Infiniti QX56 (Z62). Manual - part 137

 

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Infiniti QX56 (Z62). Manual - part 137

 

 

SYSTEM

BRC-33

< SYSTEM DESCRIPTION >

[WITH VDC]

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BRC

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ABS FUNCTION : System Description

INFOID:0000000006222574

• By preventing wheel lock through brake force (brake fluid pressure) control that is electronically controlled by

detecting wheel speed during braking, stability during emergency braking is improved so that obstacles can
be easily bypassed by steering operation.

• During braking, control units calculates wheel speed and pseudo-vehicle speed, and transmits pressure

increase, hold or decrease signals to actuator portion according to wheel slip status.

• The following effects are obtained by preventing wheel lock during

braking.

- Vehicle tail slip is prevented during braking when driving straight.
- Understeer and oversteer tendencies are moderated during brak-

ing driving on a corner.

- Obstacles may be easily bypassed by steering operation during

braking.

• Slight vibrations are felt on the brake pedal and the operation

noises occur, when ABS function operates. This is not a malfunc-
tion because it is caused by ABS function that is normally oper-
ated.

• CONSULT-III can be used to diagnose the system diagnosis.
• Fail-safe function is adopted. When a malfunction occurs in ABS

function, the control is suspended for VDC function, TCS function,
hill start assist function and brake limited slip differential (BLSD)
function. The vehicle status becomes the same as models without
VDC function, TCS function, ABS function, hill start assist function
and brake limited slip differential (BLSD) function. However, EBD
function is operated normally. Refer to 

BRC-25, "Fail-safe"

.

NOTE:
• ABS has the characteristic as described here, but it is not the

device that helps reckless driving.

• To stop vehicle efficiently, ABS does not operate and ordinary

brake operates at low speed [approx. 5 to 10 km/h (3.1 to 6.2
MPH) or less, but differs subject to road conditions).

• Self-diagnosis is performed immediately after when engine starts and when vehicle initially is driven [by vehi-

cle speed approx. 15 km/h (9.3 MPH)]. Motor sounds are generated during self-diagnosis. In addition, brake
pedal may be felt heavy when depressing brake pedal lightly. These symptoms are not malfunctions.

SYSTEM DIAGRAM

NOTE:

JPFIC0140GB

BRC-34

< SYSTEM DESCRIPTION >

[WITH VDC]

SYSTEM

Transfer control unit is applied to models with 4WD system.

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table.

*1: Communication line between yaw rate/side/decal G sensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system

EBD FUNCTION

EBD FUNCTION : System Description

INFOID:0000000006222575

• By preventing rear wheel slip increase through rear wheel brake force (brake fluid pressure) control that is

electronically controlled when slight skip on front and rear wheels are detected during braking, stability dur-
ing braking is improved.

JPFIC0184GB

Component

Signal description

Yaw rate/side/decel G sensor

Mainly transmits the following signals to ABS actuator and electric unit (control unit) via com-

munication line

*1

.

• Yaw rate signal
• Side G sensor signal
• Decel G sensor signal

Transfer control unit

*2

Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN 
communication.
• Current 4WD mode signal

Combination meter

Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN 
communication.
• ABS warning lamp signal

SYSTEM

BRC-35

< SYSTEM DESCRIPTION >

[WITH VDC]

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BRC

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• EBD function is expanded and developed from conventional ABS function and corrects rear wheel brake

force to appropriate level by electronic control according to load weight (number of passengers).

• During braking, control unit portion compares slight slip on front

and rear wheels by wheel speed sensor signal, transmits drive sig-
nal to actuator portion when rear wheel slip exceeds front wheel
slip for the specified value or more, and controls rear wheel brake
force (brake fluid pressure) so that increase of rear wheel slip is
prevented and slips on front wheel and rear wheel are nearly
equalized. ABS control is applied when slip on each wheel
increases and wheel speed is the threshold value of ABS control or
less.

• CONSULT-III can be used to diagnose the system diagnosis.
• Fail-safe function is adopted. When a malfunction occurs in EBD

function, the control is suspended for VDC function, TCS function,
ABS function, EBD function, hill start assist function and brake lim-
ited slip differential (BLSD) function. The vehicle status becomes
the same as models without VDC function, TCS function, ABS
function, EBD function, hill start assist function and brake limited
slip differential (BLSD) function. Refer to 

BRC-25, "Fail-safe"

.

JPFIC0142GB

JPFIC0143GB

BRC-36

< SYSTEM DESCRIPTION >

[WITH VDC]

SYSTEM

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table.

hill start assist FUNCTION

hill start assist FUNCTION : System Description

INFOID:0000000006222576

• This function maintains brake fluid pressure so that the vehicle does not move backwards even if brake

pedal is released to depress accelerator pedal to start the vehicle while it is stopped on an uphill slope by
depressing brake pedal.

• This function operates when the vehicle is in stop status on a uphill slope of slope ratio 10% or more and

selector lever is in the position other than P or N.

• hill start assist function is only for the start aid. It maintains the brake fluid pressure for approx. 2 seconds

after releasing the brake pedal, and then decreases the pressure gradually. If the vehicle can start by the
accelerator operation, the brake is released automatically and a smooth start can be performed.

• Fail-safe function is adopted. When a malfunction occurs in hill start assist function, the control is suspended

for VDC function, TCS function, hill start assist function and brake limited slip differential (BLSD) function.
The vehicle status becomes the same as models without VDC function, TCS function, hill start assist func-
tion and brake limited slip differential (BLSD) function. However, ABS function and EBD function are oper-
ated normally. Refer to 

BRC-25, "Fail-safe"

.

JPFIC0144GB

Component

Signal description

Combination meter

Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN 
communication.
• Brake warning lamp signal

 

 

 

 

 

 

 

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