brake sensor ACURA NSX 1997 Service Repair Manual

Troubleshooting

Engine Control Module Terminal Arrangement (cont'd)

ECM CONNECTOR F (26P)
Wire side of female terminals

NOTE: Standard battery voltage is 12 V.

*: M/T

Terminal

number

1

2

3

4

6

7

8

9

10

10*

11

12

13

14

15

16

17

18

19

20

21

22

24
Wire

color

YEL/WHT

GRN/WHT

BRN

RED

GRY

LT

GRN/BLK

LT

GRN/RED

LTGRN

BLU/ORN

BLU/ORN

BLU/BLK

YEL/RED

BLU/RED

YEL/WHT

GRN/WHT

GRN/WHT

RED/WHT

BLU

BLU/YEL

GRN/YEL

LT GRN/YEL

WHT/YEL

RED/BLU
Terminal name

VCC1

(SENSOR VOLTAGE)

SG1 (SENSOR GROUND)

IMO CODE (IMMOBILIZER

CODE)

FLR2 (FUEL PUMP RELAY 2)

BKSW2 (BRAKE SWITCH 2)

CCRESSW (CRUISE

CONTROL RESUME SWITCH)

CC SETSW (CRUISE

CONTROL SET SWITCH)

CC MSW (CRUISE

CONTROL MAIN SWITCH)

CC ATSSW (CRUISE

CONTROL A/T GEAR

POSITION SWITCH)

CC CLSW (CRUISE

CONTROL CLUTCH SWITCH)

CCIL (CRUISE CONTROL INDI-

CATOR LIGHT)

AP2 (ACCELERATOR

POSITION SENSOR CIRCUIT 2)

AP1 (ACCELERATOR

POSITION SENSOR CIRCUIT 1)

VCC3 (SENSOR VOLTAGE)

SG3 (SENSOR GROUND)

BKSW1 (BRAKE SWITCH 1)

MTSL (REVERSE LOCKOUT

RELAY OUT)

VREF (REFERENCE VOLTAGE)

VT SOLF (FRONT VTEC

SOLENOID VALVE)

VT SOLR (REAR VTEC

SOLENOID VALVE)

ATSDL B (A/T Fl DATA LINE B)

ATSDL (A/T Fl. DATA LINE A)

TCSSDL (TCS DATA LINE)
Description

Provides sensor voltage

Sensor ground

Detects immobilizer signal

Drives fuel pump relay

Detects brake switch 2 signal

Detects resume switch signal

Detects set switch signal

Power source for the cruise

control system

Detects A/T gear position switch

signal

Detects clutch switch signal

Drives cruise control indicator

light

Detects accelerator position

sensor circuit 2 signal

Detects accelerator position

sensor circuit 1 signal

Provides sensor voltage

Sensor ground

Detects brake switch 1 signal

Drives reverse lockout relay

Provides reference voltage to

TCM

Drives front VTEC solenoid

valve

Drives rear VTEC solenoid valve

Detects data from the TCM

Sends data to the TCM

Interface for TCS control unit
Signal

With ignition switch ON (II): about 5 V

With ignition switch OFF: 0 V

With engine at low rpm: battery voltage

With engine at high rpm: 0 V

With brake pedal released and cruise

control main switch ON: battery voltage

With brake pedal depressed: 0 V

With resume switch released: 0 V

With resume switch depressed: battery

voltage

With set switch released: 0 V

With set switch depressed: battery

voltage

With cruise control main switch ON:

battery voltage

With cruise control main switch OFF: 0 V

In , or position: 0 V

In any other position: approx. 8 V

With clutch pedal released: approx. 8 V

With clutch pedal depressed: 0 V

With cruise control ON: 0 V

With cruise control OFF: battery voltage

With accelerator fully open: about 4.5 V

With accelerator fully closed: about 0.5 V

With accelerator fully open: about 4.5 V

With accelerator fully closed: about 0.5 V

With ignition switch ON (II): about 5 V

With ignition switch OFF: 0 V

With brake pedal released: 0 V

With brake pedal depressed: battery

voltage

With vehicle speed above 13 mph

(20 km/h): 0 V

With vehicle speed below 9 mph

(15 km/h): battery voltage

With ignition switch ON (II): about 5 V

With ignition switch OFF: 0 V

With engine at low rpm: 0 V

With engine at high rpm: battery voltage

With engine at low rpm: 0 V

With engine at high rpm: battery voltage

With engine running: pulses

With engine running: pulses

With engine running: pulsesProCarManuals.com

11. Remove the parking brake cable holders from the rear beam rod.

12. Remove the rear beam rod.

13. Remove the front exhaust pipe A.

14. Remove the parking brake cable holder and the wheel sensor wire clamp.

1 5. Make a reference mark on the flange of the adjusting bolt, adjusting cam and lower control arm.

16. Separate the toe control arm from the side beam.

17. Remove the damper fork bolt.

18. Separate the lower control arm from the side beam.

19. Remove the right driveshaft from the intermediate shaft.ProCarManuals.com

20. Remove the intermediate shaft heat shield cover and the intermediate shaft mounting bolts.

21. Pry the intermediate shaft out of the differential. Pull and remove it.

NOTE:

• Coat all precision finished surfaces with clean engine oil.

• Tie a plastic bag over the intermediate shaft end.
Removal (cont'd)
Transmission

22. Remove the parking brake cable holder and the wheel sensor wire clamp.

23. Make a reference mark on the flange of the adjusting bolt, adjusting cam and lower control arm.

24. Separate the toe control arm from the side beam.

25. Remove the damper fork bolt.

26. Separate the lower control arm from the side beam.

27. Pry the left driveshaft out of the differential. Pull and remove it.

NOTE:

• Coat all precision finished surfaces with clean engine oil.

• Tie a plastic bag over the driveshaft end.ProCarManuals.com

Installation (cont'd)
Transmission

11. Install a new set ring on the end of the left driveshaft and intermediate shaft. Apply a light film of grease around the

set ring grooves, then center the new set ring on the shafts. The grease keeps the set ring centered, making shaft

installation easier.

12. Install the left driveshaft.

13. Install the lower control arm to the side beam.

CAUTION: Line up the reference marks on the adjusting bolt, adjusting cam, and lower control arm.

14. Install the damper fork bolt.

15. Install the toe control arm to the side beam.

CAUTION: Make sure that the reference marks on the toe control arm are aligned.

16. Install the wheel sensor wire clamp and parking brake cable holder.

17. Install the intermediate shaft, and tighten the intermediate shaft mounting bolts to the intermediate shaft support

base.

18. Install the intermediate shaft heat shield cover.ProCarManuals.com

19. Install the right driveshaft on the intermediate shaft.

20. Install the lower control arm to the side beam.

CAUTION: Line up the reference marks on the adjusting bolt, adjusting cam, and lower control arm.

21. Install the damper fork bolt.

22. Install the toe control arm to the side beam.

CAUTION: Make sure that the reference marks on the toe control arm are aligned.

23. Install the wheel sensor wire clamp and parking brake cable holder.

24. Install the front exhaust pipe A.

25. Install the rear beam rod.

26. Install the parking brake cable.ProCarManuals.com

Driveshafts

Removal

6. Remove the wheel sensor from the knuckle and the

rear of the lower arm, then secure the wheel sensor

wire to the suspension arm.

NOTE:

• Do not disconnect the wheel sensor,

• Avoid twisting the wires when reinstalling the

wheel sensor.

V Corrosion resistant bolt

8 mm FLANGE BOLTS

22 N-m (2.2 kgf-m, 16 Ibf-ft)
PARKING BRAKE CABLE

WHEEL SENSOR 6 mm BOLT-WASHER

9.8 N m (1.0 kgf m, 7.2 Ibf-ft)

8 mm BOLT-WASHER

22 N m (2.2 kgf-m, 16 Ibf-ft)

7. Disconnect the parking brake cable from the body.

8. Remove the flange bolt, then disconnect the toe

control arm from the body.

Corrosion resistant bolt

TOE CONTROL ARM
FLANGE BOLT

12 x
1.25
mm

93 N m
(9.5
kgf in, 69 Ibf ft I
9. Hold the damper lower mount of stabilizer link with

a wrench, and remove the damper mounting nut.

Corrosion resistant nut

A DAMPER MOUNTING NUT

12 x
1.25
mm

Replace.

93 N-m (9.5 kgf-m, 69 Ibf-ft)

WRENCH

HEX WRENCH

STABILIZER LINK

SELF-LOCKING NUT

12 x
1.25
mm

Replace.

83 N m (8.5 kgf m, 61 Ibf-ft)

10. Hold the ball pin of the stabilizer link with a hex

wrench, and loosen the self-locking nut.

11. Remove the self-locking nut, then remove the stabi-

lizer link from the stabilizer bar and knuckle.

Corrosion resistant nut

REAR DAMPER

SELF-LOCKING NUT

12 x
1.25
mm

Replace.

STABILIZER LINKProCarManuals.com

Features/Construction/Operation
Anti-lock Brake System (ABS) Description

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 maneuverability 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 locked due to be 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 indi-

cator 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 efects 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.

Difference Between The 3-Channel And 4-Channel 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 based

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 trans-

mits signals to the ABS control unit; a power unit, which supplies the high-pressure working fluid to the accumulator by

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

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

Wheel Sensor

The wheel sensor is a contactless type, and it detects the rotating speeds of a wheel. It is composed of a permanent

magnet and coil. When the gear pulsers attached to the rotating parts of each wheel (rear wheel: outboard joint of the

driveshaft, front: hub bearing unit) turn, the magnetic flux around the coil in the wheel sensor alternates, generating volt-

ages with frequency in proportion to wheel rotating speed. These pulses are inputted into the ABS control unit, and the

ABS control unit identifies the wheel speeds.
Features/Construction/Operation (cont'd)
Anti-lock Brake System (ABS) DescriptionProCarManuals.com

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 modu-

lator 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 indicator

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).

(cont'd)ProCarManuals.com

Pressure Switch

The pressure switch monitors the pressure accumulation (pressure from the pump) in the accumulator and is turned off

when the pressure becomes lower than a prescribed level. When the pressure switch is turned off, the switching signal is

sent to the ABS control unit. Upon receiving the signal, the ABS control unit activates the pump motor relay to operate the

motor. If the pressure doesn't reach the prescribed value, the ABS indicator light is turned on.

Operation

When the pressure in the accumulator rises, the Bourdon tube in the pressure switch deforms outwards. When the free

end of the Bourdon tube moves more than the prescribed amount, the micro-switch is activated by the force of the spring

attached to the sensing lever. When the pressure in the accumulator decreases due to anti-lock brake system operations,

the Bourdon tube moves in the direction opposite to the one described above, and the micro-switch is eventually turned

off. Upon receiving this signal, the ABS control unit activates the motor relay to operate the motor.

Power Unit

The power unit consists of a motor and a plunger-type pump. This unit transmits the revolution of the motor to the

plunger by way of an eccentric bearing and supplies high-pressure brake fluid to the accumulator by the effect of the

reciprocating movement of the plunger.

When the pressure in the accumulator drops below the prescribed pressure level, the pressure switch gives an OFF-signal.

The ABS control unit turns the motor relay ON to start the operation of the pump, upon the reception of this signal and a

signal from the wheel sensor that the vehicle is running at a speed greater than 6 mph (10 km/h). When the pressure in the

accumulator attains the prescribed pressure, the ABS control unit turns the motor relay OFF approximately three seconds

after the unit receives an ON-signal from the pressure switch. By this, the high-pressure in the accumulator is maintained.

The ABS control unit turns the pump off and lights the system indicator light if the accumulator pressure does not reach

the prescribed level after the pump has run continuously for 120 seconds.ProCarManuals.com