal b voltage)
- Disconnect the a3 stop light switch connector.
- Turn the ignition switch on.
- Measure the voltage between the terminals of the a3
stop light switch connector and body ground.
Standard voltage
- Reconnect the stop light switch connector.
- Inspect stop light switch assembly
- Remove the stop light switch.
- Check the resistance.
Standard resistance
- Reinstall the stop light switch.
- Check ecm (stp and st1 - voltage)
- Disconnect the a9 ecm connector.
- Turn the ignition switch on.
- Measure the voltage between the terminals st1- and
stp of the a9 ecm connector and body ground.
standard voltage
- Reconnect the ecm connector.
- Inspect fuse (stop and ign fuse)
- Remove the stop and ign fuses from the instrument
panel junction block.
- Measure the resistance.
Standard resistance:
below 1
- Reinstall the stop and ign fuses.
description
The speed sensor detects the wheel speed and sends the appropriate signals to
the skid control ecu.
The skid control ecu converts these wheel speed signals into a 4-pulse signal ...
Description
The idling speed is controlled by the etcs (electronic throttle control
system). The etcs is comprised
of: 1) the one valve type throttle body; 2) the throttle actuator, which
op ...
Other materials:
Throttle actuator control motor circuit
Description
The throttle actuator is operated by the ecm and opens and closes the
throttle valve using gears.
The opening angle of the throttle valve is detected by the throttle position (tp)
sensor, which is mounted
on the throttle body. The tp sensor provides feedback to the ecm. This ...
Oxygen (a/f) sensor pumping current circuit
Description
Refer to dtc p2195 (see page es-292).
Monitor description
The air-fuel ratio (a/f) sensor varies its output voltage in proportion to
the air-fuel ratio. If the a/f sensor
impedance (alternating current resistance) or output voltage deviates greatly
from the standard range ...
Brake master cylinder
Components
On-vehicle inspection
Check brake fluid level warning switch
Remove the reservoir filler cap and strainer.
Disconnect the brake fluid level warning switch
connector.
Measure the resistance of the switch.
Hint:
There is a float inside the reservoir. Its positio ...