Toyota RAV4 Service Manual: Back-up power source circuit
Description
This is the back-up power source circuit for the air conditioning amplifier. Power is supplied even when the ignition switch is turned off and is used for functions such as the diagnostic trouble code memory.
wiring diagram
Inspection procedure
- Inspect fuse (ecu-b2)
- Remove the ecu-b2 fuse from the engine room no. 2 Relay block.
- Measure the resistance of the fuse.
Standard resistance:
below 1 
- Check wire harness (air conditioning amplifier - battery)
- Disconnect the e37 amplifier connector.
- Measure the voltage of the wire harness side connector.
Standard voltage
- Check wire harness (air conditioning amplifier - body ground)
- Disconnect the e37 amplifier connector.
- Measure the resistance of the wire harness side connector.
Standard resistance
Proceed to next circuit inspection shown in problem symptoms table
Ig power source circuit
Description
This is the main power source supplied to the air conditioning amplifier when
the ignition switch is on
(ig). This power source is used for operating components, such as the air
cond ...
Other materials:
Problem symptoms table
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms
are listed in order of probability in the "suspected area"
column of the table. Check each symptom by checking the
suspected areas in the order they are listed. Re ...
Abnormal temperature inside
Description
The tire pressure warning valve and transmitter measures tire internal
temperature as well as tire
pressure, and transmits the information to the tire pressure monitor receiver
along with the transmitter id.
If the measured temperature is out of the specified range, the tire ...
Ts and cg terminal circuit
Description
If the vehicle is stationary during sensor check mode, speed sensor
malfunctions cannot be detected. The
vehicle must be driven for speed sensor malfunctions to be detected.
Hint:
Change to sensor check mode by connecting terminals tc and cg of the dlc3,
and turning the ignitio ...