1991 ACURA NSX brake light

Idle Contro l Syste m
Brake Switc h Signa l
This signal s th e EC M whe n th e brak e peda l i s depressed .
Are th e brak e light s o n withou tdepressin g th e brak e pedal ?Inspec t th e brak e switc h (se e
sectio n 19 ).
Depres s th e brak e pedal .
D o th e brak e light s com e on ?
Is th e fus e OK ?
Chec k fo r a n ope n in th e wire :
1 . Depres s th e brak e pedal .
2 . Measur e voltag e betwee n
EC M connecto r terminal s F1 6
an d A2 6 wit h th e brak e peda l
depressed . —
Repai r shor t i n th e wir e
betwee n th e brak e switc h
an d th e BRAK E LIGH T S W
HOR N (2 0 A ) fuse .
— Replac e th e BRAK E LIGH T
S W HOR N (2 0 A ) fuse .
WIR E SID E O F FEMAL E TERMINAL S
I s ther e batter y voltage ? Repai
r ope n i n th e wir e betwee n
th e EC M (F16 ) an d th e brak e
switch .
Inspectio
n o f Brak e Switc h Signal .
Inspect th e BRAK E LIGH T S W
HORN (20 A ) fus e i n th e under -
hood fuse/rela y box .
Repai r ope n i n th e wir e
betwee n th e brak e switc h
an d th e BRAK E LIGH T S W
HOR N (2 0 A ) fuse .
Inspec t th e brak e switc h (se e
sectio n 19 ).
ECM CONNECTOR S
Brak e switc h signa l i s OK .
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Pedal Heigh t
Adjustmen t
1. Loose n th e brak e switc h locknut , an d bac k of f th e
brak e switc h unti l i t i s n o longe r touchin g th e brak e
pedal .
2 . Loose n th e pushro d locknut , an d scre w th e pushro d
in o r ou t wit h plier s unti l th e standar d peda l heigh t
from th e floo r i s 21 8 m m (8. 6 in) . Afte r adjust -
ment, tighte n th e locknu t firmly .
3. Scre w in th e brak e switc h unti l it s plunge r i s full y
depresse d (threade d en d touchin g th e pa d o n th e
peda l arm) . The n bac k of f th e switc h 1/ 2 turn , an d
tighte n th e locknu t firmly .
CAUTION : Chec k tha t th e brak e light s g o of f
whe n th e peda l i s released .
NOTE : D o no t adjus t th e peda l heigh t wit h th e
pushro d depressed .
Parking Brak e
Adjustmen t
1. Remov e th e consol e mat , th e fou r screw s an d th e
consol e box .
NOTE : Afte r rea r brak e calipe r servicing , loose n
th e parkin g brak e adjustin g nut , star t th e engine ,
an d depres s th e brak e peda l severa l time s t o se t
the self-adjustin g brake s befor e adjustin g th e brak e
pedal .
Block th e fron t wheel s befor e jackin g
u p eac h sid e o f th e car .
2 . Rais e th e rea r wheel s of f th e ground .
3 . Mak e sur e th e leve r o f th e rea r brak e calipe r con -
tact s th e brak e calipe r pin .
4 . Pul l th e parkin g brak e leve r u p on e notch .
5 . Tighte n th e adjustin g nu t unti l th e rea r wheel s dra g
slightl y whe n turned .
6. Releas e th e parkin g lever , an d chec k tha t th e rea r
wheel s d o no t dra g whe n turned . Readjus t i f
necessary .
7. Wit h th e equalize r properl y adjusted , th e rea r
brake s shoul d b e full y applie d whe n th e parkin g
brak e leve r i s pulle d u p 1 0 t o 1 4 clicks .
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Brake Booste r
Tests
Functiona l Tes t
1. Wit h th e engin e stopped , depres s th e brak e peda l
severa l time s t o deplet e th e vacuu m reservoir , the n
depres s th e peda l har d an d hol d i t fo r 1 5 seconds .
I f th e peda l sinks , eithe r th e maste r cylinde r i s
bypassin g internally , o r th e brak e syste m (maste r
cylinder , lines , modulator , proportionin g valve , o r
calipers ) ar e leaking .
2 . Star t th e engin e wit h th e peda l depressed . I f th e pe -
da l sink s slightly , th e vacuu m booste r i s operatin g
normally , i f th e peda l heigh t doe s no t vary , th e
booste r o r chec k valv e i s faulty .
3 . Wit h th e engin e running , depres s th e brak e peda l
lightly . Appl y jus t enoug h pressur e t o hol d bac k au -
tomati c transmissio n creep . I f th e brak e peda l sink s
mor e tha n 2 5 m m (1. 0 in. ) i n thre e minutes , th e
maste r cylinde r i s faulty . A sligh t chang e i n peda l
heigh t whe n th e A/ C compresso r cycle s o n an d of f
i f normal . (Th e A/ C compresso r loa d change s th e
vacuu m availabl e t o th e booster. )
Leak Tes t
1. Depres s th e brak e peda l wit h th e engin e running ,
the n sto p th e engine . I f th e peda l heigh t doe s no t
var y whil e depresse d fo r 3 0 seconds , th e vacuu m
booste r i s OK . I f th e peda l rises , th e booste r i s faulty .
2 . Wit h th e engin e stopped , depres s th e brak e peda l
severa l time s usin g norma l pressure . Whe n th e pe -
da l i s firs t depressed , i t shoul d b e low . O n consecu -
tiv e applications , th e peda l heigh t shoul d graduall y
rise . I f th e peda l positio n doe s no t vary , chec k th e
booste r chec k valve .
Booste r Chec k Valv e Tes t
1. Disconnec t th e brak e booste r vacuu m hos e a t th e
booste r o r a t th e booste r sid e o f th e valve .
2 . Star t th e engin e an d le t i t idle . Ther e shoul d b e vacu -
um . I f n o vacuu m is available , th e chec k valv e is no t
workin g properly . Replac e th e chec k valv e an d
retest .
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Anti-lock Brake System (ABS) Description

Features/Construction/Operation

General

In a conventional brake system, if the brake pedal is depressed excessively, the wheels can lock before the vehicle

comes to a stop. In such a case, the stability of the vehicle is reduced if the rear wheels are locked, and maneuverabily of

the vehicle is reduced if the front wheels are locked, creating an extremely unstable condition.

The Anti-lock Brake System (ABS) modulates the pressure of the brake fluid applied to each caliper, thereby preventing

the locking of the wheels, whenever the wheels are likely to be locked due to excessive braking. It then restores normal

hydraulic pressure when there is no longer any possibility of wheel locking.

4-Channel Anti-lock Brake System (ABS) Features

• Increased braking stability can be achieved regardless of changing driving conditions.

• The maneuverability of the vehicle is improved as the system prevents the front wheels from locking.

• When the anti-lock brake system goes into action, kickback is felt on the brake pedal.

• The anti-lock brake system is equipped with a self-diagnosis function. When an abnormality is detected, the ABS in-

dicator light comes on. The location of the abnormality can be diagnosed from the frequency of the system indicator

light display blinks.

• This system has individual control of the front and rear wheels. Braking force is controlled on each of the four wheels

independently, resulting in optimum braking effects on the four wheels.

The system has a fail-safe function that allows normal braking if there's a problem with the anti-lock brake system.

Construction

In addition to the conventional braking system, the anti-lock brake system is composed of: gear pulsers attached to the

rotating part of individual wheels; wheel sensors, which generate pulse signals in correspondence to the revolution of the

gear pulsers; ABS control unit, which controls the working of the anti-lock brake system by performing calculations bas-

ed on the signals from the individual wheel sensors and the individual switches; a modulator unit, which adjusts the

hydraulic pressure applied to each caliper on the basis of the signals received from the ABS control unit; an accumulator,

in which high-pressure brake fluid is stored; a pressure switch, which detects the pressure in the accumulator and

transmits signals to the ABS control unit; a power unit, which supplies the high-pressure working fluid to the ac-

cumulator by means of a pump; a motor relay for driving the power unit; a fail-safe relay, which cuts off the solenoid

valve ground circuit when the fail-safe device is at work; and, an ABS indicator light.ProCarManuals.com

Anti-lock Brake System (ABS) Description

Features/Construction/Operation (cont'd)

ABS Control Unit

The ABS control unit consists of a main function section, which controls the operation of anti-lock brake system, and

sub-function, which controls the pump motor and "self-diagnosis."

1. Main Function

The main function section of the ABS control unit performs calculations on the basis of the signals from each wheel

sensor and controls the operation of the anti-lock brake system by putting into action the solenoid valves in the

modulator unit for each front and rear brake.

2. Sub-Function

The sub-function section gives driving signals to the pump motor and also gives "self-diagnosis" signals, necessary

for backing up the anti-lock brake system.

Self-Diagnostic Function

Since the anti-lock brake system modulates the braking pressure when a wheel is about to lock, regardless of the driver's

intention, the system operation and the braking power will be impaired if there is a malfunction in the system. To prevent

this possibility, at speeds above 6 mph (10 km/h), the self-diagnosis function monitors the main system functions. When

an abnormality is detected, the ABS indicator light comes on.

There is also a check mode of the self-diagnosis system itself: when the ignition switch is first turned on, the ABS in-

dicator light comes on and stays on for a few seconds after the engine starts, to signify that the self-diagnosis system is

functional.

Fail-Safe Function

If an abnormality is detected, the ABS control unit turns off the fail-safe relays and motor relay. In this condition, the

anti-lock brake system is prevented from functioning, yet the basic brake system continues to operate normally.

The ABS Indicator Light Comes On

1. When the fluid pressure pump runs more than 120 seconds.

2. When the parking brake is applied for more than 30 seconds while the vehicle is being driven.

3. When the rear wheel(s) is (are) locked more than a specified time.

4. When the wheel rotation signal is not transmitted due to faulty wire or sensor.

5. When the operation time of the solenoid valve(s) exceeds a predetermined valve, and the ABS control unit finds an

open in the solenoid circuit.

6. When the output signals from both main functions in the ABS control unit are not transmitted to the solenoid

valve(s).ProCarManuals.com

ALB Checke r
Function Tes t
NOTE :
• Th e AL B checke r i s designe d t o confir m prope r
operatio n of the anti-loc k brak e syste m (ABS ) b y
simulatin g eac h syste m functio n an d operatin g con -
dition . Befor e usin g th e checker , confir m tha t th e
anti-loc k brak e syste m (ABS ) indicato r ligh t i s no t in -
dicatin g som e othe r proble m wit h th e system . Th e
light shoul d g o o n whe n th e ignitio n i s firs t turne d o n
an d the n g o of f an d sta y of f on e secon d afte r th e
engin e i s started .
• Th e checke r shoul d b e use d throug h modes ,
1-5, t o
confir m prope r operatio n of the system , i n an y on e
of th e followin g situations :
Afte r replacin g an y AB S component .
Afte r replacin g o r bleedin g th e syste m flui d ( 0
mod e no t necessary) .
Afte r an y bod y o r suspensio n repai r tha t ma y
hav e affecte d th e sensor s o r thei r wiring .
• Th e procedur e fo r mode s
1-5 ar e o n thi s pag e an d
19-42 , mod e 0 (whee l senso r signal ) i s o n pag e
19-43 .
1. Wit h th e ignitio n switc h off , disconnec t th e 6- P in -
spectio n connecto r fro m th e connecto r cove r
locate d unde r th e glov e bo x an d connec t th e 6- P in -
spectio n connecto r t o th e AL B checker .
07HAJ-SG0010Bsee pag e 19- 2 fo r othe r applicabl e checkers .
NOTE: Plac e th e vehicl e o n leve l ground with th e
wheel s blocked , pu t th e transmissio n i n neutra l fo r
manua l transmissio n models , an d i n fo r
automati c transmissio n models .
2 . Star t th e engin e an d releas e th e parkin g brake .
3 . Operat e th e AL B checke r a s follows :
(1 ) Tur n th e Mod e Selecto r switc h t o "1" .
(2 ) Pus h th e Star t Tes t switch :
— Th e tes t i n progres s ligh t shoul d com e ON .
— In on e o r tw o mor e seconds , al l fou r monito r
light s shoul d com e o n (I f no t th e checke r i s
faulty) .
— Th e AB S indicato r ligh t shoul d no t com e O N (I f i t
come s o n th e checke r harnes s t o th e 6- P con -
necto r connectio n i s faulty) .
NOTE : Whe n tes t i n progres s indicato r ligh t ON ,
don't tur n th e Mod e Selecto r switch .
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ALB Checker

Function Test (cont'd)
4. Turn the Mode Selector switch further to "2". 5. Depress the brake pedal firmly and push the Start
Test switch
The ABS indicator light should not go on while the
Test in Progress light is ON. There should bekickback on the brake pedal. If not as described, go
to troubleshooting, page 19-44 ('91-'92) ('93-'96).

NOTE: The operation sequence simulated lby
Modes 2, 3, 4 and 5:
START

About 30 seconds

END

6. Turn the Mode Selector switch to 3, 4 and 5. Perform step 5 for each of the test mode positions.
Mode 1: Sends the simulated driving signal O mph (O km/h)

– > 113 mph (180 km/h) –
>
O mph (O km/h) of each

wheel to the ABS control unit. There should be NO
kickback.
Mode 2: Sends the driving signal of each wheel, then sends
the lock signal of the rear left wheel to the ABS control unit. There should be kickback.
Mode 3: Sends the driving signal of each wheel, then sends
the lock signal of the rear right wheel to the ABS control unit. There should be kickback.
Mode 4: Sends the driving signal of each wheel, then sends
the lock signal of the front left wheel to the ABS control unit. There should be kickback. Mode 5:
Sends the driving signal of each wheel, then sends
the lock signal of the front right wheel to the ABS
control unit. There should be kickback.

NOTE: If little or no kickback is felt from the brake
pedal in modes 2 – 5, repeat the function test of
modes 1–5 several times before beginning to
troubleshoot other parts of the system.
Mode 6: Not used on this model.
Inspection points: 1. The ABS indicator light goes ON in mode 1.
Check for DTCs, and refer to the appropriate
troubleshooting.
If ABS indicator light goes on 120 seconds later
but the pump motor stops, refer to page 19-47.
2. There is no kickback in modes 2 through 5. Faulty pressure switch (remains closed)
Shorted wiresFaulty or disconnected pump motor connector
Faulty pump motor relay
3. Weak kickback in modes 2 through 5. Bleed high pressure circuits.
4. Pump motor stops in mode 1, but it does not stop
and there is no kickback in modes 2 through 5.
Brake fluid leakageBleed power unit
Clogged power unit outlet
Clogged or deteriorated power unit hoseProCarManuals.com

Gauge Assembly

Bulb Locations

GAUGE LIGHTS (1.4W x 2)

SRS INDICATOR LIGHT (1.4 W)

RIGHT TURN SIGNAL INDICATOR LIGHT (1.4 W)

EPS INDICATOR LIGHT (1.4 W)

BRAKE SYSTEM LIGHT (1.4 W)

SEAT BELT REMINDER LIGHT (1.4 W)

TCS INDICATOR

LIGHT (1.96 W)

LOW FUEL INDICATOR

LIGHT (1.4 W)

GAUGE LIGHT

(1.4
W)
HIGH BEAM INDICATOR LIGHT (1.4 W)

LEFT TURN SIGNAL INDICATOR LIGHT (1.4 W)

ABS

INDICATOR LIGHT (1.4 W)

CHARGING SYSTEM LIGHT (1.4 W)

MALFUNCTION

INDICATOR

LAMP (MIL)

(1.4W)

LOW OIL PRESSURE

INDICATOR

LIGHT (1.4 W)

GAUGE LIGHT

(1.4
W)

GAUGE LIGHT

(3.0
W)
GAUGE LIGHT

(3.0
W)
GAUGE LIGHT

(3.0
W)
CRUISE INDICATOR LIGHT

(1.96
W)ProCarManuals.com