Scantool - Zero Point Calibration/Sensor Check
BRAKESBR001-02
January 11, 2002
Title:
VSC RELATED ZERO POINT CALIBRATION AND SENSOR CHECK
Models:
'01 - '02 Sequoia
Introduction
The following information is intended to clarify the repair manual procedures for using the Toyota Scantool to perform zero point calibration and sensor checks after the replacement of any of the following components on a 2001 - 2002 model year Sequoia.
^ Vehicle Skid Control Computer
^ Steering Angle Sensor
^ Master Cylinder Pressure Sensor
^ Yaw Rate Sensor
^ Deceleration Sensor
Zero point calibration of the above sensors must also be performed when replacing or repairing steering related parts and when changing the vehicle's straight ahead condition for toe adjustment.
Applicable Vehicles
^ 2001 - 2002 model year Sequoia vehicles.
Required Tools & Material
Warranty Information
Calibration Procedure
Prior to calibration, all ABS and VSC DTC codes must be cleared.
1. Clear all ABS and VSC DTC Codes.
A. Connect the Toyota Scantool to the DLC3.
B. Turn the ignition switch ON.
C. Operate the Toyota Scantool to erase the codes.
2. Perform Zero Point Calibration on Sensors.
A. Enter "Signal Check" mode on Toyota Scantool (after verifying connection, go to "Trouble Data," then to "Signal Check").
B. All remaining steps must be completed before exiting "Signal Check" mode or additional codes will be set.
NOTE:
^ Perform calibration on a level surface.
^ A new VSC ECU is set to be used on a 2WD vehicle. If the VSC ECU is being installed on a 4WD vehicle, use the following procedure to set the ECU for 4WD use
^ If VSC ECU is being replaced on a 4WD vehicle:
^ Turn the ignition switch ON, with transmission shift lever in the "P" position. Then move the transfer shift lever to the "L4" position. The transfer shift lever must remain in the "L4" position for steps 2C - 2F
^ When the VSC ECU has recognized the vehicle as a 4WD, the buzzer will sound for 3 seconds. This recognition and buzzer will occur only the first time this procedure is completed after the VSC ECU is replaced.
^ After this procedure, it will not be possible to install this VSC ECU in a 2WD vehicle.
C. Ensure transmission is in the "P" position.
D. Turn the steering wheel at least 5 degrees in each direction. Then hold the steering wheel straight ahead (0 degrees).
E. Press the VSC OFF (or TRAC OFF) switch 3 times within 3 seconds.
F. The VSC buzzer should sound for 3 seconds.
3. Perform Sensor Check.
A. Check that the shift lever is in the "P" position. Check that the steering wheel is at 0 degrees.
a. Check that the ABS warning light and VSC TRAC warning light blinks.
b. Keep the vehicle stationary for at least 4 seconds.
B. Check the Deceleration and Yaw Rate Sensor.
a. Shift the transmission into the "D" position and drive the vehicle at approximately 3 mph. Turn the steering wheel 90 degrees or more to the left or right and complete a "U-turn" (180 degrees).
NOTE:
^ When completing the U-turn, the ending position should be 180 degrees +/- 5 degrees of the starting position.
^ Do not spin the wheels while performing this check.
b. The VSC buzzer should sound at the beginning of the turn, indicating the completion of the deceleration sensor check.
c. Stop the vehicle and shift the lever to the "P" position.
d. On a 4WD vehicle, the VSC buzzer should sound for 3 seconds, indicating the completion of the yaw rate sensor check.
C. Check the master cylinder pressure sensor.
a. Keep the vehicle stationary for at least 2 seconds.
b. With the transmission in the "P" position, do not apply any pressure to the brake pedal for at least 1 second.
c. Press the pedal with at least 147 N (15 kgf, 33 lbf) for at least 2 seconds.
d. The VSC buzzer should sound for 3 seconds indicating the completion of the master cylinder pressure sensor check.
D. Check steering angle sensor.
a. Turn the steering wheel left or right to full lock position. Hold for at least 1 second, then turn the wheel to the opposite full lock position and hold for at least 1 second.
b. The VSC buzzer should sound for 3 seconds indicating the completion of the steering angle sensor check.
E. Check wheel speed sensors.
a. Drive the vehicle straight ahead at or above 28 mph for several seconds. The ABS warning light will temporarily stop blinking when this speed is reached, and stay off until the vehicle approaches 0 mph.
NOTE:
It is not a problem to drive the vehicle through turns prior to step E.a. Therefore, it is not a problem to exit the parking lot, etc. in order to perform wheel speed sensor check on a street.
b. Complete "Signal Check" by pressing "ENTER" on the Toyota Scantool. Disregard any codes while in "Signal Check" mode.
4. Check ABS and VSC DTC Codes.
A. Re-initialize the Toyota Scantool to the vehicle and check for trouble codes.
B. Refer to the Toyota hand-held tester operator's manual for further details.
C. Turn the ignition switch OFF and remove Toyota Scantool.
D. Ensure that the vehicle is in 2WD mode prior to returning it to the customer.
NOTE:
If at any time during the sensor check procedure, the appropriate buzzer does not sound, check the VSC buzzer circuit according to Repair Manual procedures.
^ 2001 Sequoia Repair Manual, Pub. No. RM832U1, page DI-321
^ 2002 Sequoia Repair Manual, Pub. No. RMB86U1, page DI-332