2005 TOYOTA AVENSIS Circuit

± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±25
AVENSIS REPAIR MANUAL (RM1018E)
SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE
HINT:

The diagnostic system in AVENSIS has various functions. The first function is the Diagnostic Trouble
Code (DTC) Check, in which a malfunction in the signal circuits to the ECU is stored in code form in
the ECU memory. 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, it is possible to quickly narrow
down potential problem areas and troubleshooting can be performed effectively. The diagnostic func-
tions are incorporated in the following systems in the AVENSIS.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
SFI System (1AZ±FE/1AZ±FSE, 1ZZ±FE/3ZZ±FE)

(with Check Mode)


ECD System (1CD±FTV)

(with Check Mode)


ABS with EBD System



ABS with EBD & BA & TRC & VSC System



Electronically Controlled Automatic Transmission [ECT]

(with Check Mode)

Air Conditioning System


Supplemental Restraint System

Audio System

Power Door Lock Control System


Wireless Door Lock Control System

Key Reminder Warning System

Engine Immobiliser System


Theft Deterrent System


Multiplex Communication System

Cruise Control System



In the DTC check, it is very important to determine whether the problem indicated by the DTC is still
occurring or has occurred in the past but returned to normal at present. In addition during the problem
symptom check, it a check must be made on whether the malfunction indicated by the DTC is directly
related to the problem symptom or not. For this reason, the DTC should be checked before and after
symptom confirmation to determine the current conditions. If this is not done, it may, depending on the
case, result in unnecessary troubleshooting for systems that are operating normally. This would make
more difficult to detect the problem area or to try to repair irrelevant areas. Therefore, always follow
the procedures in the correct order and perform the DTC check.

A flow chart showing how to proceed with troubleshooting using the diagnostic trouble code (DTC)
check is shown the this page. This flow chart shows how to utilize the DTC check effectively. Then,
by carefully checking the results, this chart indicates how to proceed either to the DTC troubleshooting
or to the troubleshooting of the problem symptoms table.
1 DTC check
2 Make a note of DTCs displayed and then clear the memory
3 Symptom confirmation

01±26±
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
AVENSIS REPAIR MANUAL (RM1018E)

Symptoms exist
No symptoms exist
a Go to step 5
b
4 Simulation test using the symptom simulation methods
5 DTC check

DTC displayed
Normal code displayed
a Troubleshooting of problem indicated by DTC
b
6 Symptom confirmation

No symptoms exist
Symptoms exist
If a DTC is displayed in the initial DTC check, it indicates that
a trouble may have occurred in a wire harness or connector in
that circuit in the past. Therefore, check the wire harness and
connectors (See page 01±32). a System normal
b
Troubleshooting of each problem symptom
The problem is still occurring in a place other than the diagnostic circ\
uit (The DTC displayed first is either
for a past problem or a secondary problem).

D25083
Vibrate Slightly
Shake Slightly
Vibrate
Slightly
D25084
Malfunction
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±27
AVENSIS REPAIR MANUAL (RM1018E)
SYMPTOM SIMULATION
HINT:
The most difficult case in troubleshooting is when no symptoms occurs. In such cases, a thorough customer
problem analysis must be carried out. Then the same or similar conditions and environment in which the
problem occurred in the customer's vehicle should be simulated. No matter how much experience a techni-
cian 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 engine is cold,
or for a problem which occurs due to vibration caused by the road during driving, etc., the problem can never
be determined when the engine is hot or when the vehicles is at a standstill. Since vibration, heat or water
penetration (moisture) is a likely cause for the problem which is difficult to reproduce, the symptom simulation
tests introduced here are effective measures in a point that the external causes are applied to the vehicle
in a stationary condition.
Important points in the symptom simulation test:
In the symptom simulation test, the problem symptoms should be confirmed, and the problem area or parts
must also be discovered. To do so, reduce the possible problem circuits according to the symptoms before
starting this type of test and have the hand±held tester connected beforehand. After that, carry out the symp-
tom simulation test, judging whether the circuit being tested is defective or normal and also confirming the
problem symptoms at the same time. Refer to the problem symptoms table of each system to narrow down
the possible causes of the symptom.
1. VIBRATION METHOD: When vibration seems to be
the major cause.
(a) PART AND SENSOR
(1) Apply slight vibration with your finger to the part of
the sensor considered to be the problem cause and
check whether the malfunction occurs.
HINT:
Applying strong vibration to relays may result in open relays.
(b) CONNECTORS
(1) Slightly shake the connector vertically and horizon-
tally.
(c) WIRE HARNESS
(1) Slightly shake the wire harness vertically and hori-
zontally.
The connector joint and fulcrum of the vibration are
the major areas that should be checked thoroughly.
2. HEAT METHOD: If the problem seems to occur when
the area in question is heated.
(a) Heat the component that is the possible cause of the mal-
function with a hair dryer or similar object. Check if the
malfunction occurs.
NOTICE:

Do not heat the components to more than 60C
(140F) (Temperature is limited to keep the compo-
nents from being damaged).

Detection Item
Indicates the system or details of the
problem. Trouble Area
Indicates the suspect areas of
the problem.
Detection Item
DTC No.
(See page)
Trouble Area
SRS


Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness
B0103/12
(05±132) B0102/11
(05±128)
DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is displayed during the DTC check, check the circuit for that code liste\
d in the table
below (Proceed to the page given for that circuit).

Short in D squib circuit

Open in D squib circuit
B0101/14
(05±124)

Short in D squib circuit (to ground)

Short in D squib circuit (to B+)
Warning Light
ON
ON
ON
ON


Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness

Steering wheel pad (squib)

Spiral cable

Airbag sensor assembly

Wire harness
B0105/53
(05±136) ON

Airbag sensor assembly

Wire harness
B0106/54

Open in P squib circuit

Airbag sensor assembly

Wire harness


Short in P squib circuit (to Ground) ON
ON
B0100/13
(05±119)

Short in P squib circuit

Front passenger airbag assembly (squib)

Airbag sensor assembly

Wire harness

Front passenger airbag assembly (squib)

Front passenger airbag assembly (squib)
Page or Instructions
Indicates the page where the inspection proce-
dures for each circuit is to be found, or gives
instructions for checking and repairs.


DTC No.
Indicates the diagnostic trouble code.



±
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±29
AVENSIS REPAIR MANUAL (RM1018E)
DIAGNOSTIC TROUBLE CODE CHART
The inspection procedures are shown in the table below. This table allows efficient and accurate trouble-
shooting using the diagnostic trouble codes displayed in the diagnostic trouble code chart. Proceed with
troubleshooting in accordance with the inspection procedures listed in the diagnostic c\
hart corresponding
to the diagnostic trouble codes displayed. The diagnostic trouble code chart for the Supplemental Restraint
System is shown below as an example.

01±30±
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
AVENSIS REPAIR MANUAL (RM1018E)
PROBLEM SYMPTOMS TABLE
The suspected circuits or parts for each problem symptom are shown in the t\
able below. Use this table to
troubleshoot the problem when a Normal code is displayed in the diagnostic trouble c\
ode chart but the prob-
lem is still occurring. Numbers in the table indicate the order in which\
the circuits or parts should be checked.
HINT:
When the problem is not detected by the diagnostic system even though the pr\
oblem symptom is present,
it may be that the problem is occurring outside the detection range of t\
he diagnostic system.
Symptom Suspected AreaSee page
1. With the ignition switch in ACC or ON position, the SRS warning
light sometimes lights up after approx. 6 seconds have elapsed.
2. SRS warning light is always lit up even when ignition switch is
in the LOCK position
1. With the ignition switch in the ACC or ON position, the SRS
warning light does not light up.
PROBLEM SYMPTOMS TABLE
1. DTC is not displayed. 05±187 05±183
Problem SymptomPage
Indicates the page where the flow chart for each circuit
is located.
Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for each problem
symptom. Check in the order indicated by the numbers.
Circuit or Part Name
Indicates the circuit or part which needs to be checked.
Proceed with troubleshooting of each circuit in the table below.
1. SRS warning light circuit
(Always lights up when ignition switch is in
LOCK position.)
1. SRS warning light circuit
(Does not light up when ignition switch is turned
to ACC or ON.)
1. Tc terminal circuit
05±180





3. DTC is displayed without Tc and CG terminal connection. 2. SRS warning light is always lit up at the time of DTC check
procedure.

SFI
SFISFI
SFISFI
SFI
D25842

Circuit Description
The major role and, operation of the circuit
and its component parts are explained.

Diagnostic Trouble Code No. and Detection Item

Indicates the diagnostic trouble codes, diagnostic
trouble code settings and suspect areas for a
problem.
Wiring Diagram
This shows a wiring diagram of the circuit.
Use this diagram together with ELECTRICAL
WIRING DIAGRAM to thoroughly understand the
circuit.
Wire colors are indicated by an alphabetical code.
B = Black, L = Blue, R = Red, BR = Brown,
LG = Light Green, V = Violet, G = Green,
O = Orange, W = White, GR = Gray, P = Pink,
Y = Yellow, SB = Sky Blue
The first letter indicates the basic wire color and
the second letter indicates the color of the stripe.
Inspection Procedures
Use the inspection procedures to determine
if the circuit is normal or abnormal. If it is ab-
normal, use it to determine whether the prob-
lem is located in the sensors, actuators, wire
harness or ECU.

Indicates the condition of the connector of the ECU
during the check.


Connections of tester are
indicated by (+), (±) after
terminals name.
Connector being checked
is connected.Connector being checked
is disconnected.
For inspection of connector
with body ground, there is
nothing about the body
ground written down.
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±31
AVENSIS REPAIR MANUAL (RM1018E)
CIRCUIT INSPECTION
How to read and use each page is shown below.

010B6±13
±
INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01±21
AVENSIS REPAIR MANUAL (RM1018E)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
There are many ECU controlled systems used in the AVENSIS. In general, ECU controlled system are con-
sidered to be very intricate and require a high level of technical knowledge an\
d expert skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, troubleshoo\
ting of these sys-
tems is not complex. If you have adequate understanding of the system and ba\
sic knowledge of electricity,
the problem can be accurately diagnosed and fixed. This manual is design\
ed based on the above principle
to help service technicians perform accurate and effective troubleshooting, and is compiled for the following
major ECU controlled systems:
The troubleshooting procedures are described on the following pages.
SystemPage
1. SFI System [1ZZ±FE, 3ZZ±FE]05±1
2. SFI System [1AZ±FE]05±143
3. SFI System [1AZ±FSE]05±290
4. ECD System [1CD±FTV]05±523
5. ABS with EBD System05±696
6. ABS with EBD & BA & TRC & VSC System05±752
7. Electronic Controlled Automatic Transmission [ECT] [U241 (1AZ±FE)]05±856
8. Electronic Controlled Automatic Transmission [ECT] [U241 (1AZ±FSE)]05±915
9. Electronic Controlled Automatic Transmission [ECT] [U341]05±980
10.Electronic Motor Power Steering System05±1042
11. Air Conditioning System05±1088
12.Combustion Type Power Heater System05±1161
13.Supplemental Restraint System05±1181
14.Audio System05±1393
15.Navigation System05±1435
16.Combination Meter05±1497
17.Power Door Lock Control System05±1534
18.Wireless Door Lock Control System05±1568
19.Key Reminder Warning System05±1586
20.Engine Immobiliser System05±1599
21.Theft Deterrent System05±1627
22.Multiplex Communication System05±1654
23.Cruise Control System05±1697
FOR USING HAND±HELD TESTER

Before using the tester, the tester's operator manual should be read thoroughly.

If the tester cannot communicate with the ECU controlled systems when you \
have connected the cable
of tester to the DLC3, turned the ignition switch ON and operated the test\
er, there is a problem on the
vehicle side or tester side.
(1) If the communication is normal when the tester is connected to another veh\
icle, inspect the diag-
nosis data link line (Bus
line) or ECU power circuit of the vehicle.
(2) If the communication is still impossible when the tester is connected to a\
nother vehicle, the prob- lem is probably in the tester itself, so perform the Self Test procedures outlined in the Tester Oper-
ator 's Manual.

A75348  



AB Temprature SensorB+
Power Transistor
Platinum Hot Wire
Output
Voltage
Platinum Hot Wire
Temprature Sensor 05±24
± DIAGNOSTICSSFI SYSTEM (1ZZ±FE/3ZZ±FE)
AVENSIS REPAIR MANUAL (RM1018E)
DTC P0100 MASS AIR FLOW CIRCUIT MALFUNCTION
CIRCUIT DESCRIPTION
The mass air flow meter uses a platinum hot wire. The hot wire air flow meter consists of a platinum hot wire,
temprature sensor and a control circuit installed in a plastic housing. The hot wire air flow meter works on
the principle that the hot wire and temprature sensor located in the intake air bypass of the housing detect
any changes in the intake air temperature.
The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This
current flow is then measured as the output voltage of the mass air flow meter.
The circuit is constructed so that the platinum hot wire and temprature sensor provide a bridge circuit, with
the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.
DTC NoDTC Detecting ConditionTrouble Area
P0100Open or short in mass air flow meter circuit with engine speed
less than 4,000 rpm for more than 3 sec.
Open or short in mass air flow meter circuit

Mass air flow meter

ECM
HINT:
After confirming DTC ºP0100º, use the hand±held tester to confirm the air flow ratio in the ºDIAGNOSIS /
OBD/MOBD / DATA LIST / ALLº.
Air Flow Value (gm/sec)Malfunction
Approx. 0.0
Mass air flow meter power source circuit open

VG circuit open or short
271.0 or more
EVG circuit open
05C68±01