Toyota Sienna Service Manual: When servicing full-time 4wd vehicles
The full-time 4WD SIENNA is equipped with the open center differential system.
If incorrect preparations or test procedures are used, the test will not only be unsuccessful, but may be dangerous as well.
Therefore, before beginning any such servicing or test, be sure to check the following items:
- Whether wheels should be touching ground or jacked up
- Transaxle gear position
- Maximum testing vehicle speed
- Maximum testing time
(a) Before Beginning Test
This vehicle does not have a center diff. lock mode or 4WD (Normal) Mode to allow only the front or rear wheel to be rotated.
The test method for this vehicle is different from that for vehicles equipped with the center diff. lock mode or 4WD (Normal) Mode, so make sure to use the correct test method.
Braking Force Test
(Vehicle Speed: Below 0.5 km/h or 0.3 mph) When performing low-speed type brake tester measurements, observe the following instructions.
(1) Position the wheels to be tested (front or rear) on the tester.
(2) Shift the transaxle shift lever to "N" position.
(3) Idle the engine, operate the brake booster and perform the test.
(c) Speedometer Test or Other Tests
(Using Speedometer Tester or Chassis Dynamometer)
When performing test at high speed or high load, use the methods shown below.
*: This is to avoid damaging the center differential.
(d) On-Vehicle Wheel Balancing
On-Vehicle Wheel Balancing
When doing on-vehicle wheel balancing on a fulltime 4WD vehicle, to prevent the wheels from rotating at different speeds in different directions from each other (which could damage the center differential), always be sure to observe the following precautions:
(1) All 4 wheels should be jacked up, clearing the ground completely.
(2) The parking brake lever should be fully released.
(3) None of the brakes should be allowed to drag.
(4) The wheels should be driven on the wheel balancer with the engine running.
HINT:
When doing this, be careful of the other wheels, which will rotate at the same time.
(5) Avoid sudden acceleration, deceleration and braking.
(6) Carry out wheel balancing with the transaxle in D position.
For vehicles equipped with mobile communication systems
FOR VEHICLES EQUIPPED WITH MOBILE COMMUNICATION SYSTEMS
(a) Install the antenna far away from the ECU and
sensors of the vehicle electronic systems as
possible.
(b) Install an antenna feeder ...
For vehicles equipped with traction control (trac) system
When using a 2-wheel drum tester such as a
speedometer tester or chassis dynamometer, etc., or
jacking up the front wheels and driving the wheels,
always push in the TRAC cut ("TRAC OFF") ...
Other materials:
Driving the vehicle
The following procedures should be observed to ensure safe
driving:
Starting the engine
Driving
With the brake pedal depressed, shift the shift lever to D.
Release the parking brake.
Gradually release the brake pedal and gently depress the accelerator
pedal to accelerate the vehicle.
...
Precaution
1. HANDLING PRECAUTION FOR CRUISE CONTROL
SYSTEM
Turn the cruise control main switch off when not
using the cruise control system.
Be careful as the vehicle speed increases when
driving downhill with the cruise control system on.
The + (ACCEL)/RES (RESUME) operation ch ...
Problem symptoms table
HINT:
Inspect the fuse and relay before confirming the suspected
areas in the table below.
Inspect each suspected area in numerical order for the
corresponding symptom.
If the malfunction still exists after checking and confirming
that all circuits and components are normal ...
