control arm TOYOTA CAMRY 1999 Service User Guide

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

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

± DIAGNOSTICSENGINE (5S±FE)
DI±71
306 Author: Date:
DTC P0133 Heated Oxygen Sensor Circuit Slow Re-
sponse (Bank 1 Sensor 1) (Ex. CA 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
P0133
Response time for heated oxygen sensor's voltage output to
change from rich to lean, or from lean to rich, is 1 sec. or more
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.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scantool. 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 P0133) being output?
YES Go to relevant DTC chart.
NO
DI4NF±01

± DIAGNOSTICSENGINE (5S±FE)
DI±75
310 Author: Date:
DTC P0135 Heated Oxygen Sensor Heater Circuit Mal-
function (Bank 1 Sensor 1) (Ex. CA Spec.)
DTC P0141 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)
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
P0135
P0141When heater operates, heater current exceeds 2 A
(2 trip detection logic)
Open or short in heater circuit of heated oxygen sensor
Htd htP0135
P0141Heater current of 0.2 A or less when heater operates
(2 trip detection logic)
Heated oxygen sensor heater

ECM
HINT:

Sensor 1 refers to the sensor closer to the engine body.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.)) on
page DI±55.
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.
DI00X±04

± DIAGNOSTICSENGINE (5S±FE)
DI±77
312 Author: Date:
DTC P0136 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 2)
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
P0136
Voltage output of heated oxygen sensor remains at
0.45*
1/0.40*2 V or more, or 0.60*1/0.50*2 V or less when ve-
hicle is driven at 40 km/h (25 mph) or more after engine is
warmed up
*
1: for California Spec.
*
2: except California Spec.
(2 trip detection logic).

Heated oxygen sensor
HINT:
Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.)) on
page DI±55.
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 P0136) being output?
YES Go to relevant DTC chart.
NO
DI00Y±08

± DIAGNOSTICSENGINE (5S±FE)
DI±79
314 Author: Date:
DTC P0171 System too Lean (Fuel Trim)
(Only for California Spec.)
DTC P0172 System too Rich (Fuel Trim)
(Only for California Spec.)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared against the basic injection time. Fuel trim
includes short±term fuel trim and long±term fuel trim.
Short±term fuel trim is the short±term fuel compensation used to maintain the air±fuel ratio at its ideal
theoretical value.
The signal from the A/F sensor is approximately proportional to the existing air±fuel ratio, and ECM compar-
ing it with the ideal theoretical value, the ECM reduces fuel volume immediately if the air±fuel ratio is rich
and increases fuel volume if it is lean.
Long±term fuel trim compensates the deviation from the central value of the short±term fuel trim stored up
by each engine tolerance, and the deviation from the central value due to the passage of time and changes
of using environment.
If both the short±term fuel trim and long±term fuel trim exceed a certain value, it is detected as a malfunction
and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When air±fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on rich side
(2 trip detection logic)

Gas leakage on exhaust system

Air intake (loose hoses)

Fuel line pressure

Injector blockage

Manifold absolute pressure sensor

Engine coolant temp. sensor

A/F sensor
P0172
When air±fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on lean side
(2 trip detection logic)

Gas leakage on exhaust system

Fuel line pressure

Injector leak, blockage

Manifold absolute pressure sensor

Engine coolant temp. sensor

A/F sensor
HINT:

When the DTC P0171 is recorded, the actual air±fuel ratio is on the lean side. When DTC P0172 is
recorded, the actual air±fuel ratio is on the rich side.

If the vehicle runs out of fuel, the air±fuel ratio is lean and DTC P0171 is recorded. The MIL then comes
on.

If the total of the short±term fuel trim value and long±term fuel trim value is within + 38 %, the system
is functioning normally.

The A/F sensor output voltage and the short±term fuel trim value can be read using the OBD II scan
tool or TOYOTA hand±held tester.

The ECM controls the voltage of AF
and AF terminals of ECM to the fixed voltage. Therefore, it
is impossible to confirm the A/F sensor output voltage without OBD II scan tool or TOYOTA hand±held
tester.
DI1JW±03

P25430
ECM
Throttle Body
EGR
Vacuum
Modulator EGR Valve
VSV
Exhaust Gas Throttle
Valve
u
± DIAGNOSTICSENGINE (5S±FE)
DI±105
340 Author: Date:
DTC P0401 Exhaust Gas Recirculation Flow Insufficient
Detected
CIRCUIT DESCRIPTION
The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the driving condi-
tions, into the intake air mixture to slow down combustion, reduce the combustion temperature and reduce
NOx emissions. The amount of EGR is regulated by the EGR vacuum modulator according to the engine
load.
If even one of the following conditions is fulfilled, the VSV is
turned ON by a signal from the ECM.
This results in atmospheric air acting on the EGR valve, closing
the EGR valve and shutting off the exhaust gas (EGR cut±off).
Under the following conditions, EGR is cut to maintain driveabil-
ity.

Before engine is warmed up.

During deceleration (throttle valve closed).

Light engine load (amount of intake air very small).

Engine idling.

Engine speed over 4,400 rpm.

High engine load (amount of intake air very large).
DTC No.DTC Detecting ConditionTrouble Area
P0401
After engine is warmed up, intake manifold absolute pressure
is larger than value calculated by ECM while EGR system is
ON
(2 trip detection logic)

EGR valve stuck closed

Open or short in VSV circuit for EGR

Vacuum or EGR hose disconnected

Manifold absolute pressure sensor

VSV for EGR open or close malfunction

ECM
DI015±05

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.

DI±130
± DIAGNOSTICSENGINE (5S±FE)
365 Author: Date:
DTC No.DTC Detecting ConditionTrouble Area
P0441
Pressure in the charcoal canister does not drop during purge
control
(2 trip detection logic)
P0441During purge cut±off, pressure in charcoal canister is very low
compared with atmospheric pressure
(2 trip detection logic)

Open or short in VSV circuit for vapor pressure sensor

VSV for vapor pressure sensor
When VSV for vapor pressure sensor is OFF, ECM judges that
there is no continuity between vapor pressure sensor and
charcoal canister
(2 trip detection logic)
Open or short in vapor pressure sensor circuit

Vapor pressure sensor

Open or short in VSV circuit for EVAP

VSV for EVAP

Vacuum hose cracks hole blocked damaged or
P0446
When VSV for vapor pressure sensor is ON, ECM judges that
there is no continuity between vapor pressure sensor and fuel
tank
(2 trip detection logic)
Vacuum hose cracks, hole, blocked, damaged or
disconnected ((1), (4), (5) holed (6) and (7) in fig. 1)

Charcoal canister cracked, holed or damaged

Fuel tank over fill check valve cracked or damaged
After purge cut off operates, pressure in charcoal canister is
maintained at atmospheric pressure
(2 trip detection logic)
WIRING DIAGRAM
Refer to DTC P0440 (Evaporative Emission Control System Malfunction) on page DI±122.
INSPECTION PROCEDURE
TOYOTA hand±held tester:
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.

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.

± DIAGNOSTICSENGINE (5S±FE)
DI±143
378 Author: Date:
DTC No.DTC Detecting ConditionTrouble Area
P0450
10 seconds or more after engine starting codition (a) or (b)
continues for 7 seconds or more:
(2 trip detection logic)
(a) vapor pressure sensor value < ±4 kpa (±30 mmHg,
±1.0 in.Hg)
(b) Vapor pressure sensor value
2.1 kpa (±15 mmHg,
0.4 in.Hg)

Open or short in vapor pressure sensor circuit

Vapor pressure sensor

ECM
F l t k fill h k l k d d d
P0451
Vapor pressure sensor output extremely changes under condi-
tions of (a), (b) and (c):
(2 trip detection logic)
(a) Vehicle speed: 0 km/h (0 mph)
(b) Engine speed: idling
(c) VSV for vapor pressure sensor is ON
Fuel tank over fill check valve cracked or damaged.
WIRING DIAGRAM
Refer to DTC P0440 (Evaporative Emission Control System Malfunction) on page DI±122.
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.

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.
1 Check voltage between terminals VC and E2 of ECM connector
(See page DI±122, step 9).
NG Check and replace ECM (See page IN±31).
OK