Isuzu N-Series. Manual - part 280

5A4-94 ABS/ASR

Installation

1. Install the inner bearing to the hub.
2. Install the inner oil seal to the hub.
3. Install the new rear sensor rotor to the hub.

• Press-fit with a bench press around the circum-

ference until it contacts.

• Refer to the rear speed sensor installation pro-

cedure step. 5 — 7.

N5A2072E

International Service & Parts

Tokyo,  Japan

WORKSHOP MANUAL

N-SERIES

HSA (HILL START AID)

SECTION 5A5

HSA (HILL START AID) 5A5-1

HSA (HILL START AID)

SECTION 5A5

HSA (HILL START AID)

Contents

HSA System........................................................ 5A5-2

Description of Function and Operation ............ 5A5-2
Part Location Diagram..................................... 5A5-4
Parts Location.................................................. 5A5-9
Connector List ...............................................5A5-12

Procedure of Trouble Diagnosis .................... 5A5-15
Function Check.............................................. 5A5-17
List of Diagnostic Trouble Code .................... 5A5-18

DTC 03 Back-up Fuse Open .........................5A5-19

DTC 08 Clutch Sensor Output Voltage Fault. 5A5-21

DTC 19 Adjust Switch “FAST” or “SLOW” 

Remain ON...................................................5A5-23

DTC 25 Vehicle Speed Sensor Output 

Voltage Fault ................................................5A5-25

DTC 33 Control Unit Fault .............................5A5-27

DTC 36 Generator Terminal Output Does not 

Exist With the Clutch Engaged and Vehicle 

Running ........................................................5A5-28

DTC 86 Clutch Switch Does not Turn ON With Clutch 

Pedal Depressed ..........................................5A5-29

DTC 91 Solenoid Valve Drive Signal and Solenoid 

Valve Monitor Conditions Are Erratic............5A5-31

List of Trouble Phenomenon .........................5A5-33

Symptom: HSA Does not Operate.................5A5-34

Symptom: HSA Does not Release Though the HSA 

Off Switch Is Depressed ...............................5A5-38

Symptom: HSA Does not Release Though the Vehi-

cle Is Operated to Start (HSA Indicator Lamp Re-

mains ON) .................................................... 5A5-40

Symptom: HSA Does not Release Though the Park-

ing Brake Is Applied......................................5A5-42

Symptom: HSA Indicator Lamp Does not Come On 

(HSA Does not Operate) ..............................5A5-44

Symptom: HSA Indicator Lamp Does not Come On 

(HSA Does Operate) ....................................5A5-45

Symptom: HSA Indicator Lamp Does not Go Off (HSA 

Released) .....................................................5A5-47

Symptom: Buzzer Does not Operate Though the Door 

Is Opened While HSA Operating..................5A5-48

Symptom: HSA Indicator Lamp Blinks Abnormally 

and Does not Output the Trouble Cord During Self-di-

agnosis .........................................................5A5-50

Symptom: Buzzer Beeps Continuously During Self-di-

agnosis (Trouble Code Output Impossible) ..5A5-52

Symptom: HSA Warning Lamp Had Blinked or 

Buzzer Had Beeped In the Past (Currently the 

System Is Normal) ........................................5A5-53

HSA Control Unit...............................................5A5-54

Removal ........................................................5A5-54
Installation .....................................................5A5-54

HSA Valve.........................................................5A5-55

Removal ........................................................5A5-55
Installation .....................................................5A5-55

Clutch Sensor.................................................... 5A5-56

Removal ........................................................5A5-56
Inspection ......................................................5A5-56
Adjustment.....................................................5A5-56

HSA Off Switch..................................................5A5-57

Removal.........................................................5A5-57
Inspection.......................................................5A5-57
Installation......................................................5A5-57

HSA Reset Switch .............................................5A5-58

Removal.........................................................5A5-58
Inspection.......................................................5A5-58
Installation......................................................5A5-58

HSA Adjust Switch.............................................5A5-59

Removal.........................................................5A5-59
Inspection.......................................................5A5-59
Installation......................................................5A5-59

Speed Sensor....................................................5A5-60

Removal.........................................................5A5-60
Inspection.......................................................5A5-60
Installation......................................................5A5-60

Door Switch .......................................................5A5-61

Removal.........................................................5A5-61
Inspection.......................................................5A5-61
Installation......................................................5A5-61

Parking Brake Switch ........................................5A5-62

Removal.........................................................5A5-62
Inspection.......................................................5A5-62
Installation......................................................5A5-62

Neutral Switch ...................................................5A5-63

Removal.........................................................5A5-63
Inspection.......................................................5A5-63
Installation......................................................5A5-63

Stop Lamp Switch..............................................5A5-64

Removal.........................................................5A5-64
Installation......................................................5A5-64

Clutch Fluid Pressure Switch.............................5A5-65

Removal.........................................................5A5-65
Installation......................................................5A5-65

Diode Box ..........................................................5A5-66

Removal.........................................................5A5-66
Inspection.......................................................5A5-66
Installation......................................................5A5-66

5A5-2 HSA (HILL START AID)

HSA System

Description of Function and Operation

The HSA (hill start aid) is the system to retain the brake
force with brake pedal not depressed when the vehicle
is parked, and to automatically release the brake force
when starting the vehicle.

The HSA control unit drives the HSA valve located in the
pipe route between the master cylinder and the wheel
cylinder, to hold/release the brake fluid pressure. Also,
alarm function (activates when the door opened with
HSA operating, when the HSA system has running long
time, when the HSA pressure goes down) and self-diag-
nosis function are equipped with the HSA control unit.

Legend

1. Servo unit master ring
2. FR wheel cylinder
3. HSA control unit
4. RR wheel cylinder

5. RL wheel cylinder
6. HSA valve
7. FL wheel cylinder
8. Oil

Contents of HSA Control

The HSA operates when all the following conditions are
completed.

1. Brake pedal depressed
2. Parking brake released
3. Vehicle standstill

Notice:
The HSA can operate wherever the gearshift lever is
set.

The HSA is released when any of the following is com-
pleted.

1. Gear except in neutral and clutch engaged more

than half

2. Parking brake applied
3. HSA off switch depressed
4. Starter switch in ACC or OFF

N5A3001E