2005 TOYOTA AVENSIS heater

B16200
A79118
Wire Harness Side
Bank 1
Sensor 2
Bank 2
Sensor 2H8
H10
Heated Oxygen Sensor ConnectorOX
HT
A65747
HT1BHT2B
E12E10
ECM Connector
OX1BOX2B

A79115
Heated Oxygen Sensor
EFI Relay
Heater
Sensor
OX1B HT1B
Duty
Control ECM
From
Battery
EFI Fuse
O1B±
MREL Reference (Bank 1 Sensor 2 System Drawing)
EFI No.2 Fuse 05±216
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
4 INSPECT EFI RELAY
(a) Remove the EFI relay from the engine room R/B No.4.
(b) Inspect the EFI relay.
Standard:
Terminal No.Specified condition
1 ± 2Continuity
No Continuity
3 ± 5Continuity
(Apply battery voltage Terminals 1 and 2)
NG REPLACE EFI RELAY
OK
5 CHECK HARNESS AND CONNECTOR(HEATED OXYGEN SENSOR ± ECM)
(a) Disconnect the H8 or H10 heated oxygen sensor connec-
tor.
(b) Disconnect the E10 and E12 ECM connector.
(c) Check for continuity between the wire harness side con-
nectors.
Standard (Check for open):
Symbols (Terminal No.)Specified condition
OX (H8±3) ± OX1B (E12±21)
HT (H8±1) ± HT1B (E10±4)ContinuityOX (H10±3) ± OX2B (E12±29)Continuity
HT (H10±1) ± HT2B (E10±3)
Standard (Check for short):
Symbols (Terminal No.)Specified condition
OX (H8±3) or OX1B (E12±21) ± Body ground
HT (H8±1) or HT1B (E10±4) ± Body groundNo continuityOX (H10±3) or OX2B (E12±29) ± Body groundNo continuity
HT (H10±1) or HT2B (E10±3) ± Body ground

 


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

B62793
Reference (Bank 1 Sensor 1 System Drawing)A/F Sensor
A/F Relay
Heater
Sensor A1A+ HA1A
Duty
Control
ECM
From
Battery A/F Fuse
A1A±
MREL
05±182
±
DIAGNOSTICS SFI SYSTEM(1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DTCP0031/21OXYGEN (A/F) SENSOR HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1)
DTCP0032/21OXYGEN (A/F) SENSOR HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 1)
DTCP0051/28OXYGEN (A/F) SENSOR HEATER CONTROL CIRCUIT LOW (BANK 2 SENSOR 1)
DTCP0052/28OXYGEN (A/F) SENSOR HEATER CONTROL CIRCUIT HIGH (BANK 2 SENSOR 1)
CIRCUIT DESCRIPTION
Refer to DTC P2237/21 on page 05±248.
HINT:

These DTCs are related to the air fuel raito (A/F) sensor, although the caption is the heated oxygen
sensor.

The ECM provides a pulse width modulated control circuit to adjust curre\
nt through the heater. The
heated oxygen sensor heater circuit uses a relay on the B+ side of the c\
ircuit.
DTC No.DTC Detection ConditionTrouble Area
P0031/21
P0051/28Heated current is 0.8 A or less when heater operates
(1 trip detection logic)
Open or short in heater circuit of A/F sensor

A/F sensor heater
P0032/21
P0052/28When the heater operates, heated current exceeds 19.7 A
(1 trip detection logic)
A/F relay

ECM
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Bank 2 refers to the bank that does not include cylinder No.1.

Sensor 1 refers to the sensor closest to the engine assembly.

Sensor 2 refers to the sensor farthest away from the engine assembly.
05C6T±01

A75325
HTAF+
+B
AF±
Bank 1, Sensor 1
A7
A/F Sensor
A79112
Bank 2, Sensor 1
A8
A/F Sensor HT
AF+
+B
AF±
B16200
±
DIAGNOSTICS SFI SYSTEM(1AZ±FE)
05±183
AVENSIS REPAIR MANUAL (RM1018E)
WIRING DIAGRAM
Refer to DTC P2237/21 on page 05±248.
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.
1 INSPECT AIR FUEL RATIO SENSOR(RESISTANCE OF A/F SENSOR HEATER)
(a) Disconnect the A/F sensor connector.
(b) Measure resistance between terminals HT and +B of the A/F sensor.
Resistance: 1.8 to 3.4
(20 C)
NG REPLACE AIR FUEL RATIO SENSOR
OK
2 INSPECT A/F RELAY
(a) Remove the A/F relay from the engine room R/B No.4.
(b) Inspect the A/F relay. Standard:
Terminal No.Specified condition
1 ± 2Continuity
No Continuity
3 ± 5Continuity
(Apply battery voltage terminals 1 and 2)
NG REPLACE A/F RELAY
OK

A73819A±A SectionAirSolid Electrolyte
(Zirconia Element)
Platinum
Electrode Heater
Exhaust Gas
Cover Element
A
A
ECM Monitored
A/F Sensor Voltage
Air±Fuel Ratio
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
05±249
AVENSIS REPAIR MANUAL (RM1018E)
DTC P2255/28 OXYGEN SENSOR REFERENCE GROUND
CIRCUIT LOW (FOR A/F SENSOR)(BANK 2
SENSOR 1)
DTC P2256/28 OXYGEN SENSOR REFERENCE GROUND
CIRCUIT HIGH (FOR A/F SENSOR)(BANK 2
SENSOR 1)
CIRCUIT DESCRIPTION
HINT:
This DTC is recorded when A/F sensor has a malfunction, although the caption is healed oxygen sensor.
The air±fuel ratio sensor are the lamination type. Compared to the conventional type, the sensor and heater
portions of the lamination type are narrower overall. Because the heat of the heater acts directly on the alumi-
na and zirconia (of the sensor portion) it accelerates the activation of the sensor.
To obtain a high purification rate of the CO, HC and NOx components of the exhaust gas, a three±way cata-
lytic 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 A/F sensor has the characteristic that it provides output voltage* being approximately proportional to
the existing air±fuel ratio. The A/F sensor output voltage* is used to provide feedback for the ECM to control
the air±fuel ratio.
By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air±fuel ratio
and control the proper injection time immediately. If the A/F sensor is out of order, ECM is unable to perform
the accurate air±fuel ratio control.
The A/F sensor is equipped with 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), the current flows to the
heater to heat the sensor for the accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.

05±250
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)DTC No.
DTC Detecting ConditionTrouble Area
A/F sensor circuit (bank 1 sensor 1)HINT : Main trouble area

Open or short in A/F sensor circuit
P2237/21
P2240/28
Conditions (a) and (b) continue for 5.0 sec. or more :
(a) AF+ less than 0.5 V
(b) AF+ greater than 4.5 V
Open or short in A/F sensor circuit

A/F sensor

A/F sensor heater
Conditions (a) and (b) continue for 5.0 sec. or more :
(a) (AF+) ± (AF±) less than 0.1 V
(b) (AF+) ± (AF±) greater than 0.8 V
A/F sensor heater

A/F sensor heater relay

A/F sensor heater and relay circuit

ECM
A/F sensor circuit low (bank 1 sensor 1)HINT : Main trouble area

Open in A/F sensor circuit
P2238/21
P2241/28Condition (a) continues for 5.0 sec. or more :
(a) AF+ less than 0.5 V
Open or short in A/F sensor circuit

A/F sensor

A/F sensor heater
Condition (a) continues for 5.0 sec. or more :
(a) (AF+) ± (AF±) less than 0.1 V
A/F sensor heater

A/F sensor heater relay

A/F sensor heater and relay circuit

ECM
A/F sensor circuit high (bank 1 sensor 1)HINT : Main trouble area

Short in A/F sensor circuit
P2239/21
P2242/28Condition (a) continue for 5.0 sec. or more :
(a) AF+ greater than 4.5 V
Open or short in A/F sensor circuit

A/F sensor

A/F sensor heater
Condition (a) continue for 5.0 sec. or more :
(a) (AF+) ± (AF±) greater than 0.8 V
A/F sensor heater

A/F sensor heater relay

A/F sensor heater and relay circuit

ECM
P2251/21
P2254/28Conditions (a) and (b) continue for 5.0 sec. or more :
(a) AF± less than 0.5 V
(b) AF± greater than 4.5 V
Open or short in A/F sensor circuit

A/F sensor

A/F sensor heaterP2252/21
P2255/28Condition (a) continue for 5.0 sec. or more :
(a) AF± less than 0.5 V
A/F sensor heater

A/F sensor heater relay


A/F sensor heater and relay circuitP2253/21
P2256/28Condition (a) continue for 5.0 sec. or more :
(b) AF± greater than 4.5 V
A/F sensor heater and relay circuit

ECM
HINT:

   
       means malfunction related
to bank 1 A/F sensor circuit.

         
means malfunction related
to bank 2 A/F sensor circuit.

Bank 1 refers to the bank that includes cylinder No. 1.

Bank 2 refers to the bank that includes cylinder No. 2.

+25 %
±12.5 %
More than 3.35 V
Less than 3.0 V
Case 1
Case 2
Case 3
Case 4
Output voltage of A/F sensor
(sensor 1)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2)Mainly suspect
trouble area
OK
+25 %
±12.5 %
More than 3.35 V
Less than 3.0V
Injection volume
Output voltage
+25 %
±12.5 %
More than 0.55 V
Less than 0.4V
Injection volume
Output voltage
A/F sensor
(A/F sensor, heater, A/F sen-
sor 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 actual
air±fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
No reaction
No reaction
No reaction No reaction


Heated oxygen sensor
(heated oxygen sensor,
heater, heated oxygen sensor
circuit)
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
05±253
AVENSIS REPAIR MANUAL (RM1018E)
The following procedure of A/F CONTROL enables the technician to check and graph voltage output of both
the A/F sensor and heated oxygen sensor.
For displaying the graph indication, enter ºACTIVE TEST/ A/F CONTROL/USER DATAº, then select ºAFS
B1S1 and O2S B1S2º or ºAFS B2S1 and O2S B2S2º by pressing ºYESº button and push ºENTERº button
before pressing ºF4º button.
HINT:

If DTC   
        is displayed, check bank 1
sensor 1 circuit.

If DTC         
 is displayed, check bank 2
sensor 1 circuit.

Read freeze frame data using the hand±held tester. 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.

A75325
HT
AF+ +B
AF±
Bank 1, Sensor 1 A7
A/F Sensor
A79112
Bank 2, Sensor 1 A8
A/F SensorHT
AF+ +B
AF±
B16200
05±254
± DIAGNOSTICSSFI SYSTEM (1AZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
1 INSPECT AIR FUEL RATIO SENSOR(RESISTANCE OF A/F SENSOR HEATER)
(a) Disconnect the A/F sensor connector.
(b) Measure resistance between terminals HT and +B of the
A/F sensor.
Resistance: 1.8 to 3.4
(20
C)
NG REPLACE AIR FUEL RATIO SENSOR
OK
2 INSPECT A/F RELAY
(a) Remove the A/F sensor heater relay from the engine
room R/B.
(b) Inspect the A/F senor heater relay.
Standard:
Terminal No.Specified condition
1 ± 2Continuity
No Continuity
3 ± 5Continuity
(Apply battery voltage Terminals 1 and 2)
NG REPLACE A/F RELAY
OK