1998 HONDA CR-V Ac system

Description
PCM
PGM.FIControl System
Throttle Position SensorSignelVehicle Speed SensorSignal
Engin€ Coolsnt TomperatureSen30r SignalService Ch€ck Connectol
A/T Control Svstem
INTERLOCK
Shift Control
Shift ConlrolSolenoid Valve ACONTROL UNITr
RShift ControlSolenoid Valve B
N
Linear SolenoidD
Lock-up Control
2
Lock-up ControlSolenoid valve A1
Lock-up ControlSolenoid Valve BOver-DriveSwitch Signal
Mainshaft Speed SensorSignalE Indicator Light
Countershaft SpeedSensor SigntlSelt-Oiagnosis SigndSelf-DiagnosisFunc{ion
O/D OFFIndicetor Light
Electronic Gontrol System (cont'd)
'99 - 00 Models
14-16
www.emanualpro.com

Shift Control
The PCM determines which gear should be selected by various signals sent from sensors, and actuates the shift control
solenoid valves A and B to control shifting. Also. a Grade Logic Control System has been adopted to control shifting in E
anO E ('gZ - gg), and E ('99 - 00) position while the vehicle is ascending or descending a slope, or reducing speeo.
PositionGearShift Control Solenoid
Valve A
Shift Control Solonoid
Valve B
E, E, Or
E
'I stOFFON
2ndONON
3rdONOFF
E orE4thOFFOFF
a2ndONON
tr1stOFFON
E-ReverseONOFF
*See page 14-37 for reverse inhibitor control description.
Lock-up Control
From sensor input signals, the PCM determines whether to turn the lock-up ON or OFF, and activates lock-up control
solenoid valve A and/or B accordingly. Lock-up does not occur until the engine is warm. The combination of driving sig-
nals to lock-up control solenoid valves A and B and the linear solenoid pressure is shown in the table below.
Lock-up ConditionsLock-up Control
Solonoid Valve A
Lock-up Control
Solenoid Valve B
Linear Solenoid
Pressuro
LOCK-Up \JrrOFFOFFHigh
Lock-up, HalfONDuty operation
OFF - ON
Lock-up, FullONONHish
Lock-up
during decelerationONDuty operation
OFF - ONLow
(cont'd)
14-17
www.emanualpro.com

Description
Electronic Control System (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 vehicle speed
sensor, the throttle position sensor, the barometric pressure sensor ('98 model). the engine coolant temperature sensor, the
brake switch signal, and the shift lever position signal, to control shifting while the vehicle is ascending or descending a
slope, or reducing speed.
SIGNALS DETECTED
Driving Rcsisl.nce
Judgemont ot Controlling Aroa
. Normal Modo {Flrt ro.d mode}. Ascending Mode. Deacending Mode. Deceleration Mode
14-14
www.emanualpro.com

Ascending Control {37 Modol}
When the PCM determines that the vehicle is climbing a hill in E] and E positions, the system extends the engagement
area of 2nd g€ar and 3rd gear to prevent the transmission from frequently shifting between 2nd and 3rd gears, and
between 3rd and 4th gears, so the vehicle can run smooth and have more power when needed.
NOTE:
. Shift schedules stored in ths PCM between 2nd and 3rd gears, and between 3rd and 4th gears. enable the PCM's fuzzy
logic to automatically select the most suitable gear according to the magnitude of 8 gradient.
t Fuzzy logic is a form of artificial intslligence that lets computers respond to changing conditions much like a human
mind would.
3RD - tlTHASCENoING MODE: UFhift Sch.dulc
- . FLAT ROAD MODE
-----------. : GRADUAL ASCENDING MODE
- - - - - : STEEPASCENDING MODEo5l)
FFN1NS
7,.,.7a
: 2ND-3RD SHIFTING CHARACTERISTICSCONTROL AREA| 3RD-aTH SHIFTING CHARACTER|SnCSCONTROL AREA
62 mph
1100 km/h)Vehicle .o..d
Asconding Conirol ('98 - 00 Mod.ls)
When the PCM determines that the vohicle is climbing a hill in E] and E positions ('98 model), and in E] position ('99 -
00 models), the system extends the engagement srea of 2nd gear and 3rd gear to prevent the transmission from frequent-
ly shifting between 2nd and 3rd gears, and between 3rd and 4th gears, so the vehicle can run smooth and have more
power when needed.
NOTE: Shift schedulss stored in the PCM between 2nd and 3rd gears, and between 3rd and 4th gears, enable to selsct the
most suitable gear according to th6 magnitude of a gradi€nt.
ASCENDING MODE: Up.hift Sch.dul.
NN : 2ND-3RD SXImNG CHARACTERISTICS- GoNTRoLAREA
VVVVVZ:IRD-ITHSHIFnNGCHARACTERISTICS- cot{TRoL AREA
850
o
6:l mph11fl) km/hl
(cont'd)
2ND - 3RD
2ND + 3RD 3RD + 4TH
Vahicl. sDctd
14-19
www.emanualpro.com

Description
Electronic Control System (cont'd)
Descending Control
When the PCM determines that the vehicle is going down a hill in E and @ positions ('97 - 98 models). and in @ posi-
tion {'99 - 00 models), the shitt-up speed from 3rd to 4th gear and from 2nd to 3rd (when the throttle is closed) becomes
faster than the set speed for flat road driving to widen the 3rd gear and 2nd gear driving areas. This, in combination with
engine braking from the deceleration lock-up, achieves smooth driving when the vehicle is descending. There are three
descending modes with different 3rd gear driving areas and 2nd gear driving areas according to the magnitude of a gradi-
ent stored in the PCM. When the vehicle is in 4th gear, and you are decelerating when you are applying the brakes on a
steep hill, the transmission will downshift to 3rd gear, When you accelerate, the transmission will then return to higher
gear.
2ND - 3RD 3RD - 4TH
o50
F
DESCENDING MODE: Downshift Schodule
- : FLAT ROAD MODE
----'-----' I GRADUAL DESCENDING MODE
- - - - - : MEDIUM OESC€NOING MODE
. . ... : STEEP DESCENDING MODE
62 mph Vehicle sp€ed1100 km/hl
Deceleration Control
When the vehicle goes around a corner, and needs to decelerate first and then accelerate, the PCM sets the data for deceleration
control to reduce the number of times the transmission shifts. When the vehicle is decelerating from speeds above 27 mph(4i| km,ih), the PCM shifts the transmission from 4th to 2nd earlier than normal to cope with upcoming acceleration,
14-20
www.emanualpro.com

Description
Electronic Control System (cont'd)
Circuit Diagram and Terminal LocationsrgS Model
GNTIONSWITCN
LOCK-UPCONIFOLSOLEIIO D VALVE A
LOCK-UPCONTSOLSOLEI.IO 0 vALvE B
SBIFICONTROLSOLEI€ DVALVE A
SH FTCONTFOLSOLEiDID VALVE 8
LIN€AA SOL€iDIDGNIION SWTCHtGr
14-22
www.emanualpro.com

Description
Hydraulic Control
The hydraulic control system is controlled by the ATF pump, valves, accumulators, and electronically controlled solenoids.
The ATF pump is driven by splines on the end of the torque converter which is aftached to the engine. Fluid from the ATF
pump flows through the regulator valve to maintain specified pressure, through the main valve body, to the manual valve,
directing pressure to each clutch. The valve body includes the main valve body, the regulator valve body, the lock-up
valve body, the secondary valve body, the servo body, the linear solenoid, the shift control solenoid valve Ay'B assembly,
and the lock-up control solenoid valve A/B assembly. The shift control solenoid valve A,/B assembly and the linear
solenoid are bolted on the outside of the transmission housing. The lock-up control solenoid valve A,/B assembly is bolted
on the outside of the torque converter housing.
LINEAR
SHIFT CONTROLSOLENOID VALVE A/BASSEMBLY
SECONDARY VALVEBODY
REGULATORVALVE BOOY
VALVE BODY
SOLENOID VALVE A/BASSEMELY
N
ATF PUMP GEARS
14-24
www.emanualpro.com

Main Valve Sody
The main valve body houses the manual valve, the 1-2 shift valve. the 2nd orifice control valve. the CPB valve, the modu-
lator valve. the servo control valve. and the relief valve. The primary functions of the main valve body are to switch fluid
pressure on and off, and to control the hydraulic pressure going to the hydraulic control system.
CP8 VALVE2ND ORIFICE CONTROLVALVE
MODULATOR VALVE
RELIEF VALVE
1-2 SHIFT VALVE
MANUAL VALVE
MAIN VALVEBOOY
SERVO CONTROI-VALVE
Secondary valve Body
The secondary valve body is located on the main valve body, The secondary valve body houses the 2-3 shift valve, the 3-4
shift valve, the 3-4 orifice control valve, the 4th exhaust valve, and the CPC valve'
3.' SHIFT VALVE
.TH EXHAUST VALVE
CPC VAL
(cont'd)
14-25
2.3 SHIFT VALVE
3na ORIFICE CONTROLVALVE
VALVE
www.emanualpro.com