1999 HONDA CIVIC system description

Description
Electronic Control System ('gG - 98 Modelsl (cont'dl
Circuit Diagram and Terminal Locations
GNITIONSWITCN
Pri - Pt coNTnoLLrN ns0LtN0t0
SIAiT CLUTCH CONTSOLLINEAFSOLENOID
sHtFT CONmOILINIAftSOLENOID
BFAXELIGHT
PAS|(ING 8MI(E SWITCH
i\c-...............- +B
i\--------.--_ rcr
: MAP(PBIg s61
E rtDiRxo
g TM8
scs
123518I1011't22578910
14172023261213t4t6171820
D
14-204

Description
Electronic Control System ('99 - 00 Modelsl (cont'dl
Grade Logic Control System
How it works:
The PcM compares actual driving conditions with memorized driving conditions. based on the input from the vehiclespeed sensor, the throttle position sensor, the manifold absolute pressure sensor, the engine coolant temperature sensor,the brake switch signal, and the shift lever position signal, to control shifting while the vehicle is ascending or descendinga slope.
Ascending Control
When the PCM determines that the vehicle is climbing a hill in E position, the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. so the vehicle can run smooth and have more powerwhen needed. There are three ascending modes with different shift schedules according to the magnitude ot a gradient inthe PCM.
Descending Control
when the PCM determines that the vehicle is going down a hill in E position. the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. This, in combinstion with engine braking, achievessmooth driving when the vehicle is descending, There are three descending modes with different shift schedules accord-ing to the magnitude of a gradient in the PCM.
L
14-206

Description
Hydraulic Control
The hydraulic control system is controlled by the ATF pump. the valves, and the solenoids. The ATF pump is driven by theinput shaft. The ATF pump and the input shaft are linked by the ATF pump drive chain and the sprockets, The inhibitorsolenoid valve and the linear solenoids. which are located on their valve body, are controlled by the TCM or pcM. Fluidfrom the ATF pump flows through the PH regulator valve to maintain specified pressure to the drive pulley, the driven pul-ley, and the manual valve,
The lower valve body assembly includes the main valve body, the PL regulator valve body, the shift valve body, the startclutch control valve body, and the secondary valve bodv.
Main Valve Eody
The main valve body contains the pH control valve, the rubrication valve, and the pitot regulator valve.
PH Control Valve
The PH control valve supplies PH control pressure (PHCI in accordance with the pH-pL control pressure (HLc), and sup-plies PH control pressure to the PH regulator valve, which also regulatss PH pressure. At kick-down, it increases pHcontrol pressure which increases the high (PH) pressure. This shortens the shift speed by releasing the reverse inhibitorpressure (Rl)from the inhibitor solenoid valve.
Lubrication Valve
The lubrication valve controls the lubrication pressure to each shaft and maintains lubrication pressure. When rne pres-sure is too high, the spring is compressed. This moves the lubrication valve and opens the fluid leak passage.
Pitot Regulalor Valv6
The pitot regulator valve controls the start clutch pressure (SC) in accordance with the engine speed, when the electron-ic control system is faulw.
MAIN VAIVEBODY
L.
14-208

Description
Hydraulic Flow (cont'd)
lll position, when th€ electronic control system is fauhy.
when the electronic control svstem (linear solenoids and sensors) is faulty, the transmission uses the pitot pipe pressure(PP) to 311o- rh" u"hicle to drive.
when all linear solenoids and sensors are off because of a faulty electronrc control system, clutch reducing pressure (cR)flows to the start clutch control valve, the manual valve, the PH-PL control valve, and the shift control valve. clutch reduc-ing pressure (cR) becomes shift varve pressure (sV) at the shift contror varve, and shift varve pressure {sv) is appried tothe left end of the shift valve and the right end of the shift inhibitor valve. The shift valve moves to the right side. anduncovers the pon that leads high pressure (PH) to the drive pulley and uncovers the po.t tlr"t r""1" ro,,"-pressure (pL) tothe driven pulley At this time, the pulley ratio is high, The shift inhibitor valve moves to the left side, and uncovers theport that leads shift inhibitor pressure (Sll to the pitot lubrication pipe and the pitot regulator valve. tne prtot lubricationpipe discharges fluid inside of the pitot flange, and discharged fluid enters into the pitot pipe and it is applied to the leftend of the pitot regulator valve. The pitot regulator valve moves lo the right side, and uncovers the port that leads pitotregulator pressure (PR) to the shift inhibitor valve. Pitot regulator pressure {pR) becomes start clutch pressure {sc1 at theshift inhibitor valve, and is applied to the stan clutch. The stan clutch rs engaged. The forward clutch pressure (FWD) isapplied to the forward crutch, and the forward crutch is engaged. This alows the vehicre to drive.
NOTE: When used. "|eft" or ,,right', indicates direction on the hydraulic circuit.
14-220
I.

PGM Terminal Voltage/Measuring Conditions ('99 - 00 Modelsl
A/T Control System
The PCM terminal voltage and measuring conditions are shown for the connector terminals that are related to the A/T con-trol system. The other PCM terminal voltage and measuring conditions are described in section 11.
PICM Connoctor Terminrl Location3
Terminal NumberSignalDescriplionMeasuring Condhions/Torminal Voltage
A7ATP DA,/T gear position switch
E position input
InEposition:OV
In other than E] position: Approx. 1O V
A9ATP NPA/T gear position switch
@ and S positions input
In E and El positions: 0 V
In other than E] and E position: Approx. 1O V
A10Timing and adjustment service
check signal
With ignition switch ON {ll} and service check
connector oDen: 5 V
With ignition switch ON (ll) and service check
connector connected with soecialtool:0 v
ATP LA,/T gear position switch
I position input
In E position; OV
In other than E position: Approx. 10 V
STOP SWBrake switch signal outputBrake pedal depressed: Battery voltage
Brake pedal released: 0 V
PCM CONNECTOR B I25P}
Terminal NumberSignalDescriptionMoasuring Condhions/Terminal Vohage
B1IGPlPower supply circuit from main
relay
With ignition switch ON (lll: Battery voltage
With ignition switch OFF: 0 V
82PG1Ground
B8HLC LSMPH-PL control linear solenoidpower supply neqative electrode
B9IGP2Power supply circuit from main
relay
With ignition switch ON (lll: Battery voltage
With ignition switch OFF:0 V
810PG2Ground
817HLC LSPPH-PL control linear solenoid
power supplypositive electrode
With ignition switch ON {ll): Pulsing signal
818SC LSMStart clutch control linear
solenoid power supply negative
electrode
s20LGIGround
821VBUBack-up power supplyAlways battery voltage
B22Ground
825SC LSPStan clutch control linear
solenoid power supply positive
electrode
With ignition switch ON (ll): Pulsing signal
t
14-232

l.
t
Steering
Speciaf Tools ....."'.....17-2
Manual Steering
Component Locations
lndex ................ ....... 17-3
Inspection and Adiustment
Steering Operation "'......"............... 17-4
Rack Guide Adiustment ................... 17-5
*Steering Wheel
(See power steering section)
*Steering Column
(See power steering sectionl
Steering Gearbox
Removal ................. 17-5
Disassembly ......."" 17-7
ReassemblY ..'......... 17-9
lnstallation ............. 17-13
Power Steering
Component Locations
lndex "......."..... """' 17-15
System DescriPtion
Fluid Flow Diagram .........""............. 17'16
Steering Pump ............'... "........"'...-- 17 -17
Steering Gearbox .".................'...'.'.' 17-20
Troubleshooting
Generaf Troubleshooting ..........--.... 17'22
Noise and Vibration ......................... 17 -26
Ffuid Leaks .............17-28
Inspection and Adiustment
Steering Operation'......."'........'...... 1 7-30
Power Assist Check
With Vehicle Parked .."................ 17-30
Steering Linkage and Gearbox ....." 17-31
Pump Beft ...--.""".. 17-32
Rack Guide Adiustment .'.......'.......'. 17'33
Fluid Replacement .....'.."................. 17-33
Pump Pressure Check .............'....-. " 17 -34
'Steering Wheel
Removal .."'........'... 17-35
lnstallation ............. 17-35
Disassembly/Reassembly ......'.....'.' 17-36
*Steering Column
Removal/lnstallation ....'........... ---.... 17'37
lnspection .............. 17'38
Power Steering Hoses, Lines
Fluid Leakage Inspeetion ............'.... 17-39
Replacement ......".. 17-39
Power Steering PumP
Removal/lnstallation .'.'..'..'............. 17-40
Disassembly ".........17-41
fnspection .......---'." 17'42
Reassembly ..'.........17-44
Steering Gearbox
Removal ....'........."' 17'47
DisassemblY ..........' 17-49
Reassembly '........... 17-55
lnstallation ............. 17-65
Ball Joint Boot Replacement .......'.. 17-68
Ir/
lp

System Description
Fluid Flow Diagram
The system is a compact rotary-valve-type power steering, connected to the steering gearbox. The fluid pressure is pro-
vided by a vane-type pump which is driven by the engine crank pulley. The amount of fluid and pressure is regulated by
the flow control valve built into the pump. The fluid pressure from the pump is delivered to the valve body unit around the
pinion of the steering gearbox. The valve inside the valve body unit controls the hydraulic pressure and changes the direc-
tion of the flow. The fluid then flows to the power cylinder. where rack thrust is generated. Fluid returning from the power
cylinder flows back to the reservoir, where the fluid is "filtered" and supplied to the pump again.
RESERVOIR
VALVE BOOY UNIT
SUB.VALVE
FLOW CONTROL VALVESTEERING GEARBOX
17-16

System Description
Steering Pump (cont'dl
The flow control valve and sub-valve in the pump per-
forms the following steps @ through @ to control the
flow of fluid, that is to increase the discharge volume
when engine speed is low, and to decrease it when the
engine speed increases. The assistance thrust of the
steering gearbox changes in compliance with the
change in the discharge volume.
When the engine starts, fluid discharged from the
discharge port starts to flow through oil passage A,
the fixed orifice and the variable orifice to the steer-
ing gearbox. When the engine speed is extremely
low, the return port is closed by the flow control
Fluid pressure discharged from the discharge port
is applied to the top of the sub-valve, and the fluid
pressure that passed through oil passage A is applied
to the bottom of the sub-valve. When this happens,
the pressure difference between the ends of oil pas-
sage A, which is caused by the resistance oil passage
A when the fluid flows through the passage. is
applied to the sub-valve, However, the pressure dif-
ference applied to the sub-valve. that is the force
that pushes the sub-valve down, is too small to
overcome the spring force, and the variable orifice is
fully open when the engine speed is extremely low.
Because the fluid volume flowing through the fixed
orifice and variable orifice increases, a pressure dif-
terence is created between the ends of these ori-
fices, and it increases in proportion to the engine
speed. As the fluid pressure that passed the fixed
orifice and variable orifice is directed to the bottom
of the flow control valve. a pressure difference is
created between the top and bottom of the valve,
which pushes down the flow control valve and
opens the return port. As a result, pan of the fluid
discharged from the discharge port feturns to the
pump suction port, keeping the discharge volume
constant.
In this condition, the sub-valve does not move. and
the variable orifice stays fully open.
lo
trrtrrlo3
J
o
PUMP R.P.M.
To STEERING GEARBOXSUB.VALVE
To STEEnING GEARBOX
FLOW CURVE
!rs+/f/ffih\
o,,-i^"l^tKzYt)91y ul3Yl
FLOW CONTNOL VALVE
su8-vALvE
ORIFICE
ToP
17-18
FLOW CONTROL VALVE