1997 HONDA CIVIC Clutch pressure Control

L
E Position
The flow of fluid through the torque convefter circuit is the same as in E position The line pressure (1) changes to the
line pressure (3) and flows to the l-2 shift valve. The iine pressure (3) changes to the line pressure (3') at the 'l-2 shift valve
and flows to the servo valve. The servo valve is moved to the right side (Reverse range position) and uncovers the port to
allow line pressure {3") to the manual valve, The line pressure {3') from the 1-2 shift valve flows through the servo valve to
the manual valve and changes the 4th clutch pressure (40). The 4th clutch pressure (40) is applied to the 4th clutch, and
the 4th clutch is engaged,
Reverse Inhibitor Control
When the E position is selected while the vehicle is moving forward at spe€ds over 6 mph (10 km/h)' the PCM outputs the
1st speed signal to shift control solenoid valves A and B; shift control solenoid valve A is turned oFF, shift control solenoid
valve B is turned ON. The 1-2 shift valve is moved to the right side and covers the port to stop line pressure (3') to the
servo valve. The line pressure (3') is not applied to the servo valve, and the 4th clutch pressure (40) is not applied to the
4th clutch, as a result, power is not transmitted to the reverse direction'
When used. 'left" or "right" indicates direction on the hydraulic circuit'
14-31

Description
Lock-up System (cont'd)
TOROUE CONVERTER
In B.rl position, in 3rd and 4th, and lDl_- position in 3rd.pressurized fluid is drajned from the back of the torqueconverter through a fluid passage. causing the lock-uppiston to be held against the torque convener cover. Asthis takes place, the mainshaft rotates at the same speedas the engine crankshaft, Together with the hydrauliccontrol, the PCM optimized the timing of the lock_upsystem. Under certain conditions, the lock_up clutch isapplied during deceleration, in 3rd and 4th gear.
The lock-up system controls the range of lock_up accord_ing to lock-up control solenoid valves A and B. and thelinear solenoid. When lock-up control solenoid valves Aand B activate, modulator pressure changes. Lock_upcontrol solenoid valves A and B and the linear solenoidare mounted on the outside of the torque converterhousing. and are controlled by the pclvl.
Lock-up Conditions/Lock-up Control Solenoid Valves/Linear Solenoid Pressure
MODULATOR PRESSURE
.-- LINEAR SOLENOID PRESSURE
LOCK.UP CONTROL. VALVE
LOCK.UP CONTROLSOLENOID VALVELock-up
Conditions
Lock-up Control
Solenoid ValveLineal
Solenoid
PressureAB
Lock-up OFFOFFOFFHig h
Lock-up. HalfONDuty operation
OFF - ON
Lock-up. FullONONHigh
Lock-up
during
decelerationONDuty operation
OFF * ONLowTOROUE CONVERTERCHECI( VALVE
RELIEF VAI-VE
LOCK.UP TIMINGVALVE
^ r______rr r cooLER RELTEF VALVE
t'-
14-34
ATF PUMP

I
TOROUE CONVERTER
No Lock-up
. Lock-up Control Solenoid Valve A: OFF
. Lock-up Control Solenoid Valve B: OFF
. Linear Solenoid Pressure: High
The pressurized fluid regulated by the modulator works
on both ends of the lock-up shift valve. Under this condi-
tion, the pressures working on both ends of the lock-up
shift valve are equal, the lock-up shift valve is moved to
the right side by the tension of the valve spring alone.
The fluid from the ATF pump will flow through the left
side of the lock-up clutch to the torque convener; that is,
the lock-up clutch is in OFF condition.
NOTE: When used, "left" or "right" indicates direction
on the hydraulic circuit.
MOOULATOR PRESSURE
LINEAR SOLENOIO PRESSURE
(cont'd)
LOCK.UP CONTROLSOLENOID VALVE
RELIEF VALVE
LOCK-UP TIMINGVALVE
9 L ] I COOLER RELIEF VALVE
ATF PUMP
14-35

Description
Lock-up System (cont'dl
TOROUE CONVERTER
Half Lock-up
. Lock-up Control Solenoid Valve A: ONLock-up Control Solenoid Valve 8: Duty Operation
OFF - ONLinear Solenoid Pressure: Low
The PCM switches the solenoid valve A on to release themodulator pressure in the left cavity of the lock_up shiftvalve. The modulator pressure in the right cavity of thelock-up shift valve overcomes the spring force; thus thelock-up shift valve is moved to the left side.The line pressure is then separated into the two pas-sages to the torque converter:
Torque Converter Inner pressure: enters into rightsade to engage lock-up clutch
Torque Converter Back pressure: enters into left sideto diseogage lock-up clutchThe back pressure (F2) is regulated by the lock-up con-trol valve, whereas the position of the lock-up timingvalve is determined by the linear solenoid Dressure andtension of the valve spring. Also the position of the lock_up control valve is determined by the back pressure ofthe lock-up control valve, torque converter pressure reg_ulated by the torque converter check valve, and modula_tor pressure determined by the lock-up control solenoidvalve B. The PCM switches the lock-up control solenoidvalve B on and off rapidly {duty operation} under certainconditions to regulate the back pressure (F2) to lock thetorque convener properly.
NOTE: When used, "left" or "right" indicates directionon the hvdraulic circuit.
MODULATOR PRESSURE
LINEAR SOLENOTD PRESSURE
LOCK.UP CONTROLVALVE
LOCK.UP CONTROLSOI.TNOID VALVE
A8
TOROUE CONVERTERCHECK VAI-VE
RELIEF VALVE
LOCK-UP TIMINGVALVE
^ L____J'r cooLER RELTEF valvE
14-36
ATF PUMP

TOROUE CONVERTER
Full Lock-up
. Lock-up Control Solenoid Valve A: ON
. Lock-up Control Solenoid Valve B: ON
o Linear Solenoid Pressure: High
When the vehicle speed further increases. the linear
solenoid pressure is increased to high in accordance
with the linear solenoid controlled bv the PCM.
The lock-up timing valve overcomes the spring force
and moves to the left side. Also, this valve closes the
fluid port leading to the left side of the lock-up control
Under this condition. the modulator pressure in the left
side of the lock-up control valve had already been
released by the lock-up control solenoid valve B; the
lock-up control valve js moved to the left side. As this
takes place, the torque converter back pressure is
released fully. causing the lock-up clutch to be engaged
fully.
NOTE: When used, "|eft" or "right" indicates direction
on the hvdraulic circuit.
MODULATOR PRESSURE
LINEAR SOLENOIO PRESSURE
{cont'd)
LOCK.UP CONTROLSOLENOID VALVE
RELIEF VALVE
LOCK.UP TIMINGVALVE
'r ,-.r' cooLER RELTEF vALvE
ATF PUMP
14-37

Troubleshooting Flowchart - Shift Control System
NOTE: Record all freeze data before vou troubleshoot.
Possible Cause
Faulty shift control system
. OBD ll Scan Tool indicates CodeP0730.. Sell-diagnosis E indicator
light indicates Code ill.
Check tor Another CoderCheck whether the OBD ll scantool or the E, indicator lightindicate another code.
Perlorm ths TroubleshoolingFlowch.rt for the indic.t.dCode(sl. Recheck tor code m730
l4'l I atter troubleshooting.
Does the oBD ll scan tool orthe E indicato'. tight indicate another code?
Test lst, 2nd, 3rd and 4th Clutch
Pressure:Measure the 1st, 2nd, 3rd and 4th
clutch pressure (see page 14119
thru 14-121).
Ropair the hydrlulic systom !snecessary {see page 14-1 19 and11-1211.
ls each clutch pressure within
the service limit?
Replace Shift Control Solenoidvalve Assembly, Linear SolenoidAssambly and Rechock:1. Replace the shift controlsolenoid valve A'/B assembly(see page 14-106).2. Replace the linear solenoidassembly lsee page 14 108).3. Turn the ignition switch OFFand reset the PCM memory byremoving the EACK UP (7.5 A)tuse in the under hood fuse/relay box for more than l0
seconds,4. Drive the vehicle at over 12mph (20 km/h) in 1st, 2nd,3rd
and 4th gear for more than 30seconds at P1 position.
5. Recheck tor code P0730 (41).
Does the OBD ll scan tool orthe Ed indicator tight indi
cate code P0730 {41)?
The swt6m is OK et this time.
NOTE: Do not continue with this troubleshooting until the causes ot any
other DTCS have been corrected.

Electrical Troubleshooting ('99 - 00 Modelsl
Troubleshooting Flowchart - Shift Control System
NOTE: Record allfreeze data before you troubleshoot.
Po33ibl. Crus6
Frulty 3hift control ryrtom
. OBD ll Scan Tool indicrtd Codem730.. Self-dirgnosis E indicatorlight indicst€. Codo 41.
Check for Anoth€. Code:Check whether the OBD ll scantool or the E indicator lightindicate another code.
Prrf orm tho Troublc!hootingFlowch.rt for th. indicrt.dCod.l3l. R.ch.ck tor cod. m730141| .tt r troubldhootlng.
Doesthe OBD llscan tool orthe E indicator light indi-cate another code?
Test 13t, 2nd, 3rd .nd 4th ClutchPrglture:Measure the 1st, 2nd,3rd and 4thclutch pressure (see page 14-119thru 14 121).
R.prir tho hydrlulic ayrtam aan.c.3t..y lr.o p!9. lil-119 rnd1+1211.
ls each clutch pressure withinthe service limit?
Roplace Shift Control SolenoidValve Asembly. Linoar Sol.noidAssembly .nd Recheck:1. Replace the shift controlsolenoid valve A/B assembly(see page 14-106).2. Replace the linear solenoidassembly {see page 14-108}.3. Turn the ignition switch OFFand reset the PCM memory byremoving the BACK UP (7.5 A)fuse in the under-hood fuse/relay box for more than 10seconds,4. Drive the vehicle at over 12mph (20 kn/h) in 1st, 2nd, 3rdand 4th gear lo. more than 30seconds at lPll position.5. Recheck for code P0730 (41).
Doesthe OBD Ilscan tool orthe E ;ndicator light indi-cate code P0730 (41)?Th. sFtcm b OK .t this time.
NOTE: Do not continue with this lroubleshooting until the causes ot anyother OTCS have beon corrected.
I
14-100

Symptom-to-Component Chart
Hydraulic System (cont'dl
G.
n,
set idle rpm in gear to specified idle speed. lf still no good, adjust motor mounts as outlined in enginesection of this manual.
lf the clutch pack is seized or is excessively worn. inspect the other clutches for wear, and check the orificecontrol valves, CPC valve and linear solenoid for free movement.
lf the linear solenoid is stuck, inspect the clutches for wear.
lmproper alignment or main valve body and torque converter housing may cause ATF pump seizure. Thesymptoms are mostly an rpm-related ticking noise or a high-pitched squeak.
lf the l st clutch feed pipe guide in the end cover is scored by the mainshaft, inspect the ball bearing forexcessive movement in the transmission housing. lf oK, replace the end cover as it is dented. The o-rinounder the guide is probably worn.
Replace the mainshaft if the bushing for the 4th feed pipe is loose or damaged. lf the 4th feed pipe is danFaged or out of round, replace the right side cover.
Replace the mainshaft if the bushing for the 1st feed pipe is loose or damaged. lf the 1st feed pipe is darn-aged or out of round, replace it.
A worn or damaged sprag clutch is mostly a result of shifting the transmission inthe wheels rotate in reverse, such as rocking the vehicle in snow.
or E position while
Inspect for damage and wear:
1. Reverse selector gear teeth chamfers.
2. Engagement teeth chamfers of countershaft 4th and reverse gear.
3. Shift fork for scuff marks in center.
4. Differential pinion shaft for wear u nder pin ion gears.
5. Bottom of 3rd clutch for swirl marks.
Replace items 1,2,3 and 4 if worn or damaged. lf transmission makes a clicking, grinding orwhirring noise,also replace mainshaft 4th gear, reverse idler gear. and countershaft 4th gear in addition to 1, 2, 3 or 4.lf differential pinion shaft is worn, overhaul differential assembly, and replace ATF strainer, and thoroughlyclean transmission, flush torque converter, cooler and lines.lf bottom of 3rd clutch is swirled and transmission makes gear noise, replace the countershaft and final drivengear.
Be very careful not to damage the torque converter housing when replacing the main ball bearing, you
may also damage the ATF pump when you torque down the main valve body. This will result in ATF pumpseizure if not detected. Use the oroper roors.
Install the main seal flush with the torque converter housing. lf you push it into the torque converterhousing until it bottoms out, it will block the fluid return passage and result in damage.
See flushing procedure, page 14-187 and 188.
lf the large clutch piston O-ring is broken, inspect the piston groove for rough machining.
lf the l-2 shift valve is stuck closed, the transmission will not upshift. lf stuck open, the transmission hasno 1st gear.
lf the znd orifice control valve is stuck. inspect the 2nd and 3rd clutch oacks for wear.
lf the 3-4 orifice control valve is stuck, inspect the 3rd and 4th clutch oacks for wear.
lf the clutch pressure control valve is stuck closed, the transmission will not shift out of 1st gear.
lf the ATF strainer is clogged with particles of steel or aluminum, inspect the ATF pump and differentialpinion shaft. lf both are OK and no cause for the contamination is found, replace the torque converter.
Inspect the frame for collision damage.
14-112