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:
Reassembly
1. INSTALL OVERDRIVE DIRECT CLUTCH O-RING
(a) Coat an O-ring with ATF, and install it to the direct
clutch drum.
NOTICE:
Make sure that the O-ring is not twisted or
pinched when it is installed.
2. INSTALL OVERDRIVE DIRECT CLUTCH DRUM SUBASSEMBLY
(a) Coat the direct clutch drum with A ...
How to proceed with troubleshooting
The intelligent tester can be used at step 2, 5, 8, 11.
1 Vehicle Brought to Workshop
2 Check and Clear DTCs and Freeze Frame Data
HINT:
See page BC-82 and BC-84.
3 Problem Symptom Confirmation
4 Symptom Simulation
5 DTC Check
HINT:
See page BC-82.
6 Problem Symptoms Table
HINT: ...
Customize parameters
HINT:
The following items can be customized.
NOTICE:
After confirming whether the items requested by the
customer are applicable or not for customization,
perform customizing operations.
Be sure to record the current settings before
customization.
When troubleshooti ...
