Sienna AWD V6-3.3L (3MZ-FE) (2004)
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.
As shown in Fig. 4, with each connector still connected, measure the voltage between the body ground and terminal 1 of connector A at the
ECU 5 V output terminal, terminal 1 of connector B, and terminal 1 of connector C, in that order.
2. If the results are:
5 V: Between terminal 1 of connector A and body ground
5 V: Between terminal 1 of connector B and body ground
0 V: Between terminal 1 of connector C and body ground
Therefore, the cause is an open circuit in the wire harness between terminal 1 of connector B and terminal 1 of connector C.
3. CHECK SHORT CIRCUIT
a. If the wire harness is ground shorted as shown in Fig. 5, locate the section by conducting a continuity check with the body ground in step (b).
b. Check the continuity with the body ground.
1. Disconnect connectors A and C and measure the resistance between terminals 1 and 2 of connector A and the body ground.
Resistance: 10 kohms or higher
HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally.
In the case of Fig. 6:
Between terminal 1 of connector A and body ground -> Continuity (short)
Between terminal 2 of connector A and body ground -> No continuity, Therefore, the cause is a short circuit between terminal 1 of
connector A and terminal 1 of connector C.