2005 TOYOTA AVENSIS diagnostic

A80089
AB B+
Power Transistor
Platinum Hot Wire
(Heater)
Output
Voltage
Temperature
sensor
Platinum Hot Wire (Heater)
Temperature sensor
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
05−55
AVENSIS Supplement (RM1045E)
DTC P0100 MASS OR VOLUME AIR FLOW CIRCUIT
DTC P0102 MASS OR VOLUME AIR FLOW CIRCUIT
LOW INPUT
DTC P0103 MASS OR VOLUME AIR FLOW CIRCUIT
HIGH INPUT
CIRCUIT DESCRIPTION
The MAF (Mass Air Flow) meter measures the amount of air flowing through the throttle valve. The ECM uses
this information to determine the fuel injection time and provide a proper air−fuel ratio. Inside the MAF meter,
there is a heated platinum wire exposed to the flow of intake air.
By applying a specific current to the wire, the ECM heats this wire to a given temperature. The flow of incom-
ing air cools the wire and an internal thermistor, changing their resistance. To maintain a constant current
value, the ECM varies the voltage applied to these components in the MAF meter. The voltage level is pro-
portional to the airflow through the sensor and the ECM interprets this voltage as the intake air amount.
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
P0100Open or short in mass air flow meter circuit for more than 3
seconds at engine speed of 4,000 rpm or lessSOpen or short in mass air flow meter circuit
SMass air flow meter
SECM
P0102Open or short in mass air flow meter circuit for more than 3
seconds at engine speed of 4,000 rpm or less
SOpen in mass air flow meter circuit
SShort in ground circuit
SMass air flow meter
SECM
P0103
Open in mass air flow meter circuit for more than 3 seconds
(EVG circuit) at engine speed of 4,000 rpm or less
Short in mass air flow meter circuit for more than 3 seconds
(+B circuit) at engine speed of 4,000 rpm or lessSOpen in mass air flow meter circuit (EVG circuit)
SShort in mass air flow meter circuit (+B circuit)
SMass air flow meter
SECM
05CJE−02

A76863
B−Y
Battery FL MAINEngine Room R/B No. 4
L−Y EFI Relay
A6
Mass Air Flow MeterMREL
B−G 4B 1
W−BB−W 53
2
1
29
E13 8
E9ECM
EFI No. 2
EC 4A 1
Engine Room
J/B No. 4 1A 1
B−G 1 2
EFI 1
Engine Room
R/B No.1and
Engine Room
J/B No.14
4
44
4
4
2
1 W−B
B−W
B−WGR
GRIE1 2
EVG 30
E13VG
G 1
3
2 EA1 13 05−56
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
HINT:
After confirming DTC P0100, P0102 or P0103, use the hand−held tester to confirm the air flow rate from the
DIAGNOSIS / OBD/MOBD / DATA LIST / ALL.
Air flow rate (gm/s)Malfunction
Approximately 0.0SMass air flow meter power source circuit open
SVG circuit open or short
271.0 or moreSEVG circuit open
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Read freeze frame data usingthe hand−held tester. Freeze frame data records the engine conditions when
a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was
running or stopped, if the engine was warmed up or not, if the air−fuel ratio was lean or rich, and other data
from the time the malfunction occurred.

A54396
+B (+)
Wire Harness Side:
A6
Front View
Mass Air Flow Meter Connector
−
DIAGNOSTICS SFI SYSTEM (2AZ−FSE)
05 −57
AVENSIS Supplement (RM 1045E)
1 READ VALUE OF HAND −HELD TESTER(MASS AIR FLOW RATE)
(a) Connect the hand −held tester to the DLC3.
(b) Start the engine.
(c) Turn the hand −held tester ON.
(d) On the hand −held tester, selsct the item: DIAGNOSIS / OBD/MOBD / DATA LIST / ALL / MAF.
(e) Read the values. Result:
Air flow rate (gm/s)Proceed to
0.0A
271.0 or moreB
Between 1.0 and 270.0 (* 1)C
*1 : The value must be changed when the throttle valve is opened or closed.
B Go to step 6
C CHECK FOR INTERMITTENT PROBLEMS(See page 05 −7)
A
2 INSPECT MASS AIR FLOW METER(POWER SOURCE)
(a) Disconnect the A6 mass air flow meter connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage between the terminal of the wire har- ness side connector and body ground.
Standard:
Tester ConnectionSpecified Condition
+B (A6 −1)− Body ground9to 14V
(d) Reconnect the mass air flow meter connector.
NG Go to step 5
OK

A76903
VG (+)
EVG (−)
E13ECM Connector
A54396
VG Wire Harness Side:E2G A6
Front View Mass Air Flow Meter Connector
A81699
VGE13ECM Connector
EVG
05−58
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
3 INSPECT ECM(VG VOLTAGE)
(a) Start the engine.
(b) Measure the voltage between the specified terminals of
the E13 ECM connector.
Standard:
Tester ConnectionConditionSpecified Condition
VG (E13−30)−
EVG (E13−29)Engine is idling0.5 to 3.0 V
HINT:
The shift position should be P or N and the A/C switch should
be turned OFF.
OK REPLACE ECM (See page10−65 of Pub. No.
RM1018E AVENSIS)
NG
4 CHECK HARNESS AND CONNECTOR(ECM−MASS AIR FLOW METER)
(a) Disconnect the A6 mass air flow meter connector.
(b) Disconnect the E13 ECM connector.
(c) Check the resistance between the wire harness side con-
nectors.
Standard (Check for open):
Tester ConnectionSpecified Condition
VG (A6−3)−VG (E13−30)Below1

E2G (A6−2)−EVG (E13−29)Below1

Standard (Check for short):
Tester ConnectionSpecified Condition
VG (A6−3) or VG (E13−30)−Body ground10k
or higher
(d) Reconnect the mass air flow meter connector.
(e) Reconnect the ECM connector.
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE MASS AIR FLOW METER

A54396
Wire Harness Side:+B (+)
A6
Front View
Mass Air Flow Meter Connector
A66053
Engine Room R/B No. 4:
EFI Relay
A76903
EVG
E13ECM Connector
−
DIAGNOSTICS SFI SYSTEM (2AZ−FSE)
05 −59
AVENSIS Supplement (RM 1045E)
5 CHECK HARNESS AND CONNECTOR(MASS AIR FLOW METER − EFI RELAY)
(a) Inspect the EFI No. 2 fuse.
(1 ) Remove the EFI No. 2 fuse from the engine room
R/B No. 4.
(2) Check for continuity in the EFI No. 2 fuse.
Standard: Continuity
(3) Reinstall EFI No. 2 fuse.
(b) Remove the EFI relay from the engine room R/B No. 4.
(c) Disconnect the A6 mass air flow meter connector.
(d) Measure the resistance between the wire harness side connectors.
Standard (Check for open):
Tester ConnectionSpecified Condition
+B (A6 −1 )− Engine room R/B No. 4 (EFI relay terminal 3)Below 1

Standard (Check for short):
Tester ConnectionSpecified Condition
+B (A6 −1 ) or Engine room R/B No. 4 (EFI relay terminal 3) −
Body ground1 0k
or higher
(e) Reconnect the mass air flow meter connector.
(f) Reinstall the EFI relay.
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
CHECK FOR ECM POWER SOURCE CIRCUIT (See Page 05 −236)
6 INSPECT ECM(SENSOR GROUND)
(a) Measure the resistance between the terminal of the E 13
ECM connector and body ground.
Standard:
Tester ConnectionSpecified Condition
EVG (E 13 − 29) −Body groundBelow 1

NG REPLACE ECM (See page 10 − 65 of Pub. No.
RM 1018E AVENSIS)
OK

A54396
VG Wire Harness Side:E2G A6
Front View Mass Air Flow Meter Connector
A81699
VGE13ECM Connector
EVG
05−60
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
7 CHECK HARNESS AND CONNECTOR(ECM−MASS AIR FLOW METER)
(a) Disconnect the A6 mass air flow meter connector.
(b) Disconnect the E13 ECM connector.
(c) Check the resistance between the wire harness side con-
nectors.
Standard (Check for open):
Tester ConnectionSpecified Condition
VG (A6−3)−VG (E13−30)Below1

E2G (A6−2)−EVG (E13−29)Below1

Standard (Check for short):
Tester ConnectionSpecified Condition
VG (A6−3) or VG (E13−30)−Body ground10k
or higher
(d) Reconnect the mass air flow meter connector.
(e) Reconnect the ECM connector.
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
REPLACE MASS AIR FLOW METER

− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
05−49
AVENSIS Supplement (RM1045E)
DTC P0031OXYGEN SENSOR HEATER CONTROL
CIRCUIT LOW (BANK1SENSOR1)
DTC P0032 OXYGEN SENSOR HEATER CONTROL
CIRCUIT HIGH (BANK1SENSOR1)
DTC P0037 OXYGEN SENSOR HEATER CONTROL
CIRCUIT LOW (BANK1SENSOR 2)
DTC P0038 OXYGEN SENSOR HEATER CONTROL
CIRCUIT HIGH (BANK1SENSOR 2)
DTC P0051OXYGEN SENSOR HEATER CONTROL
CIRCUIT LOW (BANK 2 SENSOR1)
DTC P0052 OXYGEN SENSOR HEATER CONTROL
CIRCUIT HIGH (BANK 2 SENSOR1)
DTC P0057 OXYGEN SENSOR HEATER CONTROL
CIRCUIT LOW (BANK 2 SENSOR 2)
DTC P0058 OXYGEN SENSOR HEATER CONTROL
CIRCUIT HIGH (BANK 2 SENSOR 2)
HINT:
SBank1refers to the No.1and No. 4 cylinders.
SBank 2 refers to the No. 2 and No. 3 cylinders.
SSensor1refers to the sensor closest to the engine assembly.
SSensor 2 refers to the sensor farthest away from the engine assembly.
05HI5−01

A72920
Reference (Bank1 Sensor 1 System Drawing)
Heated Oxygen Sensor
EFI Relay
Heater
SensorOX1A
HT
1A
Duty
Control
ECM
From
Battery EFI Fuse
E2
EFI No. 2
Fuse
MREL
OX HT
E 1
+B
05
−50
−
DIAGNOSTICS SFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM 1045E)
CIRCUIT DESCRIPTION
Refer to DTC P0 130 on page 05 −82.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated
oxygen sensor heater circuit uses a relay on the B+ side of the circuit.
DTC No.DTC Detection ConditionTrouble Area
P003 1
P0037
P005 1
P0057( 1 ) Heated current is 0.2 A or less when heater operates with
+B voltage between 10.5 V and 11 .5 V ( 1 trip detection logic)
(2) Heated current is 0.25 A or less when heater operates with
+B greater than 11 .5 V ( 1 trip detection logic)S Open in heater circuit of heated oxygen sensor
S Heated oxygen sensor heater
S EFI relay
S EFI No. 2 fuse
S ECM
P0032
P0038
P0052
P0058
When heater operates, heater current exceeds 2 A
(1 trip detection logic)
S Short in heater circuit of heated oxygen sensor
S Heated oxygen sensor heater
S EFI relay
S ECM
WIRING DIAGRAM
Refer to DTC P0 130 on page 05 −82.
INSPECTION PROCEDURE
HINT:
SIf different DTCs related to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may have an open circuit.
SRead freeze frame data using the hand−held tester . Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the
vehicle was running or stopped, if the engine was warmed up or not, if the air −fuel ratio was lean or
rich, and other data from the time the malfunction occurred.