2000 TOYOTA CAMRY engine

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

A03596
B±Y
Engine Room R/B No.2
Battery
IG Switch17
EFI
W±R7 7 2
5 EFI
Relay
5 3
24
W±BP±B
BR14 2314 2
3
9
II3
B±Y
B±Y
W±R B
W B±Y
B
BR6
128
25 1 2K
21 1KE8
E9
AM2
E8
E9ECM
OX1
OX2 HT1
HT2 1K 2JB±Y
J/C
1B
2F5 B±R
1W
Heated
Oxygen
Sensor
(Bank 1
Sensor 1)
II2
II3Heated
Oxygen
Sensor
(Bank 1
Sensor 2)E03
B J19 J/C
BBB
3
MAIN 2A 2L 4
F4 F6FL
Block
B±GP±B
J27 J27
1
EB
EC
6
IGN
E03 L±YE1
E1 Instrument
Panel J/B
11
B±R
*1: w/o Immobiliser
*2: w/ Immobiliser
(*2) (*1)
E9 14E8 E9 E85
1
13
(*2) (*1)(*1) (*2)(*1) (*2) (*3)
EB±Y
(*3) (*3)
(*1)FL
*3: Except California BII3
E
B±YJ27 J27
MREL
E10 B±W
II4
6
B±W(*2)
(*3)
7(*2)(*2)
BR BR
DI±62
± DIAGNOSTICSENGINE (5S±FE)
297 Author: Date:
HINT:
After confirming DTC P0125, use the OBD II scan tool or TOYOTA hand-held tester to confirm voltage output
of the heated oxygen sensor (bank 1 sensor 1) from the CURRENT DATA.
If voltage output of the heated oxygen sensor (bank 1 sensor 1) is 0 V, heated oxygen sensor (bank 1 sensor
1) circuit may be open or short.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If the vehicle run out fuel, the air±fuel ratio is LEAN and DTC P0125 will be recorded.
The MIL then comes on.

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.

± DIAGNOSTICSENGINE (5S±FE)
DI±63
298 Author: Date:
1 Are there any other codes (besides DTC P0125) being output?
YES Go to relevant DTC chart.
NO
2 Connect OBD II scan tool or TOYOTA hand±held tester, and read value for volt-
age output of heated oxygen sensor (bank 1 sensor 1).
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up the engine to normal operating temp. (above 75°C (169°F)).
CHECK:
Read voltage output of the heated oxygen sensor (bank 1 sensor 1) when the engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using the accelerator pedal.
OK:
Heated oxygen sensor (bank 1 sensor 1) output a RICH signal (0.45 V or more) at least once.
OK Go to step 10.
NG
3 Check for open and short in harness and connector between ECM and heated
oxygen sensor (bank 1 sensor 1) (See page IN±31).
NG Repair or replace harness or connector.
OK

DI±64
± DIAGNOSTICSENGINE (5S±FE)
299 Author: Date:
4 Check whether misfire is occurred or not by monitoring DTC and data list.
NG Perform troubleshooting for misfire
(See page DI±163).
OK
5 Check air induction system (See page SF±1).
NG Repair or replace.
OK
6 Check EGR system (See page EC±12).
NG Repair EGR system.
OK
7 Check fuel pressure (See page SF±6).
NG Check and repair fuel pump, fuel pipe line and
filter (See page SF±1).
OK
8 Check injector injection (See page SF±23)
NG Replace injector.
OK

± DIAGNOSTICSENGINE (5S±FE)
DI±65
300 Author: Date:
9 Check gas leakage on exhaust system.
NG Repair or replace.
OK
Replace oxygen sensor
(bank 1 sensor 1).
10 Perform confirmation driving pattern (See page DI±152).
Go
11 Is there DTC P0125 being output again?
YES Check and replace ECM.
NO
12 Did vehicle runs out of fuel in the past?
NO Check for intermittent problems.
YES
DTC P0125 is caused by running out of fuel.

DI±66
± DIAGNOSTICSENGINE (5S±FE)
301 Author: Date:
DTC P0130 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 1) (Except California Spec.)
CIRCUIT DESCRIPTION
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.)) on
page DI±55.
DTC No.DTC Detecting ConditionTrouble Area
P0130
Voltage output of heated oxygen sensor remains at 0.4 V or
more, or 0.55 V or less, during idling after engine is warmed up
(2 trip detection logic)
Heated oxygen sensor

Fuel trim malfunction
HINT:
Sensor 1 refers to the sensor closer to the engine body.
The heated oxygen sensor's output voltage and the short-term fuel trim value can be read using the OBD
II scan tool or TOYOTA hand-held tester.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.)) on
page DI±55.
DI00V±05

A01666
Vehicle speed
50 ~ 65 km/h
(31 ~ 40 mph)
Idling
IG SW OFF
(1)
1 ~ 3 min.1 min.Time
(2)(3)(4)
(5)
± DIAGNOSTICSENGINE (5S±FE)
DI±67
302 Author: Date:
CONFIRMATION DRIVING PATTERN
(1) Connect the TOYOTA hand±held tester to the DLC3.
(2) Switch the TOYOTA hand±held tester from normal mode to check mode (See page DI±3).
(3) Start the engine and warm it up with all accessory switches OFF.
(4) Drive the vehicle at 50 ~ 65 km/h (31 ~ 40 mph) for 1 ~ 3 min. to warm up the heated oxygen sensor.
(5) Let the engine idle for 1 min.
(6) Perform steps (3) to (5) three times.
HINT:
If a malfunction exists, the MIL will light up during step (6).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a TOYOTA hand±held tester, turn the ignition switch OFF after performing steps
(3) to (6), then perform steps (3) to (6) again.
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 P0130) being output?
YES Go to relevant DTC chart.
NO

P18349
DI±68
± DIAGNOSTICSENGINE (5S±FE)
303 Author: Date:
2 Check the output voltage of heated oxygen sensor during idling.
PREPARATION:
Warm up the heated oxygen sensor the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Use the OBD II scan tool or TOYOTA hand±held tester to read the output voltage of the heated oxygen sen-
sor during idling.
OK:
Heated oxygen sensor output voltage:
Alternates repeatedly between less than 0.4 V and more than 0.55 V (See the following table).
OK Go to step 8.
NG
3 Check for open and short in harness and connector between ECM and oxygen
sensor (See page IN±31).
NG Repair or replace harness or connector.
OK