heater TOYOTA AVENSIS 2005 Service Repair Manual

−
DIAGNOSTICS SFI SYSTEM (2AZ−FSE)
05 −1 01
AVENSIS Supplement (RM 1045E)
DTC P0 134 OXYGEN SENSOR CIRCUIT NO ACTIVITY
DETECTED (BANK 1 SENSOR 1)
DTC P0 154 OXYGEN SENSOR CIRCUIT NO ACTIVITY
DETECTED (BANK 2 SENSOR 1)
CIRCUIT DESCRIPTION
Refer to DTC P0 130 on page 05 −82.
DTC No.DTC Detection ConditionTrouble Area
P0 134
P0 154
After engine is warmed up, heated oxygen sensor (sensor 1)
output does not indicate RICH (greater than 0.45 V) even once
when conditions (a), (b), (c), (d) and (e) continue for at least 65
seconds ( 1 trip detection logic):
(a) Engine speed: 1,400 rpm or more
(b) Vehicle speed: 130 km/h (8 1 mph)
(c) Throttle valve is not fully closed
(d) 180 seconds or more after starting engine
(e) Engine coolant temperature is more than 40 _ C( 104 _ F)
S Open or short in heated oxygen sensor circuit
S Heated oxygen sensor (Bank 1, 2 Sensor 1)
S Heated oxygen sensor heater (Bank 1, 2 Sensor 1)
S EFI relay
S Air induction system
S Fuel pressure
S PCV hose connection
S PCV valve and hose
S Injector
S Gas leakage in exhaust system
S ECM
HINT:
S After confirming DTCs P0134 and P0154, confirm the output voltage of the heated oxygen sensor (bank
1, 2 sensor 1) in the DIAGNOSIS / OBD/MOBD / DATA LIST / ALL using the hand−held tester If the
output voltage of the heated oxygen sensor is less than 0.1 V, the heated oxygen sensor circuit may
be open or short.
S Bank 1 refers to the No. 1 and No. 4 cylinders.
SBank 2 refers to the No. 2 and No. 3 cylinders.
SSensor 1refers to the sensor closest to the engine assembly.
WIRING DIAGRAM
Refer to DTC P0 130 on page 05 −82.
05CKB −02

+25 %
−12.5 %
More than 0.5 V
Less than 0.4V
Case1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Main suspect
trouble area
OK
+25 %
−12.5 %
More than 0.5 V
Less than 0.4V
Injection volume
Output voltage
+25 %
−12.5 %
More than 0.5 V
Less than 0.4V
Injection volume
Output voltage
Sensor1: front sensor
(sensor1, heater, sensor1
circuit)+25 %
−12.5 %
More than 0.5 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
Almost no reaction


Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
Almost no reaction Almost no reactionAlmost no reaction
05−102
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
INSPECTION PROCEDURE
HINT:
Hand−held tester only:
It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The
A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble
areas are malfunctioning or not.
(a) Perform the ACTIVE TEST A/F CONTROL operation.
HINT:
The A/F CONTROL operation lowers the injection volume12.5% or increases the injection volume 25%.
(1) Connect the hand−held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch to ON.
(3) Warm up the engine by running the engine at 2,500 rpm for approximately 3 minutes.
(4) Select the item: DIAGNOSIS / OBD/MOBD / ACTIVE TEST / A/F CONTROL.
(5) Perform the A/F CONTROL operation 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 0.5 V
−12.5 %
lean output: Less than 0.4 V
NOTICE:
There is a delay of few seconds in the sensor1(front sensor) output, and there is about 20 seconds
delay at maximum in the sensor 2 (rear sensor).

A62378
1 2
3 4
+BHT
E1
OX
B1S1 H7
Heated Oxygen Sensor Component Side:
Front View
A79112
E1OX B2S1 H9
+B
HT Heated Oxygen Sensor
Component Side:
Front View
B16200
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
05−105
AVENSIS Supplement (RM1045E)
6 CHECK CONNECTION OF PCV HOSE
NG REPAIR OR REPLACE PCV HOSE
OK
7 INSPECT HEATED OXYGEN SENSOR(HEATER RESISTANCE)
(a) Disconnect the H7 or H9 heated oxygen sensor connec-
tor.
(b) Measure the resistance between the terminals of the
heated oxygen sensor connector.
Standard (Bank1, 2 Sensor1):
Tester ConnectionResistance
1(HT)−2 (+B)11to16
at 20_C (68_F)
1(HT)−4(E1)10k
or higher
(c) Reconnect the heated oxygen sensor connector.
NG REPLACE HEATED OXYGEN SENSOR
OK
8 INSPECT EFI RELAY
(a) Remove the EFI relay from the engine room R/B No. 4.
(b) Check for continuity in the EFI relay.
Standard:
Tester ConnectionSpecified Condition
1−2Continuity
3−5No Continuity
3−5Continuity
(Apply battery voltage to terminals1and 2)
(c) Reinstall the EFI relay.
NG REPLACE EFI RELAY
OK

A76821
Wire Harness Side:
B1S1B2S1 H7 H9
Heated Oxygen Sensor Connector OX
HT
OX
HT
E1E1
A76823
OX2A
ECM Connector E12
OX1A
HT2A HT1A
E2 E13
A72920
Reference (Bank1Sensor1System Drawing)
Heated Oxygen Sensor
EFI Relay
Heater
Sensor
OX1A HT1A
Duty
Control ECM
From
Battery
EFI Fuse
E2 EFI No. 2
Fuse
MREL OX HT
E1 +B
05−106
− DIAGNOSTICSSFI SYSTEM (2AZ−FSE)
AVENSIS Supplement (RM1045E)
9 CHECK HARNESS AND CONNECTOR(HEATED OXYGEN SENSOR−ECM)
(a) Disconnect the H7 or H9 heated oxygen sensor connec-
tor.
(b) Disconnect the E12 and E13 ECM connectors.
(c) Check the resistance between the wire harness side con-
nectors.
Standard (Check for open):
Tester ConnectionSpecified Condition
OX (H7−3)−OX1A(E12−22)Below1

HT (H7−1)−HT1A(E12−5)Below1

E1(H7−4)−E2 (E13−28)Below1

OX (H8−3)−OX2A (E12−23)Below1

HT (H8−1)−HT2A (E12−4)Below1

E1(H8−4)−E2 (E13−28)Below1

Standard (Check for short):
Tester ConnectionSpecified Condition
OX (H7−3) or OX1A(E12−22)−Body ground10k
or higher
HT (H7−1)orHT1A(E12−5)−Body ground10k
or higher
OX (H8−3) or OX2A (E12−23)−Body ground10k
or higher
HT (H8−1) or HT2A (E12−4)−Body ground10k
or higher
(d) Reconnect the heated oxygen sensor connector.
(e) Reconnect the ECM connector.
HINT:
SThe OX1A and HT1A means the heated oxygen sensor
bank1sensor1.
SThe OX2A and HT2A means the heated oxygen sensor
bank 2 sensor1.
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK

A91218
ECM Monitor ed
A/F Sens or Voltage
Air−Fuel Ratio
Solid Electrolyte
(Zirconia Element)
Cover Atmosphere
Exhaust Gas Flange
Platinum Electrode
Coating (Ceramic)
Heater
−
DIAGNOSTICS ECD SYSTEM (1CD−FTV)(From September, 2003)
05 −305
AVENSIS Supplement (RM1045E)
DTC P003 1 OXYGEN (A/F) SENSOR HEATER CONTROL
CIRCUIT LOW (BANK 1 SENSOR 1)
HINT:
S For more information on the A/F sensor and TOYOTA D −CAT (*1), see page 05 −255.
S If P0031 is present, refer to the diagnostic trouble codes (DTCs) table for the TOYOTA D −CAT on page
05 −255.
SThis DTC is related to the A/F sensor, although the caption is the oxygen sensor.
*1: Diesel Clean Advanced Technology.
CIRCUIT DESCRIPTION
The A/F sensor has the characteristic that it provides output voltage which is proportional to the existing air −
fuel ratio. The A/F sensor output voltage (*2) is used to provide the ECM with feedback to control the air −fuel
ratio.
The A/F sensor is located after the DPNR (*3) catalytic converter. This sensor has been developed based
on structure and technology of a sensor that is being used for gasoline engines. Its cover portion of the sen-
sor has been changed for application of use to the diesel engine with TOYOTA D −CAT in order to eliminate
influence of the sensor temperature and particulate matter (PM).
In order to reduce both PM and nitrogen oxides (NOx), the ECM adjusts the air −fuel ratio to slightly RICH
(but it is LEAN compared with a stoichiometric air −fuel ratio) with signals from the A/F sensor, if needed.
When the ECM exercises DPNR catalyst regeneration by adding fuel using the exhaust fuel addition injector,
the air −fuel ratio is also properly adjusted through the sensor.
*2: The voltage value changes inside the ECM only.
*3: Diesel Particulate −NOx Reduction system.
05I7J −01

B62793
Reference:
A/F Sensor A/F Sensor
Heater Relay
Heater
Sensor
AF2+ HAF2
Duty
Control ECM
From
Battery
A/F Fuse
AF2−
MREL 05−306
− DIAGNOSTICSECD SYSTEM (1CD−FTV)(From September, 2003)
AVENSIS Supplement (RM1045E)
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The A/F sen-
sor heater circuit uses a relay on the B+ side of the circuit.
DTC No.DTC Detection ConditionTrouble Area
P0031Heated current is 1.5 A or less when the heater operates
(1 trip detection logic)
SOpen in A/F sensor heater circuit
SA/F sensor heater
SA/F sensor heater relay
SECM
MONITOR DESCRIPTION
The inner surface of the A/F sensor element is exposed to outside air. The outer surface of the sensor ele-
ment is exposed to exhaust gases. The sensor element is made of platinum coated zirconia and includes
an integrated heating element. The zirconia element generates small voltage when there is a large differ-
ence in the oxygen concentrations of the exhaust and the outside air. The platinum coating amplifies the
voltage generation. When heated, the sensor becomes very efficient. If the temperature of the exhaust is
low, the sensor will not generate useful voltage signals without supplemental heating. The ECM regulates
the supplemental heating using a duty−cycle approach to regulate the average current in the heater ele-
ment. If the heater current is out of the normal range, the sensor’s output signals will be inaccurate and the
ECM can not regulate the air−fuel ratio properly. When the heater current is out of the normal operating
range, the ECM interprets this as a malfunction and sets a DTC.

A87894
AF−AF+
A34
Front View Component Side
(w/ Headlight Beam Level Control):
1 2
3 4
HT
+B
A/F Sensor
Connector
A87894
AF− AF+
A34
Front View
HT +B
1 2
3 4 Component Side
(w/o Headlight Beam Level Control):
A/F Sensor
Connector
B16200
05−308
− DIAGNOSTICSECD SYSTEM (1CD−FTV)(From September, 2003)
AVENSIS Supplement (RM1045E)
INSPECTION PROCEDURE
1INSPECT AIR FUEL RATIO SENSOR(RESISTANCE)
(a) Disconnect the A34 A/F sensor connector.
(b) Measure the resistance between the terminals of the A/F
sensor.
Resistance (w/ Headlight beam level control):
Tester ConnectionSpecified Condition
HT (1)−+B (2)0.86 to 1.1
at 20_C (68_F)
Resistance (w/o Headlight beam level control):
Tester ConnectionSpecified Condition
HT (2)−+B (1)0.86 to 1.1
at 20_C (68_F)
(c) Reconnect the A/F sensor connector.
NG REPLACE AIR FUEL RATIO SENSOR
OK
2 INSPECT AIR FUEL RATIO SENSOR HEATER RELAY
(a) Remove the A/F sensor heater relay.
(b) Inspect the A/F sensor heater relay.
Standard:
Tester ConnectionSpecified Condition
1−2Continuity
No continuity
3−5Continuity
(Apply battery voltage to terminals 1 and 2)
(c) Reinstall the A/F sensor heater relay.
NG REPLACE AIR FUEL RATIO SENSOR HEATER
RELAY
OK

A81086
E1 (−)
E12
HAF2 (+)
ECM Connector
−
DIAGNOSTICS ECD SYSTEM (1CD−FTV)(From September, 2003)
05 −309
AVENSIS Supplement (RM1045E)
3 INSPECT ECM(A/F SENSOR HEATER VOLTAGE)
(a) Turn the ignition switch to ON.
(b) Measure the voltage between the applicable terminals of
the E12 ECM connector.
Standard:
Tester ConnectionSpecified Condition
HAF2 (E12 −5) − E1 (E12 −7)9to14V
OK REPLACE ECM (See page 10− 29)
NG

A90355
Wire Harness Side
(w/ Headlight Beam Level Control):
+B
HT
A34
Front View A/F Sensor Connector
A90355
Wire Harness Side
(w/o Headlight Beam Level Control):
+B
HT
A34
Front View A/F Sensor Connector
A81087
E12
HAF2 (+)
ECM Connector
A90544
Wire Harness Side:
A/F Sensor Heater RelayHAF2
05−310
− DIAGNOSTICSECD SYSTEM (1CD−FTV)(From September, 2003)
AVENSIS Supplement (RM1045E)
4 CHECK HARNESS AND CONNECTOR(A/F SENSOR−ECM, A/F SENSOR−A/F
SENSOR HEATER RELAY)
(a) Check the harness and the connectors between the ECM
and the A/F sensor.
(1) Disconnect the A34 A/F sensor connector.
(2) Disconnect the E12 ECM connector.
(3) Check the resistance between the wire harness
side connectors.
Standard (Check for open)
(w/ Headlight beam level control):
Tester ConnectionSpecified Condition
HT (A34−1)−HAF2 (E12−5)Below 1

Standard (Check for open)
(w/o Headlight beam level control):
Tester ConnectionSpecified Condition
HT (A34−2)−HAF2 (E12−5)Below 1

Standard (Check for short)
(w/ Headlight beam level control):
Tester ConnectionSpecified Condition
HT (A34−1) or HAF2 (E12−5)−Body ground10 k
or higher
Standard (Check for short)
(w/o Headlight beam level control):
Tester ConnectionSpecified Condition
HT (A34−2) or HAF2 (E12−5)−Body ground10 k
or higher
(4) Reconnect the A/F sensor connector.
(5) Reconnect the ECM connector.
(b) Check the harness and connectors between the A/F sen-
sor connector and the A/F sensor heater relay.
(1) Disconnect the A34 A/F sensor connector.
(2) Remove the A/F sensor heater relay from the en-
gine room R/B.
(3) Check the resistance between the wire harness
side connectors.
Standard (Check for open)
(w/ Headlight beam level control):
Tester ConnectionSpecified Condition
+B (A34−2)−A/F sensor heater relay (3)Below 1

Standard (Check for open)
(w/o Headlight beam level control):
Tester ConnectionSpecified Condition
+B (A34−1)−A/F sensor heater relay (3)Below 1

Standard (Check for short)
(w/ Headlight beam level control):
Tester ConnectionSpecified Condition
+B (A34−2) or A/F sensor heater relay (3)−Body ground10 k
or higher

−
DIAGNOSTICS ECD SYSTEM (1CD−FTV)(From September, 2003)
05 −311
AVENSIS Supplement (RM1045E)
Standard (Check for short)
(w/o Headlight beam level control):
Tester ConnectionSpecified Condition
+B (A34 −1) or A/F sensor heater relay (3) − Body ground10 k
or higher
(4) Reconnect the A/F sensor connector.
(5) Reinstall the A/F sensor heater relay.
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE ECM (See page 10− 29)