Fail Safe Operation

If there is a problem with sensor signals or actuator systems, the skid control ECU prohibits power supply to the ABS and VSC actuator and informs the ECM of VSC system failure.

The ABS and VSC actuator turns off each solenoid and the ECM shuts off VSC control (traction control signal) from the skid control ECU accordingly, which turns out to be as if the ABS, VSC and TRAC systems were not installed.

The ABS, VSC, and TRAC control will be prohibited, but EBD control continues as much as possible. If EBD control is impossible, the brake warning light comes on to warn the driver (See DIAGNOSIS SYSTEM ).

FAIL-SAFE CHART

Malfunction

Symptom

ABS system

ABS, BA, TRAC, and VSC control prohibited

BA system

ABS, BA, TRAC, and VSC control prohibited

EBD system

ABS and EBD control prohibited

TRAC system

TRAC and VSC control prohibited

VSC system

TRAC and VSC control prohibited

• A malfunction in either the ABS or BA system will result in an identical operation, with ABS, BA, TRAC, and VSC system control prohibited.

2007 BRAKES Brake Control - Sequoia

• If control is prohibited due to a malfunction during operation, control will be disabled gradually. This is to avoid sudden vehicle instability.

DATA LIST / ACTIVE TEST

1. DATA LIST

HINT:

With the intelligent tester connected to the DLC3 and the ignition switch in the ON position, the ABS, TRAC and VSC data list can be displayed. Follow the prompts on the tester screen to access the DATA LIST.

DATA LIST

Item

Measurement Item / Range (Display)

Normal Condition

Diagnostic Note

ABS MOT RELAY

ABS motor relay / ON or OFF

ON: Motor relay ON OFF: Motor relay OFF

-

SOL RELAY

Solenoid relay / ON or OFF

ON: Solenoid relay ON OFF: Solenoid relay OFF

-

VSC / TRC OFF SW

TRAC control switch / ON or OFF

ON: TRAC control switch ON ON OFF : TRAC control switch OFF

-

AIR BLD SUPPORT

Air bleed support / ON or OFF

ON: Support ON OFF: Support OFF

-

STOP LIGHT SW

Stop lamp switch / ON or OFF

ON: Brake pedal depressed OFF: Brake pedal released

-

PKB SW

Parking brake switch / ON or OFF

ON: Parking brake applied OFF: Parking brake released

-

ABS OPERT FR

ABS operation (FR) / BEFORE or OPERATE

BEFORE : No ABS operation (FR) OPERATE : During ABS operation (FR)

-

ABS OPERT FL

ABS operation (FL) / BEFORE or OPERATE

BEFORE : No ABS operation (FL) OPERATE : During ABS operation (FL)

-

ABS OPERT RR

ABS operation (RR) / BEFORE or OPERATE

BEFORE : No ABS operation (RR)

OPERATE : During ABS operation (RR)

-

ABS OPERT RL

ABS operation (RL) / BEFORE or OPERATE

BEFORE : No ABS operation (RL)

OPERATE : During ABS operation (RL)

-

WHEEL SPD FR

Wheel speed sensor (FR) reading / min.: 0 km/h (0

Actual wheel speed

Similar speed as indicated on

2007 BRAKES Brake Control - Sequoia

MPH), max.: 326 km/h (202 MPH)

speedometer

WHEEL SPD FL

Wheel speed sensor (FL) reading / min.: 0 km/h (0 MPH), max.: 326 km/h (202 MPH)

Actual wheel speed

Similar speed as indicated on speedometer

WHEEL SPD RR

Wheel speed sensor (RR) reading / min.: 0 km/h (0 MPH), max.: 326 km/h (202 MPH)

Actual wheel speed

Similar speed as indicated on speedometer

WHEEL SPD RL

Wheel speed sensor (RL) reading / min.: 0 km/h (0 MPH), max.: 326 km/h (202 MPH)

Actual wheel speed

Similar speed as indicated on speedometer

DECELERAT SEN

Deceleration sensor 1 reading / min.: -1.869 G, max.: 1.869 G

Approximately 0 +- 0.13 G at still condition

Reading changes when vehicle is bounced

DECELERAT SEN2

Deceleration sensor 2 reading / min.: ?1.869 G, max.: 1.869 G

Approximately 0 +- 0.13 G at still condition

Reading changes when vehicle is bounced

IG VOLTAGE

ECU power supply voltage / TOO LOW / NORMAL / TOO HIGH

TOO LOW : 9.5 V or less NORMAL : 9.5 to 14.0 V TOO HIGH : 14.0 V or more

-

SFRR

ABS solenoid (SFRR) / ON or OFF

ON: Operated OFF: Not operated

-

SFRH

ABS solenoid (SFRH) / ON or OFF

ON: Operated OFF: Not operated

-

SFLR

ABS solenoid (SFLR) / ON or OFF

ON: Operated OFF: Not operated

-

SFLH

ABS solenoid (SFLH) / ON or OFF

ON: Operated OFF: Not operated

-

SRRR (SRR)

ABS solenoid (SRRR (SRR)) / ON or OFF

ON: Operated OFF: Not operated

-

SRRH (SRH)

ABS solenoid (SRRH (SRH)) / ON or OFF

ON: Operated OFF: Not operated

-

SRLR

ABS solenoid (SRLR) / ON or OFF

ON: Operated OFF: Not operated

-

SRLH

ABS solenoid (SRLH) / ON or OFF

ON: Operated OFF: Not operated

-

SRMR (SMCR, STR)

SRMR (SMCR, STR) / ON or OFF

ON: Operated OFF: Not operated

-

SRMF (SMCF SA3)

SRMF (SMCF, SA3) / ON or OFF

ON: Operated OFF: Not operated

-

SRCR (SA2)

SRCR (SA2) / ON or OFF

ON: Operated OFF: Not operated

-

2007 BRAKES Brake Control - Sequoia

SRCF (SA1)

SRCF (SA1) / ON or OFF

ON: Operated OFF: Not operated

-

YAW RATE

Yaw rate sensor/ Min.: 7128 deg/s, Max.: 127 deg/s

Min.:-128 deg/s Max.: 128 deg/s

-

YAW ZERO VALUE

Memorized zero value/ Min.: ?128 deg/s, Max.: 127 deg/s

Min.:-128 deg/s Max.: 128 deg/s

-

STEERING ANG

Steering sensor/ Min.: 71152 deg, Max.: 1150.875 deg

Left turn: Increase Right turn: Decrease

-

MAS CYL PRS1

Master cylinder pressure sensor 1 reading / min.: 0 V, max.: 5 V

When brake pedal is released : 0.3 to 0.9 V

Reading increases when brake pedal is depressed

MAS CYL PRS 2

Master cylinder pressure sensor 2 reading / min.: 0 V, max.: 5 V

When brake pedal is released: 0.3 to 0.9 V

Reading increases when brake pedal is depressed

PEDAL STROKE

Pedal Stroke Sensor min.: 0, max.: 5.1

Approximately 2.0 V without the brake pedal depressed

-

Do It Yourself Car Diagnosis

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