Page 410 of 1413
Description
Electronic Control System
Electronic Control System
The electronic control system consists of the Transmission Control Module (TCM), sensors. and 4 solenoid valves. Shift-
ing and lock-up are elect.onically controlled for comfortable driving under all conditions.
The TCM is located below the dashboard, behind the left side kick panel on the driver's side.
Lock-up ControlSolonoid Valvo A
14-18
Page 413 of 1413

. Ascending Contlol
When the TCM determines that the vehicle is climbing a hill in @ position, the system extends the engagement area
of 3rd gear to prevent the transmission Irom frequenrly shitting between 3rd and 4th gears, so the vehicle can run smooth
and have more power when needed.
NOTE: Shift schedules between 3rd and 4th gear are stored in the TCM to enable the transmission to automatically
select the most suitable gear according to the magnitude of a gradient by Fuzzy logic.
. Descending Control
When the TCM determines that the vehicle is going down a hill in @ position. the shift-up speed from 3rd to 4th gear
when the throttle is closed becomes taster than the set speed for tlat road driving to widen the 3rd gear driving area.
This, in combination with engine brake from the deceleration lock-up, achieves smooth driving when the vehicle is
descending.
There are two ascending modes with different 3rd gear driving areas according to the magnitude of a gradient stored in
the TCM.
When the vehicle is in 4th gear, and you are decelerating on a gradual hill, or when you are applying the brakes on a
steep hill, the transmission will downshitt to 3rd gear. When you accelerate the transmission will then return to 4th gear.
F
0
. Deceleration Control
Vohicle SDood
When the vehicle goes around a corner, and needs to decelerate first and then accelerate, the TCM sets the data for
deceleration control to reduce the number of times the transmission shifts to obtain smooth driving. When the vehicle
is decelerating from speeds above 27 mph (43 km/h). the TCM shifts the transmission from 4th to 3rd earlier than normal
to cope with upcoming acceleration to maintain smooth driving.
NOTE:
Fuzzy Logic: Fuzzy logic is a from at artificial intelligence that lets computers respond to changing conditions much like
a human mind would.
14-21
Page 421 of 1413
E Position
As the engine turns, the oil pump also starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and dis-
charged into (1 ). Then, ATF pressure is controlled by the regulator valve and becomes line pressure ( 1 ). The torque con-
verter inlet pressure (92) enters (94) of torque converter through the orifice and discharges into {90}.
The torque converter check valve prevents the torque converter pressure from rising'
Under this condition, the hydraulic pressure is not applied to the clutches.
NOTE:. When used, "left" or "right" indicates direction on the llowchart
. SOL-@: Shift Control Solenoid Valve A
' SOL{D:Shift Control Solenoid Valve B
. SOL@: Lock-up Control Solenoid Valve A
. SOL-@: Lock-up Control Solenoid Valve B
(cont'd)
14-29
Page 438 of 1413
Circuit Diagram
tGNtTtoN c0 -
V
I
I
IBLU
UNDER HOOD FUSE/RELAY 80X
AN GEAR POSITIONINDICATOR
BLK
T
G201
No.411100A) No.32 (7.5A)
423 424 A20 D2
TRANSMISSION CONTROL MOOUI.E {TCM)
Ar0 A8 A19 A18 A21 A17 A15 A13 Alt
I A' V A-" t2
| *---i. t,,,:----<) l1
8LK
{
G201
14-46
A/'I GEAR POSIIIONswtrcH
Page 443 of 1413

Number of @indicator light
blinks while
Service Check
Connector is
connected with
the special tool.
@ indicator
lightPossible CauseSymptomRefer to
page
'loBlinksDisconnected engine coolant tempera-
rure (ECT) sensor connector
Short or open in ECT sensor wire
Faulty ECT sensor
Lock-up clutch does not
engage.14-68
1lOFFDisconnected ignition coil connector
Short or open in ignition coil wire
Faulty ignition coil
. Lock-up clutch does not
engage.'t 4-7 0
13Blinks. Shon or open in LT GRN wire between
the D3 terminal and ECM. Faulty barometric pressure {BARO)
sensor
NOTE: The BARO sensor is built into
the ECM
. No specific symptom
appears.
14-7 1
14Blinks. Short of open in FAS {YEL} wire be-
tween the D16 terminal and ECM. Faulty ECM
. Transmission jerks hard
when shitting.
't5OFFDisconnected mainshaft speed sensor
connecror
Short or open in mainshaft speed sen-
sor wire
Faulty mainshaft speed sensor
. Transmission jerks hard
when shifting.
14-75
SymptomProbable CauseRet.page
LQ! indicator light is on steady, not blinking whenever the ignition is on.14-77
[Q3] indicator light does not come on for 2 seconds after ignition is first
turned on.14-78
Lock-up clutch does not have duty operation (ON-OFFI.Check A/C signal with
A/C on.14-80Lock-up clutch does not engage.
Shitt leve. cannot be moved lrom @ position with the brake pedal
depressed.Check brake switch signal,14-41
It the self-diagnosis LQ4 indicator light does not blink, perform an inspection according to the table below.
a lf a customer describes the symptoms for codes 3, (yet the LQ! indicator light is not blinkingl, 6, 1 1 or 15, it will
be necessa.y to recreate the symptom by test driving. and then checking the @ indicator light with the ignition still
oN.
e lt ttre @ indicator light displays codes olher than those listed above or stays lit continuously, the TCM is faulty.. Sometimes the Lqd indicator light and the Malfunction Indicator Lamp (MlL)/Check Engine light may come on simul-taneously. lf so, check the PGM-Fl system according to the numbe. of blinks on the MIL/Check Engine light. thenreset the memory by removing the BACK UP fuse in the unde.-hood fuse/relay box for more than 1O seconds. Drive
the vehicle for several minutes at speed over 30 mph (5O km/h), then recheck the MIL/Check Engine light.
NOTE:
. PGM-FI system
The PGM-Fl system on this model is a sequential multiport fuel injection system.a Disconnecting the BACK UP luse also cancels the radio anti-theft code. preset stations and the clock setting. Get
the fuse so vou can reset them.the customer's code number and make note ot the radio
14-51
Page 467 of 1413

Possible Cause
. Disconnected mainshaft speedsensor connecror. Short or open in mainshaltspeed sensor wrre.. Faulty mainshatt speed sensor.
NOTE:. A code 15 on the TCM doesn't alwsysmean there's an electrical problem in themainshaft or countershaft speed sensor cir-cuit; code '15 may also indicate a mechani-cal Droblem in the transmission.
3P CONNECTOR
II o o o o o o o oo o o o o I:OtlO$O$g:Sl!:OlXOl*Ofill o o o o o o o o o O o | |
I ooooooooooooo l Sciii:ddii:ijii:l:i$idi$;d6#:l o oooop oo ooo | 6
"-f
1-L(0)Y-!
(cont'd)
solf-diagnosis E indicator lightblink tiftoon timos.
Are the mainshaft and counter-shalt speed sensors installedproperly?
Disconnect the 3P connector lromthe mainshaft speed sensor.
Measure the resistance ot themainshaft speed sensor.
ls the resistance 4OO-600 O?
Disconnect the 22P connectorfrom the TCM.Connect the Test Harness "D"
conneclor to the wire harnessonly, not ot the TCM (see page14-49).
Check the continuity betweenD19 and D12 terminals and bodyground.
Rcoair short in ORN/BLU otWHT/BLU wiros botween Dlgand Dl2 to.minals and tho main-shatt speod ronsor.
Reconnect the 3P connector tothe mainshatt speed sensor,
To page 14-76
14-75
Page 476 of 1413
Transmission Control Module
Replacement
I The Transmission Control Module (TCMI is located be-
low the dashboard, behind the lelt side kick panel on
the driver's side.
CAUTION:
a All SRS electrical wiring hahesses are covered withyellow insulation.
a Betore disconnecting any pan ot the SRS wile har-
ness. connect the short connectors lsee page 23-7O).
a Replace the entir6 affected SRS harness ass€mbly if
it has an open circuit or damaged wiring.
1. Remove two clips securing the kick panel then
move it.
2. Disconnect the connectors and remove the TCM.
6 x 1.0 mm12 N'm{1.2 kgf.m,8.7 tbf.Itl
WIRE HARNESS/CONNECTORS6 x 1.0 mm12 N.m(1.2 kgf.m, 8.7 lbt.ftl
KICK PANEL
SRS MAIN HARNESS
14-84
Page 477 of 1413
Mainshaft/Countershaft
Speed Sensors
Replacement
Disconnect the speed sensor connectors, then re-
move the harness clamp on the countershatt speed
sensor harness from the harness stay.
Remove the 6 mm bolts securing the mainshaft and
countershalt speed sensors from the transmission
housrng.
Remove the mainshaft and countershaft speed
sensors,
Installthe mainshatt and countershalt speed sensors
in the reverse order of the removal.
COUNTERSHAFTSPEED SENSOR
I{ARNESS STAY
6 x'l,O mml2 N.m{1.2 kgf.m,8.7 tbf.fr)
6 x 1.O mm12 N.m(1.2 kgf.m,8.7 tbf.ltl
14-85