2005 TOYOTA AVENSIS Circuit

A58684
ECM
5V
VC
VTA1
E2 Throttle Position
Sensor 05±204
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0120/41 THROTTLE/PEDAL POSITION
SENSOR/SWITCH ºAº CIRCUIT
DTC P0122/41 THROTTLE/PEDAL POSITION
SENSOR/SWITCH ºAº CIRCUIT LOW INPUT
DTC P0123/41 THROTTLE/PEDAL POSITION
SENSOR/SWITCH ºAº CIRCUIT HIGH INPUT
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle.
When the throttle valve is fully closed, a voltage of approximate-
ly 0.7 V is applied to terminal VTA1 of the ECM. The voltage ap-
plied to terminal VTA1 of the ECM increases in proportion to the
opening angle of the throttle valve and becomes approximately
3.5 to 5.0 V when the throttle valve is fully opened. The ECM
judges the vehicle driving conditions from these signals input
from terminal VTA1, uses them as one of the conditions for de-
ciding the air±fuel ratio correction, power increase correction
and fuel±cut control etc.
DTC No.DTC Detection Condition
Condition (a) of DTC P0120/41, P0122/41 or P0123/41 continues for 2 sec.
(Open or short in throttle position sensor circuit)Trouble Area
P0120/41
Detection conditions for DTCs P0122 and P0123 are not satis-
fied but condition (a) is satisfied
(a) VTA1 less than 0.1 V, or VTA1 greater than 4.9 V
Throttle position sensor (built in throttle body)

ECM
P0122/41(a) VTA1 less than 0.1 V

Throttle position sensor (built in throttle body)

Short in VTA1 circuit

Open in VC circuit

ECM
P0123/41(a) VTA1 greater than 4.9 V

Throttle position sensor (built in throttle body)

Open in VTA1 circuit

Open in E2 circuit

VC and VTA1 circuit are short±circuited

ECM
NOTICE:
When a malfunction is detected, the throttle valve is locked at a certain opening angle. Also, the
whole electronically controlled throttle operation is cancelled until the system returns to normal and
the ignition switch is turned OFF.
HINT:

After confirming DTCs, use the hand±held tester to confirm the throttle valve opening percentage and
closed throttle position switch condition.
05C6W±01

A12544
VCECM
VTA1
E2 L±W R±W
BR T2
Throttle Position Sensor
1
3
218
E13
21
E13
28
E13 VC
E2 VTA5V
E1
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
05±205
AVENSIS REPAIR MANUAL (RM1018E)Throttle valve opening position expressed as percentage
Trouble AreaThrottle valve fully closedThrottle valve fully openTrouble Area
0 %0 %VC circuit open
VTA circuit open or short
Approx. 100 %Approx. 100 %E2 circuit open
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

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.

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.

A72925
ECM
THW
E2 19
E13
28
E13 BR B±W
1 25V
R E2
Engine Coolant Temperature Sensor
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
05±199
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0115/22 ENGINE COOLANT TEMPERATURE CIRCUIT
DTC P0117/22 ENGINE COOLANT TEMPERATURE CIRCUIT
LOW INPUT
DTC P0118/22 ENGINE COOLANT TEMPERATURE CIRCUIT
HIGH INPUT
CIRCUIT DESCRIPTION
A thermistor is built in the engine coolant temperature sensor and changes the resistance value according
to the engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as those of the intake air temperature
sensor.
HINT:
If the ECM detects the DTC ºP0115/22, P0117/22 or P0118/22º it enters the fail±safe mode in which the en-
gine coolant temperature is assumed to be 80 C (176 F).
DTC No.Proceed toDTC Detection ConditionTrouble Area
P0115/22Step 1
Open or short in engine cool-
ant temp. sensor circuit for
0.5 sec.

Open or short in engine coolant temperature sensor circuit
P0117/22Step 4Short in engine coolant temp.
sensor circuit for 0.5 sec.

Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM
P0118/22Step 2Open in engine coolant temp.
sensor circuit for 0.5 sec.
HINT:
After confirming DTC ºP0115/22, P0117/22 or P0118/22º, use the hand±held tester to confirm the engine
coolant temperature in the ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALLº.
Temperature DisplayedMalfunction
±40 C (±40 F)Open circuit
140  (284   Short circuit
WIRING DIAGRAM
05C6V±01

05±200
±
DIAGNOSTICS SFI SYSTEM(1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
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
\b\b
\b 
\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.
When using hand±held tester:
1READ VALUE OF HAND±HELD TESTER(ENGINE COOLANT TEMPERATURE)
(a)Connect the hand±held tester to the DLC3.
(b)Turn the ignition switch ON and push the hand±held tester main switch \
ON.
(c)Select the item ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALL / COOLANT TEMPº and read its value displayed on the hand±held tester.
Temperature: Same value as the actual intake air temperature.
Result:
Temperature DisplayedProceed to
±40C (±40 )A
140 C (284 ) or moreB
OK (Same as present temperature)C
HINT:

If there is an open circuit, the hand±held tester indicates ±40 C (±40 F).

If there is a short circuit, the hand±held tester indicates 140 C (284 F) or more.
BGo to step 4
CCHECK FOR INTERMITTENT PROBLEMS (See page 05±149)
A

± 20 0 20 40 60 80 100
(± 4) 32 68 104 140 176 212 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
A67628
Acceptable (Fig.1)
Resistance K

Temp. C (F)
05±194
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0110/24 INTAKE AIR TEMPERATURE CIRCUIT
MALFUNCTION
DTC P0112/24 INTAKE AIR TEMPERATURE CIRCUIT LOW
INPUT
DTC P0113/24 INTAKE AIR TEMPERATURE CIRCUIT HIGH
INPUT
CIRCUIT DESCRIPTION
The intake air temperature sensor is built in the mass air flow
meter and senses the intake air temperature.
A thermistor built in the sensor changes the resistance value
according to the intake air temperature.
The lower the intake air temperature is the greater the thermis-
tor resistance value becomes and the higher the intake air tem-
perature is the lower the thermistor resistance value becomes
(See Fig. 1).
The intake air temperature sensor is connected to the ECM
(See below ). The 5 V power source voltage in the ECM is ap-
plied to the intake air temperature sensor from terminal THA
(THAR) via resistor R.
That is, the resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in the
intake air temperature, the potential at terminal THA (THAR)
also changes. Based on this signal, the ECM increases the fuel
injection volume to improve the driveability during cold engine
operation.
DTC No.Proceed toDTC Detection ConditionTrouble Area
P0110/24Step 1
Open or short in intake air
temp. sensor circuit for 0.5
sec.

Open or short in intake air temperature sensor circuit
P0112/24Step 4Short in intake air temp. sen-
sor circuit for 0.5 sec.

Oen or short in intake air tem erature sensor circuit

Intake air temperature sensor (built in mass air flow meter)

ECM
P0113/24Step 2Open in intake air temp. sen-
sor circuit for 0.5 sec.
After confirming DTC ºP0110/24, P0112/24 or P0113/24º, use the hand±held tester to confirm the intake air
temperature from the ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALLº.
Temperature DisplayedMalfunction
±40C (±40Open circuit
140C (284  Short circuit
05C7G±01

A72925
BR
G±R
28
20
E13 THA
E2 ECM
5 4
A6
Intake Air Temperature Sensor
(Built in Mass Air Flow Meter)
E135V
R
THA
E2
±
DIAGNOSTICS SFI SYSTEM(1AZ±FE)
05±195
AVENSIS REPAIR MANUAL (RM1018E)
WIRING DIAGRAM
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
\b\b
\b 
\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.
When using hand±held tester:
1READ VALUE OF HAND±HELD TESTER(INTAKE AIR TEMPERATURE)
(a)Connect the hand±held tester to the DLC3.
(b)Turn the ignition switch ON and push the hand±held tester main switch \
ON.
(c)Select the item ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALL / INTAKE AIRº and read its value dis- played on the hand±held tester.
Temperature: Same value as the actual intake air temperature.
Result:
Temperature DisplayedProceed to
±40C (±40 )A
140 C (284 ) or moreB
OK (Same as present temperature)C
HINT:

If there is an open circuit, the hand±held tester indicates ±40 C (±40 F).

If there is a short circuit, the hand±held tester indicates 140 C (284 F) or more.
BGo to step 4
CCHECK FOR INTERMITTENT PROBLEMS (See page 05±149)
A

 


AB B+
Power Transistor
Platinum Hot Wire
(Heater)
Output
Voltage
Temperature
sensor
Platinum Hot Wire (Heater)
Temperature sensor
A53295
05±186
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0100/31 MASS OR VOLUME AIR FLOW CIRCUIT
DTC P0102/31 MASS OR VOLUME AIR FLOW CIRCUIT
LOW INPUT
DTC P0103/31 MASS OR VOLUME AIR FLOW CIRCUIT
HIGH INPUT
CIRCUIT DESCRIPTION
The mass air flow meter uses a platinum hot wire. The hot wire mass air flow meter consists of a platinum
hot wire, a temperature sensor and a control circuit installed in a plastic housing. The hot wire mass air flow
meter works on the principle that the hot wire and temperature sensor located in the intake air bypass of the
housing detect any changes in the intake air temperature.
The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This
current flow is then measured as the output voltage of the mass air flow meter.
The circuit is constructed so that the platinum hot wire and temperature sensor provide a bridge circuit, with
the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.
DTC No.DTC Detection ConditionTrouble Area
P0100/31Open or short in mass air flow meter circuit with engine speed
4,000 rpm or less for more than 3 sec.
Ohti ifltiit
P0102/31Open in mass air flow meter circuit with engine speed 4,000
rpm or less for more than 3 sec.
Open or short in mass air flow meter circuit

Mass air flow meter


ECM
P0103/31Short in mass air flow meter circuit with engine speed 4,000
rpm or less for more than 3 sec. (+B circuit)
ECM
HINT:
After confirming DTC ºP0100/31, P0102/31 or P0103/31º, use the hand±held tester to confirm the mass air
flow ratio in the ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALLº.
Air Flow Value (gm/s)Malfunction
Approx. 0.0
Mass air flow meter power source circuit open

VG circuit open or short
271.0 or more
E2G circuit open
05C6U±01

A66053
Engine Room R/B No.4EFI Relay



A79066
Engine Room R/B No.4EFI No.1 Fuse
1
2
A54396Mass Air Flow Meter Connector
Wire Harness Side
+B
A6
A18294
EVG
ECM Connector E12
05±190
±
DIAGNOSTICS SFI SYSTEM(1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
5CHECK HARNESS AND CONNECTOR(MASS AIR FLOW METER ± EFI RELAY)
(a)Remove the EFI relay from the engine room R/B No.4.
(b)Remove the EFI No.1 fuse from the engine room R/B No.4.
(c)Disconnect the mass air flow meter connector.
(d)Check for continuity between the wire harness side con- nectors.
Standard (Check for open):
Symbols (Terminal No.)Specified condition
EFI relay (3) ± EFI No.1 fuse (1)ContinuityEFI No.1 fuse (2) ± +B (A6±1)Continuity
Standard (Check for short):
Symbols (Terminal No.)Specified condition
EFI relay (3) or EFI No.1 fuse (1) ± Body groundNocontinuityEFI No.1 fuse (2) or +B (A6±1) ± Body groundNo continuity
NOTICE:
Do not insert the tester leads hard in the procedure (c), the
holder may be damaged.
NGREPAIR OR REPLACE HARNESS OR CONNECTOR
OK
CHECK FOR ECM POWER SOURCE CIRCUIT (See page 05±257)
6 INSPECT ECM(SENSOR GROUND)
(a) Check for continuity between the terminal of the E12 ECM connector and the body ground.
Standard:
Symbols (Terminal No.)Specified condition
EVG (E12±32) ± Body groundContinuity
NG CHECK AND REPLACE ECM (See page 01±32)
OK