1996 HONDA CIVIC control unit

Description
The Continuously Variable Transmission (CVT) is an electronically controlled automatic transmission with drive and driv
en Oullevs, and a steel belt. The CVT provides non stage speeds forward and one reverse. The entire unit is positioned in
line with the engine.
Transmission
Around the outside of the flywheel is a ring gear which meshes with the starter pinion when the engine is being staned.
The transmission has four parallel shafts: the input shaft, the drive pulley shaft. the driven pulley shaft, and the secondary
gear shaft. The input shaft is in line with the engine crankshaft. The drive pulley shaft and the driven pulley shaft consist of
movable and fixed face pulleys. Both pulleys are linked by the steel belt.
The input shaft includes the sun gear. The drive pulley shaft includes the forward clutch which mounts the carrier assem-
bly on the forward clutch drum. The carrier assembly includes the pinion gears which mesh with the sun gear and the ring
gear. The ring gear has a hub-mounted reverse brake disc.
The driven pulley shaft includes the start clutch and the secondary drive gear which is integral with the park gear' The sec-
ondary gear shaft is positioned between the secondary drive gear and the final driven gear. The secondary gear shaft
includes the secondary driven gear which serves to change the rotation direction. because the drive pulley shaft and the
driven oullev shaft rotate the same direction. When certain combinations of planetary gears in the transmission are
engaged by the clutches and the reverse brake, power is transmitted from the drive pulley shaft to the driven pulley shaft
to provide E, E, E, and El.
Electronic Control'96 - 98 Models:
The electronic control system consists of the Transmission Control Module (TCM), sensors, three linear solenoids, and a
inhibitor solenoid. Shifting is electronically controlled under all conditions'
The TCM is located below the dashboard, behind the kick panel on the driver's side.'99 - 00 Models:
The electronic control svstem consists of a Powertrain Control Module (PCM), sensors, three linear solenoids and an
inhibitor solenoid. Shifting is electronically controlled under all conditions. A Grade Logic Control System to control shift-
ing in E position while the vehicle is ascending or descending a slope.
The PCM is located below the dashboard, under the kick panel on the passenger's side.
Hydraulic Control
The lower valve body assembly includes the main valve body, the Pressure Low (PL) reguiator valve body, the shift valve
body, the start clutch control valve body, and the secondary valve body. They are positioned on the lower part of the
transmission housing.
The main valve body contains the Pressure High (PH) control valve, the lubrication valve, and the pitot regulator valve.
The secondary valve body contains the PH regulator valve, the clutch reducing valve, the start clutch valve accumulator,
and the shift inhibitor valve. The PL regulator valve body contains the PL regulator valve and the PH-PL control valve
which is ioined to the PH,PL control linear solenoid. The inhibitor solenoid valve is bolted on the PL regulator valve body.
The shift valve body contains the shift valve and the shift control valve. which is joined to the shift control linear solenoid.
The start clutch control valve body contains the start clutch control valve, which is joined to the start clutch control linear
solenoid. The linear solenoids and the inhibitor solenoid are controlled by the TCM or PCM. The manual valve body which
contains the manual valve and the reverse inhibitor valve, is bolted on the intermediate housing.
The ATF pump assembly is located on the transmission housing, and is linked with the input shaft by the sprockets and
the sprocket chain. The pulleys and the clutch receive fluid from their respective feed pipes, and the reverse brake receives
fluid from internal hydraulic circuit.
Shift Control Mechanism
Input from various sensors located throughout the vehicle determines which linear solenoid the TCM or PCM will activate.
Activating the shift control linear solenoid changes the shift control valve pressure, causing the shift valve to move. This
pressurizes the drive pulley pressure to the drive pulley and the driven pulley pressure to the driven pulley and changes
their effective pulley ratio. Activating the start clutch control linear solenoid moves the start clutch control valve. The start
clutch control valve uncovers the port, providing pressure to the start clutch to engage it(cont'd)
14-195
,!

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 Gearbox
The rack-and-pinion type steering gearbox has a valve body unit incorporated with the pinion to control the steering fluidpressure. Steering fluid from the pump is regulated by a rotary valve in the valve body unit and is sent through the cylin,der line to the power cylinder, where hydraulic pressure is applied. The steering fluid in the other side of the power cylin,der returns through the cylinder line and valve body unit to the reservoii.
VALVE EODY UNIT
CYLINDER LINE
To RESERVOm +-From PUMP -;
POWER CYLINDER
Valve Body Unit
Inside the valve body unit is the valve, which is coaxial with the pinion shaft, and controls the steering fluid pressure. Thevalve housing is connected with the fluid line from the pump, the return line to the reservoir, and the two cylinder linesfrom the respective power cylinder. The pinion shaft is double - structured with the input shaft connected to the piniongear, both of which are interconnected with the torsion bar.
The pin inserted in the valve and the pinion shaft groove engage; this allows the pinion shaft to rotate together with thevalve. Because of this construction, the difference in angle in the circumferential direction between the input shaft and thevalve becomes larger according to the torsional strength of the pinion or steering resistance. However, maximum torsionbetween the shafts is regulated by the engaged splines of the shafts at the pin engagement section to hold the torsion barwithin the set value,
This allows the steering system to function as an ordinary rack-and-pinion type steering if the steering fluid is not pressur-
ized because of a faulty pump,
VALVE
Difforence in angle botwoon theinput shaft and pinion shsft
PINION SHAFT
lo
INPUT SHAFT
-l
a
17-20
INPUT SHAFT

Troubleshooting
General Troubleshooting
Check the following before you begin:. Has the suspension been modified in a way that would affect steering?. Are tire sizes, tire variety and air pressure correct?. lsthe steering wheel original equipment or equivalent?. lsthe powersteering pump belt properlyadiusted?
. ls steeringfluid reservoirfilledto proper level?. ls the engine idle speed correct and steady?
Hard Steering (Check the powor assist. se€ page 17-3o. lfthe torce is over 29 N (3.0 kgf, 6.6lbo, Procede with this troubleshootinq.)
Abnormallluid pressure
{fluid pressureis too high)
Faulty valve body unit
Relief pres-sure too low
Abnormal
Faulty llow control valve(Replace the pump es anassembly)
Ch€ck the feed snd return circuit lin€s ano nosebetw6€n the gearbox and pump for clogging andd€lormation.
Normal line and hose
Check the pump fluid pressure(soe page 17-34).l/easure steady-state tluid pres-s!re while idling with the bothvalves tully open.It should be 1.500 kPa (15 kgf/cmr,213 psi) or below.
Normal
Check th€ flow control vslve (see page 17-42).. Chock the valvo lor smooth movement in the hous-ing.. Check the reliefvalve for leaks.
Check the pump fluid pressure
{see page 17-34).Measure pump relief pressurewhile idling with the pressure con-trol valve Iully closed.It should be 6,400 - 7,400 kPa (65 -
75 kgflcm,,920 - 1,070 psi)
Normal relisf pressure
17-22
Go to page 17-23Faulty pump assembly

lnspection and Adjustment
Pump Pressure Check
Check the fluid pressure as follows to determine
whether the trouble is in the pump or gearbox.
NOTE: First check the power steering fluid level andpump belt tension.
CAUTION: Disconnect the high pr$sure hos€ with care
so as not lo spill the power sieering tluid on tha frame
and other parts.
1. Disconnect the outlet line from the Dumo outlet fit-
ting, then installthe P/S joint adaptor (pump) on the
Dumo outlet.
2. Connect the P/S joint adaptor (hose) to the power
steering pressure gauge, then connect the outlet
hose to the adaptor.
3. Install the power steering pressure gauge to the P/Sjoint adaptor (pump) as shown.
ourlEr HosE FnrNo ,t"ll lrilu"ott
P/S JOINT ADAPTOB IHOSEI07RAK - S0i10l2rol07RAK- 50{{)120
P/S PRESSURE GAUGE07406 - 001000Aor07406 - 0010001
4. Open the shut-off valve fully.
5. Open the pressure control valve fully.
17-34
(Pa.t of tooll11 N.m11.1 kgt m, 8 lbf.ftl
PRESSURECONTROL VALVE
SHUT.OFFVALVE
PUMP OUTLETFITTING
6 x 1.0 mm BOLTlPart of tool)11 N.m11.1 kgf m, 8 lbtftl
7.
Start the engine and let it idle.
Turn the steering wheel from lock-to-lock several
times to warm the fluid to operating temperature.
Measure steady-state fluid pressure while idling. If
the pump is in good condition, the gauge should
read less than 1500 kPa (15 kgf/cmr, 213 psi).
lf it reads high, check the outlet line or valve body
unit (see General Troubleshooting 17-22).
Close the pressure control valve, then close the
shut-off valve gradually until the pressure gauge
needle is stable. Read the oressure.
lmmediately open the pressure control valve fully.
GAUTION: Do not keep lhe prossure control valve
clos€d more then 5 soconds or the pump could be
damagod by over-heating.
lf the pump is in good condition, the gauge should
read at least 6,400 - 7,400 kPa (65 - 75 kgflcm,, 920 -
1,070 psi). A low reading means pump output is too
low for full assist. Repair or replace the pump,
9.
P/S PBESSURE GAUGE07{16 -@1@OA
oi
SI{UT.OFF VALVE

Master Cylinder/Brake Booster
IRemovaUlnstallation
CAUTION:
. Be care{ul nol to bend or damage the brake lines when
rsmoving the mastsr cYlinder.
. Do not soill brakefluid on the vehicle; it may damage
the paint; if brake fluid does contact the paint, wssh
it off immediatelY with water'
. To prevent spill3, cover the hose ioints with rags or
shop towels.
9. Remove the four booster mountlng nuts
10. Pull the brake booster forward until the clevis is
clear of the bulkhead.
11. Remove the brake booster from the engine com-
panmenr.'12. Install the brake booster and master cylinder in the
reverse order of removal.
CAUTION:
. When connecting the brake lines. make sure
that there is no inte erence between the brake
lines and oth6r Parts.
r Be careful not to bend or damage the brake lines
when installing the master cylinder.
NOTE: lf replacing the master cylinder or brake
booster, check and adiust the pushrod clearance
be{ore installing the master cylinder (see page 19-221'
Fill the master cylinder reservoir, and bleed the
brake svstem (see Page 19-7).
After installation. check the brake pedal height and
brake pedal tree play (see page l9-5) and adjust if
necessary.
BRAKE BOOSTER(With ABS: 7" + 8" tandem brake booster)
BRAKE FLUIO LEVELSWITCH CONNECTORS
MASTER CYLINDER
VACUUM HOSE
1.
2.
3,
5.
Disconnect the brake fluid level switch connectors'
Remove the reservoir cap from the master cylinder'
The brake fluid may be sucked out through the top
of the master cylinder reservoir with a syrlnge.
Disconnect the brake lines from the master cylinder'
Remove the master cylinder mounting nuts and
washers.
\l/
6. Remove the master cylinder from the brake booster'
7. Disconnect the vacuum hose trom the brake booster'
8. Remove the cotter pin and clevis pin from the clevis'
CAUTION: Do not disconnect the clevb by remov-
ing it from the operating rod of the brako booster' lf
the clevis is loosened, adiust the pushrod length
before installing th€ brake booster (see page 19-221'
COTTER PINReplace.
To Rear Wheel Cylinders
14.
-6.4CLEVIS PIN
To Front Caliper(Without ABS)$
t'N't'ttrnt'-''
To Front CaliperlWithout ABSi
PBOPORTIONING CONTROL VALVE
15 N.m {1.5 kgl m,11 tbtft)
15 N.m {1.5 kgif.m, 11 lbtft}(With ABS: To modulator unit)lr
19-21

Brake Hoses/Lines
LJ
Inspection/Torque Specifications
t. Inspect the brake hoses for damage, deterioration, leaks, interference, and twisting.
2. Check the brake lines for damage, rusting. and leakage. Also check for bent brake lines.
3. Check for ieaks at hose and line ioints and connections, and retighten if necessary'
4. Check the master cylinder and ABS modulator unit for damage and leakage
CAUTION: Replace tho brake hose clip whenev€r the brake hose is serviced.
ABS MODULATOR UNIT-Io-BRAKE l-lNE19 N.m (1.9 kgf.m, 14lbl.ftl
PROPOBTIONING CONTROL VALVE.io-BRAKE LINEl5 N.m (1.511 tbf.ftl
MASTER CYLINDER-Io-BMKE LINE
15 N.m (1.5 ksrf.m, 11 lbf'ft)
REAR DISG BRAKE:BRAKE HOSE-to4ALlPER
{BANJO BOLT}34 N.m (3.5 kgtm,25 lbf ftlBLEEO SCREW9 N'm (0.9 kgf.m, 6.5 lM.ftlBRAKE LINE-to-WHEEL CYLINDER15 N.m (1.5 kgl.m, 11 lbf.ftlBLEED SCREW7 N.m {0.7 kst m, 5 lbf,ttl
JBRAKE LINE-io-aRAKE HOSE15 N.m {1.511 tbtft)
BRAKE LINE-Io-BRAKE HOSE15 N.m (1.5 kgt.m, 11 lbf'ft)
(BANJO BOLT}3,1 N.m 13.5 kgf.m, 25 lbf.ft)
J
19-39

L-
t
Anti-lock Brake System (ABSI
Special Tools ............. 19-44
Component Locations ......................... 19-45
Anti-lock Brake System (ABS)
Features/Construction ..................., 19-46
Operation ............... 19-47
Circuit Diagram ......... 19-50
ABS Control Unit Terminal
Arrangement ......... 19-52
Troubleshooting Precautions ............. 19-54
Diagnostic Trouble Code (DTCI
Diagnostic Trouble Gode (DTCI
Indication ........... 19-56
DTC Erasure ........... 19-57
Symptom-to System Chart ............. 19-58
Troubleshooting
ABS Indicator Light Does Not
Come On ............ 19-60
ABS Indicator Light Does Not
Go Off ............................................ 19-62
Wheel Sensor ........ 19-64
Solenoid ................. 19-60
ABS Pump Motor ............................. 19-68
Main Relay ............. 19-71
lgnition Voltage .... 19-73
Central Processing Unit {CPU} ........ 19-74
Modulator Unit
Removal/lnstallation ....................... 19-75
ABS Control Unit
Replacement ......... 19-76
Pulsers/Wheel Sensors
Inspection .............. 19-76
Wheel Sensor Replacement ............ 19-77
t/