Yaw Rate Sensor: Testing and Inspection

TEST MODE PROCEDURE

1. TEST MODE (SIGNAL CHECK) PROCEDURE (SST CHECK WIRE)

When having replaced the master cylinder solenoid and/ or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor.

HINT:
- If the ignition switch is turned from the ON to the ACC or LOCK position during test mode (SIGNAL CHECK), DTCs of the signal check function will be erased.
- During test mode (SIGNAL CHECK), the skid control ECU records all DTCs of the test mode (SIGNAL CHECK) function. By performing the test mode (SIGNAL CHECK), the codes are erased if normality is confirmed. The codes left over are the codes where an abnormality was found.

a. Turn the ignition switch off.
b. Check that the steering wheel is in the straight ahead position and move the shift lever to the P position.




c. Using SST, connect terminals TS and CG of the DLC3.

SST 09843-18040

d. Turn the ignition switch to the ON position.




e. Check that the ABS and VSC TRAC warning lights blink in test mode.

HINT: If the ABS and VSC TRAC warning lights do not blink, inspect the TS and CG terminal circuit and the ABS and VSC TRAC warning light circuits.

Trouble Area TS and CG terminal circuit
ABS warning light circuit
VSC TRAC warning light circuit

f. Start the engine.
g. Using a check wire, perform the ABS sensor (acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch, L4 detection switch and speed sensor) and VSC sensor (yaw rate sensor and downhill assist control operation switch) signal checks in test mode (ABS sensor: See procedure "A" to "F", VSC sensor: See procedure "G" to "I").




2. ACCELERATION SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "A")

a. Check that the ABS warning light is blinking in test mode.
b. Keep the vehicle in a stationary condition on a level surface for 1 second or more.




3. MASTER CYLINDER PRESSURE SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "B")

a. Check that the ABS warning light is blinking in test mode.
b. Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more for 1 second or more.

HINT:
- At this time, the ABS warning light stays on for 3 seconds.
- While the ABS warning light stays on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more.
- The ABS warning light comes on for 3 seconds every time the brake pedal operation is performed.




4. CENTER DIFF. LOCK DETECTION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "C")

a. Check that the ABS warning light is blinking in test mode.

b. Check the center diff. lock switch.
1. Push the center diff. lock switch on to lock the center differential.
2. Push the center diff. lock switch off to unlock the center differential.




5. L4 DETECTION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "D")

a. Check that the ABS warning light is blinking in test mode.

b. Check the transfer indicator (L4) switch.
1. Turn the H-L switch to the L position to put the vehicle in L4 mode.
2. Turn the H-L switch to the H position to put the vehicle in H4 mode.




6. SPEED SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "E")

a. Check that the ABS warning light is blinking in test mode.

b. Check the backward signal.
1. Drive the vehicle in reverse for more than 1 second at 2 mph (3 km/h) or higher.

HINT: Drive the vehicle in reverse and check the speed sensor signal. Note that the signal check cannot be completed if the vehicle speed is 28 mph (45 km/h) or more.

c. Check the forward signal.
1. Drive the vehicle straight forward. Drive the vehicle at a speed of 28 mph (45 km/h) or higher for several seconds and check that the ABS warning light goes off.

HINT: The signal check may not be completed if the vehicle has its wheels spun or the steering wheel turned during this check.

d. Stop the vehicle

NOTE:
- Before performing the speed sensor signal check, complete the acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch and L4 detection switch signal checks.
- The speed sensor signal check may not be completed if the speed sensor signal check is started while turning the steering wheel or spinning the wheels.
- After the ABS warning light goes off, if the vehicle speed exceeds 50 mph (80 km/h), signal check code will be stored again. Decelerate or stop before the speed reaches 50 mph (80 km/h).
- If the signal check has not been completed, the ABS warning light blinks while driving and the ABS system does not operate.

HINT: When the signal check has been completed, the ABS warning light goes off while driving and blinks in the test mode pattern while stationary.




7. READ DTC OF ABS SENSOR (SST CHECK WIRE) (Procedure "F")

a. Using SST, connect terminals TC and CG of the DLC3.

SST 09843-18040

b. Read the number of blinks of the ABS warning light.

HINT:
- See the list of DTC (See procedure "J").
- If every sensor is normal, the normal system code is output. (A cycle of 0.25 second ON and 0.25 second OFF is repeated.)
- If more than 1 malfunction is detected at the same time, the lowest numbered code will be displayed first.




c. After the check, disconnect the SST from terminals TC and CG of the DLC3.




8. YAW RATE SENSOR SIGNAL CHECK (SST CHECK WIRE) (Procedure "G")

a. Check that the VSC TRAC warning light is blinking in test mode.

b. Check the zero point voltage of the yaw rate sensor.
1. Keep the vehicle in a stationary condition on a level surface for 1 second or more.




c. Check the output of the yaw rate sensor and the direction of the steering angle sensor.
1. Shift the shift lever to the D position and drive the vehicle at a vehicle speed of approximately 3 mph (5 km/h), turn the steering wheel either to the left or right 90° or more, until the vehicle makes a 180° turn.
2. Stop the vehicle and shift the shift lever to the P position. Check that the skid control buzzer sounds for 3 seconds.

HINT:
- If the skid control buzzer sounds, the signal check is completed normally.
- If the skid control buzzer does not sound, check the skid control buzzer circuit, then perform the signal check again.
- If the skid control buzzer still will not sound, there is a malfunction in the yaw rate sensor, so check the DTC.
- Drive the vehicle in a 180° circle. At the end of the turn, the direction of the vehicle should be within 180° ± 5° of its start position.
- Do not spin the wheels.




9. DOWNHILL ASSIST CONTROL OPERATION SWITCH SIGNAL CHECK (SST CHECK WIRE) (Procedure "H")

a. Check that the VSC TRAC warning light is blinking in test mode.

b. Check the downhill assist control switch.
1. Push the downhill assist control switch on.
2. Push the downhill assist control switch off.




10. READ DTC OF VSC SENSOR (SST CHECK WIRE) (Procedure "I")

a. Using SST, connect terminals TC and CG of the DLC3.

SST 09843-18040

b. Read the number of blinks of the VSC TRAC warning light.

HINT:
- See the list of DTC (See procedure "J").
- If every sensor is normal, the normal system code is output. (A cycle of 0.25 second ON and 0.25 second OFF is repeated.)
- If more than 1 malfunction is detected at the same time, the lowest numbered code will be displayed first.




c. After performing the check, disconnect the SST from terminals TS and CG, TC and CG of the DLC3 and turn the ignition switch off.
d. Turn the ignition switch to the ON position.










11. DTC OF SIGNAL CHECK FUNCTION (SST CHECK WIRE) (Procedure "J")

HINT: The codes in this table are output only in test mode (signal check).

12. TEST MODE (SIGNAL CHECK) PROCEDURE (INTELLIGENT TESTER)

When having replaced the master cylinder solenoid and/ or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor.

HINT:
- If the ignition switch is turned from the ON to the ACC or LOCK position during test mode (SIGNAL CHECK), DTCs of the signal check function will be erased.
- During test mode (SIGNAL CHECK), the skid control ECU records all DTCs of the signal check function. By performing the test mode (SIGNAL CHECK), the codes are erased if normality is confirmed. The codes left over are the codes where an abnormality was found.

a. Turn the ignition switch off.
b. Check that the steering wheel is in the straight ahead position and move the shift lever to the P position.




c. Connect the intelligent tester to the DLC3.
d. Turn the ignition switch to the ON position.




e. Operate the intelligent tester in test mode (SIGNAL CHECK).

HINT: Refer to the intelligent tester operator's for further details.




f. Check that the ABS and VSC TRAC warning lights blink in test mode.

HINT: If the ABS and VSC TRAC warning lights do not blink, inspect the TS and CG terminal circuit and the ABS and VSC TRAC warning light circuits.

Trouble Area TS and CG terminal circuit
ABS warning light
VSC TRAC warning light

g. Start the engine.
h. Using the intelligent tester, perform the ABS sensor (acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch, L4 detection switch and speed sensor) and VSC sensor (yaw rate sensor and downhill assist control operation switch) signal checks in test mode (ABS sensor: See procedure "K" to "P", VSC sensor: See procedure "Q" to "S").




13. ACCELERATION SENSOR SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "K")

a. Check that the ABS warning light is blinking in test mode.
b. Keep the vehicle in a stationary condition on a level surface for 1 second or more.




14. MASTER CYLINDER PRESSURE SENSOR SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "L")

a. Check that the ABS warning light is blinking in test mode.
b. Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more for 1 second or more.

HINT:
- At this time, the ABS warning light stays on for 3 seconds.
- While the ABS warning light stays on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more.
- The ABS warning light comes on for 3 seconds every time the brake pedal operation is performed.




15. CENTER DIFF. LOCK DETECTION SWITCH SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "M")

a. Check that the ABS warning light is blinking in test mode.

b. Check the center diff. lock switch.
1. Push the center diff. lock switch on to lock the center differential.
2. Push the center diff. lock switch off to unlock the center differential.




16. L4 DETECTION SWITCH SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "N")

a. Check that the ABS warning light is blinking in test mode.

b. Check the transfer indicator (L4) switch.
1. Turn the H-L switch to the L position to put the vehicle in L4 mode.
2. Turn the H-L switch to the H position to put the vehicle in H4 mode.




17. SPEED SENSOR SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "O")

a. Check that the ABS warning light is blinking in test mode.

b. Check the backward signal.
1. Drive the vehicle in reverse for more than 1 second at 2 mph (3 km/h) or higher.

HINT: Drive the vehicle in reverse and check the speed sensor signal. Note that the signal check cannot be completed if the vehicle speed is 28 mph (45 km/h) or more.

c. Check the forward signal.

1. Drive the vehicle straight forward. Drive the vehicle at a speed of 28 mph (45 km/h) or higher for several seconds and check that the ABS warning light goes off.

HINT: The signal check may not be completed if the vehicle has its wheels spun or the steering wheel turned during this check.

d. Stop the vehicle.

NOTE:
- Before performing the speed sensor signal check, complete the acceleration sensor, master cylinder pressure sensor, center diff. lock detection switch and L4 detection switch signal checks.
- The speed sensor signal check may not be completed if the speed sensor signal check is started while turning the steering wheel or spinning the wheels.
- After the ABS warning light goes off, if the vehicle speed exceeds 50 mph (80 km/h), a signal check code will be stored again. Decelerate or stop before the speed reaches 50 mph (80 km/h).
- If the signal check has not been completed, the ABS warning light blinks while driving and the ABS system does not operate.

HINT: When the signal check has been completed, the ABS warning light goes off while driving and blinks in the test mode pattern while stationary.

18. READ DTC OF ABS SENSOR (INTELLIGENT TESTER) (Procedure "P")

a. Read the DTC(s) by following the tester screen.

HINT:
- Refer to the intelligent tester operator's for further details.
- See the list of DTC (See procedure "T").




19. YAW RATE SENSOR SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "Q")

a. Check that the VSC TRAC warning light is blinking in test mode.

b. Check the zero point voltage of the yaw rate sensor.
1. Keep the vehicle in a stationary condition on a level surface for 1 second or more.




c. Check the output of the yaw rate sensor and the direction of the steering angle sensor.

1. Shift the shift lever to the D position and drive the vehicle at a vehicle speed of approximately 3 mph (5 km/h), turn the steering wheel either to the left or right 90° or more until the vehicle makes 180° turn.
2. Stop the vehicle and shift the shift lever to the P position. Check that the skid control buzzer sounds for 3 seconds.

HINT:
- If the skid control buzzer sounds, the signal check is completed normally.
- If the skid control buzzer does not sound, check the skid control buzzer circuit, then perform the signal check again.
- If the skid control buzzer still will not sound, there is a malfunction in the yaw rate sensor, so check the DTC.
- Drive the vehicle in a 180° circle. At the end of the turn, the direction of the vehicle should be within 175° to 185° of its start position.
- Do not spin the wheels.




20. DOWNHILL ASSIST CONTROL OPERATION SWITCH SIGNAL CHECK (INTELLIGENT TESTER) (Procedure "R")

a. Check that the VSC TRAC warning light is blinking in test mode.

b. Check the downhill assist control switch.
1. Push the downhill assist control switch on.
2. Push the downhill assist control switch off.

21. READ DTC OF VSC SENSOR (INTELLIGENT TESTER) (Procedure "S")

a. Read the DTC(s) by following the tester screen.

HINT:
- Refer to the intelligent tester operator's for further details.
- See the list of DTC (See procedure "T").










22. DTC OF SIGNAL CHECK FUNCTION (INTELLIGENT TESTER) (Procedure "T")

HINT: The codes in this table are output only in test mode (signal check).