Downloaded from www.Manualslib.com manuals search engine 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
Datas Problem
ConstantSometimes ( times per day/month)
Inspector’s
Name
CUSTOMER PROBLEM ANALYSIS CHECK
− INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN−17
1996 TOYOTA T100 (RM449U)
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 judgement. 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 the troubleshooting section for each
system for your use.
Downloaded from www.Manualslib.com manuals search engine 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 TOYOTA T100 (RM449U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the TOYOTA T100 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 TOYOTA
T100.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Other Diagnosis
Function
Engine (3RZ−FE, 5VZ−FE)
Automatic Transmission
Anti−Lock Brake system
Supplemental Restraint System
Cruise Control (with Test Mode)
(with Test Mode)
Cancel Signal
Check
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.
Downloaded from www.Manualslib.com manuals search engine IN02M−01
− INTRODUCTIONTERMS
IN−33
1996 TOYOTA T100 (RM449U)
GLOSSARY OF SAE AND TOYOTA TERMS
This glossary lists all SAE−J1930 terms and abbreviations used in this manual in compliance with SAE rec-
ommendations, as well as their Toyota equivalents.
SAE
ABBREVIATIONSSAE TERMSTOYOTA TERMS
( )−−ABBREVIATIONS
A/CAir ConditioningAir Conditioner
ACLAir CleanerAir Cleaner
AIRSecondary Air InjectionAir Injection (AI)
APAccelerator Pedal−
B+Battery Positive Voltage+B, Battery Voltage
BAROBarometric Pressure−
CACCharge Air CoolerIntercooler
CARBCarburetorCarburetor
CFIContinuous Fuel Injection−
CKPCrankshaft PositionCrank Angle
CLClosed LoopClosed Loop
CMPCamshaft PositionCam Angle
CPPClutch Pedal Position−
CTOXContinuous Trap Oxidizer−
CTPClosed Throttle Position−
DFIDirect Fuel Injection (Diesel)Direct Injection (DI)
DIDistributor Ignition−
DLC1
DLC2
DLC3Data Link Connector 1
Data Link Connector 2
Data Link Connector 31: Check Connector
2: Total Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
DTCDiagnostic Trouble CodeDiagnostic Code
DTMDiagnostic Test Mode−
ECLEngine Control Level−
ECMEngine Control ModuleEngine ECU (Electronic Control Unit)
ECTEngine Coolant TemperatureCoolant Temperature, Water Temperature (THW)
EEPROMElectrically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
(EEPROM),
Erasable Programmable Read Only Memory (EPROM)
EFEEarly Fuel EvaporationCold Mixture Heater (CMH), Heat Control Valve (HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR)
EIElectronic IgnitionDistributorless Ignition (DI)
EMEngine ModificationEngine Modification (EM)
EPROMErasable Programmable Read Only MemoryProgrammable Read Only Memory (PROM)
EVAPEvaporative EmissionEvaporative Emission Control (EVAP)
FCFan Control−
FEEPROMFlash Electrically Erasable Programmable
Read Only Memory−
FEPROMFlash Erasable Programmable Read Only Memory−
FFFlexible Fuel−
FPFuel PumpFuel Pump
GENGeneratorAlternator
GNDGroundGround (GND)
Downloaded from www.Manualslib.com manuals search engine DI0T5−02
Vehicle Brought to Workshop
Customer Problem Analysis P. DI−2
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 Freezed Frame Data (Precheck)
Record or Print DTC and Freezed Frame Data P. DI−3
Clear DTC and Freezed 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
Problem Symptoms Table P. DI−21
Circuit Inspection P. DI−22
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
− DIAGNOSTICSENGINE (3RZ−FE)
DI−1
258 Author: Date:
1996 TOYOTA T100 (RM449U)
ENGINE (3RZ−FE)
HOW TO PROCEED WITH TROUBLESHOOTING
Troubleshoot in accordance with the procedure on the following page.
Downloaded from www.Manualslib.com manuals search engine FI0534
DI0T7−03
FI7231
TOYOTA Hand−Held Tester
DLC3
− DIAGNOSTICSENGINE (3RZ−FE)
DI−3
1996 TOYOTA T100 (RM449U)
PRE−CHECK
1. DIAGNOSIS SYSTEM
(a) Description
When troubleshooting OBD II vehicles, the only dif-
ference from the usual troubleshooting procedure
is that you connect to the vehicle the OBD II scan
tool complying with SAE J1978 or TOYOTA hand−
held tester, and read off various data output from
the vehicle’s ECM.
OBD II regulations require that the vehicle’s on−
board computer lights up the Malfunction Indicator
Lamp (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable Diagnostic
Trouble Code (DTC) prescribed by SAE J2012 are
recorded in the ECM memory (See page DI−13).
If the malfunction does not reoccur in 3 trips, the MIL goes off
but the DTCs remain recorded in the ECM memory.
To check the DTCs, connect the OBD II scan tool or
TOYOTA hand−held tester to the Data Link Con-
nector 3 (DLC3) on the vehicle. The OBD II scan
tool or TOYOTA hand−held tester also enables you
to erase the DTCs and check freezed frame data
and vaious forms of engine data (For operating
instructions, see the OBD II scan tool’s instruction
book.).
DTCs include SAE controlled codes and manufac-
turer controlled codes. SAE controlled codes must
be set as prescribed by the SAE, while manufactur-
er controlled codes can be set freely by the
manufacturer within the prescribed limits (See DTC
chart on page DI−13).
The diagnosis system operates in normal mode
during normal vehicle use. It also has a check mode
for technicians to simulate malfunction symptoms
and troubleshoot. Most DTCs use 2 trip detection
logic* to prevent erroneous detection, and ensure
thorough malfunction detection. By switching the
ECM to check mode when troubleshooting, the
technician can cause the MIL to light up for a mal-
function that is only detected once or momentarily
(TOYOTA hand−held tester only) (See step 2).
*2 trip detection logic: When a logic malfunction is
first detected, the malfunction is temporarily stored
in the ECM memory. If the same malfunction is de-
tected again during the 2nd drive test, this 2nd
detection causes the MIL to light up.
Downloaded from www.Manualslib.com manuals search engine N09214
DLC3 DI−4
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
The 2 trip repeats the same mode a 2nd time (How-
ever, the ignition switch must be turned OFF be-
tween the 1st trip and 2nd trip.).
Freeze frame data:
Freeze frame data records the engine condition
when a misfire (DTCs P0300 − P0304) or fuel trim
malfunction (DTCs P0171, P0172) or other mal-
function (first malfunction only), is detected.
Because freeze frame data records the engine
conditions (fuel system, calculator load, engine
coolant temperature, fuel trim, engine speed, ve-
hicle speed, etc.) when the malfunction is detected,
when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the en-
gine warmed up or not, the air−fuel ratio lean or rich,
etc. at the time of the malfunction.
Priorities for troubleshooting:
If troubleshooting priorities for multiple DTCs are given in the
applicable DTC chart, these should be followed.
If no instructions are given troubleshoot DTCs according to the
following priorities.
(1) DTCs other than fuel trim malfunction (DTCs
P0171, P0172), EGR (DTCs P0401, P0402), and
misfire (DTC P0300 − P0304).
(2) Fuel trim malfunction (DTCs P0171, P0172), and
EGR (DTCs P0401, P0402).
(3) Misfire (DTCs P0300 ∼ P0304).
(b) Check the DLC3.
The vehicle’s ECM uses V.P.W. (Variable Pulse Width) for
communication to comply with SAE J1850. The terminal
arrangement of DLC3 complies with SAE J1962 and
matches the V.P.W. format.
Terminal No.Connection / Voltage or ResistanceCondition
2Bus Line / Pulse generationDuring transmission
4Chassis Ground ↔ Body Ground / 1 Ω or lessAlways
5Signal Ground ↔ Body Ground / 1 Ω or lessAlways
16Battery Positive ↔ Body Ground / 9 − 14 VAlways
Downloaded from www.Manualslib.com manuals search engine A00653
w/o Tachometer
w/ Tachometer
− DIAGNOSTICSENGINE (3RZ−FE)
DI−5
1996 TOYOTA T100 (RM449U)
HINT:
If your display shows ”UNABLE TO CONNECT TO VEHICLE”
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 itself, so consult the Service Department listed in the
tool’s instruction manual.
2. INSPECT DIAGNOSIS (Normal Mode)
(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 normal mode to check mode, it
erases all DTCs and freezed frame data recorded in normal
mode. So before switching modes, always check the DTCs
and freezed frame data, and note them down.
(1) Prepare the OBD II scan tool (complying with SAE
J1978) or TOYOTA hand−held tester.
(2) Connect the OBD II scan tool or TOYOTA hand−
held tester to the DLC3 at the lower of the instru-
ment 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 DTCs 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
DTCs.
Downloaded from www.Manualslib.com manuals search engine FI3605
ON
OFFFlashing
0.13 Second
DI−6
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
NOTICE:
When simulating symptoms with an OBD II scan tool (ex-
cluding TOYOTA hand−held tester) to check the DTCs, use
normal mode. For code on the DTC chart subject to ”2 trip
detection logic”, turn the ignition switch OFF after the
symptom is simulated the 1st time. Then repeat the simula-
tion process again. When the problem has been simulated
twice, the MIL lights up and the DTCs are recorded in the
ECM.
3. INSPECT DIAGNOSIS (Check Mode)
HINT:
TOYOTA hand−held tester only:
Compared to the normal mode, the check mode has an in-
creased sensitivity to detect malfunctions.
Furthermore, the same diagnostic items which are detected in
the normal mode can also be detected in the check mode.
(a) Check the DTC.
(1) Initial conditions
Battery positive voltage 11 V or more
Throttle valve fully closed
Transmission in ”P” or ”N” position
Air conditioning switched OFF
(2) Turn the ignition switch OFF.
(3) Prepare the TOYOTA hand−held tester.
(4) Connect the TOYOTA hand−held tester to DLC3 at
the lower of the instrument panel.
(5) Turn the ignition switch ON and switch the TOYOTA
hand−held tester ON.
(6) Switch the TOYOTA hand−held tester normal mode
to check mode (Check that the MIL flashes.).
(7) Start the engine (The MIL goes out after the engine
start.).
(8) Simulate the conditions of the malfunction de-
scribed by the customer.
NOTICE:
Leave the ignition switch ON until you have checked the
DTCs, etc.
(9) After simulating the malfunction conditions, use the
TOYOTA hand−held tester diagnosis selector to
check the DTCs and freezed frame data, etc.
HINT:
Take care not to turn the ignition switch OFF. Turning the ignition
switch OFF switches the diagnosis system from check mode to
normal mode. so all DTCs, etc. are erased.
(10) After checking the DTC, inspect the applicable cir-
cuit.