1999 TOYOTA AVENSIS display

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
– INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN–21
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the AVENSIS/ CORONA fulfills various functions. The first function is the Diagnos-
tic 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 AVENSIS/
CORONA.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Other Diagnosis
Function
Supplemental Restraint System
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.

Diagnostic trouble code check
Making a note of and clearing of the diagnostic trouble codes displayed
Symptom confirmation
No problem symptoms
exist Problem symptoms
exist
Simulation test using the symptom
simulation methods
 Normal code displayed
 Problem symptoms exist Normal code displayed
 No problem symptoms exist Diagnostic trouble code check
Troubleshooting of problem indicated
by diagnostic trouble code Diagnostic trouble code displayed
 Problem symptoms exist
System Normal Troubleshooting of each
problem symptom
If a diagnostic trouble code was
displayed in the initial diagnostic
trouble code check, it indicates
that the trouble may have occurred
in a wire harness or connector in
that circuit in the past. Therefore,
check the wire harness and con-
nectors (See page IN–29).
IN–22– INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
Taking into account the above points, a flow chart showing how to proceed with troubleshooting using the
diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnostic trouble
code check effectively, then by carefully checking the results, indicates how to proceed either to diagnostic
trouble code troubleshooting or to troubleshooting of problem symptoms.

Detection Item DTC No.
(See page)Trouble AreaSRS
DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the table
below. (Proceed to the page given for that circuit).
Warming Light
ON
ON
ON
ON
ON
ON
ON
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. 
11
(DI–165)
12
(DI–170)
13
(DI–174)
14
(DI–178)
15
(DI–178)
16
airbag sensor assembly malfunction Front airbag sensor assembly (RH)
malfunction Short in D squib circuit (to ground)
Short in D squib circuit (to B)
Short in D squib circuit
Open in D squib circuit
Front airbag sensor assembly (LH)
malfunction Steering wheel pad (squib)
 Spiral cable
 Airbag sensor assembly
 Wire harness
 Front airbag sensor assembly (RH)
 Wire harness
 Front airbag sensor assembly (LH)
 Wire harness  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
Airbag sensor assembly
 Front passenger airbag sensor assembly (squib)
 Airbag sensor assembly Short in P squib circuit (to ground)ON
– INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN–25
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 Supplemental Restraint System diagnostic trouble code chart is
shown below as an example.

IN–26– INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
5. PROBLEM SYMPTOMS TABLE
The suspected circuits or parts for each problem symptom are shown in the table below. Use this table to
troubleshoot the problem when a ”Normal” code is displayed in the diagnostic trouble code check but the
problem is still occurring. Numbers in the table indicate the inspection order in which the circuits or parts
should be checked.
HINT:
When the problem is not detected by the diagnostic system even though the problem symptom is present,
it is considered that the problem is occurring outside the detection range of the diagnostic system, or that
the problem is occurring in a system other than the diagnostic system.
Symptom
Suspect AreaSee page
With the ignition switch in the ACC or ON position, the SRS warning
light sometimes lights up after approx. 6 seconds have elapsed.
SRS warning light is always lit up even when ignition switch is in
the LOCK position
With the ignition switch in the ACC or ON position, the SRS warning
light does not light up.
PROBLEM SYMPTOMS TABLE
DTC is not displayed.
SRS warning light is always lit up at the time of DTC check
procedure.
DTC is displayed without Tc and E1 terminal connection.DI–294 DI–290
 Problem Symptom
Proceed with troubleshooting of each circuit in the table below.
 SRS warning light circuit
(Always lights up when ignition switch is in
LOCK position.)
 SRS warning light circuit
(Dose not light up when ignition switch is turned to
ACC or ON.)
 Tc terminal circuit
DI–288
Circuit Inspection, Inspection Order
Indicates the circuit which needs to be checked for each problem
symptom. Check in the order indicated by the numbers. Page
Indicates the page where the flow chart for each circuit
is located. 
Circuit or Part Name
Indicates the circuit or part which needs to be checked. 







– INTRODUCTIONTERMS
IN–35
FFFront–Engine Front–Wheel–Drive
FIPGFormed In Place Gasket
FLFusible Link
FrFront
FRFront–Engine Rear–Wheel–Drive
FWDFront–Wheel–Drive
GNDGround
H/BHatchback
HIHigh
HIDHigh Intensity Discharge (Head Lamp)
HTHard Top
HWSHeated Windshield System
IACIdle Air Control
IFSIndependent Front Suspension
IGIgnition
INTIntermittent
I/PInstrument Panel
IRSIndependent Rear Suspension
J/BJunction Block
J/CJunction Connector
LANLocal Area Network
LBLiftback
LCDLiquid Crystal Display
LEDLight Emitting Diode
LHLeft–Hand
LHDLeft–Hand Drive
LOLow
LSDLimited Slip Differential
LSP & PVLoad Sensing Proportioning And Bypass Valve
LSPVLoad Sensing Proportioning Valve
MAPManifold Absolute Pressure
MAX.Maximum
MICMicrophone
MILMalfunction Indicator Lamp
MIN.Minimum
MPMultipurpose
MPIMultipoint Electronic Fuel Injection
MPXMultiplex Communication System
M/TManual Transmission
NNeutral
No.Number
O2SOxygen Sensor
O/DOverdrive
OPTOption
P & BVProportioning And Bypass Valve
PCSPower Control System

DI694–01
DI–4
– DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DIAGNOSTIC TROUBLE CODE CHART
If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the table
below (Proceed to the page given for that circuit.).
DTC No.
(See Page)Detection ItemTrouble AreaSRS
Warning Light
81
(DI–8)Short in curtain shield airbag (RH) cir-
cuit (to ground)
Curtain shield airbag (RH) (squib)

Airbag sensor assembly

Wire harness
Blink
82
(DI–12)Short in curtain shield airbag (RH) cir-
cuit circuit (to B+)
Curtain shield airbag (RH) (squib)

Airbag sensor assembly

Wire harness
Blink
83
(DI–15)Short in curtain shield airbag (RH) squib
circuit
Curtain shield airbag (RH) (squib)

Airbag sensor assembly

Wire harness
Blink
84
(DI–18)Open in curtain shield airbag (RH) squib
circuit
Curtain shield airbag (RH) (squib)

Airbag sensor assembly

Wire harness
Blink
85
(DI–21)Short in curtain shield airbag (LH) circuit
(to ground)
Curtain shield airbag (LH) (squib)

Airbag sensor assembly

Wire harness
Blink
86
(DI–25)Short in curtain shield airbag (LH) circuit
circuit (to B+)
Curtain shield airbag (LH) (squib)

Airbag sensor assembly

Wire harness
Blink
87
(DI–28)Short in curtain shield airbag (LH) squib
circuit
Curtain shield airbag (LH) (squib)

Airbag sensor assembly

Wire harness
Blink
88
(DI–31)Open in curtain shield airbag (LH) squib
circuit
Curtain shield airbag (LH) (squib)

Airbag sensor assembly

Wire harness
Blink
HINT:

When the SRS warning light remains lit up and the DTC is the normal code, this means a voltage source
drops.
This malfunction is not stored in memory by the airbag sensor assembly and if the power source volt-
age returns to normal, the SRS warning light will automatically go out.

When 2 or more codes are indicated, the codes will be displayed in numeral order starting from the
lowest numbered code.

If a code not listed on the chart is displayed, the airbag sensor assembly is faulty.

I04818
SPEEDOMETER
TACHOMETER
WATER TEMP.
FUEL
OIL LEVEL
ODO / TRIP
METER
OUTSIDE TEMP.
CLOCK
RHEOSTATLCD
DISPLAY
LCD
DISPLAY S
T
W
FA18
B7
B20 A5
A15
A3
A6
A7
A8
A12
A11
A19
A10
A9
B11
B24
B5
A22
B4
A23
B14
A23
A25
B16
B14
B21
A22
A14VOLTAGE
STABILIZER
B17
B22
B9
B26
A24 Brake Warning
Fuel filter Warning
Discharge Waring
Economy Indicator
Turbo / Glow Plug Indicator
Glow Plug Indicator
ABS Warning
Low Oil Pressure Warning
Check Engine Warning
O / D OFF Indicator
ECT SNOW Indicator
ECT PWR Indicator
Rear Fog Light Indicator
High Beam Indicator
Right Turn Indicator
Left Turn Indicator
Open Door Warning
SRS Warning
Front Fog light Indicator A1
B15
B18A26
B2
A17
B1
B13
B6
B3 B19
BE–4
– BODY ELECTRICALCOMBINATION METER

AC29V–02



I12508
DTC Check Harness
Current DisplayControl PanelPast Record DTC Display
In Normal
In Malfuction
”Heating”
Symbol
Memory Clear Button
DTC Calling ButtonDTC Calling Button
Connector BConnector A
– AIR CONDITIONINGCOMBUSTION TYPE POWER HEATER
AC–9
COMBUSTION TYPE POWER HEATER
ON–VEHICLE INSPECTION
NOTICE:

If the glow plug breaks, the ECU detects the breakage and stops the automatic operation, so
the burner heater does not activate. (For other failures, similarly activated.)

The cause of failures (such as voltage malfunction, overheating malfunction, short–circuit or
breakage of functional componects, etc.) and how to remedy are shown by connecting the DTC
tester and reading the DTC.
1. OPERATION
(a) Connect the DTC tester between the connector A (Vehicle harness) of DTC check harness and con-
nector B (Power heater harness).
(b) Start the engine.
(c) Pressing the DTC calling button displays a 3–digit number DTC.