2001 TOYOTA AVALON Service Repair Manual

- DIAGNOSTICSENGINE
DI-57
213 Author
: Date
:
8 Check for open and short in harness and connector between ECM and A/F sen-
sors (bank 1, 2 sensor 1) (See page IN-30).
NG Repair or replace harness or connector.
OK
Replace A/F sensor.
9 Perform confirmation driving pattern (See page DI-106).
Go
10 Is there DTC P0171, P0172, P0174 or P0175 being output again?
YES Check and replace ECM (See page IN-30).
NO
11 Did vehicle runs out of fuel in past?
NO Check for intermittent problems
(See page DI-3).
YES
DTC P0171, P0172, P0174 or P0175 is caused
by running out of fuel.

A11665
IG Switch
BatteryECM Engine Room J/B
MAIN
Park/Neutral
Position SwitchAM2
W-B
Starter
B
58
3
2
110
4
1
B-W2C 2G2A
S1E8 ST Relay
E1 STA 7 1
ED
B-R B-R
II2
W-R
W-B
4
2D
42F 2A6
3
2B2
B-R 8
7
II1
B-W
FL
MainJ1
J/C
B-R
S212C7
7
B
IF1
1F74
W-R
B-R F6Fusible
Link
Block6 512
B
B
W-B DI-142
- DIAGNOSTICSENGINE
298 Author
: Date
:
2001 AVALON (RM808U)
Starter Signal Circuit
CIRCUIT DESCRIPTION
When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore
necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection
volume for the starting injection control and after-start injection control.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is not
cranked, proceed to the problem symptoms table on page DI-22.
DI08B-09

A02045
START
STA
(+) (-)
- DIAGNOSTICSENGINE
DI-143
299 Author
: Date
:
2001 AVALON (RM808U)
TOYOTA hand-held tester:
1 Connect TOYOTA hand-held tester, and check STA signal.
PREPARATION:
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand-held tester main switch ON.
CHECK:
Read the STA signal on the TOYOTA hand-held tester while the starter operates.
OK:
Ignition Switch PositionONSTART
STA SignalOFFON
OK Proceed to next circuit inspection shown on
problem symptom table (See page DI-22).
NG
2 Check for open in harness and connector between ECM and starter relay (Mark-
ing: ST) (See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check voltage between terminal STA of ECM connector and body ground.
PREPARATION:
Remove the glove compartment (See page SF-83).
CHECK:
Measure the voltage between terminal STA of the ECM connec-
tor and body ground during the engine cranking.
OK:
Voltage: 6 V or more
OK Proceed to next circuit inspection shown on
problem symptom table (See page DI-22).

DI-144
- DIAGNOSTICSENGINE
300 Author
: Date
:
2001 AVALON (RM808U)
NG
2 Check for open in harness and connector between ECM and starter relay (Mark-
ing: ST) (See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).

DI079-04
ENGINE CONTROL SYSTEM Check Sheet
Customer's Name
Driver's Name
Date Vehicle
Brought in
License No.
Model and Model
Year
Frame No.
Engine Model
Odometer Reading
Problem Symptoms
Engine does
not Start
Difficult to
Start
Poor Idling
Poor
Driveability
Engine Stall
Others
Engine does not crankNo initial combustionNo complete combustion
Engine cranks slowly
Other
Incorrect first idleIdling rpm is abnormalHigh ( rpm)Low ( rpm)
Rough idling
Other
HesitationBack fireMuffler explosion (after-fire)Surging
Knocking
Other
Soon after startingAfter accelerator pedal depressed
After accelerator pedal released
During A/C operation
Shifting from N to D
Other
Dates Problem
Occurred
Problem Frequency
Condition When
Problem Occurs
Weather
Engine Operation
Engine Temperature Place Outdoor
TemperatureConstant
Sometimes ( times per day/month)Once only
Other
Fine
CloudyRainySnowyVarious/Other
Hot
Warm CoolCold (approx. °F/ °C)
Highway
SuburbsInner cityUphillDownhill
Rough road
Other
Cold
Warming upAfter warming upAny temperatureOther
Starting
Just after starting ( min.)IdlingRacing
Driving
Constant speedAccelerationDeceleration
A/C switch ON/OFF
Other
Condition of MILRemains on Sometimes light up Does not light up
NormalMalfunction code(s) (code )
Freezed frame data ( )
NormalMalfunction code(s) (code )
Freezed frame data ( )
Normal Mode
(Precheck)
Check Mode DTC InspectionInspector's
Name
km
miles
DI-2
- DIAGNOSTICSENGINE
158 Author
: Date
:
2001 AVALON (RM808U)
CUSTOMER PROBLEM ANALYSIS CHECK

DI07B-20
DI-14
- DIAGNOSTICSENGINE
170 Author
: Date
:
DIAGNOSTIC TROUBLE CODE CHART
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check in check mode, check the circuit for the codes listed
in the table below. For details of each code, turn to the page referred to under the ''See page '' for the respec-
tive ''DTC No.'' in the DTC chart.
SAE CONTROLLED
DTC No.
(See page)Detection ItemTrouble AreaMIL*1Memory
P0100
(DI-23)Mass Air Flow Circuit Malfunc-
tionOpen or short in mass air flow meter circuit
Mass air flow meter
ECM

P0101
(DI-27)Mass Air Flow Circuit Range/
Performance ProblemMass air flow meter
P0110
(DI-28)Intake Air Temp. Circuit Malfunc-
tionOpen or short in intake air temp. sensor circuit
Intake air temp. sensor (built into mass air flow meter)
ECM

P0115
(DI-32)Engine Coolant Temp. Circuit
MalfunctionOpen or short in engine coolant temp. sensor circuit
Engine coolant temp. sensor
ECM

P0116
(DI-36)Engine Coolant Temp. Circuit
Range/Performance ProblemCooling system
Engine coolant temp. sensor
P0120
(DI-38)Throttle/Pedal Position Sensor/
Switch ºAº Circuit MalfunctionOpen or short in throttle position sensor circuit
Throttle position sensor
ECM

P0121
(DI-42)Throttle/Pedal Position Sensor/
Switch ºAº Circuit Range/Perfor-
mance Problem
Throttle position sensor
P0125
(DI-43)Insufficient Coolant Temp. for
Closed Loop Fuel Control
Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
A/F sensor (bank 1, 2 sensor 1)
Air induction system
Fuel pressure
Injector
Gas leakage on exhaust system
ECM

P0128
(DI-48)Thermostat Malfunction
Thermostat
Cooling system
Engine coolant temp. sensor
ECM
P0136
(DI-49)Oxygen Sensor Circuit Malfunc-
tion (Bank 1 Sensor 2)Open or short in heated oxygen sensor circuit
Heated oxygen sensor
P0141
(DI-51)Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)Open or short in heater circuit of heated oxygen sensor
Heated oxygen sensor heater
ECM


- DIAGNOSTICSENGINE
DI-15
171 Author
: Date
:
P0171
(DI-53)System too Lean (Fuel Trim)
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
(DI-53)System too Rich (Fuel Trim)
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

P0174
(DI-53)System too Lean
(A/F Lean Malfunction)Same as DTC P0171
P0175
(DI-53)System too Rich
(A/F Rich Malfunction)Same as DTC P0172
P0300
(DI-58)Random/Multiple Cylinder Misfire
Detected
P0301
(DI-58)Cylinder 1 Misfire DetectedOpen or short in engine wire
Connector connection
Vh tiP0302
(DI-58)Cylinder 2 Misfire Detected
Vacuum hose connection
Ignition system

Injector
P0303
(DI-58)Cylinder 3 Misfire Detected
Injector
Fuel pressure
Mass air flow meter
*2
P0304
(DI-58)Cylinder 4 Misfire Detected
Mass air flow meter
Engine coolant temp. sensor
Compression pressure
Vl lP0305
(DI-58)Cylinder 5 Misfire Detected
Valve clearance
Valve timing

ECM
P0306
(DI-58)Cylinder 6 Misfire Detected
ECM
P0325
(DI-64)Knock Sensor 1 Circuit Malfunc-
tion (Bank 1)Open or short in knock sensor 1 circuit
Knock sensor 1 (looseness)
ECM

P0330
(DI-64)Knock Sensor 2 Circuit Malfunc-
tion (Bank 2)Open or short in knock sensor 2 circuit
Knock sensor 2 (looseness)
ECM

P0335
(DI-67)Crankshaft Position Sensor ºAº
Circuit Malfunction
Open or short in crankshaft position sensor circuit
Crankshaft position sensor
Crankshaft timing pulley
ECM

P0340
(DI-69)Camshaft Position Sensor Circuit
Malfunction
Open or short in camshaft position sensor circuit
Camshaft position sensor
Camshaft timing gear
ECM

P0420
(DI-71)Catalyst System Efficiency Be-
low Threshold (Bank 1)
Gas leakage on exhaust system
A/F sensor (bank 1, 2 sensor 1)
Heated oxygen sensor (bank 1 sensor 2)
Three-way catalytic converter