Coolant Temperature Sensor TOYOTA RAV4 1996 Service Repair Manual

DI−12
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
7. ENGINE OPERATING CONDITION
NOTICE:
The value given below for ”Normal Condition” are representative values, so a vehicle may still be
normal even it its value varies from those listed here. So do not decide whether a part is faulty or not
solely according to the ”Normal Condition” here.
(a) CARB Mandated Signals
TOYOTA hand−held tester displayMeasurement ItemNormal Condition *
FUEL SYS #1
Fuel System Bank 1
OPEN: Air−fuel ratio feedback stopped
CLOSED: Air−fuel ratio feedback operating
Idling after warning up: CLOSED
CALC LOAD
Calculator Load:
Current intake air volume as a proportion of max.
intake air volumeIdling: 20.7 − 48.4 %
Racing without load (2,500 rpm) : 17.7 − 45.3 %
COOLANT TEMPEngine Coolant Temperature Sensor ValueAfter warning up: 80 − 95°C (176 − 203°F)
SHORT FT #1Short−term Fuel Trim Bank 10 ± 20 %
LONG FT #1Long−term Fuel Trim Bank 10 ± 20 %
ENGINE SPDEngine SpeedIdling: 700 ± 50 rpm
VEHICLE SPDVehicle SpeedVehicle Stopped: 0 km/h (0 mph)
IGN ADVANCEIgnition Advance
Ignition Timing of Cylinder No.1Idling: BTDC 0 − 10°
INTAKE AIRIntake Air Temperature Sensor ValueEquivalent to Ambient Temp.
MAPAbsolute Pressure Inside Intake ManifoldIdling: 21 − 49 kPa
Racing without load (2,500 rpm): 17 − 46 kPa
THROTTLE POS
Voltage Output of Throttle Position Sensor
Calculated as a Percentage
0V → 0 %, 5V → 100 %Throttle Fully Closed: 6 − 16 %
Throttle Fully Open: 64 − 98 %
O2S B1, S1Voltage Output of Oxygen Sensor
Bnak 1,Sensor 1Idling : 0.1 − 0.9 V
O2FT B1, S1Oxygen Sensor Fuel Trim Bank 1, Sensor 1
(Same as SHORT FT #1)0 ± 20 %
O2S B1, S2Voltage Output of Oxygen Sensor
Bank 1, Sensor 2Driving 50 km/h (31 mph): 0.1 − 0.9 V
*: If no conditions are specifically stated for ”Idling”, it means the shift lever is at N or P position, the A/C switch
is OFF and all accessory switches are OFF.

P19745
Intake Air Temp. Sensor
Y−B
BRE5
E5E2 THAR5V
E1 93ECM
2
1
DI−26
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTC ”P0105” (Manifold Absolute Pressure / Barometric Pressure Circuit Malfunction), ”P0110” (Intake Air
Temp. Circuit Malfunction), ”P0115” (Engine Coolant Temp. Circuit Malfunction), ”P0120” (Throttle / Pedal
Position Sensor / Switch ”A” Circuit Malfunction) are output simultaneously, E2 (sensor ground) may be
open.
1 Connect the OBDII scan tool or TOYOTA hand−held tester, and read value of
intake air temperature.
PREPARATION:
(a) Connect the OBDII scan tool or TOYOTA hand−held tester to the DLC3.
(b) Turn ignition switch ON and OBDII scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA hand−held tester.
OK:
Same as actual intake air temperature.
HINT:
If there is open circuit, OBDII scan tool or TOYOTA hand−held tester indicates − 40°C (− 40°F).
If there is short circuit, OBDII scan tool or TOYOTA hand−held tester indicates 140°C (284°F) or more.
NG− 40°C (− 40°F) .... Go to step 2.
140°C (284°F) .... Go to step 4.
OK
Check for intermittent problems.
(See page DI−3).

P19746
Engine Coolant Temp. Sensor
W
BRE5
E5E2THW5V
E1 94ECM
2
1
− DIAGNOSTICSENGINE
DI−29
1996 RAV4 (RM447U)
DTC P0115 Engine Coolant Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the
engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the intake air temp. circuit malfunc-
tion shown on page DI−25.
If the ECM detects the DTC P0115, it operates the fail safe function in which the engine coolant temp. is
assumed to be 80°C (176°F).
DTC No.DTC Detecting ConditionTrouble Area
P0115Open or short in engine coolant temp. sensor circuit
Open or short in engine coolant temp. sensor circuit
Engine coolant temp. sensor
ECM
HINT:
After confirming DTC P0115 use the OBDII scan tool or TOYOTA hand−held tester to confirm the engine
coolant temperature from ”CURRENT DATA”.
Temperature DisplayedMalfunction
− 40°C (− 40°F)Open circuit
140°C (284°F) or moreShort circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTC ”P0105” (Manifold Absolute Pressure / Barometric Pressure Circuit Malfunction), ”P0110” (Intake Air
Temp. Circuit Malfunction), ”P0115” (Engine Coolant Temp. Circuit Malfunction), ”P0120” (Throttle / Pedal
Position Sensor / Switch ”A” Circuit Malfunction) are output simultaneously, E2 (sensor ground) may be
open.
DI3ZF−01

A00395
Engine Coolant
Temp. Sensor
E5
E2
THW
5V
94ECM
E5E1
1 2
ON
DI−30
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
1 Connect the OBDII scan tool or TOYOTA hand−held tester, and read value of en-
gine coolant temperature.
PREPARATION:
(a) Connect the OBDII scan tool or TOYOTA hand−held tester to the DLC3.
(b) Turn ignition switch ON and OBDII scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA hand−held tester.
OK:
Same as actual engine coolant temperature.
HINT:
If there is open circuit, OBDII scan tool or TOYOTA hand−held tester indicates − 40°C (− 40°F).
If there is short circuit, OBDII scan tool or TOYOTA hand−held tester indicates 140°C (284°F) or more.
NG− 40°C (− 40°F) .... Go to step 2.
140°C (284°F) or more .... Go to step 4.
OK
Check for intermittent problems
(See page DI−3).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Connect sensor wire harness terminals together.
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA
hand−held tester.
OK:
Temperature value: 140°C (284°F) or more.
OK Confirm good connection at sensor. If OK,
replace engine coolant temp. sensor.
NG

A00396
Engine Coolant
Temp. Sensor
E5E2
THW
5V
94ECM
E5
E1
12
ON
THWE2
A00397
Engine Coolant
Temp. Sensor
E5E2
THW
5V
94ECM
E5
E1
ON
− DIAGNOSTICSENGINE
DI−31
1996 RAV4 (RM447U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove side trim cover. (See page SF−61).
(b) Connect between terminals THW and E2 of ECM connec-
tor.
HINT:
Engine coolant temp. sensor connector is disconnected. Be-
fore checking, do a visual and contact pressure check for the
ECM connector (See page IN−30).
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA
hand−held tester.
OK:
Temperature value: 140°C (284°F) or more
OK Open in harness between terminals E2 or THW,
repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM.
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Turn ignition switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA
hand−held tester.
OK:
Temperature value : − 40°C (− 40°F)
OK Replace engine coolant temp. sensor.
NG

A00398
Engine Coolant
Temp. Sensor
E2
THW
5V ECM
E1
ON
E5connector
DI−32
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove side trim cover. (See page SF−61).
(b) Disconnect the E5 connector of ECM.
HINT:
Engine coolant temp. sensor connector is disconnected.
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBDII scan tool or TOYOTA
hand−held tester.
OK:
Temperature value : − 40°C (− 40°F)
OK Repair or replace harness or connector.
NG
Check and replace ECM
(See page IN−30).

− DIAGNOSTICSENGINE
DI−49
1996 RAV4 (RM447U)
2 Check for oxygen sensor data.
PREPARATION:
(a) Connect the OBDII scan tool or TOYOTA hand−held tester to the DLC3.
(b) Warm up engine to normal operating temperature.
CHECK:
Read the oxygen sensor output voltage and short−term fuel trim.
RESULT:
PatternOxygen sensor output voltageShort−term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about +20 %
2Rich condition (Changes at 0.35 V or more)Changes at about −20 %
3Except 1 and 2
3 Check for oxygen sensor
(See page DI−42).
1, 2
3 Check fuel pressure (See page SF−5).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF−1).
OK
4 Check injector injection (See page SF−21).
NG Replace injector.
OK
5 Check manifold absolute pressure sensor and engine coolant temp. sensor
(See page DI−21, DI−29).
NG Repair or replace.
OK

SF0R7−01
S01930
ECT Sensor Connector
ECT Sensor
 Gasket
 Non−reusable part SF−48
− SFIENGINE COOLANT TEMPERATURE (ECT) SENSOR
1996 RAV4 (RM447U)
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
COMPONENTS

SF0R8−01
S01196S01699
Z17274
35 1020 30
TEMPERATURE°C (°F) Acceptable
RESISTANCE kΩ
2
1
0.5
0.3
0.2
0.1
−20 0
2040 60
(32)(68)(104)(140)(176)(212)
(−4)100 80
Ohmmeter
− SFIENGINE COOLANT TEMPERATURE (ECT) SENSOR
SF−49
1996 RAV4 (RM447U)
INSPECTION
1. DRAIN ENGINE COOLANT
2. REMOVE ECT SENSOR
3. INSPECT ECT SENSOR RESISTANCE
Using an ohmmeter, measure the resistance between the ter-
minals.
Resistance: Refer to the graph
If the resistance is not as specified, replace the sensor.
4. REINSTALL ECT SENSOR
Install a new gasket to the ECT sensor.
Torque: 25 N·m (250 kgf·cm, 18 ft·lbf)
5. FILL WITH ENGINE COOLANT