2001 TOYOTA AVALON check engine

IG0147
Megger
Ground
B02629
P13225
16 mm Plug
Wrench
B02630
1.1 mm IG-2
- IGNITIONIGNITION SYSTEM
1245 Author
: Date
:
2001 AVALON (RM808U)
2. INSPECT SPARK PLUGS
NOTICE:

Never use a wire brush for cleaning.

Never attempt to adjust the electrode gap on a used
spark plug.

Spark plugs should be replaced every 193,000 km
(120,000 miles).
(a) Remove the 6 ignition coils (with igniters) (See page
IG-5).
(b) Inspect the electrode.

Using a megger (insulation resistance meter), mea-
sure the insulation resistance.
Standard correct insulation resistance:
10 MW or more
If the resistance is less than specified, proceed to step (d).
HINT:
If a megger is not available, these simple method of inspection
provides fairly accurate results.

Simple Method:

Quickly race the engine to 4,000 rpm 5 times.

Remove the spark plug (See step (c)).

Visually check the spark plug.
If the electrode is dry ... OK
If the electrode is wet ... Proceed to step (d)

Reinstall the spark plug (See step (g)).
(c) Using a 16 mm plug wrench, remove the 6 spark plugs.
(d) Visually check the spark plug for thread damage and insu-
lator damage.
If abnormal, replace the spark plug.
Recommended spark plug:
DENSO madeSK20R11
NGK madeIFR6A11
(e) Inspect the electrode gaps.
Maximum electrode gap for used spark plug:
1.3 mm (0.051 in.)
If the gap is greater than maximum, replace the spark plug.
Correct electrode gap for new spark plug:
1.1 mm (0.043 in.)
NOTICE:
If adjusting the gap of a new spark plug, bend only the base
of the ground electrode. Do not touch the tip. Never attempt
to adjust the gap on the used plug.

- INTRODUCTIONFOR ALL OF VEHICLES
IN-17
17 Author
: Date
:
2001 AVALON (RM808U)
2. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If large amount of unburned gasoline flows into the converter, it may overheat and create a fire haz-
ard. To prevent this, observe the following precautions and explain them to your customer.
(a) Use only unleaded gasoline.
(b) Avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 minutes.
(c) Avoid spark jump test.
(1) Perform spark jump test only when absolutely necessary. Perform this test as rapidly as possible.
(2) While testing, never race the engine.
(d) Avoid prolonged engine compression measurement.
Engine compression tests must be done as rapidly as possible.
(e) Do not run engine when fuel tank is nearly empty.
This may cause the engine to misfire and create an extra load on the converter.
(f) Avoid coasting with ignition turned off.
(g) Do not dispose of used catalyst along with parts contaminated with gasoline or oil.
3. IF VEHICLE IS EQUIPPED WITH MOBILE COMMUNICATION SYSTEM
For vehicles with mobile communication systems such as two-way radios and cellular telephones, observe
the following precautions.
(1) Install the antenna as far as possible away from the ECU and sensors of the vehicle's electronic
system.
(2) Install the antenna feeder at least 20 cm (7.87 in.) away from the ECU and sensors of the ve-
hicle's electronic systems. For details about ECU and sensors locations, refer to the section on
the applicable component.
(3) Avoid winding the antenna feeder together with other wiring as much as possible, and also avoid
running the antenna feeder parallel with other wire harnesses.
(4) Check that the antenna and feeder are correctly adjusted.
(5) Do not install powerful mobile communications system.
4. FOR USING OBD II SCAN TOOL OR TOYOTA HAND-HELD TESTER
CAUTION:
Observe the following items for safety reasons:

Before using the OBD II scan tool or TOYOTA hand-held tester, the OBD II scan tool's instruc-
tion book or TOYOTA hand-held tester's operator manual should be read thoroughly.

Be sure to route all cables securely when driving with the OBD II scan tool or TOYOTA hand-
held tester connected to the vehicle. (i.e. Keep cables away from feet, pedals, steering wheel
and shift lever.)

Two persons are required when test driving with the OBD II scan tool or TOYOTA hand-held
tester, one person to drive the vehicle and the other person to operate the OBD II scan tool or
TOYOTA hand-held tester.

B09711
B09808
B09711
IN-18
- INTRODUCTIONFOR ALL OF VEHICLES
18 Author
: Date
:
2001 AVALON (RM808U)
5. FOR VEHICLES EQUIPPED WITH TRACTION CON-
TROL (TRAC) & VEHICLE SKID CONTROL (VSC) SYS-
TEM
NOTICE:

When replacing the steering angle sensor or ECU, or
when adjusting the front wheel alignment or steering
wheel center point in accordance with the removing
and installing or replacing the suspension, axle, or
steering parts, make sure to perform the steering
angle sensor zero point calibration (See page
DI-252).

Do not remove or install the VSC related parts unless
necessary. Otherwise, there is a possibility that the
setting of the VSC to be affected.

When working on the VSC related operation, make
sure to check that the preparations before and after
work are completed according to the following
instruction.

When using a drum tester such as a speedometer tes-
ter or chassis dynamometer, etc., or jacking up the
front wheels and driving the wheels, always push in
the TRAC & VSC cut (ºVSC OFFº) switch and turn the
TRAC & VSC system OFF.
(a) Press the VSC OFF switch.
(b) Check that the VSC OFF indicator light comes ON.
HINT:
The VSC OFF indicator light should be always OFF when the
engine is restarted.
(c) Begin measurements.
(d) Press the VSC OFF switch again to change the TRAC &
VSC system to operational condition and check that the
VSC OFF indicator light goes off.
HINT:

The SLIP indicator light blinks when the TRAC system is
operational.

The SLIP indicator light blinks and the VSC buzzer
sounds when the VSC system is operational.

Important Points in the Customer Problem Analysis

What ----- Vehicle model, system name

When ----- Date, time, occurrence frequency

Where ----- Road conditions

Under what conditions? ----- Running conditions, driving conditions, weather conditions

How did it happen? ----- Problem symptoms
(Sample) Engine control system check sheet.
ENGINE CONTROL SYSTEM Check Sheet
Customer's Name
Driver's Name
Data Vehicle
Brought in
License No.
Model and Model
Year
Frame No.
Engine Model
Odometer Reading
km
miles
Problem Symptoms
Engine does
not Start
Difficult to
Start
Poor Idling
Poor
Drive ability
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
Data Problem
ConstantSometimes ( times per day/month)
Inspector's
Name
CUSTOMER PROBLEM ANALYSIS CHECK
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-21
21 Author
: Date
:
2001 AVALON (RM808U)
1. CUSTOMER PROBLEM ANALYSIS
In troubleshooting, the problem symptoms must be confirmed accurately and all preconceptions must be
cleared away in order to give an accurate judgment. To ascertain just what the problem symptoms are, it is
extremely important to ask the customer about the problem and the conditions at the time it occurred.
Important Point in the Problem Analysis:
The following 5 items are important points in the problem analysis. Past problems which are thought to be
unrelated and the repair history, etc. may also help in some cases, so as much information as possible should
be gathered and its relationship with the problem symptoms should be correctly ascertained for reference
in troubleshooting. A customer problem analysis table is provided in Diagnostics section for each system
for your use.

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit
Normal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past
IN-22- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
22 Author
: Date
:
2001 AVALON (RM808U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the AVALON fulfills various functions. The first function is the Diagnostic Trouble
Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the ECU memory
at the time of occurrence, to be output by the technician during troubleshooting. Another function is the Input
Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the AVALON.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
Engine
Automatic Transaxle
Anti-Lock Brake System With Electronic Brake Force Distribution (EBD)
ABS With EBD & BA & TRAC & VSC System
Supplemental Restraint System
Cruise Control System
Engine Immobilizer System
Multiplex Communication System
Air Conditioning System (with Check
Mode)
 (with Check
Mode)











In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble
code check.

V07268
VIBRATION METHOD: When vibration seems to be the major cause.
CONNECTORS
WIRE HARNESS
PARTS AND SENSOR1
Slightly shake the connector vertically and horizontally.
Slightly shake the wire harness vertically and horizontally.
The connector joint, fulcrum of the vibration, and body
through portion are the major areas to be checked thorough-
ly.
Apply slight vibration with a finger to the part of the sensor
considered to be the problem cause and check that the mal-
function occurs.Shake Slightly
Swing Slightly
Vibrate Slightly
HINT:
Applying strong vibration to relays may result in open relays. IN-24
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
24 Author
: Date
:
2001 AVALON (RM808U)
3. SYMPTOM SIMULATION
The most difficult case in troubleshooting is when there are no problem symptoms occurring. In such cases,
a thorough customer problem analysis must be carried out, then simulate the same or similar conditions and
environment in which the problem occurred in the customer's vehicle. No matter how much experience a
technician has, or how skilled he may be, if he proceeds to troubleshoot without confirming the problem
symptoms he will tend to overlook something important in the repair operation and make a wrong guess
somewhere, which will only lead to a standstill. For example, for a problem which only occurs when the en-
gine is cold, or for a problem which occurs due to vibration caused by the road during driving, etc., the prob-
lem can never be determined so long as the symptoms are confirmed with the engine hot condition or the
vehicle at a standstill. Since vibration, heat or water penetration (moisture) is likely cause for problem which
is difficult to reproduce, the symptom simulation tests introduced here are effective measures in that the ex-
ternal causes are applied to the vehicle in a stopped condition.
Important Points in the Symptom Simulation Test:
In the symptom simulation test, the problem symptoms should of course be confirmed, but the problem area
or parts must also be found out. To do this, narrow down the possible problem circuits according to the symp-
toms before starting this test and connect a tester beforehand. After that, carry out the symptom simulation
test, judging whether the circuit being tested is defective or normal and also confirming the problem symp-
toms at the same time. Refer to the problem symptoms table for each system to narrow down the possible
causes of the symptom.

B02389
B02390
HEAT METHOD: When the problem seems to occur when the suspect area is heated. 2
NOTICE:3 WATER SPRINKLING METHOD:
(1)
(2)
4 OTHER: When a malfunction seems to occur when electrical load is excessive.When the malfunction seems to occur on a rainy day or in a
high-humidity condition. Heat the component that is the likely cause of the malfunction
with a hair dryer or similar object. Check to see if the malfunction
occurs.
Sprinkle water onto the vehicle and check to see if the malfunc-
tion occurs.
Turn on all electrical loads including the heater blower, head
lights, rear window defogger, etc. and check to see if the mal-
function occurs.ON HINT:
If a vehicle is subject to water leakage, the leaked water may
contaminate the ECU. When testing a vehicle with a water leak-
age problem, special caution must be taken.
Malfunc-
tion
Do not heat to more than 60 °C (140 °F). (Temperature
is limited not to damage the components.)
Do not apply heat directly to parts in the ECU. (1)
(2)
Never sprinkle water directly into the engine compart-
ment, but indirectly change the temperature and hu-
midity by applying water spray onto the radiator front
surface.
Never apply water directly onto the electronic compo-
nents. NOTICE:
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-25
25 Author
: Date
:
2001 AVALON (RM808U)

DTC No.
Indicates the diagnostic trouble code.

Page or Instructions
Indicates the page where the inspection procedure
for each circuit is to be found, or gives instructions
for checking and repairs.

Detection Item
Indicates the system of the problem or
contents of the problem.
Trouble Area
Indicates the suspect area of the
problem.
Mass Air Flow Circuit MalfunctionDetection Item

Open or short in mass air flow meter circuit

Mass air flow meter

ECM DTC No.
(See page)Trouble AreaMIL* MemoryP0100
(DI-24)
P0101
(DI-28)
P0115
(DI-33)
Open or short in intake air temp. sensor
circuit

Intake air temp. sensor

ECM Intake Air Temp. Circuit
Malfunction P0110
(DI-29)

Open or short in engine coolant temp. sensor circuit

Engine coolant temp. sensor

ECM
Throttle/ Pedal Position Sensor/Switch
ºAº Circuit MalfunctionEngine Coolant Temp.
Circuit Malfunction

Open or short in throttle position sensor circuit

Throttle position sensor

ECM
DTC CHART (SAE Controlled)
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 mode, check the circuit for that code listed in the table
below. For details of each code, turn to the page referred to under the ºSee pageº for the respective ºDTC No.º
in the DTC chart.
Mass Air Flow Circuit
Range/ Performance Problem
Mass air flow meter

Throttle position sensor Throttle/ Pedal Position Sensor/ Switch
ºAº Circuit Range / Performance Prob-
lem P0116
(DI-37)Engine Coolant Temp.
Circuit Range/ Performance Problem
Engine coolant temp. sensor

Cooling system
IN-26- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26 Author
: Date
:
2001 AVALON (RM808U)
4. DIAGNOSTIC TROUBLE CODE CHART
The inspection procedure is shown in the table below. This table permits efficient and accurate troubleshoot-
ing using the diagnostic trouble codes displayed in the diagnostic trouble code check. Proceed with trouble-
shooting in accordance with the inspection procedure given in the diagnostic chart corresponding to the
diagnostic trouble codes displayed. The engine diagnostic trouble code chart is shown below as an example.