TOYOTA CAMRY 1999 Service Repair Manual

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

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

± 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.

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

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.

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

± DIAGNOSTICSENGINE (5S±FE)
DI±125
360 Author: Date:
5 Check filler neck for damage.
PREPARATION:
Remove the fuel tank cap.
CHECK:
Visually check the filler neck for damage.
NG Replace filler neck.
OK
6 Check vacuum hoses between vapor pressure sensor and VSV for vapor pres-
sure 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 hose and tube between fuel tank and charcoal canister.
CHECK:
(a) Check for proper connection of the fuel tank and fuel evap pipe, 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

A03008A03419
ON
E2
(±)VC
(+) w/o Immobiliser
w/ Immobiliser
E2
(±)VC
(+)
DI±126
± DIAGNOSTICSENGINE (5S±FE)
361 Author: Date:
8 Check charcoal canister (See page EC±6).
NG Replace charcoal canister.
OK
9 Check voltage between terminals VC and E2 of ECM connector.
CHECK:
(a) Remove the glove compartment (See page SF±64).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals VC and E2 of the ECM
connector.
OK:
Voltage: 4.5 ~ 5.5 V
NG Check and replace ECM (See page IN±31).
OK

A03018
A03420
PTNK (+)E2 (±)
(1)(2)
Vacuum ON
w/o Immobiliser
w/ Immobiliser
PTNK (+)
E2 (±)
± DIAGNOSTICSENGINE (5S±FE)
DI±127
362 Author: Date:
10 Check voltage between terminals PTNK and E2 of ECM connector.
PREPARATION:
(a) Remove the glove compartment (See page SF±64).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals PTNK and E2 of the ECM
connector.
(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, 19.7 in.Hg).
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±31).
NG Repair or replace harness or connector.
OK
Replace vapor pressure sensor.

DI±128
± DIAGNOSTICSENGINE (5S±FE)
363 Author: Date:
12 Check fuel tank and fuel tank over fill check valve for cracks and damage
(See page EC±6).
NG Replace fuel tank or fuel tank over fill check
valve.
OK
It is likely that vehicle user did not properly close fuel tank cap. Please explain to customer how
to properly install fuel tank cap.