coolant temperature TOYOTA CAMRY 1994 XV10 / 4.G Wiring Diagrams Workshop Manual

243
FAN MOTOR OPERATION
WITH THE IGNITION SW IS TURNED ON, CURRENT FLOWS FROM ECU±IG FUSE TO RADIATOR FAN RELAY NO. 1 (COIL SIDE) AND
RADIATOR FAN RELAY NO. 2 (COIL SIDE) " TERMINAL 2 OF THE A/C SINGLE PRESSURE SW " TERMINAL 3 " TERMINAL 2 OF THE
WATER TEMP. SW " TERMINAL 1 " GROUND, AND RADIATOR FAN RELAY NO. 1 AND NO. 2 ARE TURNED ON.
*RADIATOR FAN MOTOR OPERATION
WHEN THE IGNITION SW IS TURNED ON, RADIATOR FAN RELAY NO. 1 IS TURNED ON. IF AT THIS TIME THE ENGINE COOLANT
TEMPERATURE IS APPROX. 90°C (194°F) OR HIGHER, THE WATER TEMP. SW IS TURNED OFF, RADIATOR FAN RELAY NO. 1 IS
TURNED OFF.
AS A RESULT, CURRENT FROM THE RDI FAN FUSE TO RADIATOR FAN RELAY NO. 1 (POINT SIDE) " TERMINAL 2 OF THE
RADIATOR FAN MOTOR " TERMINAL 1 " GROUND, THUS ACTIVATING THE ROTATION OF THE RADIATOR FAN MOTOR.
*LOW SPEED OPERATION
WHEN THE IGNITION SW IS TURNED ON AND THE A/C ACTIVATED, RADIATOR FAN RELAY NO. 1 AND RADIATOR FAN RELAY NO. 2
ARE TURNED ON, CURRENT FLOWS FROM A/C MAGNETIC CLUTCH RELAY (POINT SIDE) TO RADIATOR FAN RELAY NO. 3 (COIL
SIDE) " GROUND, AND RADIATOR FAN RELAY NO. 3 IS TURNED ON.
AS A RESULT, CURRENT FLOWS FROM CDS FAN FUSE TO TERMINAL 2 OF THE A/C CONDENSER FAN MOTOR " TERMINAL 1 "
RADIAOTR FAN RELAY NO. 2 (POINT SIDE) " RADIATOR FAN RELAY NO. 3 (POINT SIDE) " TERMINAL 2 OF THE RADIATOR FAN
MOTOR " TERMINAL 1 " GROUND, FLOWING TO EACH FAN MOTOR IN SERIES, CAUSING THE FAN TO AT LOW SPEED.
*HIGH SPEED OPERATION OF THE FAN MOTOR DUARING A/C OPERATION
WHEN THE A/C OPERATION, THE REFRIGERRANT PRESSURE BECOME HIGHER THAN OR DINARY LEVEL (APPROX. 15.58 KG/CM
2
(221.2 PSI, 1527 KPA)) THE A/C SINGLE PRESSURE SW IS TURNED OFF. AS A RESULT, RADIATOR FAN RELAY NO. 1 AND RADIATOR
FAN RELAY NO. 2 ARE TURNED OFF, AND CURRENT FLOWS FROM RDI FUSE TO RADIATOR FAN RELAY NO. 1 (POINT SIDE) "
TERMINAL 2 OF THE RADIATOR FAN MOTOR " TERMINAL 1 " GROUND, AND CURRENT FLOWS FROM CDS FAN FUSE TO
TERMINAL 2 OF THE A/C CONDENSER FAN MOTOR " TERMINAL 1 " RADIATOR FAN RELAY NO. 2 (POINT SIDE) " GROUND, AND
TO EACH FAN MOTOR IN PARALLEL, THUS CAUSING THE FAN MOTORS OPERATE HIGH SPEED.
NOTE THAT, BECAUSE THE CURRENT FLOWS IN THE SAME MENNER EVEN IF THE ENGINE COOLANT TEMPERATURE IS APPROX.
90°C (194°F) OR HIGHER, THE FAN MOTOR OPERATE AT HIGH SPEED.
A 2 A/C SINGLE PRESSURE SW
2±3 : OPEN ABOVE APPROX. 15.58 KG/CM2 (221.2 PSI, 1527 KPA)
CLOSE BELOW APPROX. 15.56 KG/CM2 (178.4 PSI, 1231 KPA)
2 1
2 1 A1R1 BLACKGRAY
12E5 A2BLACK
23
SYSTEM OUTLINE
SERVICE HINTS

245
THE COOLING FAN ECU RECEIVES VARIOUS SIGNAL, I.E., THE ENGINE RPM SIGNAL FROM THE IGNITER, COOLANT TEMPERATURE
SIGNAL FROM THE ENGINE COOLANT TEMP. SENSOR (WATER TEMP. SENSOR), A/C REFRIGERANT PRESSURE SIGNAL FROM A/C
SINGLE PRESSURE SW.
THE COOLING FAN ECU JUDGES THE ENGINE BASED ON SIGNALS FROM ABOVE MENTION, DRIVES THE SOLENOID VALVE AND
CONTROLS THE SPEED OF THE COOLING FAN STEPLESSLY
FAIL±SAFE FUNCTION
WHEN THE MALFANCTION IS DETECTED BY THE ENGINE COOLANT TEMP. SENSOR (WATER TEMP. SENSOR) OR SOLENOID VALVE,
THE FAIL±SAFE FUNCTION OF THE COOLING FAN ECU JUDGES THE SITUATION TO ALLOWS THE COOLING SYSTEM TO CONTINUE
OPERATION.
A 2 A/C SINGLE PRESSURE SW
2±3 : OPEN ABOVE APPROX. 15.58KG/CM2 (221.2PSI, 1527KPA)
CLOSED BELOW APPROX. 12.56 KG/CM2
(178.4PSI, 1231KPA)
C14 COOLING FAN ECU
1±GROUND : APPROX. 12 VOLTS WITH THE IGNITION SW ON
9±10 :2.5 VOLTS AT 20°C (68°F) AND IGNITION SW ON
1.2 VOLTS AT 80°C (176°F) AND IGNITION SW ON
8± 4 :10±14 VOLTS AT A/C PRESSURE SW ON (OPEN)
0±3 VOLTS AT A/C PRESSURE SW OFF (CLOSE)
4±GROUND : ALWAYS CONTINUITY
E 5 ENGINE COOLANT TEMP. SENSOR (WATER TEMP. SENSOR) (FOR COOLING FAN)
1±2 :1.5K
AT 80°C (176°F)
0.7K
AT 11 0°C (230°F)
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A 228D 128S 129
C1432E 530
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1A20COWL WIRE AND J/B NO. 1 (INSTRUMENT PANEL LEFT)
3A24COWL WIRE AND J/B NO 3 (BEHIND COMBINATION METER)3C24COWL WIRE AND J/B NO. 3 (BEHIND COMBINATION METER)
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
EC138 (1MZ±FE)ENGINE WIRE AND ENGINE ROOM MAIN WIRE
IP244ENGINE WIRE AND COWL WIRE
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EB38 (1MZ±FE)FRONT LEFT FENDER
EC38 (1MZ±FE)INTAKE MANIFOLD RH
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I1844ENGINE WIRE
2312
534
6X8 91012
12 A2 C14S1 E5BROWN GRAY BLACKD1BLACK
6
XX X
XX X XX
X
SYSTEM OUTLINE
SERVICE HINTS