Toyota Sienna Service Manual: Check for open circuit
(a) For an open circuit in the wire harness in Fig. 1, the resistance or voltage, as described below.
(b) Check the resistance.
Check the resistance
Standard resistance (Fig. 2)
HINT:
Measure the resistance while lightly shaking the wire harness vertically and horizontally. If the results match the examples above, an open circuit exists between terminal 1 of connector A and terminal 1 of connector C.
(2) Disconnect connector B and measure the resistance between the terminals of the connectors.
Standard resistance (Fig. 3)
If the results match the examples above, an open circuit exists between terminal 1 of connector B2 and terminal 1 of connector C.
(c) Check the voltage.
Check the voltage
(1) In a circuit in which voltage is applied to the ECU connector terminal, an open circuit can be checked by conducting a voltage check.
With each connector still connected, measure the voltage between the body ground and these terminals (in this order): 1) terminal 1 of connector A, 2) terminal 1 of connector B, and 3) terminal 1 of connector C.
Standard voltage (Fig. 4)
If the results match the examples above, an open circuit exists in the wire harness between terminal 1 of connector B and terminal 1 of connector C.
Basic inspection
(a) WHEN MEASURING RESISTANCE OF
ELECTRONIC PARTS
(1) Unless otherwise stated, all resistance
measurements should be made at an ambient
temperature of 20°C (68°F). Resistance
measurements may b ...
Check for short circuit
(a) If the wire harness is ground shorted (Fig. 5), locate the section by
conducting a resistance check with the body ground (below).
(b) Check the resistance with the body ground.
...
Other materials:
Evaporator temperature sensor (for rear air conditioning system)
ON-VEHICLE INSPECTION
1. INSPECT REAR A/C EVAPORATOR TEMPERATURE SENSOR
(a) Remove the rear evaporator temperature sensor.
(b) Disconnect the connector from the rear evaporator
temperature sensor.
(c) Measure the resistance according to the value(s) in
the table below.
Standard re ...
If your vehicle overheats
The following may indicate that your vehicle is overheating.
The needle of the engine coolant temperature gauge
enters the red zone or a loss of engine power is experienced. (For
example, the vehicle speed does not increase.)
The warning message indicating overheats is shown on the
mult ...
Precaution
1. INSPECTION PROCEDURE FOR VEHICLE INVOLVED
IN ACCIDENT
Perform the zero point calibration and sensitivity
check if any of the following conditions occur.
The occupant classification ECU is replaced.
Accessories (seatback tray and seat cover, etc.)
are installed.
...
