Page 2537 of 4770

FI7132
Engine Speed
2,500 ~ 3,000 rpm
Idling
IG SW OFF
Warmed up3 min. or soCheck
Time (a)(c)
(d)
(b)
FI6514
OX Signal Waveform (Oscilloscope)
1.0 V
0 V
200 msec. /Division
± DIAGNOSTICSENGINE (5S±FE)
DI±117
352 Author: Date:
CONFIRMATION ENGINE RACING PATTERN
(a) Connect the TOYOTA hand±held tester to the DLC3, or connect the probe of the oscilloscope between
terminals OX1, OX2 and E1 of the ECM connector.
(b) Start engine and warm it up with all accessories switched OFF until water temp. is stable.
(c) Race the engine at 2,500 ~ 3,000 rpm for about 3 min.
(d) After confirming that the waveforms of the heated oxygen sensor (bank 1 sensor 1 (OX1)), oscillate
around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor (bank
1 sensor 2 (OX2)).
HINT:
If there is a malfunction in the system, the waveform of the
heated oxygen sensor (bank 1 sensor 2 (OX2)) is almost
the same as that of the heated oxygen sensor (bank 1
sensor 1 (OX1)) on the left.
There are some cases where, even though a malfunction
exists, the MIL may either light up or not light up.
Page 2538 of 4770
DI±118
± DIAGNOSTICSENGINE (5S±FE)
353 Author: Date:
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check gas leakage on exhaust system.
NG Repair or replace.
OK
3 Check heated oxygen sensor (bank 1 sensor 1) (See page DI±66).
NG Repair or replace.
OK
4 Check heated oxygen sensor (bank 1 sensor 2) (See page DI±77).
NG Repair or replace.
OK
Replace three±way catalytic converter.
Page 2539 of 4770

A00357
Waveform of
A/F SensorNormal CatalystWaveform of Heated Oxygen
Sensor behind Catalyst
Abnormal Catalyst
± DIAGNOSTICSENGINE (5S±FE)
DI±119
354 Author: Date:
DTC P0420 Catalyst System Efficiency Below Threshold
(Only for California Spec.)
CIRCUIT DESCRIPTION
The ECM observes the waveform of the heated oxygen sensor located behind the catalyst to determine
whether the catalyst performance has deteriorated.
If the catalyst is functioning normally, the waveform of the heated oxygen sensor located behind the catalyst
switches back and forth between rich and lean much more slowly.
When the waveform of the heated oxygen sensor located behind the catalyst alternates flutteringly between
rich and lean, it indicates that catalyst performance has deteriorated.
DTC No.DTC Detecting ConditionTrouble Area
P0420
After engine and catalyst are warmed up, and while vehicle is
driven within set vehicle and engine speed range, waveform of
heated oxygen sensor (bank 1 sensor 2) alternates flutteringly
between rich and lean
(2 trip detection logic)Three±way catalytic converter
Open or short in heated oxygen sensor (bank 1 sensor 2)
circuit
Heated oxygen sensor (bank 1 sensor 2)
Open or short in A/F sensor circuit
A/F sensor
DI1JY±03
Page 2540 of 4770

A00479
Engine Speed
3,000 rpm
Idling
IG SW OFF
Warmed up
3 min. or so
CheckTime (a)(c) (d)
(b) 2,000 rpm
2 sec. 2 sec.
DI±120
± DIAGNOSTICSENGINE (5S±FE)
355 Author: Date:
CONFIRMATION ENGINE RACING PATTERN
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Start the engine and warm it up with all accessories switched OFF until water temp. is stable.
(c) Race the engine at 2,500 ~ 3,000 rpm for about 3 min.
(d) When racing the engine at 3,000 rpm for 2 sec. and 2,000 rpm for 2 sec. alternately, check the wave-
form of the heated oxygen sensor (bank 1 sensor 2).
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check gas leakage on exhaust system.
NG Repair or replace.
OK
Page 2541 of 4770
± DIAGNOSTICSENGINE (5S±FE)
DI±121
356 Author: Date:
3 Check A/F sensor (See page DI±66).
NG Repair or replace.
OK
4 Check heated oxygen sensor (bank 1 sensor 2) (See page DI±77).
NG Repair or replace.
OK
Replace three±way catalytic converter.
Page 2542 of 4770

A06549
ECM
VSV for
EVAPVapor Pressure
Sensor
VSV for Vapor
Pressure Sensor
Charcoal CanisterFuel Tank fig.1
(1)
(2)
(3)Fuel Tank Over Fill
Check Valve
(9) (8) (4) (6)
(5) (7) DI±122
± DIAGNOSTICSENGINE (5S±FE)
357 Author: Date:
DTC P0440 Evaporative Emission Control System
Malfunction
CIRCUIT DESCRIPTION
The vapor pressure sensor and VSV for vapor pressure sensor are used to detect abnormalities in the evap-
orative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system based on the
vapor pressure sensor signal.
DTC P0440 is recorded by the ECM when evaporative emissions leak from the components within the dotted
line in fig. 1 below, or when the vapor pressure sensor malfunctions.
DTC No.DTC Detecting ConditionTrouble Area
P0440Fuel tank pressure is atmospheric pressure after vehicle is
driven for 20 min. (2 trip detection logic)
Vapor pressure sensor
Fuel tank cap incorrectly installed
Fuel tank cap cracked or damaged
Vacuum hose cracked, holed, blocked, damaged
or disconnected ((1) or (2) in fig. 1)
Hose or tube cracked, holed, damaged or loose seal
((3) in fig. 1)
Fuel tank cracked, holed or damaged
Charcoal canister cracked, holed or damaged
Fuel tank over fill check valve cracked or damaged
DI1JZ±04
Page 2543 of 4770

A07552
3
2
1Y
P
BRECM
1
1
7
9
22 J19
J/C
8
E8
E8
EBE8
E01 E9
E8
EJ/C
J28
J27
10
1V
6
2F From
BatteryB±Y VSV
for EVAP
2V±W
VSV for Vapor
Pressure
Sensor
9
Engine Room J/B No.2 B±Y
EFI II3
53
B±Y
VC
PTNK
E2
EVP
TPC5 V
E1
E01
2J 2A
2K
2
*1: w/o Immobiliser
*2: w/ Immobiliser
(*1) (*2)
MREL(*2)
E8
8
E9
3
E8
16
E10
7 Y Y Vapor Pressure Sensor
P P
BR BR
E
ID1 ID1
1
V V
B±Y
B±W B±W
II4 II4
5
ID1
ID1
ID1
6 5
237
8
II4 II4
II2
(*1) (*2)(*1) (*2)
W±B
B±Y12
BB
B±Y
12
7 4
EFI Relay J27 J27B±Y
B
BJ/C
(*2) (*2)
B±R(*1)From
Ignition SW
± DIAGNOSTICSENGINE (5S±FE)
DI±123
358 Author: Date:
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTC P0441 (Evaporative Emission Control System Incorrect Purge Flow), P0446 (Evaporative
Emission Control System Vent Control Malfunction), P0450 (Evaporative Emission Control System
Pressure Sensor Malfunction) or P0451 is output after DTC P0440 (Evaporative Emission Control Sys-
tem Malfunction), first troubleshoot DTC P0441, P0446, P0450 or P0451. If no malfunction is detected,
troubleshoot DTC P0440 next.
Ask the customer whether, after the MIL came on, the customer found the fuel tank cap loose and tight-
ened it. Also ask the customer whether the fuel tank cap was loose when refuelling. If the fuel tank cap
was not loose, it was the cause of the DTC. If the fuel tank cap was not loose or if the customer was
not sure if it was loose, troubleshoot according to the following procedure.
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame
records the engine conditions when the malfunction is detected, when troubleshooting it is useful for
determining whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel
ratio lean or rich, etc. at the time of the malfunction.
When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the
VSV for EVAP, charcoal canister and vapor pressure sensor.
Page 2544 of 4770
A01653
DI±124
± DIAGNOSTICSENGINE (5S±FE)
359 Author: Date:
1 Check whether hose close to 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 fuel tank and charcoal
canister
NG Repair or replace.
OK
2 Check that fuel tank cap is TOYOTA genuine parts.
NG Replace to TOYOTA genuine parts.
OK
3 Check that fuel tank cap is correctly installed.
NG Correctly install fuel tank cap.
OK
4 Check fuel tank cap (See page EC±6).
NG Replace fuel tank cap.
OK