engine sensor TOYOTA AVALON 2001 Service Owner's Manual

- DIAGNOSTICSBODY CONTROL SYSTEM
DI-621
777 Author
: Date
:
2001 AVALON (RM808U) B5-6 e B5-14
RLWBIgnition switch ON10 - 14 VB5 6 e B5 14
(ALTL e GND1)R-L e W-BEngine runningBelow 1 V
B5-7 e B5-14
(CLTE e GND1)Y-B e W-BAutomatic light control sensor communication circuit-
B5-8 e B5-14
(CLTS e GND1)LG e W-BAutomatic light control sensor communication circuit-
B5-9 e B5-14
(MPX3 e GND1)R-Y e W-BMultiplex communication circuit-
B5-10 e B5-14
(RRU e GND1)G-B e W-BRear right side power window UP operationBelow 1 V
B5-1 1 e B5-14GRWBPassenger seat belt unfastenedBelow 1 VB5 1 1 e B5 14
(PBEW e GND1)G-R e W-BPassenger seat belt fastened10 - 14 V
B5-13 e Body ground
(CLTC e Body ground)W-B e Body groundConstantBelow 1 V
B5-14 e Body ground
(GND1 e Body ground)W-B e -ConstantBelow 1 V
B5-16 e B5-14RWWBRear door closed10 - 14 VB5 16 e B5 14
(RCTY e GND1)R-W e W-BRear door openedBelow 1 V
B5-17 e B5-14GWBPassenger seat belt unfastenedBelow 1 VB5 17 e B5 14
(PBKL e GND1)G e W-BPassenger seat belt fastened10 - 14 V
B5-18 e B5-14LBWBLuggage compartment door opener switch is operatedBelow 1 VB5 18 e B5 14
(TKU e GND1)L-B e W-BLuggage compartment door opener switch is not operated10 - 14 V
B5-20 e B5-14
(CLTB e GND1)L e W-BAutomatic light control sensor communication circuit-
B5-21 e B5-14
(MPX4 e GND1)G-B e W-BMultiplex communication circuit-
B5-22 e B5-14
(RRD e GND1)R-B e W-BRear right side power window DOWN operationBelow 1 V
B5-23 e B5-14GWWBPassenger seat belt unfastenedBelow 1 VB5 23 e B5 14
(DBEW e GND1)G-W e W-BPassenger seat belt fastened10 - 14 V
B5-25 e B5-14RWBEach door closed10 - 14 VB5 25 e B5 14
(AJAR- e GND1)R e W-BEach door openedBelow 1 V

I13614
IDL 13
IDLOE725 ECMCruise Control ECU
Y
C15
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-575
731 Author
: Date
:
2001 AVALON (RM808U)
DTC 51 Idle Signal Circuit
CIRCUIT DESCRIPTION
When the idle switch is turned ON, a signal is sent to the ECU. The ECU uses this signal to correct the dis-
crepancy between the throttle valve position and the actuator position sensor value to enable accurate
cruise control at the set speed. If the idle switch is malfunctioning, problem symptoms also occur in the en-
gine, so also inspect the engine.
DTC No.Detection ItemTrouble Area
51Short in idle signal circuit.

Harness or connector between ECM and throttle position
sensor

Throttle position sensor

Harness or connector between cruise control ECU and ECM

Cruise control ECU
WIRING DIAGRAM
DI6L6-01

I13611
Cruise Control ECU
9
B
Y-R
IG B 3 1
4IG1 RELAY
2
AM1 ECU-IG NO. 2
5 5
B-L
ALT FL Block
F6
B
FL MAIN
BatteryW-BW-B 1
2G
F8
W-B AA
J5
J/C 1 F101 1
1G
3
1B
1
2H13
1B
4
1C2
3C2
3D
7
IF1
7
3A20
3BGND
1W-B16 W-B WY-R
W-R42
I15Ignition Switch
C15
W-L
W-L
B-LIG1 AM1
2
1J/B No. 3
Driver Side J/B
Engine Room J/B
Engine Room R/B No. 5
J/B No. 3
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-587
743 Author
: Date
:
2001 AVALON (RM808U)
ECU Power Source Circuit
CIRCUIT DESCRIPTION
The ECU power source supplies power to the actuator and sensors, etc, when terminal GND and the cruise
control ECU case are grounded.
WIRING DIAGRAM
DI08X-15

I13679
(a)
(a)(b)
No.Operation MethodCRUISE MAIN Indicator Light
Blinking PatternDiagnosis
1 Push SET/COAST switch ON
2Push RES/ACC switch ON
3Push CANCEL switch ON
Turn stop light switch ON
Depress brake pedal
Turn PNP switch OFF
(Shift to except D position)
4Drive at about 40 km/h
(25 mph)or higher
Drive at about 40 km/h
(25 mph) or below
LightON
OFF
LightON
OFF
LightON
OFFSwitch ON
Switch OFF
LightON
OFFSwitch OFF
Switch ONSET/COAST switch circuit
is normal
RES/ACC switch circuit
is normal
CANCEL switch circuit
is normal
Stop light switch circuit
is normal
PNP switch circuit is
normal
Vehicle Speed Sensor is
normal
LightON
OFF LightON
OFF
1sec.
0.25 sec.0.25 sec.
Turn clutch switch OFF
(Depress clutch pedal)Clutch switch circuit
is normal
- DIAGNOSTICSCRUISE CONTROL SYSTEM
DI-555
711 Author
: Date
:
2001 AVALON (RM808U)
5. INPUT SIGNAL CHECK
HINT:
(1) For check No.1 ~ No.3:
Turn ignition switch ON.
(2) For check No.4:

Jack up the vehicle.

Start the engine.

Shift to D position.
(a) Push the control switch to SET/COAST or RES/ACC posi-
tion and hold it down or up.
(b) Push the main switch ON.
(c) Check that the CRUISE MAIN indicator light blinks twice
or 3 times repeatedly after 3 seconds.
(d) Push the SET/COAST or RES/ACC switch OFF.
(e) Operate each switch as listed in the table below.
(f) Read the blinking pattern of the CRUISE MAIN indicator
light.
(g) After performing the check, turn the main switch OFF.
HINT:
When 2 or more signals are input to the ECU, the lowest num-
bered code will be displayed 1st.

FI4741
Fig. 1
Acceptable
Resistance kW
- 20 0 20 40 60 80 100
(- 4) (32) (68) (104) (140) (176) (212) 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
Te m p .°C (F°)
DI-28
- DIAGNOSTICSENGINE
184 Author
: Date
:
2001 AVALON (RM808U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temperature sensor is built into mass air flow me-
ter and senses the intake air temperature.
A thermistor built in the sensor changes the resistance value
according to the intake air temperature.
The lower the intake air temperature, the greater the thermistor
resistance value, and the higher the intake air temperature, the
lower the thermistor resistance value (See Fig. 1).
The intake air temperature sensor is connected to the ECM.
The 5 V power source voltage in the ECM is applied to the in-
take air temperature sensor from terminal THA via resistor R.
That is, resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in the
intake air temperature, the potential at terminal THA also
changes. Based on this signal, the ECM increases the fuel in-
jection volume to improve driveability during cold engine opera-
tion.
If the ECM detects the DTC P0110, it operates the fail-safe
function in which the intake air temperature is assumed to be
20°C (68°F).
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit

Open or short in intake air temp. sensor circuit

Intake air temp. sensor (built into mass air flow meter)

ECM
HINT:
After confirming DTC P0110, use the OBD II scan tool or TOYOTA hand-held tester to confirm the intake
air temperature form the CURRENT DATA.
Temperature DisplayedMalfunction
-40°C ( -40°F )Open circuit
140°C ( 284°F ) or moreShort circuit
DI07H-10

A00310A09772
5 V
THA
E2
E1 22
18 4
5R Intake Air Temp. Sensor
(Built into Mass Air Flow Meter)ECM
L-B
W
E5 E5
- DIAGNOSTICSENGINE
DI-29
185 Author
: Date
:
2001 AVALON (RM808U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs P0110, P0115, P0120 and P1410 are output simultaneously, E2 (sensor ground) may be open.

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 Connect OBD II scan tool or TOYOTA hand-held tester, and read value of intake
air temperature.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand-held tester main switch
ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYOTA hand-held tester.
OK:
Same as actual intake air temperature.
HINT:

If there is open circuit, OBD II scan tool or TOYOTA hand-held tester indicates -40°C (-40°F).

If there is short circuit, OBD II scan tool or TOYOTA hand-held tester indicates 140°C (284°F) or more.
NG -40°C (-40°F) ... Go to step 2.
140°C (284°F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI-3).

A00210
ON
Intake Air
Temp. Sensor
ECM
5 V
E2
THA22
18 1
2E5
E5
BE6653
FI7055
A02019
ON
Intake Air Temp. SensorECM
5 V
E2 22
18 E5
E5
E2
THA
THA
DI-30
- DIAGNOSTICSENGINE
186 Author
: Date
:
2001 AVALON (RM808U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: 1405C (2845F) or more
OK Confirm good connection at sensor. If OK, re-
place mass air flow meter.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See page SF-82).
(b) Connect between terminals THA and E2 of the ECM con-
nector.
HINT:
The mass air flow meter connector is disconnected. Before
checking, do a visual and contact pressure check for the ECM
connector (See page IN-30).
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: 1405C (2845F) or more
OK Open in harness between terminal E2 or THA,
repair or replace harness.
NG
Confirm good connection at ECM. If OK,
check and replace ECM (See page IN-30).

A00212
ON
Intake Air
Temp. Sensor
ECM
5 V
E2 22
18
THA
BE6653
FI7054E5
E5
A02043
ON
Intake Air Temp. Sensor
E5 ConnectorECM
5 V
E2 THA
- DIAGNOSTICSENGINE
DI-31
187 Author
: Date
:
2001 AVALON (RM808U)
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: -405C (-405F)
OK Replace mass air flow meter.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See page SF-82).
(b) Disconnect the E5 connector from the ECM.
HINT:
Mass air flow meter connector is disconnected.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: -405C (-405F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN-30).

A00310
A09772
Engine Coolant Temp. SensorECM
5 V
THW
E2
E1 14
18 2
1G-Y
W
E5 E5 DI-32
- DIAGNOSTICSENGINE
188 Author
: Date
:
2001 AVALON (RM808U)
DTC P0115 Engine Coolant Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the
engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the intake air temperature circuit
malfunction shown on page DI-28.
If the ECM detects the DTC P0115, it operates the fail-safe function in which the engine coolant temperature
is assumed to be 80°C (176°C).
DTC No.DTC Detecting ConditionTrouble Area
P0115Open or short in engine coolant temp. sensor circuit

Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
HINT:
After confirming DTC P0115, use the OBD II scan tool or TOYOTA hand-held tester to confirm the engine
coolant temperature from the CURRENT DATA.
Temperature DisplayedMalfunction
-40°C (-40°F)Open circuit
140°C (284°F) or moreShort circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs P0110, P0115, P0120 and P1410 are output simultaneously, E2 (sensor ground) may be open.

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.
DI07I-09

A00214
ON
Engine Coolant
Temp. Sensor
ECM
5V
E2 14
18 2
1
THW
BE6653
FI7055
E5 E5
- DIAGNOSTICSENGINE
DI-33
189 Author
: Date
:
2001 AVALON (RM808U)
1 Connect OBD II scan tool or TOYOTA hand-held tester, and read value of engine
coolant temperature.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand-held tester main switch
ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYOTA hand-held tester.
OK:
Same as actual engine coolant temperature.
HINT:

If there is open circuit, OBD II scan tool or TOYOTA hand-held tester indicates -40°C (-40°F).

If there is short circuit, OBD II scan tool or TOYOTA hand-held tester indicates 140°C (284°F) or more.
NG -40°C (-40°F) ... Go to step 2.
140°C (284°F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI-3).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: 1405C (2845F) or more
OK Confirm good connection at sensor. If OK, re-
place engine coolant temperature sensor.
NG