2005 TOYOTA AVENSIS heater circuit

010B6±13
±
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±21
AVENSIS REPAIR MANUAL (RM1018E)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
There are many ECU controlled systems used in the AVENSIS. In general, ECU controlled system are con-
sidered to be very intricate and require a high level of technical knowledge an\
d expert skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, troubleshoo\
ting of these sys-
tems is not complex. If you have adequate understanding of the system and ba\
sic knowledge of electricity,
the problem can be accurately diagnosed and fixed. This manual is design\
ed based on the above principle
to help service technicians perform accurate and effective troubleshooting, and is compiled for the following
major ECU controlled systems:
The troubleshooting procedures are described on the following pages.
SystemPage
1. SFI System [1ZZ±FE, 3ZZ±FE]05±1
2. SFI System [1AZ±FE]05±143
3. SFI System [1AZ±FSE]05±290
4. ECD System [1CD±FTV]05±523
5. ABS with EBD System05±696
6. ABS with EBD & BA & TRC & VSC System05±752
7. Electronic Controlled Automatic Transmission [ECT] [U241 (1AZ±FE)]05±856
8. Electronic Controlled Automatic Transmission [ECT] [U241 (1AZ±FSE)]05±915
9. Electronic Controlled Automatic Transmission [ECT] [U341]05±980
10.Electronic Motor Power Steering System05±1042
11. Air Conditioning System05±1088
12.Combustion Type Power Heater System05±1161
13.Supplemental Restraint System05±1181
14.Audio System05±1393
15.Navigation System05±1435
16.Combination Meter05±1497
17.Power Door Lock Control System05±1534
18.Wireless Door Lock Control System05±1568
19.Key Reminder Warning System05±1586
20.Engine Immobiliser System05±1599
21.Theft Deterrent System05±1627
22.Multiplex Communication System05±1654
23.Cruise Control System05±1697
FOR USING HAND±HELD TESTER

Before using the tester, the tester's operator manual should be read thoroughly.

If the tester cannot communicate with the ECU controlled systems when you \
have connected the cable
of tester to the DLC3, turned the ignition switch ON and operated the test\
er, there is a problem on the
vehicle side or tester side.
(1) If the communication is normal when the tester is connected to another veh\
icle, inspect the diag-
nosis data link line (Bus
line) or ECU power circuit of the vehicle.
(2) If the communication is still impossible when the tester is connected to a\
nother vehicle, the prob- lem is probably in the tester itself, so perform the Self Test procedures outlined in the Tester Oper-
ator 's Manual.

0505J±04
05±16
±
DIAGNOSTICS SFI SYSTEM (1ZZ±FE/3ZZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DIAGNOSTIC TROUBLE CODE CHART
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to \
the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check in the check mode, check the circuit f\
or the codes
listed in the table below. For details of each code, refer to the ''See page '' under the respective ''DTC No.''
in the DTC chart.
DTC No.
(See page)Detection ItemTrouble Area*1
CHK ENGMemory
P0100
(05±24)Mass Air Flow Circuit Malfunc-
tion
Open or short in mass air flow meter circuit

Mass air flow meter

ECM

P0110
(05±30)Intake Air Temperature Circuit
Malfunction
Open or short in intake air temp. sensor circuit

Intake air temp. sensor (built into mass air flow meter)

ECM

P0115
(05±34)Engine Coolant Temperature Cir-
cuit Malfunction
Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM

P0116
(05±38)Engine Coolant Temperature Cir-
cuit Range/Performance Prob-
lem
Engine coolant temperature sensor

Thermostat
P0120
(05±39)Throttle Pedal Position Sensor/
Switch ºAº Circuit Malfunction
Open or short in throttle position sensor circuit

Throttle position sensor

ECM

P0121
(05±44)Throttle Pedal Position Sensor/
Switch ºAº Circuit Range/Perfor-
mance Problem

Throttle position sensor
P0125
(05±45)Insufficient Coolant Temp. for
Closed Loop Fuel Control

Open or short in heated oxygen sensor circuit

Heated oxygen sensor

Air induction system

Fuel pressure

Injector

Gas leakage on exhaust system

ECM

P0130*3
(05±54)
Oxygen Sensor Circuit Malfunc-
tion (Bank 1 Sensor 1)

Open or short in heated oxygen sensor circuit

Heated oxygen sensor

Air induction system

Fuel pressure

Injector

P0133*3
(05±60)
Oxygen Sensor Circuit Slow Re-
sponse (Bank 1 Sensor 1)

Open or short in heated oxygen sensor circuit

Heated oxygen sensor

Air induction system

Fuel pressure

Injector

ECM

P0135
(05±65)Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 1)
Open or short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

ECM

P0136
(05±54)Oxygen Sensor Circuit Malfunc-
tion (Bank 1 Sensor 2)
Open or short in heated oxygen sensor circuit

Heated oxygen sensor
P0141
(05±65)Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)
Open or short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

ECM


+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air±fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
No reaction
No reaction
No reaction No reaction

Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit) 05±68
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION PROCEDURE
HINT:
Hand±held tester only:
Narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CONTROLº
(heated oxygen sensor or other trouble areas can be distinguished).
(a) Perform ACTIVE TEST using the hand±held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is an ACTIVE TEST which changes the injection volume ±12.5 % or +25 %.
(1) Connect the hand±held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 sec.
(4) Select the item ºDIAGNOSIS / OBD/MOBD / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
Result:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
+25 %
rich output: More than 0.55 V
±12.5 %
lean output: Less than 0.4 V
NOTICE:
There is a few second delay in the sensor 1 (front sensor) output, and there is about 20 seconds delay
in the sensor 2 (rear sensor) output.

±
DIAGNOSTICS SFI SYSTEM(1ZZ±FE/3ZZ±FE)
05±65
AVENSIS REPAIR MANUAL (RM1018E)
DTCP0135OXYGEN SENSOR HEATER CIRCUIT
MALFUNCTION (BANK 1 SENSOR 1)
DTCP0141OXYGEN SENSOR HEATER CIRCUIT MALFUNCTION (BANK 1 SENSOR 2)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page 05±45.
DTC No.DTC Detecting ConditionTrouble Area
P0135

When the heater operates, heater current exceeds 3.5 A
(1 trip detection logic)

Heater current is 0.2 A or less when the heater operates
(1 trip detection logic)
Open or short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

ECM
P0141

When the heater operates, heater current exceeds 2 A
(1 trip detection logic)

Heater current is 0.2 A or less when the heater operates
(1 trip detection logic)
Open or short in heater circuit of heated oxygen sensor

Heated oxygen sensor heater

ECM
WIRING DIAGRAM
Refer to DTC P0125 on page 05±45.
INSPECTION PROCEDURE
HINT:

If different DTCs that are related to a different system are output simultaneously while terminal E2 is
used as a ground terminal, terminal E2 may be open.

Read freeze frame data using \f \b\f\f
 Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, it is useful for d\
etermining whether the vehicle
was running or stopped, the engine was warmed up or not, the air±fuel ra\
tio was lean or rich, etc. at
the time of the malfunction.
1INSPECT HEATED OXYGEN SENSOR(HEATER RESISTANCE) (See page 05±45)
NG REPLACE HEATED OXYGEN SENSOR
OK
2INSPECT EFI RELAY (See page 10±3)
NG REPLACE EFI RELAY
OK
3CHECK FUSE(EFI No.2) (See page 05±45)
NG CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED FUSE
OK
05C6A±01

+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air±fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
No reaction
No reaction
No reaction No reaction


Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
05±61
AVENSIS REPAIR MANUAL (RM1018E)
The following procedure of A/F CONTROL enable the technician to check and graph volatge output of the
heated oxygen sensor.
For displaying the graph indication, enter ºACTIVE TEST / A/F CONTROL / USER DATA,º then select ºO2S
B1S1 and O2S B1S2º by pressing ºYESº button and push ºENTERº button before pressing ºF4º button.
NOTICE:
If the vehicle is lack of fuel, the air±fuel ratio becomes LEAN and DTC P0133 will be set, and the CHK
ENG then comes on.
HINT:

If different DTCs that are related to a different system are output simultaneously while terminal E2 is
used as a ground terminal, terminal E2 may be open.

Read freeze frame data using    
 Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle
was running or stopped, the engine was warmed up or not, the air±fuel ratio was lean or rich, etc. at
the time of the malfunction.

A high heated oxygen sensor (sensor 1) voltage (0.55 V or more) could be caused by a rich air fuel
mixture. Check for conditions that would cause the engine to run rich.

A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mix-
ture. Check for conditions that would cause the engine to run lean.

+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air±fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
No reaction
No reaction
No reaction No reaction


Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit) 05±56
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
NOTICE:
There is a few second delay in the sensor 1 (front sensor) output, and there is about 20 seconds delay
in the sensor 2 (rear sensor) output.
The following procedure of A/F CONTROL enable the technician to check and graph voltage output of the
heated oxygen sensor.
For displaying the graph indication, enter ºACTIVE TEST / A/F CONTROL / USER DATA,º then select ºO2S
B1S1 and O2S B1S2º by pressing ºYESº button and push ºENTERº button before pressing ºF4º button.
NOTICE:
If the vehicle has low fuel, the air±fuel ratio becomes LEAN and heated oxygen sensor DTCs will be
recorded, and the CHK ENG lamp then comes on.
HINT:

If different DTCs that are related to a different system are output simultaneously while terminal E2 is
used as a ground terminal, terminal E2 may be open.

Read freeze frame data using    
 Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle
was running or stopped, the engine was warmed up or not, the air±fuel ratio was lean or rich, etc. at
the time of the malfunction.

A high heated oxygen sensor (sensor 1) voltage (0.55 V or more) could be caused by a rich air fuel
mixture. Check for conditions that would cause the engine to run rich.

A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mix-
ture. Check for conditions that would cause the engine to run lean.

A66651A±A SectionAir Solid Electrolyte
(Zirconia Element)
Platinum ElectrodeHeater
Exhaust Gas
CoverIdeal Air±Fuel Mixture
Output Voltage
Richer ± Air Fuel Ratio ± Leaner Element
AA
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
05±45
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0125 INSUFFICIENT COOLANT TEMP. FOR
CLOSED LOOP FUEL CONTROL
CIRCUIT DESCRIPTION
The heated oxygen sensor is the planar type. Compared to the conventional type, the sensor element and
the heater portions have a narrower overall. The heater can directly conduct its heat to the zirconia element
via the alumina, it helps to accerate the sensor activation.
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three ± way
catalytic converter is used. 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 whereby 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 the ECM with feedback control the air±fuel ratio.
When the air±fuel ratio becomes LEAN, the oxygen concentration in the exhaust gas increases. And the
heated oxygen sensor informs the ECM of the LEAN condition (low voltage, i. e. less than 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 heated oxygen sensor informs the ECM of the RICH condition (high voltage,
i. e. more than 0.45V). The ECM judges by the voltage output from the heated oxygen sensor whether the
air±fuel ratio is RICH or LEAN and controls the injection time accordingly. If the malfunction of the heated
oxygen sensor causes an output of abnomal voltage, the ECM becomes 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 in order to heat the sensor for the accurate oxygen concentration detection.
DTC NoDTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor output* does
not change when conditions (a), (b), (c) and (d) continue for at
least 1.5 min:
*: Output value changes at inside of the ECM only
(a) Engine speed: 1,400 rpm or more
(b) Vehicle speed: 40 to 100 km/h (25 to 62 mph)
(c) Throttle valve is not fully closed
(d) 180 sec. or more after starting engine
Open or short in heated oxygen sensor circuit

Heated oxygen sensor

Air induction system

Fuel pressure

Injector

Gas leakage in exhaust system

ECM
05C69±01

+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NG
+25 %
±12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air±fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
No reaction
No reaction
No reaction No reaction

Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
05±47
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION PROCEDURE
HINT:
Hand±held tester only:
Narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CONTROLº
(heated oxygen sensor or other trouble areas can be distinguished).
(a) Perform ACTIVE TEST by the hand±held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is an ACTIVE TEST which changes the injection volume ±12.5 % or +25 %.
(1) Connect the hand±held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 sec.
(4) Select the item ºDIAGNOSIS / OBD/MOBD / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
Result:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
+25 %
rich output: More than 0.55 V
±12.5 %
lean output: Less than 0.4 V
NOTICE:
There is a few second delay in the sensor 1 (front sensor) output, and there is about 20 seconds delay
in the sensor 2 (rear sensor)output.