1996 TOYOTA RAV4 oxygen

(4) (3)
(2)
(1)
FI7132
2500 − 3000 rpm Engine Speed
Warmed up 3 minutes IG SW OFFIdling
Time
Check
FI6514
OX Signal Waveform (Oscilloscope)
200 msec./Division 1.0 V
0 V DI−74
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
CONFIRMATION ENGINE RACING PATTERN
(1) Connect the TOYOTA hand−held tester to the DLC3, or connect the probe of the oscilloscope between
terminals OX1, OX2 and E1 of ECM.
(2) Start engine and warm it up with all accessories switched OFF until water temperature is stable.
(3) Race the engine at 2500 − 3000 rpm for about 3 min.
(4) After confirming that the waveforms of the oxygen sensor, bank 1 sensor 1 (OX1), oscillate around 0.5
V during feedback to the ECM, check the waveform of the oxygen senor, bank 1 sensor 2 (OX2).
HINT:
If there is a malfunction in the system, the waveform of the oxy-
gen senor, bank1 sensor 2 (OX2), is almost the same as that
of the oxygen sensors, bank 1 senor 1 (OX1), on the left.
There are some cases where, even though a malfunction ex-
ists, the MIL may either light up or not light up.

− DIAGNOSTICSENGINE
DI−75
1996 RAV4 (RM447U)
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check oxygen senor (bank 1 sensor 1) (See page DI−42).
NG Repair or replace.
OK
3 Check oxygen senor (bank 1 sensor 2) (See page DI−45).
NG Repair or replace.
OK
Replace both of front TWC (front catalyst)
and TWC w/ pipe (rear catalyst) (See page
EC−11).

EM−2
− ENGINE MECHANICALCO/HC
1996 RAV4 (RM447U)
6. TROUBLESHOOTING
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
(a) Check the oxygen sensor operation (See page DI−42).
(b) See the table below for possible causes, then inspect and
correct the applicable causes if necessary.
HCCOProblemsCauses
HighNormalRough idle4. Faulty ignitions:
Incorrect timing
Fouled, shorted or improperly gapped plugs
Open or or crossed high−tension cords
Cracked distributor cap
5. Incorrect valve clearance
6. Leaky EGR valve
7. Leaky intake and exhaust valves
8. Leaky cylinder
HighLowRough idle
(Fluctuating HC reading)1. Vacuum leaks:
PCV hose
EGR valve
Intake manifold
Throttle body
IAC valve
Brake booster line
2. Lean mixture causing misfire
HighHighRough idle
(Black smoke from exhaust)1. Restricted air filter
2. Faulty SFI system:
Faulty pressure regulator
Clogged fuel return line
Defective ECT sensor
Defective IAT sensor
Faulty ECM
Faulty injector
Faulty throttle position sensor
MAP sensor

EM1B8−02
S01285
S01557
− ENGINE MECHANICALCYLINDER HEAD
EM−33
1996 RAV4 (RM447U)
REMOVAL
1. REMOVE RH ENGINE UNDER COVER
2. DRAIN ENGINE COOLANT
3. A/T only:
DISCONNECT THROTTLE CABLE FROM THROTTLE
BODY
4. DISCONNECT ACCELERATOR CABLE FROM
THROTTLE BODY
5. REMOVE AIR CLEANER CAP AND CASE
6. REMOVE GENERATOR (See page CH−7)
7. REMOVE DISTRIBUTOR
8. REMOVE FRONT EXHAUST PIPE
(a) Using a 14 mm deep socket wrench, remove the 3 nuts
holding the front exhaust pipe to the front TWC.
(b) Remove the 2 bolts holding the front exhaust pipe to the
TWC w/ pipe.
(c) Remove the front exhaust pipe and 2 gaskets.
9. REMOVE EXHAUST MANIFOLD AND HEAT INSULA-
TOR ASSEMBLY
(a) Disconnect the oxygen sensor (bank 1 sensor 1) connec-
tor.
(b) Disconnect the oxygen sensor (bank 1 sensor 2) connec-
tor.
(c) Remove the 6 bolts and manifold upper heat insulator.
(d) Remove the 2 bolts holding the RH exhaust manifold stay
to the cylinder block.
(e) Remove the 6 nuts, the exhaust manifold and heat insula-
tor assembly.

S01823
Oxygen Sensor
(Bank 1 Sensor 1)
Oxygen Sensor (Bank 1 Sensor 2)
P03152
S01368
S01365
S01594
EM−34
− ENGINE MECHANICALCYLINDER HEAD
1996 RAV4 (RM447U)
10. REMOVE OXYGEN SENSOR (BANK 1 SENSOR 1)
FROM EXHAUST MANIFOLD
11. REMOVE OXYGEN SENSOR (BANK 1 SENSOR 2)
FROM FRONT TWC
12. SEPARATE EXHAUST MANIFORD AND FRON TWC
(a) Remove the 5 bolts and lower manifold heat insulator.
(b) Remove the 8 bolts and 2 TWC heat insulators.
(c) Remove the 3 bolts, 2 nuts, TWC, gasket retainer and
cushion.
13. DISCONNECT OIL PRESSURE SWITCH CONNECTOR
14. REMOVE WATER OUTLET
(a) Disconnect the ECT sensor connector.
(b) Disconnect the ECT sender gauge connector.
(c) Disconnect the radiator hose from the water outlet.
(d) Disconnect the water bypass pipe hose from the water
outlet.
(e) Disconnect the heater water hose from the water outlet.
(f) Remove the 2 nuts, water outlet and gasket.
15. REMOVE WATER BYPASS PIPE
(a) Remove the bolt, 2 nuts and oil cooler heat protector.
(b) Disconnect the IAC valve water bypass hose from the wa-
ter bypass pipe.
(c) Disconnect the heater water hose from the water bypass
pipe.
(d) Disconnect the 2 oil cooler water bypass hoses from the
oil cooler.
(e) Remove the nut and disconnect the wire protector.
(f) Remove the 2 bolts and 2 nuts.
(g) Disconnect the water bypass pipe from the water pump
cover, and remove the water bypass pipe.
(h) Remove the gasket and O−ring.
16. REMOVE THROTTLE BODY (See page SF−30)

P03469
Retainer
Cushion
New Gasket
S01823
Oxygen Sensor
(Bank 1 Sensor 1)
Oxygen Sensor (Bank 1 Sensor 2)
S01557
− ENGINE MECHANICALCYLINDER HEAD
EM−63
1996 RAV4 (RM447U)
29. CONNECT OIL PRESSURE SWITCH CONNECTOR
30. ASSEMBLE EXHAUST MANIFOLD AND FRONT TWC
(a) Place the cushion, retainer and a new gasket on the
TWC.
(b) Install the TWC to the exhaust manifold with the 3 bolts
and 2 nuts.
Torque: 29 N·m (300 kgf·cm, 22 ft·lbf)
(c) Install the lower manifold heat insulator with the 5 bolts.
(d) Install the 2 TWC heat insulators with the 8 bolts.
31. INSTALL OXYGEN SENSOR (BANK 1 SENSOR 1) TO
EXHAUST MANIFOLD
Install a new gasket and the oxygen sensor with 2 new nuts.
Torque: 20 N·m (200 kgf·cm, 14 ft·lbf)
32. INSTALL OXYGEN SENSOR (BANK 1 SENSOR 2) TO
FRONT TWC
Torque: 44 N·m (450 kgf·cm, 33 ft·lbf)
33. INSTALL EXHAUST MANIFOLD AND FRONT TWC AS-
SEMBLY
(a) Install a new gasket, the exhaust manifold and TWC as-
sembly with the 6 nuts. Uniformly tighten the nuts in sev-
eral passes.
Torque: 49 N·m (500 kgf·cm, 36 ft·lbf)
(b) Install the RH exhaust manifold stay with the 2 bolts and
2 new nuts.
Torque: 42 N·m (452 kgf·cm, 31 ft·lbf)
(c) Install the upper manifold heat insulator with the 6 bolts.
(d) Connect the oxygen sensor (bank 1 sensor 1) connector.
(e) Connect the oxygen sensor (bank 1 sensor 2) connector.
34. INSTALL FRONT EXHAUST PIPE (See page EM−74)
35. INSTALL GENERATOR (See page CH−19)
36. INSTALL AIR CLEANER CASE AND CAP
37. CONNECT ACCELERATOR CABLE TO THROTTLE
BODY AND CABLE BRACKET
38. A/T only:
CONNECT THROTTLE CABLE TO THROTTLE BODY
AND CABLE BRACKET

29
G
Position of Parts in Engine Compartment
I 1 Idle Air Control Valve R 1Radiator Fan Motor
I 2 Igniter R 2 Rear Washer Motor
I 3 Ignition Coil and Distributor
I 4 Ignition Coil and Distributor S 1 Solenoid Valve SLD
I 5 Injector No. 1 S 2 Starter
I 6 Injector No. 2 S 3 Starter
I 7 Injector No. 3
I 8 Injector No. 4 T 1 Throttle Position Sensor
I 9 Intake Air Temp. Sensor
V 1 Vapor Pressure Sensor
K 1 Knock Sensor V 2 Vehicle Speed Sensor (Combination Meter)
V 3 Vehicle Speed Sensor (Front)
M 1 Manifold Absolute Pressure Sensor V 4 Vehicle Speed Sensor (Rear)
V 5 VSV (Center Diff. Lock No. 1)
N 1 Noise Filter (Ignition System) V 6 VSV (Center Diff. Lock No. 2)
V 7 VSV (EGR)
O 1 Oil Pressure SW V 8 VSV (EVAP)
O 2 Oxygen Sensor (Bank 1 Sensor 1) V 9 VSV (Vapor Pressure Sensor)
O 3 Oxygen Sensor (Bank 1 Sensor 2)
W 1 Water Temp. Sender
P 1 Park/Neutral Position SW (A/T)

64
ENGINE CONTROL
THE ENGINE CONTROL SYSTEM UTILIZES A MICROCOMPUTER AND MAINTAINS OVERALL CONTROL OF THE ENGINE ETC. AN
OUTLINE OF ENGINE CONTROL IS GIVEN HERE.
1. INPUT SIGNALS
(1) ENGINE COOLANT TEMP. SENSOR SIGNAL SYSTEM
THE ENGINE COOLANT TEMP. SENSOR DETECTS THE ENGINE COOLANT TEMP. AND HAS A BUILT-IN THERMISTOR WITH A
RESISTANCE WHICH VARIES ACCORDING TO THE ENGINE COOLANT TEMP. THUS THE ENGINE COOLANT TEMP. IS INPUT IN
THE FORM OF A CONTROL SIGNAL TO TERMINAL THW OF THE ENGINE CONTROL MODULE.
(2) INTAKE AIR TEMP. SIGNAL SYSTEM
THE INTAKE AIR TEMP. SENSOR DETECTS THE INTAKE AIR TEMP. , WHICH IS INPUT AS A CONTROL SIGNAL TO TERMINAL THA
OF THE ENGINE CONTROL MODULE.
(3) OXYGEN SENSOR SIGNAL SYSTEM
THE OXYGEN SENSOR DETECTS THE OXYGEN DENSITY IN THE EXHAUST EMISSION WHICH IS INPUT AS A CONTROL SIGNAL
TO TERMINALS OX1 AND OX2 OF THE ENGINE CONTROL MODULE.
(4) THROTTLE SIGNAL SYSTEM
THE THROTTLE POSITION SENSOR DETECTS THE THROTTLE VALVE OPENING ANGLE, WHICH IS INPUT AS A CONTROL
SIGNAL TO TERMINAL VTA OF THE ENGINE CONTROL MODULE, OR WHEN THE VALVE IS FULLY CLOSED.
(5) VEHICLE SPEED CIRCUIT
THE VEHICLE SPEED IS DETECTED BY VEHICLE SPEED SENSOR INSTALLED IN THE TRANSMISSION AND THE SIGNAL IS INPUT
TO TERMINAL SPD OF THE ENGINE CONTROL MODULE VIA THE COMBINATION METER.
(6) PARK/NEUTRAL POSITION SW SIGNAL SYSTEM
THE PARK/NEUTRAL POSITION SW DETECTS WHETHER THE SHIFT POSITION IS IN NEUTRAL OR NOT, AND INPUTS A CONTROL
SIGNAL TO TERMINAL NSW OF THE ENGINE CONTROL MODULE.
(7) A/C SW SIGNAL SYSTEM
THE OPERATING VOLTAGE OF THE A/C MAGNETIC CLUTCH IS DETECTED AND INPUT IN THE FORM OF A CONTROL SIGNAL TO
TERMINAL ACI OF THE ENGINE CONTROL MODULE.
(8) BATTERY SIGNAL SYSTEM
VOLTAGE IS CONSTANTLY APPLIED TO TERMINAL BATT OF THE ENGINE CONTROL MODULE. WHEN THE IGNITION SW IS
TURNED TO ON, VOLTAGE FOR THE ENGINE CONTROL MODULE OPERATION IS APPLIED VIA THE EFI MAIN RELAY TO
TERMINAL +B OF THE ENGINE CONTROL MODULE.
(9) INTAKE AIR VOLUME SIGNAL SYSTEM
INTAKE AIR VOLUME IS DETECTED BY THE MANIFOLD ABSOLUTE PRESSURE SENSOR AND IS INPUT AS A CONTROL SIGNAL
TO TERMINAL PIN OF THE ENGINE CONTROL MODULE.
(10) STARTER SIGNAL SYSTEM
TO CONFIRM THAT THE ENGINE IS CRANKING, THE VOLTAGE APPLIED TO THE STARTER MOTOR DURING CRANKING IS
DETECTED AND IS INPUT AS A CONTROL SIGNAL TO TERMINAL STA OF THE ENGINE CONTROL MODULE.
(11) ELECTRICAL LOAD SIGNAL SYSTEM
THE SIGNAL WHEN SYSTEMS SUCH AS THE REAR WINDOW DEFOGGER, HEADLIGHT, ETC. WHICH CAUSE A HIGH ELECTRICAL
BURDEN ARE ON IS INPUT TO TERMINAL ELS AS A CONTROL SIGNAL.
SYSTEM OUTLINE