2001 TOYOTA AVALON Air fuel ratio sensor
[x] Cancel search: Air fuel ratio sensorPage 994 of 1897
A02032
HAFL ON
HAFR
(+)
(-)
- DIAGNOSTICSENGINE
DI-1 15
271 Author: Date:
2001 AVALON (RM808U)
DTC P1135 A/F Sensor Heater Circuit Malfunction (Bank
1 Sensor 1)
DTC P1155 A/F Sensor Heater Circuit Malfunction (Bank
2 Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page DI-43.
DTC No.DTC Detecting ConditionTrouble Area
P1135
When the heater operates, heater current exceeds 8 A
(2 trip detection logic)Open or short in heater circuit of A/F sensor
A/F h tP1135
P1155Heater current of 0.25 A or less when the heater operates
(2 trip detection logic)A/F sensor heater
ECM
WIRING DIAGRAM
Refer to DTC P0125 on page DI-43.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the 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.
1 Check voltage between terminals HAFL, HAFR of ECM connector and body
ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminals HAFL, HAFR of the
ECM connector and body ground.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-30).
NG
2 Check resistance of A/F sensor heater (See page SF-79).
DI2H9-03
Page 1002 of 1897
- DIAGNOSTICSENGINE
DI-123
279 Author: Date:
2001 AVALON (RM808U)
DTC P1335 Crankshaft Position Sensor Circuit Malfunc-
tion (During engine running)
CIRCUIT DESCRIPTION
Refer to DTC P0335 on page DI-67.
DTC No.DTC Detecting ConditionTrouble Area
P1335No crankshaft position sensor signal to ECM with engine
speed 1,000 rpm or more
Open or short in crankshaft position sensor circuit
Crankshaft position sensor
Crankshaft timing pulley
ECM
WIRING DIAGRAM
Refer to DTC P0335 on page DI-67.
INSPECTION PROCEDURE
Refer to DTC P0335 on page DI-67.
HINT:
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the 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.
DI085-09
Page 1003 of 1897
A11663
VV1, VV2 and NE Signal Waveforms2 V
/Division
20 msec./Division (Idling)
VV1
NE VV2GND
GND
GND
DI-124
- DIAGNOSTICSENGINE
280 Author: Date:
2001 AVALON (RM808U)
DTC P1345 VVT Sensor/Camshaft Position Sensor Cir-
cuit Malfunction (Bank 1)
DTC P1350 VVT Sensor/Camshaft Position Sensor Cir-
cuit Malfunction (Bank 2)
CIRCUIT DESCRIPTION
VVT sensor (VV signal) consists of a magnet, iron core and pickup coil.
The VV signal plate has 3 teeth on its outer circumference and is installed the camshaft timing gear.
When the camshafts rotate, the protrusion on the signal plate and the air gap on the pickup coil change,
causing fluctuations in the magnetic field and generating an electromotive force in the pickup coil.
The actual camshaft angle is detected by the VVT sensor and it provides feedback to the ECM to control
the intake valve timing in response to during condition.
DTC No.DTC Detecting ConditionTrouble Area
No VVT sensor (Camshaft position sensor) signal to ECM
during cranking at 4 sec. or more
Open or short in VVT sensor (camshaft position sensor) cir-
P1345
P1350No VVT sensor (Camshaft position sensor) signal to ECM with
5 sec. or more engine speed 600 rpm or morecuit
VVT sensor (camshaft position sensor)
Camshaft timing gearP1350
While crankshaft rotates twice, VVT sensor (Camshaft position
sensor) signal will be input to ECM 5 times.Camshaft timing gear
ECM
WIRING DIAGRAM
Refer to DTC P0335 on page DI-67.
INSPECTION PROCEDURE
HINT:
If DTC P1345 is displayed, check left bank VVT sensor (camshaft position sensor).
If DTC P1350 is displayed, check right bank VVT sensor (camshaft position sensor).
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame
records the engine conditions when the 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.
1 Check resistance of VVT sensor (See page IG-7).
Reference: INSPECTION USING OSCILLOSCOPE
During idling, check the waveforms between terminals VV1 and
NE+, and VV2 and NE- of the ECM connector.
HINT:
The correct waveforms are as shown.
The waveform frequency is shortened as the engine
speed becomes higher.
NG Replace VVT sensor.
DI6T9-01
Page 1005 of 1897
DI-126
- DIAGNOSTICSENGINE
282 Author: Date:
2001 AVALON (RM808U)
DTC P1346 VVT Sensor/Camshaft Position Sensor Cir-
cuit Range/Performance Problem (Bank 1)
DTC P1351 VVT Sensor/Camshaft Position Sensor Cir-
cuit Range/Performance Problem (Bank 2)
CIRCUIT DESCRIPTION
Refer to DTC P1345, P1350 on page DI-124.
DTC No.DTC Detection ConditionTrouble Area
P1346Deviation in crankshaft position sensor signal and VVT sensor
(bank 1) signal (2 trip detection logic)Mechanical system malfunction (Jumping teeth of timing belt,
blt t thd)
P1351Deviation in crankshaft position sensor signal and VVT sensor
(bank 2) signal (2 trip detection logic)belt stretched)
ECM
WIRING DIAGRAM
Refer to DTC P1345, P1350 on page DI-124.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the 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.
1 Check valve timing (Check for loose and jumping teeth of timing belt) (See page
EM-15).
NG Adjust valve timing (Repair or replace timing
belt).
OK
Check and replace ECM (See page IN-30).
DI6TA-01
Page 1013 of 1897
A11416
Fusible
Link
Block
FL
Main
BatteryStop Light
Switch
ALT
B
F10
F6STOP
R
211D 1B
1E
45
Light
Failure
Sensor 7
2
To Stop LightE8 15ECM
STP
E1 Driver Side J/B
3 11
W
1 1
16
4C 3C
3164F3F 3
5IK1 1D 1
1GG-W
G-WDriver Side J/B
J/B No.3
J/B No.4
G-W
G-W G-W G-W
DI-134
- DIAGNOSTICSENGINE
290 Author: Date:
2001 AVALON (RM808U)
DTC P1520 Stop Light Switch Signal Malfunction
CIRCUIT DESCRIPTION
This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut-off engine speed (The fuel cut-off engine speed is re-
duced slightly when the vehicle is braking.).
DTC No.DTC Detecting ConditionTrouble Area
P1520
Stop light switch does not turn off when repeating driving at 30
km or more 10 time or more after depressing brake (2 trip
detection logic)Short in stop light switch signal circuit
Stop light switch
ECM
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the 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.
1 Check operation of stop light.
CHECK:
Check if the stop lights go on and off normally when the brake pedal is operated and released.
NG Check and repair stop light circuit.
DI088-09
Page 1021 of 1897
- DIAGNOSTICSENGINE
DI-53
209 Author: Date:
DTC P0171 System too Lean (Fuel Trim)
DTC P0172 System too Rich (Fuel Trim)
DTC P0174 System too Lean (A/F Lean Malfunction,
Bank2)
DTC P0175 System too Rich (Bank2)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared to the basic injection time. Fuel trim includes
short-term fuel trim and long-term fuel trim.
Short-term fuel trim is the short-term fuel compensation used to maintain the air-fuel ratio at its ideal
theoretical value.
The signal from the A/F sensor is approximately proportional to the existing air-fuel ratio, and ECM compar-
ing it with the ideal theoretical value, the ECM reduces fuel volume immediately if the air-fuel ratio is rich
and increases fuel volume if it is lean.
Long-term fuel trim compensates the deviation from the central value of the short-term fuel trim stored up
by each engine tolerance, and the deviation from the central value due to the passage of time and changes
of using environment.
If both the short-term fuel trim and long-term fuel trim exceed a certain value, it is detected as a malfunction
and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
P0174When air-fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on rich side (2 trip detection
logic)
Air induction system
Injector blockage
Mass air flow meter
Engine coolant temp. sensor
Fuel pressure
Gas leakage on exhaust system
Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
A/F sensor (bank 1, 2 sensor 1)
ECM
P0172
P0175When air-fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on lean side (2 trip detection
logic)
Injector leak, blockage
Mass air flow meter
Engine coolant temp. sensor
Ignition system
Fuel pressure
Gas leakage on exhaust system
Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
A/F sensor (bank 1, 2 sensor 1)
ECM
DI6T4-03
Page 1022 of 1897
DI-54
- DIAGNOSTICSENGINE
210 Author: Date:
HINT:
When the DTC P0171 or P0174 is recorded, the actual air-fuel ratio is on the lean side. When DTC
P0172 or P0175 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 P0171 or P0174 is recorded. The MIL
then comes on.
If the total of the short-term fuel trim value and the long-term fuel trim value is within + 35 % (80°C
(176°F) or more), the system is functioning normally.
The A/F sensors (bank 1, 2 sensor 1) output voltage and the short-term fuel trim value can be read
using the OBD II scan tool or hand-held tester.
The ECM controls the voltage of AFR+, AFL+, AFR- and AFL- terminals of ECM to the fixed voltage.
Therefore, it is impossible to confirm the A/F sensor output voltage without OBD II scan tool or hand-
held tester.
OBD II scan tool (excluding hand-held tester) displays the one fifth of the A/F sensors (bank 1, 2 sen-
sor 1) output voltage which is displayed on the hand-held tester.
WIRING DIAGRAM
Refer to DTC P0125 on page DI-43.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the 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.
1 Check air induction system (See page SF-1).
NG Repair or replace.
OK
2 Check injector injection (See page SF-23).
NG Replace injector.
OK
Page 1045 of 1897
B04941
- DIAGNOSTICSENGINE
DI-1 1
167 Author: Date:
2001 AVALON (RM808U)
OK
8 Check for spark.
PREPARATION:
(a) Remove the ignition coil from the spark plug.
(b) Remove the spark plug.
(c) Install the spark plug to the ignition coil.
(d) Disconnect the injector connector.
(e) Be sure to ground the screw of the spark plug securely.
CHECK:
Check if spark occurs while the engine is being cranked.
NOTICE:
Do not crash the electrode gap.
To prevent excess fuel being injected from the injec-
tors during this test, don't crank the engine for more
than 5 - 10 seconds at a time.
NG Proceed to page IG-1, and continue to trouble-
shoot.
OK
Proceed to problem symptoms table on page
DI-22.
7. ENGINE OPERATING CONDITION
NOTICE:
The values given below for ºNormal Conditionº are representative values, so a vehicle may still be
normal even if its value varies differ from those listed here. So do not decide whether a part is faulty
or not solely according to the ºNormal Conditionº here.
(a) CARB mandated signals.
TOYOTA hand-held tester displayMeasurement ItemNormal Condition*
FUEL SYS #1
Fuel System Bank 1
OPEN: Air-fuel ratio feedback stopped
CLOSED: Air-fuel ratio feedback operating
Idling after warming up: CLOSED
FUEL SYS #2
Fuel System Bank 2
OPEN: Air-fuel ratio feedback stopped
CLOSED: Air-fuel ratio feedback operating
Idling after warming up: CLOSED
CALC LOADCalculator Load: Current intake air volume as a
proportion of max. intake air volumeIdling: 13.1 - 18.7 %
Racing without load (2,500rpm): 11.7 - 17.3 %
COOLANT TEMPEngine Coolant Temp. Sensor ValueAfter warming up: 80 - 95°C (176 - 203°F)
SHORT FT #1Short-term Fuel Trim Bank 10 ± 20 %
LONG FT #1Long-term Fuel Trim Bank 10 ± 20 %