Page 693 of 2189
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
14-15
Page 791 of 2189

Road Test
NOTE: Warm up the engine to normal operating tem peratu re (the rad iator fan comes on )'
1. Apply parking brake and block the wheels. Start the engine, then shift to E position while depressing the brake
Dedal, Depress the accelerator pedal and release it suddenly. The engine should not stall'
2. Repeat same test in E Position.
3. Test-drive the vehicle on a flat road in the E position. Check that the shift points occur at approximate speeds shown
in the table. Also check for abnormal noise and clutch slippage.
NOTE: Throttle position sensor voltage represents the throttle opening
a. Unbolt the PCM for road testing; refer to page 14-50.
b. Setthedigital multimeter to check the th rottle position sensor voltage between PCM terminals;
. '96 - 98 models: D1 {+) and A9 (-) or 422 (-}.
. '99 - 00 models: C27 (+) andB20t-) orB22{-}.
BACKPROBE ADAPTER
BACKPROBE SET07sAz - 001oq)A{two requiredl
DIGIIAL MULTIMETERlCommercially available)KS-AHM-32-003,or equivalenl
'96 - 98 Modelsr
Wire side ol temale terminals
PCM CONNECTORS
B t25Pl c (31P)
LG1 IBRN/BLK)
I (25P1c (31P}
A t32PtD (16P)
Wire side ol female terminals
'9!t - 00 Models:
1+113
Page 792 of 2189

Road Test
(cont'dl
.91 Position: Dl6Y7 engine
. Upshift
Throttle OpeningUnit of speedlst + znd2nd * 3rd3rd t 4thLock-up ON
Throttle position sensor
voltage: 0.75 V
mph9-1220-2328-3221 -24
km/h15-1932-3745-5234-39
Throttle position sensor
voltage:2.25 V
mph40-4562-67
km/h34-4095 - 10499 - 't08
Fully-opened throttle
Throttle position sensor
voltage: 4.5 V
mph33-38101 - 't1299 - 109
km/h53-61102-115163 - 180'159 - 176
Downshift
Throftle OpeningUnit of speedLock-up OFF'lth + 3rd3rd + 2nd2nd t lst
Fully closed throttle
Throttle position sensor
voltage: 0.5 V
mph't9 - 2217 -206-9(3rd+lst)
km/h30-3527 -3210 - 15 (3rd + 1st)
Fully-opened throttle
Throttle position sensor
voltage: 4.5 V
mpn95 - 10585-9554-6125-30
km/h153 - 169137 - 15387-9840-48
-q1 Position: DI6YB engine
. Upshift
Downshift
NOTE:
. Lock-up ON: The lock-up control solenoid valve A turns ON.. Lock-up OFF: The lock-up control solenoid valve A turns OFF.
Throttle OpeningUnit of speedlst + 2nd2nd - 3rd3rd + 4thLock-up ON
Throftle position sensor
voltage: 0.75 V
mph9-1220-232A-3221 -24
km/h15-1932-3745-5234-39
Throttle position sensor
voltage:2.25 V
mpn21 -2540-4559-65
km/h34-4095 - 10499 - 108
Fully-opened throttle
Throttle position sensor
voltage: 4.5 V
mph32-3762 -7096 - 10795 - 106
km/h52-60100 - 113't55 - 112't53 - ' 170
Throttle OpeningUnit ot speedLock-up OFF'lth + 3rd3rd+2nd I 2nd+lst
Fully-closed throttle
Throttle position sensor
voltage: 0.5 V
mph19-2217 -206-9(3rd+ 1st)
km/h30-3527 -32l0 - 15 (3rd + lst)
Fully opened throttle
Throttle position sensor
voltage: 4.5 V
mpn91 - 10154-61 25-30
km/h'147 - 163137 - 15387-98 I 40-48
l.
14-114
Page 881 of 2189

Electronic Control System ('96 - 98 Modelsl
The electronic control system consists of the Transmission control Module (TcM), sensors, three linear solenoids, and an
inhibitor solenoid. Shifting is electronically controlled under all conditions
The TCIM is located below the dashboard, behind the kick panel on the driver's side'
The TcN4 controls the transmission to reduce engine speed and retain the engine's cooling efficiency when the vehicle is
driven with Iull throttle acceleration
lf the vehicle is continuously driven at full throttle acceleration, the TCM regulates the pulley hydraulic pressure to
increase the pulley ratio, which, as the result. reduces the engine speed and retains the designed cooling efficiency After
the vehicle has been driven at a lower engine speed for a while, the TCM increases the pulley ratio to the original ratio.
For smooth starting in the E position, the TcM sends a signal to the EcM to cut off the rvc clutch {if the A!/c is on) and
increases the engine speed to 900 rpm when the transmission is shifted to the E position'
The start clutch functions to make smooth starting possible. To let the start clutch function properly. the TCM regulates
the start clutch hydraulic pressure based on the entine's negative pressure memorized in the E position'
:
:
z
z
z
S*ond.ry G..r Sh:ft
(cont'd)
14-203
Page 883 of 2189

Electronic Gontrol System ('99 - 00 Modelsl
The electronic controt system conststs 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'
fn"pCVirlocatedbelowthedashboard,underthekickpanelonthepassenger'sside'
The pCM controls the transmassion to reduce engine speed and retain the engine's cooling efficiency when the vehicle is
driven with full throftle acceleration
lf the vehicle is continuously driven at lull throttle acceleration, the PCM regulates the pulley hydraulic pressure to
increase the pulley ratio which. as the result, reduces the engine speed and retains the designed cooling efficiency After
the vehicle has been driven at a lower engine speed for a while, the PCM increases the pulley ratio to the original ratio'
i"i ".nl",rr starting in the E position, the PcM cuts off the ,Vc clutch (if the A/c is on) and increases the engine speed to
900 rpm when the transmission is shifted to the E position'
The start clutch functions to make smooth starting possible. To let the start clutch function properly, the PcM regulates
the start clutch hydraulic pressure based on the engine's negative pressure memorized in the E position'
FCM
s*o.d.ry G..t Sh.h
(cont'd)
14-205
Page 884 of 2189

Description
Electronic Control System ('99 - 00 Modelsl (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 vehiclespeed sensor, the throttle position sensor, the manifold absolute pressure sensor, the engine coolant temperature sensor,the brake switch signal, and the shift lever position signal, to control shifting while the vehicle is ascending or descendinga slope.
Ascending Control
When the PCM determines that the vehicle is climbing a hill in E position, the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. so the vehicle can run smooth and have more powerwhen needed. There are three ascending modes with different shift schedules according to the magnitude ot a gradient inthe PCM.
Descending Control
when the PCM determines that the vehicle is going down a hill in E position. the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. This, in combinstion with engine braking, achievessmooth driving when the vehicle is descending, There are three descending modes with different shift schedules accord-ing to the magnitude of a gradient in the PCM.
L
14-206
Page 906 of 2189

TCM CONNECTOR B (22P}
Terminal NumbelSignalDescriptionMeasuring Conditions/Terminal Voltage
B1SOL INHInhibitor solenoid controlWith inhibitor solenoid ON: Baftery voltage
With inhibitor solenoid OFF: 0 V
82MAP (PB)-M an if old Absol r-rte Pressure IMAP)
sensor signal inPUtWith iqnition switch ON (ll): Approx.2.5 V
With e;gine adling: Approx. 1.0 V (depending on
engine speed)
B3Not used
B4TPS-Throttle Position (TP) sensor signal
input
With ignition switch ON (ll) and throftle fully open:
4.14 - 4.42 VWith ignition switch ON (ll) and throttle fully
closed: 0.44 - 0.56 V
VSSVehicle Speed Sensor (VSS) signal
Inpur
With ignition switch ON (ll) and rotating front
wheelsr 0-5Vcycle
TMBData communication with ECM:
Transmission control data outpUt
With ignilion swltch UN lll): rulslng slgnar
81TMAData communication with EClvl:
PGM Fl control data inPut
With ignition swltch uN {ll,: l-ulslng slgnal
B8NDN SGDriven pulley speed sensor ground
B9NDNDriven pulley speed sensor signal
input
ln other thTnE and E position: Pulsing signal
810NDRDrive pulley speed sensor signal
Input
-tn ottrer ttran E ana E position: Pulsing signal
811Not used
812STOP SWBrake switch signal inPutWith brake pedal depressed: Battery voltage
With brake pedal released: 0 V
813DIAG-H(TXD/RXD)Data communication:Diagnostic trouble code outPut
Wittr ignitio.r s*itct' ON (ll): Approx 5.0 V
814Se-ice ctrect signatWith ignition switch ON (ll) and service check
connector oPen: APProx.5 V
With iqnition switch ON (ll) and service check
"onn"itot. connect"d with special tool: 0 V
Secondary gear shaft speed sensor
signal input
Depending on vehicle speed: Pulsing signal
When vehicle is stoPped: 0 V815VEL
816VEL SGSecondary gear shaft speed sensorgrouno
817NDR SGDrive pulley speed sensor ground
818HBRK SWParking brake switch signal inPutWith parking brake lever pulledr 0 V
With parking brake lever released: Battery voltage
819Not used
B 20VREF+5 V relerenceWith ignition switch ON (ll): Approx 5 V
821Not used
Not used
Page 915 of 2189

Symptom-to-Component Chart
Electrical System -'96 - 98 Models
*: The DTC in parentheses is the code @ indicator light indicates when the Data Link Connector is connected to the HondaPGM Tester.
DTC*O Indicator
LightMILDetection ltemPage
P1790
(3)BlinksONThrottle position sensor14-242
P179'l
(4)BlinksONVehicle speed sensor14-243
P1705
(5)BlinksONAy'T gear position switch (short to groundl't 4-244
P1706
(6)OFFONA/T gear position switch {open)14-246
P0725
(11)BlinksONlgnition coil14-248
P1793
112lBlinksONManifold absolute pressure sensor14-249
P 1870(30)BlinksONShift control linear solenoid14-250
P'1873
(311BlinksONPH-PL control linear solenoid14-25'l
P1879(32)BlinksONStart clutch control linear sotenoid14-252
P1882BlinksONInhibitor solenoid14-253
P1885
(34)BlinksONDrive pulley speed sensor1l-Zb4
P1886(35)BlinksONDriven pulley speed sensor14-255
P1888
(36)BlinksONSecondary gear shaft speed sensor14-256
T to55
(37)BlinksONECM or TCM14-257
P1890
l42lBlinksONShift control system14-259
P1891
(43)BlinksONStart clutch control svstem14-260
14-23a