check engine TOYOTA RAV4 1996 Service Manual PDF

DI−68
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
4 Check EGR vacuum modulator (See page EC−8).
NG Repair or replace.
OK
5 Check EGR valve (See page EC−8).
NG Repair or replace.
OK
6 Check manifold absolute pressure sensor (See page DI−21).
NG Repair or replace.
OK
Check and replace ECM (Se page IN−30).
OBDII scan tool (excluding TOYOTA hand−held tester)
1 Check the connection of vacuum hose, EGR hose (See page EC−5).
NG Repair or replace.
OK

A00408
ON
EGR
(+)ONOFFE4 connector
Air
(ON) (OFF) G
Air FilterE
GEAir
− DIAGNOSTICSENGINE
DI−69
1996 RAV4 (RM447U)
2 Check the VSV for EGR.
PREPARATION:
(a) Remove side trim cover (See page SF−62).
(b) Disconnect the E4 connector of ECM.
(c) Turn ignition switch ON.
CHECK:
Check VSV function.
(1) Connect between terminal EGR of ECM connector
and body ground. (ON)
(2) Disconnect between terminal EGR of ECM connec-
tor and body ground. (OFF)
OK:
(1) VSV is ON:
Air from pipe E is Flowing out through the air filter.
(2) VSV is OFF:
Air from pipe E is flowing out pipe G.
OK Go to step 4.
NG
3 Check operation of the VSV for EGR (See page SF−43).
NG Replace VSV for EGR.
OK
Check for open and short in harness and con-
nector between R/B No.6 and ECM
(See page IN−30).

DI−70
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
4 Check EGR vacuum modulator (See page EC−8).
NG Repair or replace.
OK
5 Check EGR valve (See page EC−8).
NG Repair or replace.
OK
6 Check manifold absolute pressure sensor (See page DI−21).
NG Repair or replace.
OK
Check and replace ECM
(See page IN−30).

− DIAGNOSTICSENGINE
DI−71
1996 RAV4 (RM447U)
DTC P0402 Exhaust Gas Recirculation Flow Excessive
Detected
CIRCUIT DESCRIPTION
Refer to Exhaust Gas Recirculation Flow Insufficient Detected on page DI−65.
DTC No.DTC Detecting ConditionTrouble Area
P0402
After the engine is warmed up, conditions (a) and (b) continue
(a) The intake manifold absolute pressure is larger than the
value calculated by the ECM while the EGR system is ON.
(b) Misfiring is detected during idling
(2 trip detection logic)EGR valve stuck open
Vacuum or EGR hose is connected to wrong post
Manifold absolute pressure sensor
ECM
See DTC P0140 for System Check Driving Pattern and Wiring Diagram.
INSPECTION PROCEDURE
HINT:
If DTC ”P0105” and / or ”P0106” and ”P0402” are output simultaneously, perform troubleshooting of
DTC ”P0105” first.
If DTC ”P0401” and ”P0402” are output simultaneously, perform troubleshooting of DTC ”P0402” first.
1 Check the connection of the vacuum hose, EGR hose (See page EC−5).
NG Repair or replace.
OK
2 Check EGR valve (See page EC−8).
NG Repair or replace.
OK
3 Check the VSV for EGR * .
* If you have TOYOTA hand−held tester, see page DI−65, step 2.
If you have no TOYOTA hand−held tester, see page DI−65, step 2.
OK Go to step 5.
NG
DI3ZU−01

DI−72
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
4 Check operation of the VSV for EGR (See page SF−43).
NG Replace VSV for EGR.
OK
Check for open and short in harness and con-
nector between R/B No.6 and ECM
(See page IN−30).
5 Check EGR vacuum modulator (See page EC−8).
NG Repair or replace.
OK
6 Check manifold absolute pressure sensor (See page DI−21).
NG Repair or replace.
OK
Check and replace ECM
(See page IN−30).

(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).

S00046
DI−78
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
1 Check whether the hoses close to the fuel tank have been modified, and check
whether there are signs of any accident near the fuel tank or charcoal canister.
CHECK:
Check for cracks, deformation and loose connection of the fol-
lowing parts.
Fuel tank
Charcoal canister
Fuel tank filler pipe
Hoses and tubes around the fuel tank and charcoal
canister
NG Repair or replace.
OK
2 Check that the fuel tank cap is TOYOTA genuine parts.
NG Replace to TOYOTA genuine parts.
OK
3 Check that the fuel tank cap is correctly installed.
NG Correctly install the fuel tank cap.
OK
4 Check the fuel tank cap (See page EC−5).
NG Replace fuel tank cap.
OK

− DIAGNOSTICSENGINE
DI−79
1996 RAV4 (RM447U)
5 Check the filler neck for damage.
PREPARATION:
Remove the fuel tank cap.
CHECK:
Visually inspect the filler neck for damage.
NG Replace the filler neck.
OK
6 Check the vacuum hoses between vapor pressure sensor and VSV for vapor
pressure sensor, and VSV for vapor pressure sensor and charcoal canister.
CHECK:
(a) Check that the vacuum hose is connected correctly.
(b) Check the vacuum hose for looseness and disconnection.
(c) Check the vacuum hose for cracks, hole and damage.
NG Repair or replace.
OK
7 Check the hose and tube between fuel tank and charcoal canister.
CHECK:
(a) Check for proper connection of the fuel tank and fuel evap pipe (See page SF−1), fuel evap pipe and
fuel tube under the floor, fuel tube under the floor and charcoal canister.
(b) Check the hose and tube for cracks, hole and damage.
NG Repair or replace.
OK
8 Check the charcoal canister for cracks, hole and damage (See page EC−5).
NG Replace charcoal canister.
OK

A00389
ON
E2
(−)VC
(+)
A00409
ON
PTNK (+) E2 (−)
Vacuum
DI−80
− DIAGNOSTICSENGINE
1996 RAV4 (RM447U)
9 Check voltage between terminals VC and E2 of ECM connector.
PREPARATION:
(a) Remove side trim cover (See page SF−61).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VC and E2 of ECM con-
nector.
OK:
Voltage: 4.5 − 5.5 V
NG Check and replace ECM (See page IN−30).
OK
10 Check voltage between terminals PTNK and E2 of ECM connector.
PREPARATION:
(a) Remove side trim cover (See page SF−61).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals PTNK and E2 of ECM con-
nector.
(1) Disconnect the vacuum hose from the vapor pres-
sure sensor.
(2) Using the MITYVAC (Hand−Held Vacuum Pump),
apply vacuum (4.0 kPa, 30 mmHg, 1.18 in. Hg) to
the vapor pressure sensor.
NOTICE:
The vacuum applied to the vapor pressure sensor must be
less than 66.7 kPa (500 mmHg).
OK:
(1) Voltage: 2.9 − 3.7 V
(2) Voltage: 0.5 V or less
OK Go to step 12.
NG
11 Check for open and short in harness and connector between vapor pressure
sensor and ECM (See page IN−30).