2005 TOYOTA AVENSIS Circuit

05±394
± DIAGNOSTICSSFI SYSTEM (1AZ±FSE)
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0171 SYSTEM TOO LEAN (BANK 1)
DTC P0172 SYSTEM TOO RICH (BANK 1)
DTC P0174 SYSTEM TOO LEAN (BANK 2)
DTC P0175 SYSTEM TOO RICH (BANK 2)
CIRCUIT DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim in-
cludes the short±term fuel trim and the long±term fuel trim.
The short±term fuel trim is the short±term fuel compensation used to maintain the air±fuel ratio at stoichio-
metric air±fuel ratio. The signal from the heated oxygen sensor indicates whether the air±fuel ratio is RICH
or LEAN compared to the stoichiometric air±fuel ratio. This variance triggers a reduction in the fuel volume
if the air±fuel ratio is RICH, and an increase in the fuel volume if it is LEAN.
The long±term fuel trim is the overall fuel compensation carried out in long±term to compensate for a continu-
al deviation of the short±term fuel trim from the central value, due to individual engine differences, wear over-
time and changes in the operating environment.
If both the short±term fuel trim and the long±term fuel trim are LEAN or RICH beyond a certain value, it is
detected as a malfunction and the CHK ENG is illuminated.
DTC No.DTC Detection ConditionTrouble Area
P0171
P0174When air±fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)

Air induction system

Injector blockage

Mass air flow meter

Manifold absolute pressure sensor

Engine coolant temperature sensor

Fuel pressure

Gas leakage in exhaust system

Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit

Heated oxygen sensor (bank 1, 2 sensor 1)

Heated oxygen sensor heater (bank 1, 2 sensor 1)

EFI relay

PCV valve and hose

PCV hose connection

ECM
P0172
P0175When air±fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on RICH side
(2 trip detection logic)

Injector leakage blockage

Mass air flow meter

Manifold absolute pressure sensor

Engine coolant temperature sensor

Ignition system

Fuel pressure

Gas leakage in exhaust system

Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit

Heated oxygen sensor (bank 1, 2 sensor 1)

ECM
HINT:

When DTC ºP0171 or P0174º is recorded, the actual air±fuel ratio is on the LEAN side. When DTC
ºP0172 or P0175º is recorded, the actual air±fuel ratio is on the RICH side.

If the vehicle runs out of fuel, the air±fuel ratio is LEAN and DTC ºP0171 or P0174º is recorded. The
CHK ENG then comes on.
05CKD±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 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±396
± DIAGNOSTICSSFI SYSTEM (1AZ±FSE)
AVENSIS REPAIR MANUAL (RM1018E)
The following A/F CONTROL procedure enables the technician to check and graph the voltage outputs of
both the heated oxygen sensors.
For displaying the graph indication, enter ºACTIVE TEST / A/F CONTROL / USER DATAº, then select ºO2S
B1S1 and O2S B1S2º or ºO2S B2S1 and O2S B2S2º by pressing ºYESº button and push ºENTERº button
before pressing ºF4º button.
HINT:

If different DTCs related to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may be open.

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.

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.

± DIAGNOSTICSSFI SYSTEM (1AZ±FSE)
05±363
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0130 OXYGEN SENSOR CIRCUIT (BANK 1
SENSOR 1)
DTC P0150 OXYGEN SENSOR CIRCUIT (BANK 2
SENSOR 1)
DTC P2195 OXYGEN SENSOR SIGNAL STUCK LEAN
(BANK 1 SENSOR 1)
DTC P2196 OXYGEN SENSOR SIGNAL STUCK RICH
(BANK 1 SENSOR 1)
DTC P2197 OXYGEN SENSOR SIGNAL STUCK LEAN
(BANK 2 SENSOR 1)
DTC P2198 OXYGEN SENSOR SIGNAL STUCK RICH
(BANK 2 SENSOR 1)
05CK9±01

A00798
Atmosphere
Housing
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust Gas CoverIdeal Air±Fuel Mixture
Output Voltage
Richer ± Air Fuel Ratio ± Leaner
05±364
± DIAGNOSTICSSFI SYSTEM (1AZ±FSE)
AVENSIS REPAIR MANUAL (RM1018E)
CIRCUIT DESCRIPTION
To obtain a high purification rate for 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 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 will be vanished from
the exhaust gas. And the heated oxygen sensor informs the ECM of the RICH condition (high voltage, i.e.
more than 0.45 V). 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 abnormal 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 No.DTC Detection ConditionTrouble Area
P0130
P0150Output voltage of heated oxygen sensor (sensor 1) remains at
0.4 V or more, or 0.55 V or less, during idling after engine is
warmed up (2 trip detection logic)
Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit

Heated oxygen sensor (bank 1, 2 sensor 1)
P2195
P2197Output voltage of heated oxygen sensor (sensor 1) remains at
0.55 V or less, during idling after engine is warmed up (2 trip
detection logic)
Heated oxygen sensor (bank 1, 2 sensor 1)

Heated oxygen sensor heater (bank 1, 2 sensor 1)

EFI relay

Air induction system
P2196
P2198Output voltage of heated oxygen sensor (sensor 1) remains at
0.4 V or more, during idling after engine is warmed up (2 trip
detection logic)
y

Fuel pressure

Injector

ECM
HINT:

Bank 1 refers to the No. 1 and No. 4 cylinders.

Bank 2 refers to the No. 2 and No. 3 cylinders.

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

The output voltage of the heated oxygen sensor and the short±term fuel trim value can be read using
the hand±held tester.

+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 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 (1AZ±FSE)
05±367
AVENSIS REPAIR MANUAL (RM1018E)
INSPECTION PROCEDURE
HINT:
Hand±held tester only:
Narrowing down the trouble area is possible by performing the ºA/F CONTROLº ACTIVE TEST (heated oxy-
gen 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 by running the engine 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 seconds delay in the sensor 1 (front sensor) output. And there is about 20 seconds
delay in the sensor 2 (rear sensor).

05±474
±
DIAGNOSTICS SFI SYSTEM(1AZ±FSE)
AVENSIS REPAIR MANUAL (RM1018E)
DTCP0705TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT)
CIRCUIT DESCRIPTION
The park/neutral position switch goes on when the shift lever is in the N o\
r P shift position. If the shift lever
is moved from the N position to the D position, this signal is used for \
air±fuel ratio correction and for idle speed
control (estimated control), etc.
DTC No.DTC Detection ConditionTrouble Area
P07052 or more switches are ON simultaneously for N, P, D and R
positions (2 trip detection logic)
Short in park/neutral position switch circuit

Park/neutral position switch

ECM
HINT:
After confirming DTC P0705, use the hand±held tester to confirm the park/n\
eutral position switch signal from
the ºDIAGNOSIS / OBD/MOBD / DATA LIST / ALLº.
WIRING DIAGRAM
Refer to DTC P0705 on page 05±938.
INSPECTION PROCEDURE
Refer to DTC P0705 on page 05±938.
05CJ8±01

A76870
I13
Ignition SW
B±R
StarterECM
FL MAIN
BatterySTA E1317 B±Y
B±Y
B±W
W±B 1
2 35
9
W±B 1
1
B±R B±G 1
1B±G
4A 1A 2
DA Engine
Room
R/B No. 4Driver
Side J/B
S4
S5 14B1AM2Engine
Room
R/B No. 1 1IE41
(LHD)IP11
(RHD)B±R B±R
B±R
55
55
2DJ
IJ IK1 7B
BST
RelayDriver
Side
R/B5
4
AM2 ST2
B±Y
B±Y
A J12 B J12C J13 B J13
A J12
B±Y
(M/T) 6
6 1
2STFuse
Block
J/C
B±Y
(A/T) B±W
(A/T)
96
N1
Park/Neutral Position SwitchB±Y
± DIAGNOSTICSSFI SYSTEM (1AZ±FSE)
05±471
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0617 STARTER RELAY CIRCUIT HIGH
CIRCUIT DESCRIPTION
While the engine is being cranked, the battery positive voltage is applied to terminal STA of the ECM.
DTC No.DTC Detection ConditionTrouble Area
P0617
When all conditions (a), (b) and (c) are satisfied with battery
(+B) voltage 10.5 V or more for 20 sec.
(a) Vehicle speed greater than 20 km/h
(b) Engine revolution greater than 1,000 rpm
(c) STA signal ON
Short in park/neutral position switch (A/T)

Park/neutral position switch (A/T)

Ignition switch

ECM
WIRING DIAGRAM
05CJ9±01

05±470
±
DIAGNOSTICS SFI SYSTEM(1AZ±FSE)
AVENSIS REPAIR MANUAL (RM1018E)
DTCP0604INTERNAL CONTROL MODULE RANDOM ACCESS MEMORY (RAM) ERROR
DTCP0606ECM/PCM PROCESSOR
DTCP0607CONTROL MODULE PERFORMANCE
DTCP0657ACTUATOR SUPPLY VOLTAGE CIRCUIT/OPEN
CIRCUIT DESCRIPTION
DTC No.DTC Detection ConditionTrouble Area
P0604
P0606
P0607
P0657
ECM inside error
ECM
INSPECTION PROCEDURE
HINT:
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 determi\
ning whether the vehicle was running
or stopped, the engine warmed up or not, the air±fuel ratio lean or ric\
h, etc. at the time of the malfunction.
REPAIR OR REPLACE ECM (See page 01±32)
05CJA±01