1998 HONDA CIVIC Transmission

Description
The automatic transmission is a 3-element torque converter and a dual-shaft electronically controlled unit which provides
4 soeeds forward and 1 reverse.
Torque Convertel, Geats, and Clutches
The torque converter consists of a pump, turbine and stator, assembled in a single unit. They are connected to the engine
crankshaft so they turn together as a unit as the engine turns. Around the outside of the torque converter is a ring gear
which meshes with the starter pinion when the engine is being started. The entire torque converter assembly seryes as a
flywheel while transmiuing power to the transmission mainshaft.
The transmission has two parallel shafts: the mainshaft and the countershaft. The mainshaft is in Iine with the engine
crankshaft. The mainshaft includes the 1st, 2nd and 4th clutches, gears tor 2nd, 4th, reverse and lst (3rd gear is integral
with the mainshaft, while the reverse gear is integral with the 4th gear). The countershaft includes the 3rd clutch, and
gears for 3rd,2nd, 4th, reverse. 1st and park. The gears on the mainshaft are in constant mesh with those on the counter-
shaft. When certain combinations of gears in transmission are engaged by clutches. power is transmitted from the main-
shaft to the countershaft to provide E, ld, E, and E positions.
Electronic Control
The electronic control svstem consists of the Powertrain Control Module {PCM), sensors, a linear solenoid and four
solenojd valves. Shifting and lock-up are electronically controlled for comtonable driving under all conditions. The PCM is
located below the dashboard, under the front lower panel on the passenger's side
Hydraulic Control
The valve bodies include the main vatve body, the secondary valve body, the regulator valve body, the servo body and the
lock-up valve body through the respective separator plates, They are bolted on the torque converter housang
The main valve body contains the manual valve, the 1-2 shift valve. the 2nd orifice control valve, the CPB {Clutch Pressure
Back-up) valve, the modulator valve. the servo control valve, the relief valve, and ATF pump gears The secondary valve
body contains the 2-3 shift valve. the 3-4 shift valve, the 3-4 orifice control valve, the 4th exhaust valve and the CPC (Clutch
pressure Control) valve. The regulator valve body contains the pressure regulator valve, the torque converter check valve,
the cooler relief valve, and the lock-up control valve. The servo body contains the servo valve which is integrated with the
reverse shift fork, and the accumulators. The lock-up valve body contains the lock-up shift valve and the lock-up timing
valve. The linear solenoid and the shift control solenoid valve Ay'B are bolted on the outside of the transmission housing,
and the lock-up control solenoid valve Ay'B is bolted on the outside of the torque converter housing. Fluid from regulator
passes through the manual valve to the various control valves. The clutches receive fluid from their respective teed pipes
or internal hydraulic circuit.
Shift Control Mechanism
Input from various sensors located throughout the car determines which shift control solenoid valve the PCM will activate
Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes a line
to one of the clutches, engaging that clutch and its corresponding gear, The shift control solenoid valves A and B are con-
trolled by the PCM.
Lock-up Mechanism
In ,Dt1 position, in 3rd and 4th. and in E position in 3rd, pressurized fluid is drained from the back of the torque converter
through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the
mainshaft rotates at the same as the engine crankshaft. Together with hydraulic control, the PCM optimizes the timing of
the lock-up mechanism. The lock-up valves control the range of lock-up according to lock-up control solenoid valves A and
B, and linear solenoid. When lock-up control solenoid valves A and B activate, the modulator pressure changes The lock-
up control solenoid valves A and B and the linear solenoid are controlled by the PCM.
(cont'd)
14-3

Description
(cont'dl
Gear Selection
The shift lever has six positions: E PARK. E REVERSE, N NEUTRAL, E 1st through 4th gear ranges, E 1st through 3rdgear ranges, @ 2nd gear.
Starting is possible only in E and E positions through the use of a slide-type, neutral-safety switch.
Automatic Transaxle (A/f, Gear Position Indicator
The Ay'T gear position indicator in the instrument panel shows which gear has been selected without having to look downat the console.
Clutch€s
The four-speed automatic transmission uses hydraulically-actuated clutches to engage or disengage the transmission gears.When hydraulic pressure is introduced into the clutch drum, the clutch piston moves. This presses the friction discs andsteel plates together, locking them so they don't slip. Power is then transmitted through the engaged clutch pack to itshub-mounted gear. Likewise, when the hydraulic pressure is bled from the clutch pack, the piston releases the friction discsand the steel plates, and they are free to slide past each other. This allows the gear to spin independently on its shaft,transmitting no power.
lst Clutch
The 1st clutch engages/disengages 1st gear, and is located at the end of the mainshaft, just behind the right sroe cover.The 1st clutch is supplied hydraulic pressure by its ATF feed pipe within the mainshaft.
2nd Clulch
The 2nd clutch engagegdisengages 2nd gear, and is located at the middle of the mainshaft. The 2nd clutch is joined
back-to-back to the 4th clutch. The 2nd clutch is supplied hydraulic pressure through the mainshaft by a circutr connect-ed to the internal hvdraulic circuit,
3rd Clutch
The 3rd clutch engages/disengages 3rd gear, and is located at the end of the countershaft. The 3rd clutch is suooliedhydraulic pressure by its ATF feed pipe within the countershaft.
ilth Clutch
The 4th clutch engages/disengages 4th gear, as well as reverse gear, and is located at the middle of the mainshaft. The4th clutch is joined back-to-back to the 2nd clutch. The 4th clutch is supplied hydraulic pressure by its ATF feed pipewith in the mainshaft.
\-a
PositionDe3cription
E PARK
E REVERSE
N NEUTRAL
E DRIVE
{1st through 4th)
Ei DRtvE('lst through 3rd)
B SECOND
Front wheels locked; park pawl engaged with pa* on countershaft. All clutches released.
Reverse; reverse selector engaged with countershaft reverse gear and 4th clutch locked.
All clutches released.
General driving; starts off in 1st, shifts automatically to 2nd, 3rd, then 4th, depending on vehiclespeed and throttle position. Downshift through 3rd, 2nd and 1st on deceleration to stop. The lock-upmechanism comes into operation in @ position in 3rd and 4th gear.
Use for rapid acceleration at highway speeds and general driving; up-hill and down,hill dfiving; stansotf in 1st, shifts automatically to 2nd, then 3rd, depending on vehicle speed and throttle position.
Downshifts through 2nd to lst on deceleration to stop. The lock-up mechanism comes into operationin 3rd gear,
Use for engine braking or better traction starting off on loose or slippery surfaces; stays in 2ndgear, does not shift up and down.
14-4

Description
Electronic Control System {cont'dl
Ascending Control
When the PCM determines that the vehicle is climbing a hill in E position, the system oxtends the sngagement area of2nd gear and 3rd gear to prevent ths transmission from fr€quently shifting between 2nd and 3rd gears, and between 3rdand 4th gears, so the vehicle can run smooth and have more power when needed. There are two ascending modes withdifferent 3rd gear driving areas according to the magnitude of a gradient stored in the pCM.
NOTE:
. The PCM memory contains shift schedules between 2nd and 3rd gears, and between 3rd and 4th gears that enable thePCM's fuzzy logic to automatically select the most suitable gear according to the magnitude of a gradient. Fuzzy logic is a form of artificial intelligence that lets computers respond to changing conditions much like a humanmind would,
Dssconding Control
When the PCM determines that the vehicle is going down a hilt in E position, the shift-up speed from 3rd to 4th gearwhen th€ throftle is closed becomes faster than the set speed for flat road driving to widen the 3rd gear driving area.This, in combination with engine braking from the deceleration lock-up, achieves smooth driving when the vehicle isdescending. There are two descending modes with different downshift (4 - 3) schedules according to the magnitude of agradient stored in the PCM. When the vehicle is in 4th gear, and you are decelerating on a gradual hill, or when you areapplying the brakes on a steep hill, the transmission will downshift to 3rd gear. When you accel6rate, the transmission willthen return to 4th gear.
ASCENDING MODEDESCENDING MODE
4TH SHIFTING
L.
F
CHARACTERISIICSCONTROL AREA
ff.1"11", vehicr. 3pe€dff;Tlr., vohicre speed
GRADUAL ASCENOINGCONTROL AREA
Docel6ration Control
When the vehicle goes around a corner. and needs to first decelerate and then accelerate. the rcM sets the data for decelerationcontrol to reduce the number of times the transmission shifts. When the vehicle is decelerating from speeds above 26 mph(41 km/h), the rcM shifts the transmission from 4th to 2nd earlier than normal to cope with upcoming acceleration.
14-16

Hydraulic Control
The hydraulic control system is controlled by the ATF pump, valves, accumulators, and electronically controlled solenoids'
TheATFpUmpisdrivenbysp||nesontheendofthetorqueconverterWhichisattachedtotheengine.F|uidfromtheATF
pumpf|owsthroughtheregu|atorva|vetomajntainspecifiedpressurethroughthemainva|vebodytothemanuaIva|ve'
directingpressuretoeachofthec|utches.Theva|vebodyinc|udesthemainvaivebody,theregu|atorvalvebody,the
|ock-upva|vebody,thesecondaryVa|vebody,theservobody,theIinearso|enoid,theshiftcontro|so|enoidva|velVB
assembly, and the lock up control solenoid valve A/B assembly. The shift control solenoid valve Ay'B assembly and the lin-
ear 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
SHIFT CONTROLSOLENOIO VALVE A/8
ASSEMBLY
LINEAR SOLENOID
SERVO BOOY
REGULATORVALVE BODY
VALVE
VALVE BOOY
(cont'd)
CONTROLSOLENOID VALVE A/BASSEMBLY
ATF PUMP GEARS
14-19

\
@ Position
As the engine turns, the ATF pump also starts to operate, Automatic transmission fluid (ATF) is drawn from (99) and dis-
charged into (1). Then, ATF flowing from the ATF pump becomes the line pressure (1). The line pressure (1) is regulated
by the regulator valve. The torque conv€rter inlet pressure (92) enters (94) of the torque converter through the lock-up
shift valve and discharges into (901. The torque converter ch€ck valve prevents the torque converter pressure from rising'
Under this condition, the hydraulic pressure is not applied to the clutches'
NOTE: When used, "1eft" or "right" indicates direction on the hydraulic circuit'
14-25

Symptom-to-Component Ghart
Electrical System -'gG - 98 Models
*1: The DTC in the parentheses is the code E indicator light indicates when the Data Link connector is connected to theHonda PGM Tester.*2: Whenever the Honda PGM Tester or Scan Tool detects an automatic transmission control system DTC, p07OO will beset in the PGM-FI control svstem.
DTCIIE Indicaior
LightMILDotection ltemPage
P1753
fl)BlinksONLock-up control solenoid valve A14-56
P1758
\21BlinksONLock-up control solenoid valve B14-58
P1705
(51BlinksONAy'T gear position switch (short to groundl14-60
P1706
(6)OFFONA,/T gear position switch (open)14-62
P0753
l7lBlinksONShift control solenoid valve A14-64
P0758
{8)ElinksONShift control solenoid valve B14-66
POl20
(9)BlinksONCountershaft speed sensor14-68
P0715
{15)
'96 - 97
models:
OFF'98 model:
Blinks
ON
Mainshaft speed sensor
14-70
P1768
{16)BlinksONLinear solenoid't 4-72
P0740
(40)OFFONLock-up control system14-7 4
P0730
(41)OFFONShift control system14-75
P0700*,
(none)Automatic transmission control svstem in the pGM-Fl
control svstem
14-52

Symptom-to-Component Chart
Electrical System -'99 - 00 Models
*1: The DTc in the parentheses is the code E indicator tight indicates when the Data Link connector is connected to theHonda PGM Tester.*2: Whenever the Honda PGM Tester or scan Tool detects an automatic transmission control system DTc, p07oo will beset in the PGM-FI control svstem
DTC*IE Indicator
LightMILDotostion ltemPage
P1753
fi)BlinksONLock-up control solenoid valve A'14-80
P1758
t2lBlinksONLock-up control solenoid valve B14-82
P1705
{5}BlinksONAy'T gear position switch {short to ground)14-84
P1706
(6)OFFONy'VT gear position switch {open)14-81
P0753
\71BlinksONShift control solenoid valve A14-89
P0758
(8)BlinksONShift control solenoid valve B14-9r
P0720
(9)BlinksONCountershaft speed sensorr4-93
P0715
(15)B linksONMainshaft speed sensor14-95
P1768
(16)BlinksONLinear solenoid't 4-97
PO7 40(40)OFFONLock-up control system14-99
P0730
(41)OFFONShift control svstem14- 100
P0700*,
(none)OFFAutomatic transmission control system in the pGM_Fl
controt svstem
14-54

Electrical Troubleshooting ('96 - 98 Modelsl
Troubleshooting Flowchart - Mainshaft Speed Sensor
NOTE: Record all freeze data before you troubleshoot.
Po$ible Cause
. Disconnect€d mainshaft sD€edSensor @nnoctot. Short or open in mainshattsJt€ed s6nsoa wire. Faulty mainshaft lpeed s6nso.
NOTE: Code P0715 (15) on the PCMdoesn't always mean there's an electricalproblem in the mainshaft or countershaftspeed sensor circuit; code P0715 (15)may also indicate a mechanical problemin the transmission.
MAINSHAFT SPEEOSENSOR CONNECTOR
Terminal side of male terminals
PCM CONNECTOR B I25PI
. OBD ll Scan Tool indicates Codem715.. Self-dirgnosi3 E indicatorlight indicstes Code 15.
Check the mainshaft and counter-shaft speed sensor installation.
Are the mainshaft and countershaftspeed sensor installed properly?
Moasure Mainshaft Spoed SgnsolRosistance at the Sensor Con-n€ctor:1. Disconnect the 2P connectorfrom the mainshaft speed sen-sor connector.2. Measure the resistance ot themainshaft speed sensor.
ls the resistance 400 600 O?
Check Mainshaft Sp6ed Sensorfor a Short Circuil:1. Disconnect the B {25P) connec'tor lrom the PCM.2. Check for continuity betweenbody ground and 815 terminaland the 814 terminal individu,
Repai. shon in the wi.os bstwoenthe 815 and 814 te.minals andthe mainshatt .Dood 3ensor.
ls there continuity?
To page 14-71
14-70
Wire side of female terminals