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Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS composition which is available to NISSAN MODEL R20 is as follows (The composition
varies according to the destination and optional equipment.):
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), front seat
belt pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
I For a side collision
The Supplemental Restraint System consists of front side air bag module (located in the outer side of front
seat), side air bag (satellite) sensor, diagnosis sensor unit (one of components of air bags for a frontal
collision), wiring harness, warning lamp (one of components of air bags for a frontal collision).
WARNING:
I To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance should be per-
formed by an authorized NISSAN dealer.
I Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system.
I Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Precautions for SRS ªAIR BAGº and ªSEAT
BELT PRE-TENSIONERº Service
IDo not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
I Before servicing the SRS, turn ignition switch ªOFFº, disconnect both battery cables and wait at least 3
minutes.
For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt
pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes
have passed.
I Diagnosis sensor unit must always be installed with their arrow marks ª +º pointing towards the front of
the vehicle for proper operation. Also check diagnosis sensor unit for cracks, deformities or rust before
installation and replace as required.
I The spiral cable must be aligned with the neutral position since its rotations are limited. Do not attempt to
turn steering wheel or column after removal of steering gear.
I Handle air bag module carefully. Always place driver and front passenger air bag modules with the pad
side facing upward and place front side air bag module (built-in type) standing with stud bolt side setting
bottom.
I Conduct self-diagnosis to check entire SRS for proper function after replacing any components.
I After air bag inflates, the front instrument panel assembly should be replaced if damaged.
Precautions
IBefore proceeding with disassembly, thoroughly clean the outside of the transmission. It is important to
prevent the internal parts from becoming contaminated by dirt or other foreign matter.
I Disassembly should be done in a clean work area.
I Use lint-free cloth or towels for wiping parts clean. Common shop rags can leave fibers that could inter-
fere with the operation of the transmission.
I Place disassembled parts in order for easier and proper assembly.
I All parts should be carefully cleaned with a general purpose, non-flammable solvent before inspection or
reassembly.
I Gaskets, seals and O-rings should be replaced any time the transmission is disassembled.
I It is very important to perform functional tests whenever they are indicated.
I The valve body contains precision parts and requires extreme care when parts are removed and serviced.
Place removed parts in a parts rack in order to replace them in correct positions and sequences. Care will
also prevent springs and small parts from becoming scattered or lost.
I Properly installed valves, sleeves, plugs, etc. will slide along bores in valve body under their own weight.
PREPARATION AND PRECAUTIONS
AT- 4
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IBefore assembly, apply a coat of recommended ATF to all parts. Apply petroleum jelly to protect O-rings
and seals, and to hold bearings and washers in place during assembly. Do not use grease.
I Extreme care should be taken to avoid damage to O-rings, seals and gaskets when assembling.
I After overhaul, refill the transmission with new ATF.
I When the A/T drain plug is removed, only some of the fluid is drained. Old A/T fluid will remain in torque
converter and ATF cooling system.
Always follow the procedures under ªChanging A/T Fluidº in the MA section when changing A/T fluid.
Service Notice or Precautions
FAIL-SAFE
The TCM has an electronic Fail-Safe (limp home mode). This allows the vehicle to be driven even if a major
electrical input/output device circuit is damaged.
Under Fail-Safe, the vehicle always runs in third gear even with a shift lever position of ª1º, ª2º or ªDº. Cus-
tomer may complain of ªsluggish or poor accelerationº.
When the Fail-Safe operation occurs the next time the key is turned to the ªONº position, the SPORT indica-
tor lamp will blink for about 8 seconds. (For diagnosis, refer to AT-33.)
Fail-Safe may activate without electrical circuit damages if the vehicle is driven under extreme conditions (such
as excessive wheel spins and emergency braking immediately afterwards). In this case, turn the ignition key
ªOFFº for 5 seconds and then ªONº to recover normal shift pattern.
The blinking of the SPORT indicator lamp for about 8 seconds will appear only once and be cleared. The cus-
tomer may resume normal driving conditions by chance.
Always follow the ªWORK FLOWº (Refer to AT-26).
The SELF-DIAGNOSIS results will be as follows:
The first SELF-DIAGNOSIS will indicate the damage of the vehicle speed sensor or the revolution sensor.
During the next SELF-DIAGNOSIS performed after checking the sensor, no damages will be indicated.
PREPARATION AND PRECAUTIONS
Precautions (Cont'd)
AT- 5
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A/T Electrical Parts Location
YAT410
OVERALL SYSTEM
AT- 6
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Wiring Diagram Ð A/T Ð
YAT399
OVERALL SYSTEM
AT- 7
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Cross-sectional View
SAT125BA
OVERALL SYSTEM
AT- 8
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Hydraulic Control Circuits
SAT624GA
OVERALL SYSTEM
AT- 9
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Shift Mechanism
The automatic transmission uses compact, dual planetary gear systems to improve power-transmission
efficiency, simplify construction and reduce weight.
It also employs an optimum shift control and superwide gear ratios. They improve starting performance and
acceleration during medium and high-speed operation.
Two one-way clutches are also employed: one is used for the forward clutch and the other for the low clutch.
These one-way clutches, combined with four accumulators, reduce shifting shock to a minimum.
CONSTRUCTION
q1Torque converter clutch piston
q
2Torque converter
q
3Oil pump
q
4Input shaft
q
5Brake band
q
6Reverse clutch
q
7High clutch
q
8Front pinion gear q
9Front sun gear
q
10Front internal gear
q
11Front planetary carrier
q
12Rear sun gear
q
13Rear pinion gear
q
14Rear internal gear
q
15Rear planetary carrier
q
16Forward clutch q
17Forward one-way clutch
q
18Overrun clutch
q
19Low one-way clutch
q
20Low & reverse brake
q
21Parking pawl
q
22Parking gear
q
23Output shaft
FUNCTION OF CLUTCH AND BRAKE
Control members Abbr. Function
q
6Reverse clutch R/C To transmit input power to front sun gear q9.
q
7High clutch H/C To transmit input power to front planetary carrier q11.
q
16Forward clutch F/C To connect front planetary carrier q11with forward one-way clutchq17.
q
18Overrun clutch O/C To connect front planetary carrier q11with rear internal gearq14.
q
5Brake band B/B To lock front sun gear q9.
q
17Forward one-way clutch F/O.C When forward clutch is engaged, to stop rear internal gear
q14from rotating in opposite
direction.
q
19Low one-way clutch L/O.C At D1position, to prevent rear internal gear q14from rotating in opposite direction.
q
20Low & reverse brake L & R/B To lock rear internal gear
q14(2, 12and 11), to lock front planetary carrier q11
(R position).
SAT509I
OVERALL SYSTEM
AT-10
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CLUTCH AND BAND CHART
Shift positionq6Reverse
clutch q7High
clutch q16Forward
clutch q18Overrun
clutch Band servo
q
17Forward
one-way
clutch q19Low
one- way
clutch q20Low &
reverse brake Lock-up Remarks
2nd
apply 3rd
release 4th
apply
P PARK
POSITION
R q qREVERSE
POSITION
N NEUTRAL
POSITION
D*4 1st
q*1
vv
Automatic shift
1 ) 2) 3) 4
2nd
q*1
q v
3rd qq*1
*2v
4th q
*3qq
2 1st
q
vv
Automatic shift
1) 2
2nd q
qv
1 1st
qq vqLocks (held sta-
tionary)
in 1st speed 1+ 2
2nd
qqq v
*1: Operates when overdrive control or A/T mode switch is being set in ªOFFº or ªSPORTº position.
*2: Oil pressure is applied to both 2nd ªapplyº side and 3rd ªreleaseº side of band servo piston. However, brake band does not contract because oil pressure area on the ªreleaseº side is greater than that on the ªapplyº side.
*3: Oil pressure is applied to 4th ªapplyº side in condition *2 above, and brake band contracts.
*4: A/T will not shift to 4th when overdrive control or A/T mode switch is set in ªOFFº or ªSPORTº position.
q : Operates.
: Operates when throttle opening is less than 3/16, activating engine brake.
v : Operates during ªprogressiveº acceleration.
: Operates but does not affect power transmission.
: Operates when throttle opening is less than 3/16, but does not affect engine brake.
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-11
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