1998 HONDA CIVIC din

GRADE LOGIC CONTROL SYSTEM
How it works:
The pCM compares actual driving conditions with driving conditions memorized in the PCM, based on the input from the
vehicle speed sensor, the throttle position sensor, the barometoric pressure sensor, the engine coolant temperature sensor,
the brake switch signal, and the shift lever position signal, to control shifting while a vehicle is ascending or descending a
slope, or reducing speed.
SIGNALS OETECTED
O.iving Resi3lence
Judgemenl ot Conirolling Arca
. Ascending mod€
lFuzzy loqicl. Gradual Ascending mode' Ste€p Ascending mode. Oescending mode. Gr.du.l Descending mode. Steep D6cending mode
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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.
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Description
Hydraulic Control (cont'dl
Regulator Valve
The regulator valve maintains a constant hydraulic pressure from the ATF pump to the hydraulic control system, whitealso furnishing fluid to the lubricating system and torque converter. The fluid from the ATF pump flows through B and 8,.The regulator valve has a valve orifice. The fluid entering from B flows through the orifice to the A cavity. This pressure ofthe A cavity pushes the regulator valve to the right side, and this movement of the regulator valve uncovers the fluid portto the torque converter and the relief valve. The fluid flows out to the torque converter, and the relief valve and regulatorvalve moves to the left side. According to the level of the hydraulic pressure through B, the position of the regutator vatvechanges and the amount of the fluid from B' through D and c also changes. This operation is continued. maantaining theline pressure,
NOTE: When used. "|eft" or "right" indicates direction on the illustration betow.
ENGINE NOT RUNNING
TOROUE CONVERTER
ENGINE RUNNING
To TOROUE CONVERTER Lubrication
Stator Roaction Hydraulic Prossur6 Control
Hydraulic pressure increases according to torque, are performed by the regulator valve using the stator torque reaction.The stator shaft is splined with the stator in the torque converter, and its arm end contacts the regulator sprang cap. whenthe vehicle is accelerating or climbing (Torque Convert€r Range), the stator torque reaction acts on the stator shaft, andthe stator arm pushes the regulator spring cap in the direction of the arrow in proponion to the reaction. Jne stator reac-tion spring compresses, and th€ reoulator valve moves to increase the line pressure which is regulated by the regulatorvalve. The line pressure reaches its maximum when the stator torque reaction reaches its maximum.
STATOR SHAFT ARM
REGULATOR VALVE
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STATORATOR SHAFT ARM
SPRING CAP

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
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I
PCM CONNECTOR B {25P1 {cont'dl
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Vohage
811SHBShift control solenoid valve B
control
In 1st gear and 2nd gear in -q1, q11 position,
and in E] position: Battery voltage
In 3rd gear and 4th gear in lD.J, [Dr- position: 0 V
B't2SLUInterlock controlWhen ignition switch is ON (ll), brake pedal
deoressed and accelerator Dedal released: 0 V
813D4 INDD4 Indicator light controlWhen ignition switch is first turned ON (ll):
Battery voltage for two seconds
In E position: Baftery voltage
B't 4NMSGMainshaft speed sensor groundAlways: 0 V
E tcNMMainshaft speed sensor signal
input
Depending on engine speed: Pulsing signal
When engine is stopped: 0 V
816ATP RAy'T gear position switch Eposition signal input
InE position: 0V
In other than E position: Battery voltage
817ATP 2A/T gear position switch E posi-
tion signal input
InE position: 0V
In orher than E position: Battery voltage
818 to 821Not used
s22NCSGCountershatt speed sensor groundAlwaysr 0 V
B23NCCountershaft speed sensor signal
input
Depending on vehicle speed: Pulsing signal
When vehicle is stopped: 0 V
B24ATP D4Ay'T gear position switch lor posi-
tion signal input
InEposition:0V
In other than 6 position: 5 V
ATP NPA,/T gear position switch E and
N position signals input
InE and E positions: 0V
In otherthan E and N] positions: Battery voltage
PCM CONNECTOR C {31P)
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
Cl to C6- see section 11 -
c1Service check signalWith ignition switch ON (ll) and service check
connector oDen; 5 V
With ignition switch ON (ll) and service check
connector connected with sDecial tool: 0 V
C8 to Cg- see section 11 -
c10VBUBack-up power systemAlways battery voltage
C11 to C31- see section '11 -
PCM CONNECTOR D (16P}
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
Dl to D4- see section 11 -
D5STOP SWBrake switch signal inputBrake pedal depressed: Battery voltage
Brake pedal released: 0 V
D6 to D16- see section 1 l -
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FCM CONNECTOR D {16P)
\o
14-47
Terminal NumberSignalDo3criptionMeasuring Conditions/Torminal Vohage
D1LCALock-up control solenoid valve A
control
When lock-up is ON: Battery voltage
With no lock-up: 0 V
SHBShift control solenoid valve B
control
In E position, in 1st and 2nd gear in E, E
position: Battery voltage
ln 3rd gear in E, E, in 4th gear in E posi-
tion;0 V
D3LCBLock-up control solenoid valve B
control
When full lock-up: Battery voltage
With half lock-up: Pulsing signal
D4Not used
D5VB SOLLock-up control solenoids, shift
control solenoids and linear
solenoid power supply electrode
with ignition switch oN (ll): Battery voltage
With ignition switch OFF: 0 V
D6ATP RAy'T gear position switch
E position input
tnEposition:0V
In other than E position: Approx. 10 V
SHAShift control solenoid valve A
control
In E] position, in 2nd and 3rd gear in p!, [Q]
position: Battery voltage
In 1st gear in E, @ position, in 4th gear in El
Dosition: 0 V
D8ATP D3A/T gear position switch
E position input
In E position:0V
In otherthan @ position: Approx. 10 V
D9ATP D4Ay'T gear position switch
E position switch
In El position: 0 V
In other than E position: Approx. 5 V
D10NCCountershaft speed sensor signal
input
Depending on vehicle speed: Pulsing signal
When vehicle is stooped: 0 V
D11NMMainshaft speed sensor signal
Inpur
Depending on engine speed: Pulsing signal
When engine is stopped: 0 V
D't2NMSGMainshaft speed sensor ground
D13ATP NPAy'T gear position switch E and
E position input
InE and E positions: 0V
In other than E and E positions: Approx. 10 V
D14AfP 2Ay'T gear position switch
E position input
tnEposition;0V
In other than E position: Approx. 10 V
D16NCSGCountershaft speed sensor
ground

Troubleshooting Procedures
1.
2.
(cont'dl
Remove the kick panel on the passenger's side {see section 20}.
Remove the PCM. and turn the PCM over.
Inspect the circuit on the PCM according to the troubleshooting flowchart with the spocial tools and a digital multime-ter as shown.
How lo Use tha Backprobe Set
Connect the backprobe adapters to the stacking patch cords, and connect the cords to a multimeter. Using the wireinsulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from thewire side until it comes in contact with the terminal end ofthe wire.
BACKPROSE
BACKPROBE SET07saz - (xtl(xtoA
{two required)
DIGITAL MULNMEIER(Comm€rcially 6vailabl€l-aHM-32-003
t..
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or equival€nt

SYmPtom
E indicator light does not come on tor two seconds after ignition
switch is first turned ON {ll}.
E indicator light is on constantly (not blinking) whenever the ignition
switch is ON (ll).
Shift lever cannot be moved from @ position with the brake pedal
depressed.
Inspection Ref. Page
11-16
14-78
Inspection't4-79
lf the self-diagnostic l-d indicator light does not blink, perform an inspection according to the table below.
NOTE: lf a customer describes the symptom for code Pl706 {6), it will be necessary to recreate the symptom by test-driv-
ing, then recheck the DTC.
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