traction control NISSAN GT-R 1998 Service Manual

ENGINE AND EMISSION CONTROL OVERALL SYSTEM
A 1 System Description
The engine control system, which performs various controls such
as the fuel injection control and ignition timing control with a single
control unit, has been adopted.
Diagnostic system applicable to
CONSULT has been adopted for
easier inspection, service, and trouble diagnostic operations.
Description of Engine Control
I
Description \,
Performs optimum fuel injection for every operation condition for
improved exhaust performance and response.
Adopts
SOFlS (Sophisticated and Optimized Fuel Injection System)
control for optimized fuel injection.
Adopts
airbuel ratio feedback
learning control that performs
com-
0
pensation of airfiuel ratio for improved drivability when the system is
in a transitional condiiion due to sudden change in
airfiuel ratro.
Uses an ignition timing map stored in the control unit to perform
controls so that the optimum ignition timing is obtained for every
operating condition.
Performs knock control, in which the ignition timing is advancedl
retarded according to the presence of knocking, so that the
opti- 0
mum i nition timing is obtained for every operating condition and
type
oPfue1.
Performs feedback control to obtain the target idle speed for various
conditions, such as during warm-up or when the air conditioner is
actuated, via the
AAC valve that adjusts the intake air amount when
O
the throttle valve is fully closed.
Turns the fuel pump relay OWOFF according to the engine speed
Fuel
injection control
Ignition timing control
Idle
speed
control
Fuel pump drive signal. In RB25DET model, FPCM (Fuel Pump Control Modulatoi) control O
has been adopted for reduced idle noise.
Heated oxygen sensor
heater control
Air conditioner cut control
Promotes warm-up of the heated oxygen sensor for improved air1
fuel ratio feedback function. 0
Tums the air conditioner relay OFF at starting or during acceleration to reduce the engine load. 0 -- Auxiliary electric fan con-
trol
Engine,
M, TCS,ABS integrated control
Tums the auxiliary electric fan relay ONIOFF according to the - engine coolant temperature signal and air conditioner signal.
Reduces engine toque during gearshift or when TCS (Traction
Control System) is being operated via a multiplex communication
lino 0
- -
Variable valve timing con-
trol According to the engine speed and load, controls the cam phase by
hydraulic pressure to change intake valve
open/close timing for
Increased engine torque at low and middle speeds and for
enhanced
out~ut.
I o I
Canister purge control air
intake valve control
Air
jet swirl control Performs duty
control of the canister purge air according to various ooeratina conditions.
0 -r-~ e-- ---
-
Controls the intake air passage in the intake manifold collector to
increase engine torque at low and middle speeds and to enhance
output. 0
According to operation conditions, turns the air jet swirl control sole-
noid valve ONIOFF to openlclose the air jet swirl control valve
for 0
pressure control
stable combustion.
Tums the Turbo pressure control solenoid valve ONIOFF according - to operation conditions.
Ensures the vehicle's safe operation and enables the vehicle
to be
Fail-safe and backup con-
trols
Diagnostic system driven
in an emergency when any of the system major components
(microcomputer in the control unit, engine coolant temperature
0
sensor, etc.) fails.
For easier trouble diagnosis, self-diagnostic system is adopted and
the existing diagnostic system is modified so that CONSULT can be
0 used.

TCSIABS SYSTEM
System
Description
ABS FUNCTION
During ABS operation, the brake pedal pulsates along with a mechanical noise. This ensures that the ABS
is working properly. mP
When starting up the engine or immediately after the vehicle starts to run, the brake pedal pulsates and G'
a motor noise from the engine compartment can be heard. They are caused by the ABS operation check
and should not be considered abnormal.
A vehicle with the ABS may stop in a longer distance than a vehicle without the ABS when the brake is
EC
applied on a bad road, gravel road, or deep fresh snow.
TCS FUNCTION
TCS/ABS control unit monitors the speed of the driving wheels through 4 wheel speed sensors. If driving
wheel slip is detected, fuel to the engine is cut
ol
and the throttle valve is adjusted so that the engine
a
torque is reduced. On vehicles with automatic transmission, transmission shift schedule is also changed
to control the rear wheel driving torque, which results
in the reduction of wheel slip. This system enables
the throttle valve to be controlled so that optimum engine torque can be achieved in accordance with the
driver's acceleration request.
The driver may not feel satisfied with acceleration on some road surfaces. This poor acceleration occurs
because the operating TCS gives priority to maintaining optimum traction. Therefore, this condition should
R8
be considered normal.
When shiftdown is made or the acceleration pedal is depressed while the vehicle is driven on the road
surface that has different friction coefficients, the TCS may operate temporarily.
r-- 4 Lrd[-i
On vehicles with manual transmission, the SLlP indicator lamp and the TCS OFF indicator lamp may light
up when the engine is about to stall in the conditions shown below.
If the lamps go off when engine speed
increases, there is no problem in the system.
At start, the engine almost stalls and the engine speed is much lower than the idle speed.
The vehicle is driven at an extremely low speed with a high-speed gear engaged.
The clutch has been engaged until the vehicle almost stops. 8D
FAIL-SAFE FUNCTION
ABS system
If any malfunction is detected in the system, the ABS warning lamp, the TCS OFF indicator lamp and the SLlP
indicator lamp in the instrument panel is turned on with the TCSIABS deactivated and the vehicle's brake sys-
tem reverts to normal operation.
TCS system
If any malfunction is detected in the system, both the SLlP indicator lamp and the TCS indicator lamp on the
instrument panel light up and the TCS is shut down. The vehicle operates in the same manner as a vehicle
without the
TCS, while the ABS is operational.
If there is a malfunction in the throttle control system, the TCS becomes inoperative while the ABS
remains functional.
When fail-safe operation is activated, perform the self-diagnosis procedure for the TCSIABS first.
Refer to
BR-27 for details.