oxygen sensors TOYOTA CAMRY 2000 Service Owner's Guide

± DIAGNOSTICSENGINE (1MZ±FE)
DI±275
510 Author: Date:
8 Check for open and short in harness and connector between ECM and heated
oxygen sensors (bank1, 2 sensor1) (See page SF±71).
NG Repair or replace harness or connector.
OK
Replace heated oxygen sensors
(bank1, 2 sensor1).
9 Perform confirmation driving pattern (See page DI±255).
Go
10 Is there DTC P0171 or P0172 being output again ?
YES Check and replace ECM.
NO
11 Did vehicle runs out of fuel in the past ?
NO Check for intermittent problems.
YES
DTC P0171 or P0172 is caused by running out of fuel.

FI7081
Waveform of Oxygen Sensor
before CatalystNormal Catalyst Waveform of Oxygen Sensor
after Catalyst
FI7132
Engine Speed
2,500 ~ 3,000 rpm
Idling
IG SW OFF(a)(b)(c) (d)
Time Warmed up 3 min. or so Check
± DIAGNOSTICSENGINE (1MZ±FE)
DI±305
540 Author: Date:
DTC P0420 Catalyst System Efficiency Below Threshold
(Except California Spec.)
CIRCUIT DESCRIPTION
The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deterio-
rated.
Air±fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeat-
edly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the cata-
lyst.
But when both waveforms change at a similar rate, 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, waveforms
of heated oxygen sensors (bank 1 sensor 1, 2) have the same
amplitude
(2 trip detection logic)

Three±way catalytic converter

Open or short in heated oxygen sensor circuit

Heated oxygen sensor
CONFIRMATION ENGINE RACING PATTERN
DI07Y±06

± DIAGNOSTICSENGINE (1MZ±FE)
DI±307
542 Author: Date:
3 Check heated oxygen sensor (bank 1, sensor 1) (See page DI±255).
NG Repair or replace.
OK
4 Check heated oxygen sensors (bank 1, 2 sensor 2) (See page DI±265).
NG Repair or replace.
OK
Replace three±way catalytic converter.

A01674
Waveform of
A/F Sensor
Normal CatalystWaveform of Heated Oxygen
Sensor Behind Catalyst
Abnormal Catalyst DI±308
± DIAGNOSTICSENGINE (1MZ±FE)
543 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 is 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 flatteringly 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 flatteringly
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 sensors (bank 1, 2 sensor 1) circuit

A/F sensors (bank 1, 2 sensor 1)
DI1K4±03

DI±310
± DIAGNOSTICSENGINE (1MZ±FE)
545 Author: Date:
3 Check A/F sensors (bank 1, 2 sensor 1) (See page DI±255).
NG Repair or replace.
OK
4 Check heated oxygen sensor (bank 1 sensor 2) (See page DI±265).
NG Repair or replace.
OK
Replace three±way catalytic converter.

S05042
Bank 1 Sensor 1
Bank 2 Sensor 1+B
HTOhmmeter
+B HTOhmmeter
SF08P±04
± SFI (1MZ±FE)HEATED OXYGEN SENSOR (Bank 1,2 Sensor 1)
SF±71
1570 Author: Date:
HEATED OXYGEN SENSOR (Bank
1,2 Sensor 1)
INSPECTION
Except California A/T:
INSPECT HEATER RESISTANCE OF HEATED OXYGEN
SENSORS (Bank 1 Sensor 1, Bank 2 Sensor 1)
(a) Disconnect the oxygen sensor connector.
(b) Using an ohmmeter, measure the resistance between the
terminals +B and HT.
Resistance:
At 20°C (68°F)11 ± 16 W
At 800°C (1,472°F)23 ± 32 W
If the resistance is not as specified, replace the sensor.
Torque: 44 N´m (450 kgf´cm, 32 ft´lbf)
(c) Reconnect the oxygen sensor connector.

During vehicle processing by Dealers, care must be taken to avoid applying undercoating in the
area surrounding the Oxygen Sensors. Application of undercoating on or near the Oxygen Sensors
can cause insufficient air to flow around the sensor, and inaccurate information storage by the ECM.
If this condition occurs, the Malfunction Indicator Light (MIL) may illuminate.
UNDERCOATING ON OXYGEN SENSORSPage 1 of 1
OCTOBER 11, 1996 ENGINE
EG003-96
ALL MODELS
Sub Oxygen Sensor
Main Oxygen SensorCenter Pipe to Muffler
Avoid undercoating this area
Front Pipe to Manifold

Toyota Supports ASE CertificationPage 1 of 1
EG003-03Title:
SULFUR ODOR FROM EXHAUST
Models:
All Models
Technical Service
BULLETIN
February 24, 2003

Some owners of Toyota vehicles may experience a sulfur±like or ªrotten eggº odor from
the exhaust system. Sulfur is a natural component of crude oil from which gasoline is
refined and the amount of sulfur can be decreased through the refining process. The
amount of sulfur in fuel sold in California is regulated, however gasoline sold in other
states can have substantially higher sulfur content. Sulfur content also varies
considerably between gasoline brands and locations.
All Models.
A sulfur odor emitted from the vehicle's tailpipe does not necessarily indicate that there is
an issue with the engine's running condition, but is most likely directly related to the fuel.
If the vehicle is exhibiting an excessive sulfur odor, the following checks should be
performed:
If the MIL light is ON, check for DTCs and repair as necessary.
If no trouble is found after performing the above check, recommend the customer try a
different source of fuel.
Replacement of oxygen sensors, air/fuel ratio sensors or catalytic converters will not
reduce the odor and will therefore not
be considered warrantable.
OP CODEDESCRIPTIONTIMEOFPT1T2
N/ANot Applicable to Warranty±±±±
ENGINE
Introduction
Applicable
Vehicles
Repair
Procedure
Warranty
Information

O2S TEST RESULTS (MODE 05) ± SS002-03December 17, 2003
Page 3 of 43
1. On the Diagnostic Tester* screen,
select the following menus:
DIAGNOSTICS
CARB OBD II
O2S TEST RESULTS
A list of the available oxygen sensors
will be displayed.
2. Select the desired oxygen sensor and
press Enter.
NOTE:
The monitor result of the A/F sensor will
not be displayed. If you select
ªBank 1±Sensor 1º or Bank 2±Sensor 1º
for a vehicle equipped with an A/F
sensor, the Diagnostic Tester will
display ªNo parameter to display.º
3. Compare the test results with the
values listed in the Failure
Threshold Chart.
* Although this procedure references the Toyota
Diagnostic Tester, the O2S test results can be
checked using a generic OBDII scantool.
Refer to your OBDII scantool operator's manual
for specific procedures.
Accessing
O2S Test
ResultsO2S TEST RESULT Screen
01 BANK 1 ± SENSOR 1
01 BANK 1 ± SENSOR 2
01 BANK 2 ± SENSOR 1
01 BANK 2 ± SENSOR 2
TEST DATA Screen
LOW SW V 0.400 V
HIGH SW V 0.550 V
MIN O2S V 0.100 V
MAX O2S V 0.900 V
TIME $81 17