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-18- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 TERCEL (RM440U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the TERCEL 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 TERCEL.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
1. Engine
(with Check Mode)
2. Anti-Lock Brake System
3. Supplemental Restraint System
4. Power Door Lock Control System
5. Theft Deterrent 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-26).
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-19
1996 TERCEL (RM440U)
Taking into account the points on the previous page, a flow chart showing how to proceed with troubleshoot-
ing using the diagnostic trouble code check is shown below. This flow chart shows how to utilize the diagnos-
tic 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 table.
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
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 the 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
SAE CONTROLLED
DIAGNOSTIC TROUBLE CODE CHART
IN-22- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
1996 TERCEL (RM440U)
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.
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN-23
1996 TERCEL (RM440U)
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 ºNormalº 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
Suspected AreaSee page
Engine does not crank (Does not start)
No initial combustion (Does not start)
No complete combustion (Does not start)1. Starter and starter relay
1. ECM power source circuit
2. Fuel pump control circuit
3. ECM
1. Starter signal circuit
2. Fuel pump control circuit1. Fuel pump control circuitDI-147
DI-151
IN-29
PROBLEM SYMPTOMS TABLE
1. Compression
2. Fuel pump control circuit 1. A/C signal circuit
2. Fuel pump control circuit 1. A/C signal circuit (Compressor circuit)
2. ECM power source circuit 1. Starter signal circuit
2. Fuel pump control circuit1. Starter signal circuit
2. Fuel pump control circuit
3. Compression
idling) High engine idle speed (Poor idling) Hot engine Cold engine (Difficult to start)Engine cranks normally (Difficult to start)
AC-88 DI-144
DI-151
EM-3 DI-151
Problem Symptom Page
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.
ST-2
ST-17
DI-144
DI-151
DI-144
DI-151
- INTRODUCTIONTERMS
IN-33
33 Author: Date:
1996 TERCEL (RM440U) H/B
Hatchback
H-FUSEHigh Current Fuse
HIHigh
HIDHigh Intensity Discharge (Head Lamp)
HPUHydraulic Power Unit
HSGHousing
HTHard Top
HWSHeated Windshield System
IACIdle Air Control
ICIntegrated circuit
IDIIndirect Diesel Injection
IFSIndependent Front Suspension
IGIgnition
IIAIntegrated Ignition Assembly
INIntake (Manifold, Valve)
INTIntermittent
I/PInstrument Panel
IRSIndependent Rear Suspension
J/BJunction Block
J/CJunction Connector
KDKick-Down
LANLocal Area Network
LBLiftback
LCDLiquid Crystal Display
LEDLight Emitting Diode
LHLeft-Hand
LHDLeft-Hand Drive
L/H/WLength, Height, Width
LLCLong-Life Coolant
LNGLiquified Natural Gas
LOLow
LPGLiquified Petroleum Gas
LSDLimited Slip Differential
LSP & PVLoad Sensing Proportioning And Bypass Valve
LSPVLoad Sensing Proportioning Valve
MAX.Maximum
M-FUSEMedium Current Fuse
MICMicrophone
MILMalfunction Indicator Lamp
MIN.Minimum
MPMultipurpose
MPXMultiplex Communication System
M/TManual Transmission (Transaxle)
MTMount
MTGMounting
NNeutral
DI4LC-02
Vehicle Brought to Workshop
Customer Problem Analysis
Problem Symptom Confirmation
If the engine does not start, perform steps 10 and 12 firstConnect the OBD II scan tool or TOYOTA hand-held tester to DLC3 P. DI-3
If the display indicates a communication fault in the tool, inspect DLC3 P. DI-3
Check DTC and Freeze Frame Data (Pre-check)
Record or Print DTC and Freeze Frame Data P. DI-3
Clear DTC and Freeze Frame Data P. DI-3
Visual Inspection
Setting the Check Mode Diagnosis P. DI-3
Symptom Simulation P. IN-16
Basic Inspection P. DI-3DTC Chart P. DI-13
Matrix Chart of Problem Symptom P. DI-19
Circuit Inspection P. DI-20
Adjustment, Repair
DTC Check P. DI-3
Titles insideare titles of pages in
in the bottom portion. See the indicated
pages for detailed explanations. this manual, with the page number indicated
Malfunction
occurs.Malfunction does not occur.
Parts Inspection
Check for Intermittent Problems P. DI-3
Identification of Problem
Confirmation Test
End 1
2
3
4
5
6
7
108
9
11
12
13
15 14
16
Normal Malfunction code.
17
P. DI-2
- DIAGNOSTICSENGINE
DI-1
175 Author: Date:
1996 TERCEL (RM440U)
ENGINE
HOW TO PROCEED WITH TROUBLESHOOTING
Troubleshoot in accordance with the procedure on the following pages.
S00840
- DIAGNOSTICSENGINE
DI-5
1996 TERCEL (RM440U)Terminal No.
Connection / Voltage or ResistanceCondition
7Bus + Line / Pulse generationDuring transmission
4Chassis Ground - Body Ground / 1 W or lessAlways
5Signal Ground - Body Ground / 1 W or lessAlways
16Battery Positive - Body Ground / 9 - 14 VAlways
HINT:
If your display shows ºUNABLE TO CONNECT TO VEHICLEº
when you have connected the cable of the OBD II scan tool or
TOYOTA hand-held tester to DLC3, turned the ignition switch
ON and operated the scan tool, there is a problem on the ve-
hicle side or tool side.
If communication is normal when the tool is connected to
another vehicle, inspect DLC3 on the original vehicle.
If communication is still not possible when the tool is con-
nected to another vehicle, the problem is probably in the
tool its self, so consult the Service Department listed in
the tool's instruction manual.
2. Normal Mode:
INSPECT DIAGNOSIS
(a) Check the MIL.
(1) The MIL comes on when the ignition switch is turned
ON and the engine is not running.
HINT:
If the MIL does not light up, troubleshoot the combination meter.
(2) When the engine started, the MIL should go off. If
the lamp remains on, the diagnosis system has de-
tected a malfunction or abnormality in the system
(b) Check the DTC.
NOTICE:
TOYOTA hand-held tester only: When the diagnosis sys-
tem is switched from the normal mode to the check mode,
it erases all DTC and freeze frame data recorded in the nor-
mal mode. So before switching modes, always check the
DTC and freeze frame data, and note them down.
(1) Prepare the OBD II scan tool (complying with SAE
J 1978) or TOYOTA hand-held tester.
(2) Connect the OBD II scan tool or TOYOTA hand-
held tester to DLC3 in the fuse box at the lower left
of the instrument panel.
(3) Turn the ignition switch ON and turn the OBD II scan
tool or TOYOTA hand-held tester switch ON.
(4) Use the OBD II scan tool or TOYOTA hand-held
tester to check the DTC and freezed frame data;
note them down (For operating instructions, see the
OBD II scan tool's instruction book.).
(5) See page DI-13 to confirm the details of the
DTC.
- DIAGNOSTICSENGINE
DI-1 1
1996 TERCEL (RM440U)
Proceed to matrix chart of problem symp-
toms on page DI-19.
7. ENGINE OPERATING CONDITION
NOTICE:
The values given below for ºNormal Conditionº are representative values, so a vehicle may still be
normal even if its value from those listed here. So do not decide whether a part is faulty or not solely
according to the ºNormal Conditionº here.
CARB mandated signals:
TOYOTA hand-held tester displayMeasurement ItemNormal Condition*
FUEL SYS #1
Fuel System Bank 1
OPEN: Air-fuel ratio feedback stopped
CLOSED: Air-fuel ratio feedback operating
Idling after warming up: CLOSED
CALC LOAD
Calculator Load:
Current intake air volume as a proportion of max.
intake air volumeIdling: 19.7 - 47.4 %
Racing without load (2,500rpm): 18.8 - 46.4 %
COOLANT TEMP.Engine Coolant Temp. Sensor ValueAfter warming up: 80 - 95°C (176 - 203°F)
SHORT FT #1Short-term Fuel Trim Bank 10 ± 20%
LONG FT #1Long-term Fuel Trim Bank 10 ± 20%
ENGINE SPDEngine SpeedIdling: 700 - 800 rpm
VEHICLE SPDVehicle SpeedVehicle Stopped: 0 km/h (0 mph)
IGN ADVANCEIgnition Advance:
Ignition Timing of Cylinder No. 1Idling: BTDC 7 - 14°
INTAKE AIRIntake Air Temp. Sensor ValueEquivalent to Ambient Temp.
MAPAbsolute Pressure Inside Intake Manifold
Idling: 20 - 48 kPa
Racing without load (2,500 rpm):
19 - 47 kPa
THROTTLE POS
Voltage Output of Throttle Position Sensor
Calculated as a percentage:
0 V "0%, 5 V "100%Throttle Fully Closed: 6 - 16 %
Throttle Fully Open: 64 - 98 %
O2S B1, S1Voltage Output of Heated Oxygen Sensor
Bank 1, Sensor 1Idling: 0.1 - 0.9 V
O2FT B1, S1Oxygen Sensor Fuel Trim Bank 1, Sensor 1
(Same as SHORT FT #1)0 ± 20 %
O2S B1, S2Voltage Output of Oxygen Sensor
Bank 1, Sensor 2Driving at 50 km/h (31 mph): 0.1 - 0.9 V
*: If no conditions are specifically stated for ºldlingº, it means the shift lever is at N or P position, the A/C switch
is OFF and all accessory switches are OFF.