1999 TOYOTA CAMRY temperature sensors

P21242 FI7210
A00027
Atmosphere
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust GasCoverIdeal Air±Fuel Mixture
Output Voltage
Richer ± Air Fuel Ratio ± Leaner
± DIAGNOSTICSENGINE (5S±FE)
DI±61
296 Author: Date:
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control (Except California Spec.)
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way
catalytic converter is used, but for the most efficient use of the three±way catalytic converter, the air±fuel
ratio must be precisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The heated oxygen sensor has the characteristic where by its output voltage changes suddenly in the vicinity
of the stoichiometric air±fuel ratio. This is used to detect the oxygen concentration in the exhaust gas and
provide feedback to the computer for control of the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the heated
oxygen sensor informs the ECM of the LEAN condition (small electromotive force: 0 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio the oxygen concentration in the ex-
haust gas is reduced and the heated oxygen sensor informs the ECM of the RICH condition (large electromo-
tive force: 1 V).
The ECM judges by the electromotive force from the heated oxygen sensor whether the air±fuel ratio is RICH
or LEAN and controls the injection time accordingly. However, if malfunction of the heated oxygen sensor
causes output of abnormal electromotive force, the ECM is unable to perform accurate air±fuel ratio control.
The heated oxygen sensors include a heater which heats the zirconia element. The heater is controlled by
the ECM. When the intake air volume is low (the temperature of the exhaust gas is low) current flows to the
heater to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor (bank 1
sensor 1) output does not indicate RICH even once when
conditions (a), (b) and (c) continue for at least 1.5 min.:
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 ~ 100 km/h (25 ~ 62 mph)
(c) Throttle valve does not fully closed

Fuel system

Injector

Ignition system

Gas leakage on exhaust system

Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit

Heated oxygen sensor (bank 1 sensor 1)

ECM
DI00T±05

P21242 FI7210
A00027
Atmosphere
CoverIdeal Air±Fuel Mixture
Air Fuel Ratio
RicherLeaner
Exhaust GasFlange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platium Electrode
Heater
Coating(Ceramic)
Output Voltage
DI±244
± DIAGNOSTICSENGINE (1MZ±FE)
479 Author: Date:
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control (Except California Spec.)
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three±way
catalytic converter is used, but for the most efficient use of the three±way catalytic converter, the air±fuel
ratio must be precisely controlled so that it is always close to the stoichiometric air±fuel ratio.
The oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the
stoichiometric air±fuel ratio. This characteristic is used to detect the oxygen concentration in the exhaust
gas and provide feedback to the computer for control of the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: < 0.45 V).
When the air±fuel ratio is RICHER than the stoichiometric air±fuel ratio the oxygen concentration in the ex-
haust gas is reduced and the oxygen sensor informs the ECM of the RICH condition (large electromotive
force: > 0.45 V). The ECM judges by the electromotive force from the oxygen sensor whether the air±fuel
ratio is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sen-
sor causes output of abnormal electromotive force, the ECM is unable to perform accurate air±fuel ratio con-
trol.
The heated oxygen sensors include a heater which heats the zirconia element. The heater is controlled by
the ECM. When the intake air volume is low (the temperature of the exhaust gas is low) current flows to the
heater to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor (bank 1, 2
sensor 1) output does not indicate RICH ( 0.45 V ) even
once when conditions (a), (b), (c) and (d) continue for at least
2 min.:
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40
SPD and 100 km/h (25
SPD and
62 mph)
(c) Throttle valve does not fully closed
(d) 140 sec. or more after starting engine
Fuel system

Injector

Ignition system

Gas leakage on exhaust system

Open or short in heated oxygen sensors (bank 1, 2 sensor 1)
circuit

Heated oxygen sensors (bank 1, 2 sensor 1)

ECM
DI07M±08

A09421
E7
E51
9ECM
5 V
THCNG1
E2
E1 R
BR 3
4
BR Fuel Temperature
Sensor for Fuel Tank
BR IB1
IG2 LG±B
IB1IG2 LG±B LG±B 42
3 2
A09294BE6653
A09393
ON
THCNG1 E2
(±) (+)
± DIAGNOSTICSENGINE
DI±125
Fuel Temperature Sensor Circuit for Fuel Tank
CIRCUIT DESCRIPTION
A fuel temperature sensor that detects the temperature in the fuel tank is provided on the tank valve assem-
bly. A fuel pressure sensor that detects the pressure in the fuel main pipe is provided immediately upstream
of the fuel pressure regulator.
The pressure and the temperature of the fuel are detected by these sensors and are input into the ECM.
Those values are then converted by the ECM into the equipment pressure at 20°C (68°F) to actuate the
the fuel gauge.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals THCNG1 and E2 of ECM connector.
PREPARATION:
(a) Remove the glove compartment (See Pub. No. RM654U,
page SF±64).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals THCNG1 and E2 of
ECM connector.
Temperature°C (°F)Voltage V
±30 (22)0.56 ± 0.45
25 (77)3.39 ± 3.29
40 (104)4.0 ± 3.9
100 (212)4.85 ± 4.82
OK:
OK Check for intermittent problem
(See page DI±3).
DI652±01

IG0DB±01
SPARK TEST
CHECK CONNECTION OF IGNITION COIL WITH
CHECK RESISTANCE OF HIGH±TENSION CORDS
CHECK POWER SUPPLY TO IGNITION COILS WITH
1. Turn ignition switch to ON.
2. Check that there is battery positive voltage at ignition
CHECK RESISTANCE OF IGNITION COILS
Resistance:
SecondaryCold Hot
9.7 ± 16.7 kW12.4 ± 19.6 kW
CHECK RESISTANCE OF SENSORS
Resistance: Cold Hot
Camshaft position sensor
Crankshaft position sensor835 ± 1,400 W
985 ± 1,600 W1,060 ± 1,645 W
1,265 ± 1,890 W
CHECK IGT SIGNAL FROM ECM
TRY ANOTHER IGNITERIGNITER CONNECTORS
(See step 2)
Maximum resistance: 25 kW per cord
IGNITERS
coil positive (+) terminal.
(See step 4)
(See steps 5 and 6)
(See page DI±22) NO
OK
OK
OK
OK
OK
BAD
BAD
BAD
BAD
BAD
BAD
Connect securely.
Replace cord(s).
Check wiring between ignition switch to ignition
Replace ignition coil(s) with igniter(s).
Replace sensor(s).
Check wiring between ECM and igniters, and coils with igniters.
then try another ECM.
± IGNITION (5S±FE)IGNITION SYSTEM
IG±1
1683 Author: Date:
IGNITION SYSTEM
ON±VEHICLE INSPECTION
NOTICE:
ºColdº and ºHotº in these sentences express the temperature of the coils themselves. ºColdº is from
±10°C (14°F) to 50°C (122°F) and ºHotº is from 50°C (122°F) to 100°C (212°F).
1. INSPECT SPARK TEST
Check that the spark occurs.
(1) Disconnect the high±tension cord from the spark plug.
(2) Remove the spark plug.
(3) Install the spark plug to the high±tension cord.
(4) Ground the spark plug.
(5) See if spark occurs while engine is being cranked.
NOTICE:
To prevent gasoline from being injected from injectors during this test, crank the engine for no more
than 5 ± 10 seconds at time.
If the spark does not occur, do the test as follows:

IN0253
WRONG CORRECT
IN0252
WRONG CORRECT IN±6
± INTRODUCTIONREPAIR INSTRUCTIONS
6 Author: Date:
(k) Care must be taken when jacking up and supporting the
vehicle. Be sure to lift and support the vehicle at the prop-
er locations (See page IN±8).
Cancel the parking brake on the level place and
shift the transmission in Neutral (or N position).
When jacking up the front wheels of the vehicle at
first place stoppers behind the rear wheels.
When jacking up the rear wheels of the vehicle at
first place stoppers before the front wheels.
When either the front or rear wheels only should be
jacked up, set rigid racks and place stoppers in front
and behind the other wheels on the ground.
After the vehicle is jacked up, be sure to support it
on rigid racks . It is extremely dangerous to do any
work on a vehicle raised on a jack alone, even for
a small job that can be finished quickly.
(l) Observe the following precautions to avoid damage to the
following parts:
(1) Do not open the cover or case of the ECU unless
absolutely necessary. (If the IC terminals are
touched, the IC may be destroyed by static electric-
ity.)
(2) To disconnect vacuum hoses, pull off the end, not
the middle of the hose.
(3) To pull apart electrical connectors, pull on the con-
nector itself, not the wires.
(4) Be careful not to drop electrical components, such
as sensors or relays. If they are dropped on a hard
floor, they should be replaced and not reused.
(5) When steam cleaning an engine, protect the elec-
tronic components, air filter and emission±related
components from water.
(6) Never use an impact wrench to remove or install
temperature switches or temperature sensors.
(7) When checking continuity at the wire connector, in-
sert the tester probe carefully to prevent terminals
from bending.
(8) When using a vacuum gauge, never force the hose
onto a connector that is too large. Use a step±down
adapter for adjustment. Once the hose has been
stretched, it may leak air.

IN0253
WRONG CORRECT
IN0252
WRONG CORRECT IN±6
± INTRODUCTIONREPAIR INSTRUCTIONS
6 Author: Date:
(k) Care must be taken when jacking up and supporting the
vehicle. Be sure to lift and support the vehicle at the prop-
er locations (See page IN±8).
Cancel the parking brake on the level place and
shift the transmission in Neutral (or N position).
When jacking up the front wheels of the vehicle at
first place stoppers behind the rear wheels.
When jacking up the rear wheels of the vehicle at
first place stoppers before the front wheels.
When either the front or rear wheels only should be
jacked up, set rigid racks and place stoppers in front
and behind the other wheels on the ground.
After the vehicle is jacked up, be sure to support it
on rigid racks . It is extremely dangerous to do any
work on a vehicle raised on a jack alone, even for
a small job that can be finished quickly.
(l) Observe the following precautions to avoid damage to the
following parts:
(1) Do not open the cover or case of the ECU unless
absolutely necessary. (If the IC terminals are
touched, the IC may be destroyed by static electric-
ity.)
(2) To disconnect vacuum hoses, pull off the end, not
the middle of the hose.
(3) To pull apart electrical connectors, pull on the con-
nector itself, not the wires.
(4) Be careful not to drop electrical components, such
as sensors or relays. If they are dropped on a hard
floor, they should be replaced and not reused.
(5) When steam cleaning an engine, protect the elec-
tronic components, air filter and emission±related
components from water.
(6) Never use an impact wrench to remove or install
temperature switches or temperature sensors.
(7) When checking continuity at the wire connector, in-
sert the tester probe carefully to prevent terminals
from bending.
(8) When using a vacuum gauge, never force the hose
onto a connector that is too large. Use a step±down
adapter for adjustment. Once the hose has been
stretched, it may leak air.

SF08N±03
S04740
EGR Gas Temperature
Sensor Connector EGR Gas Temperature
Sensor Bracket
Air Cleaner Hose
Gasket
Throttle Body
Throttle Position
Sensor Connector
IAC Valve Connector
Water Bypass Hose
Air Assist Hose EGR Gas Temperature Sensor
Accelerator Cable
(A/T)
Throttle Cable
N´m (kgf´cm, ft´lbf): Specified torque

Non±reusable partWater Bypass Hose
19.5 (200, 14)
± SFI (1MZ±FE)EXHAUST GAS RECIRCULATION (EGR) GAS
TEMPERATURE SENSORSF±69
1568 Author: Date:
EXHAUST GAS RECIRCULATION (EGR) GAS
TEMPERATURE SENSOR
COMPONENTS

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 7 of 14
ECHO Monitor Sequence
CCV Open
Purge
ClosedOpenClosed
Purge ClosedOpen Open
Cold Start ECT/IAT
Near Same TempNegative
Pressure
(Vacuum)
OccursTank &
Canister
Leak CheckCCV
Testing Vapor
Pressure
Sensor
Signal
Monitor Operation
The monitor sequence begins with a cold
engine start. The IAT and ECT sensors
must have approximately the same
temperature reading.
The ECM is constantly monitoring fuel
tank pressure. As the temperature of the
fuel increases, pressure slowly rises.
The ECM will purge the charcoal canister
at the appropriate time (see Figure 1).
With bypass VSV closed, pressure will
continue to rise in fuel tank.
Late Type
System
Monitor
Sequence
(Continued)
Except ECHO
Figure 1. Canister Purge
ECHO
Figure 1. Canister Purge