traction control NISSAN X-TRAIL 2003 Electronic Repair Manual

GENERAL INFORMATION
BRC-57
[ESP/TCS/ABS]
C
D
E
G
H
I
J
K
L
MA
B
BRC
lWhen starting the engine, or just after starting the vehicle, the brake pedal may vibrate or the
motor operating noise may be heard from the engine compartment. This is a normal status of the
operation check.
lThe stopping distance may be longer than that of vehicles without ABS when the vehicle drives on
rough, gravel, or snowy (fresh deep snow) road.
TCS FunctionsEFS0019V
1. With the wheel speed sensor signals from 4 wheels, the ESP/TCS/ABS control unit detects a wheel spin.
If a wheel spins, the control unit controls brake fluid pressure to the spinning wheel, and cuts the fuel to
the engine. It also closes the throttle valve to reduce the engine torque. Furthermore, throttle position is
controlled to the appropriate engine torque.
2. If a wheel spins, the TCS system works same as LSD (Limited Slip Differential) function applying brake
fluid pressure to the spinning wheel.
3. During TCS operation, it informs a driver of system operation by flashing SLIP indicator lamp.
CAUTION:
lDuring TCS operation, the body and the brake pedal lightly vibrate and the mechanical noise may
be heard. This is a normal condition.
lDepending on road circumstances, the driver may have a sluggish feel. This is not abnormal,
because the optimum traction has the highest priority by TCS operation.
lWhen the vehicle is passing through a road where the surface friction coefficient varies, down-
shifting or depressing the accelerator pedal fully may activate TCS temporarily.
ESP FunctionsEFS0019W
1. The Electronic Stability Program is called the ESP for short.
The ESP is indicated as the VDC (the Vehicle Dynamics Control) on the CONSULT-II screen.
2. In addition to the ABS/TCS function, ESP detects the driver's steering operation amount and brake opera-
tion amount from the steering angle sensor and pressure sensor. Using the information from the yaw rate/
side G sensor and wheel speed sensors, ESP judges the driving condition (conditions of understeer and
oversteer) to improve the stability by controlling the brake on 4 wheels and engine output.
3. During ESP operation, the SLIP indicator lamp flashes to inform the driver of the operation.
CAUTION:
lDuring ESP operation, the body and the brake pedal lightly vibrate and their mechanical noise
may be heard. This is a normal condition.
lIf the vehicle is rotated on a turn table, or rolled and rocked on a ship, the ABS warning lamp,
ESP OFF indicator lamp, and SLIP indicator lamp may turn ON. In this case, start the engine on a
normal road again. If the ABS warning lamp, ESP OFF indicator lamp, and SLIP indicator lamp
turn OFF after the restart, it is normal.
lWhen driving in a steep slope such as a bank, the ABS warning lamp, ESP OFF indicator lamp,
and SLIP indicator lamp may turn ON. In this case, start the engine on a normal road again. If the
ABS warning lamp, ESP OFF indicator lamp, and SLIP indicator lamp turn OFF after the restart, it
is normal.

BRC-88
[ESP/TCS/ABS]
TROUBLE DIAGNOSIS
For Correct and Quick Diagnosis
EFS001A8
PRECAUTIONS FOR TROUBLE DIAGNOSIS
lBefore performing the trouble diagnosis, always read theGI-3, "PRECAUTIONS"to confirm the general
precautions.
lAfter replacement of ESP/TCS/ABS control unit, steering angle sensor, steering parts, suspension parts,
or tires, and adjustment of alignment, always adjust the neutral position of steering angle sensor before
driving.
lWhen the ESP/TCS/ABS control unit is replaced, check that the label on the computer unit is identical
color.
lAfter completing the trouble diagnosis, always erase the malfunctioning memory.BRC-77, "Functions of
CONSULT-II"
lWhen inspection of the continuity or voltage between units is performed, check the connector terminals for
disconnection, looseness, bend, or collapse. If any malfunction is detected, repair or replace the applica-
ble part.
lIntermittent problems may be caused by a malfunction on harness, connector, or terminal. Move the har-
nesses, harness connectors, or terminals by hand to make sure that there is no contact malfunction.
lIf a circuit tester is used for the check, be careful not to forcibly extend any connector terminal.
lFor self-diagnosis, active test, and work support of ESP/TCS/ABS control unit with CONSULT-II, stop and
connect CONSULT-II and select²ABS².
lCONSULT-II self-diagnosis results are displayed without regard to occurrence timing. In some case, the
later ones (timing value is small) appear on the next screen.
lWhile the self-diagnosis results of CONSULT-II shows a malfunction, if CONSULT-II active test is per-
formed, an engine system malfunction may be indicated. In this case, start the engine to resume the nor-
mal screen.
lESP/TCS/ABS system electronically controls the brake operation and engine output. The following symp-
toms may be caused by the normal operations.
Symptom Symptom description Result
Motor operation noiseDuring ESP, TCS, or ABS operation, sometimes a faint noise can be
heard. This is a motor operation noise in the ESP/TCS/ABS actuator.
Normal
Just after the engine starts, the motor operating noise may be heard.
This is a normal status of the system operation check.
System operation check
noiseWhen the engine starts, a²click²noise may be heard from the engine
compartment. This is a normal status of the system operation check.Normal
ESP/TCS operation
(SLIP lamp ON)When the vehicle is passing through a road where the surface friction
coefficient varies or the wheel speed changes suddenly by downshifting
or depressing of the accelerator pedal fully, TCS may be activated tem-
porarily.
Normal
Cancel the ESP/TCS
function for the
inspection on a chas-
sis dynamometer. Before the speedometer inspection, turn ESP OFF switch off to cancel
the ESP/TCS function.
When the accelerator pedal is depressed on a chassis dynamometer,
the vehicle speed will not increase. This is not malfunction, because
TCS is activated by the wheel speed difference between front and rear.
The warning lamp may also illuminate to show²sensor system failure²in
this case. This is not malfunction either, because the stationary front
wheels are detected. Restart the engine, and drive the vehicle at 30 km/
h or higher to check that the warning lamp no longer illuminates.
ABS operation (Longer stop-
ping distance)The stopping distance may be longer for the vehicles with ABS when the
vehicle is driver on snowy and rough road. When driving on the road like
that, slow down the speed.Normal
Sluggish feelDepending on road circumstances, the driver may have a sluggish feel.
This is not abnormal, because the optimum traction has the highest pri-
ority (safety first) by TCS operation. Sometimes the driver has a slight
sluggish feel against the substantial accelerator pedal operation.Normal