Toyota Sienna Service Manual: ECU Power Source Circuit
DESCRIPTION
This is the power source for the tire pressure warning ECU.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE: When replacing the tire pressure warning ECU, read the transmitter IDs stored in the old ECU using the intelligent tester and write them down before removal.
It is necessary to register an ID code after replacing the tire pressure warning valve and transmitter and/or the tire pressure warning ECU (See page TW-20).
1 INSPECT FUSE (ECU-IG)
(a) Remove the ECU-IG fuse from the instrument panel junction block.
(b) Measure the resistance of the fuse.
Standard resistance: Below 1 Ω
2 INSPECT IGNITION RELAY NO. 1
(a) Remove the IG1 relay from the instrument panel junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
3 CHECK HARNESS AND CONNECTOR (ECU - BATTERY AND BODY GROUND)
(a) Disconnect the T15 ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage 
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE (See page TW-28)
Tire Pressure Warning Light Circuit
DESCRIPTION
If the ECU detects trouble, the tire pressure warning light blinks (comes on
after blinking for 1 minute) and
tire pressure monitor is cancelled at the same time. At this time, the ECU ...
TC and CG Terminal Circuit
DESCRIPTION
DTC output mode is set by connecting terminals 13 (TC) and 4 (CG) of the
DLC3. The DTCs are indicated
by blinks of the tire pressure warning light.
WIRING DIAGRAM
HINT:
When eac ...
Other materials:
Problem symptoms table
HINT:
Proceed to the troubleshooting for each circuit in the table
below.
AIRBAG SYSTEM
Symptom
Suspected Area
The SRS warning light goes off after the primary
check, but then comes on.
SRS Warning Light Remains ON
When the ignition switch is turned to t ...
Initialization
1. RESET
Reset the power slide door system:
The power slide door ECU records the fully open
position of the power slide door in its memory and
the power slide door fully opens and closes based
on this memory. The power slide door cannot
operate without this memory. In the case wh ...
Camshaft Position Sensor "B" Circuit
DESCRIPTION
The exhaust camshaft's Variable Valve Timing (VVT) sensor consists of a
magnet and MRE (Magneto
Resistance Element).
The exhaust camshaft has a sensor plate with 3 teeth on its outer circumference.
When the exhaust camshaft rotates, changes occur in the air gaps between the ...
