Toyota RAV4 Service Manual: System description
- Brief description
- The can (controller area network) is a serial data
communication system for real time application. It is
a vehicle multiplex communication system which
has a high communication speed (500 kbps) and
the ability to detect malfunctions.
- By pairing the canh and canl bus lines, the can
performs communication based on differential
voltages.
- Many ecus (sensors) installed on the vehicle
operate by sharing information and communicating
with each other
- The can has 2 resistors of 120 ù which are
necessary to communicate with the main wire.
- Definition of terms
- Main wire
- The main wire is a wire harness between the 2
terminus circuits on the bus (communication
line). This is the main bus in the can
communication system.
- Branch wire
- The branch wire is a wire harness which
diverges from the main wire to an ecu or
sensor.
- Terminus circuit
- The terminus circuit is a circuit which converts
the communication current of the can
communication into the bus voltage. It consists
of a resistor and condenser. 2 Terminus circuits
are necessary on a bus.
- Can j/c
The can j/c is a junction designed for can
communication, which contains a terminus
circuit.
- Ecu or sensor which communicate via can communication system
- Abs and traction actuator (skid control ecu)
- Power steering ecu
- Steering angle sensor
- Yaw rate sensor
- Ecm
- Center airbag sensor
- Air conditioning amplifier
- Combination meter ecu
- Main body ecu
- 4Wd control ecu*
Hint:
*: For 4wd
- Diagnostic codes for can communication
system
- Dtcs for the can communication system are as
follows: u0073, u0100, u0105, u0121, u0122,
u0123, u0124, u0126, u0129, c1280, c1296,
c1297, and b1499.
- Notes regarding troubleshooting
- Trouble in the can bus (communication line) can be
checked through the dlc3 (except when there is a
wire break other than in the branch wire of the
dlc3).
Notice:
Do not connect the tester directly to the dlc3
connector. Be sure to use a service wire.
- Dtcs regarding the can communication system
can be checked using the intelligent tester.
- The can communication system cannot detect
trouble in the branch line of the dlc3 even though
the dlc3 is also connected to the can
communication system.
System diagram
Hint:
The abs and traction actuator (skid control ecu)
detects and stores steering sensor and yaw rate
sensor dtcs and performs dtc communication by
receiving ...
Notice:
Dtcs for the can communication system are as
follows: u0073, u0100, u0105, u0121, u0122, u0123,
u0124, u0126, u0129, c1280, c1296, c1297, and
b1499.
Refer to the troubleshooting pr ...
Other materials:
Control module communication bus off
Description
Inspection procedure
The skid control ecu inputs the signals from the ecm, steering angle sensor,
and yaw rate and
acceleration sensor via can communication system.
Check harness and connector (momentary interruption)
Using the data list of the intelligent test ...
Hazard warning switch
Components
Removal
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove no. 1 Instrument cluster finish
panel cente ...
Active test
Hint:
Performing an active test enables components
including the relays, vsv (vacuum switching valve) and
actuators, to be operated without removing any parts.
The active test can be performed with the intelligent
tester. Performing the active test as the first step of
troubleshooting is one ...