TOYOTA CAMRY 1999 Service Repair Manual

± INTRODUCTIONFOR ALL OF VEHICLES
IN±15
15 Author: Date:
(g) AIRBAG SENSOR ASSEMBLY
(1) Never reuse the airbag sensor assembly involved
in a collision when the SRS has deployed.
(2) The connectors to the airbag sensor assembly
should be connected or disconnected with the sen-
sor mounted on the floor. If the connectors are con-
nected or disconnected while the airbag sensor as-
sembly is not mounted to the floor, it could cause
undesired ignition of the supplemental restraint sys-
tem.
(3) Work must be started after 90 seconds from the
time the ignition switch is turned to the ºLOCKº posi-
tion and the negative (±) terminal cable is discon-
nected from the battery, even if only loosing the set
bolts of the airbag sensor assembly.
(h) WIRE HARNESS AND CONNECTOR
The SRS wire harness is integrated with the instrument
panel wire harness assembly. All the connectors in the
system are a standard yellow color. If the SRS wire har-
ness becomes disconnected or the connector becomes
broken due to an accident, etc., repair or replace it as
shown on page RS±73 in Pub. No. RM654U .

IN±16
± INTRODUCTIONFOR ALL OF VEHICLES
16 Author: Date:
2. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If large amount of unburned compressed neutral gas (CNG) flows into the converter, it may overheat
and create a fire hazard. To prevent this, observe the following precautions and explain them to your
customer.
(a) Use only unleaded compressed neutral gas (CNG).
(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 neutral gas 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.

± INTRODUCTIONFOR ALL OF VEHICLES
IN±17
17 Author: Date:
4. FOR USING OBD II SCAN TOOL OR HAND±HELD TESTER
CAUTION:
Observe the following items for safety reasons:

Before using the OBD II scan tool or hand±held tester, the OBD II scan tool's instruction book
or 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 hand±held tester
connected to the vehicle. (i.e. Keep cables away from feet, pedals, steering wheel and shift le-
ver.)

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

IN05Y±10
IN±18± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
18 Author: Date:
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in the 1999 CAMRY CNG. In general, the ECU con-
trolled system is considered to be a very intricate system requiring a high level of technical knowledge and
expert skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, trouble-
shooting of these systems is not complex. If you have adequate understanding of the system and a basic
knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the
problem. This manual is designed through emphasis of the above standpoint to help service technicians
perform accurate and effective troubleshooting, and is compiled for the following major ECU controlled sys-
tems:
The troubleshooting procedure and how to make use of it are described on the following pages.
1. EngineDI±1
2. Automatic TransaxleDI±131
3. Anti±Lock Brake SystemDI±175
4. Supplemental Restraint SystemDI±221
5. Cruise Control SystemDI±317
FOR USING OBD II SCAN TOOL OR HAND±HELD TESTER

Before using the scan tool or tester, the scan tool's instruction book or tester's operator manual should
be read thoroughly.

If the scan tool or tester cannot communicate with ECU controlled systems when you have connected
the cable of the scan tool or tester to DLC3, turned the ignition switch ON and operated the scan tool,
there is a problem on the vehicle side or tool side.
(1) If communication is normal when the tool is connected to another vehicle, inspect the diagnosis
data link line (Bus
line) or ECU power circuit of the vehicle.
(2) If communication is still not possible when the tool is connected to another vehicle, the problem
is probably in the tool itself, so perform the Self Test procedures outline in the Tester Operator's
Manual.

IN05W±12
Vehicle Brought to Workshop
Customer Problem
Analysis
Symptom Confirmation
and Diagnostic Trouble
Code Check
Symptom Simulation
Diagnostic Trouble
Code Chart
Problem Symptoms Table
Circuit Inspection or Parts
Inspection
Repair
Confirmation Test
End 1
2
43
5
6
7
8Ask the customer about the conditions and the
environment when the problem occurred.1
Confirm the symptoms and the problem conditions,
and check the diagnostic trouble codes.
(When the problem symptoms do not appear
during confirmation, use the symptom simulation
method described later on.)2, 3
Check the results obtained in Step 2, then confirm
the inspection procedure for the system or the part
which should be checked using the diagnostic
trouble code chart or the problem symptoms table.4, 5, 6
Check and repair the affected system or part in
accordance with the instructions in Step 6. 7
After completing repairs, confirm that the problem
has been eliminated.
(If the problem is not reproduced, perform the
confirmation test under the same conditions and
in the same environment as when it occurred for
the first time.)8
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±19
HOW TO PROCEED WITH TROUBLESHOOTING
Carry out troubleshooting in accordance with the procedure on the following page. Here, only the basic pro-
cedure is shown. Details are provided in Diagnostics section, showing the most effective methods for each
circuit. Confirm the troubleshooting procedures first for the relevant circuit before beginning troubleshooting
of that circuit.

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
IN±20± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
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
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±21
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the 1999 CAMRY CNG 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 1999 CAMRY
CNG.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
Engine
Automatic Transaxle
Anti±Lock Brake System
Supplemental Restraint System
Cruise Control 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.

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 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.

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.
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±23
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: IN±24
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS