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Infiniti FX35 / FX45. Manual - part 256

BRC-10

< SERVICE INFORMATION >

[VDC/TCS/ABS]

SYSTEM DESCRIPTION

SYSTEM DESCRIPTION

Schematic

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Functions

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VDC

• In addition to the TCS/ABS function, the driver steering amount and brake operation amount are detected

from steering angle sensor and pressure sensor, and the vehicle's driving status (amount of under steering /
over steering) is determined from information from G sensor, wheel sensor, etc., and this information is used
to improve vehicle stability by controlling the braking and engine power to all four wheels.

• SLIP indicator lamp flashes to inform the driver of VDC operation.
• During VDC operation, body and brake pedal lightly vibrate and mechanical noises may be heard. This is

normal.

• ABS warning lamp, VDC OFF indicator lamp, and SLIP indicator lamp might turn on when vehicle is subject

to strong shaking or large vibration, such as when vehicle is on a turn table, a ship or a steep slope such as
bank while engine is running. In this case, restart engine on a normal road, and if ABS warning lamp, VDC
OFF indicator lamp, and SLIP indicator lamp turn off, there is no malfunction.

TCS

• The wheel spin of the drive wheels is detected by ABS actuator and electric unit (control unit) from the wheel

speed signals from four wheels, so if wheel spin occurs, drive wheel right and left brake fluid pressure con-
trol and engine fuel cut are performed while throttle value is restricted to reduce the engine torque and
decrease the amount of wheel spin. In addition, the degree throttle is opened is controlled to achieve the
optimum engine torque.

• Depending on road circumstances, the driver may have a sluggish feel. This is normal, because the opti-

mum traction has the highest priority under TCS operation.

• TCS may be activated any time vehicle suddenly accelerates, suddenly down/upshifts, or is driven on a road

with a varying surface friction coefficient.

• During TCS operation, it informs a driver of system operation by flashing SLIP indicator lamp.

ABS

• The Anti-Lock Braking System is a function that detects wheel revolution while braking, and it improves han-

dling stability during sudden braking by electrically preventing 4 wheel lock. Maneuverability is also improved
for avoiding obstacles.

• If the electrical system malfunctions, then the fail-safe function starts, the ABS becomes inoperative, and

ABS warning lamp turns on.

• Electrical system diagnosis by CONSULT-III is available.
• During ABS operation, brake pedal lightly vibrates and a mechanical noise may be heard. This is normal.
• When starting engine, or just after starting vehicle, brake pedal may vibrate or motor operating noises may

be heard from engine compartment. This is a normal status of operation check.

SFIA1160E

SYSTEM DESCRIPTION

BRC-11

< SERVICE INFORMATION >

[VDC/TCS/ABS]

BRC

• Stopping distance may be longer than that of vehicles without ABS when vehicle drives on rough, gravel, or

snow-covered (fresh, deep snow) roads.

EBD

• The Electronic Brake Distribution is a function that detects subtle slippages between front and rear wheels

during braking, and it improves handling stability by electronically controlling the brake fluid pressure which
results in reduced rear wheel slippage.

• In case of electrical system malfunction, the fail-safe function is activated, EBD and ABS becomes inopera-

tive, and ABS warning lamp and brake warning lamp are turned on.

• Electrical system diagnosis by CONSULT-III is available.
• During EBD operation, brake pedal lightly vibrates and a mechanical noise may be heard. This is normal.
• When starting engine, or just after starting vehicle, brake pedal may vibrate or motor operating noises may

be heard from engine compartment. This is a normal status of operation check.

• Stopping distance may be longer than that of vehicles without EBD when vehicle drives on rough, gravel, or

snow-covered (fresh, deep snow) roads.

Fail-Safe Function

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VDC / TCS SYSTEM

In case of malfunction in the VDC/TCS system, VDC OFF indicator lamp and SLIP indicator lamp are turned
on, and the condition of vehicle is the same as the condition of vehicles without VDC/TCS system. In case of
malfunction in the VDC/TCS system, the ABS control continues to operate normally without VDC/TCS control.

CAUTION:

If the fail-safe function is activated, then perform the self-diagnosis for VDC/TCS/ABS control system.

ABS, EBD SYSTEM

In case of electrical malfunctions with the ABS, ABS warning lamp, VDC OFF indicator lamp and SLIP indica-
tor lamp will turn on. In case of electrical malfunctions with the EBD, brake warning lamp, ABS warning lamp,
VDC OFF indicator lamp and SLIP indicator lamp will turn on. Simultaneously, the VDC/TCS/ABS become one
of the following conditions of the fail-safe function.
• For malfunction of ABS, only the EBD is activated and the condition of vehicle is the same condition of vehi-

cles without TCS/ABS system.
NOTE:
ABS self-diagnosis sound may be heard. That is a normal condition because a self-diagnosis for “Ignition
switch ON” and “The first starting” are being performed.

• For malfunction of EBD, EBD and ABS become inoperative, and the condition of vehicle is the same as the

condition of vehicles without TCS/ABS, EBD system.

BRC-12

< SERVICE INFORMATION >

[VDC/TCS/ABS]

SYSTEM DESCRIPTION

Hydraulic Circuit Diagram

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CAN Communication

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SYSTEM DESCRIPTION

CAN (Controller Area Network) is a serial communication line for real time application.It is an on-vehicle multi-
plex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and kinks with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. Refer to

LAN-43, "CAN Sys-

tem Specification Chart"

SFIA1163E

TROUBLE DIAGNOSIS

BRC-13

< SERVICE INFORMATION >

[VDC/TCS/ABS]

BRC

TROUBLE DIAGNOSIS

Fail-Safe Function

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VDC/TCS SYSTEM

CAUTION:

If the fail-safe function is activated, then perform the self-diagnosis for VDC/TCS/ABS control system.

ABS, EBD SYSTEM

In case of electrical malfunctions with the ABS, ABS warning lamp, VDC OFF indicator lamp, SLIP indicator
lamp will turn on. In case of electrical malfunctions with the EBD, brake warning lamp, ABS warning lamp,
VDC OFF indicator lamp and SLIP indicator lamp will turn on. Simultaneously, the VDC/TCS/ABS become one
of the following conditions of the fail-safe function.
• For malfunction of ABS, only the EBD is activated and the condition of vehicle is the same condition of vehi-

• For malfunction of EBD, EBD and ABS become inoperative, and the condition of vehicle is the same as the

condition of vehicles without TCS/ABS, EBD system.

How to Proceed with Diagnosis

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BASIC CONCEPT

• Most important point to perform diagnosis is to understand systems (control and mechanism) in vehicle thor-

oughly.

• It is also important to clarify customer complaints before inspec-

tion.
First of all, reproduce symptom, and understand it fully.
Ask customer about his/her complaints carefully. In some cases, it
will be necessary to check symptom by driving vehicle with cus-
tomer.
NOTE:
Customers are not professionals. Do not assume “maybe cus-
tomer means...” or “maybe customer mentioned this symptom”.

• It is essential to check symptoms right from beginning in order to

repair a malfunction completely.
For an intermittent malfunction, it is important to reproduce symp-
tom based on interview with customer and past examples. Do not
perform inspection on ad hoc basis. Most intermittent malfunctions
are caused by poor contacts. In this case, it will be effective to
shake suspected harness or connector by hand. When repairs are
performed without any symptom check, no one can judge if mal-
function has actually been eliminated.

• After diagnosis, make sure to perform “erase memory”. Refer to

BRC-26, "Self-Diagnosis"

• For an intermittent malfunction, move harness or harness connec-

tor by hand to check poor contact or false open circuit.

• Always read “GI General Information” to confirm general precautions. Refer to

GI-3, "General Precaution"

SEF234G

SEF233G

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