Page 2234 of 2572
010QM-01
01-26- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
HOW TO PROCEED WITH TROUBLESHOOTING
HINT:
Carry out troubleshooting in accordance with the procedures below. Only a basic procedure is shown. De-
tails in the Diagnostic Section show the most effective methods for each circuit. Confirm the troubleshooting
procedures for the relevant circuit before beginning troubleshooting.
1 VEHICLE BROUGHT TO WORKSHOP
2 CUSTOMER PROBLEM ANALYSIS
(a) Ask the customer about the conditions and environment when the problem occurred.
3 SYMPTOM CONFIRMATION AND DTC (AND FREEZE FRAME DATA) CHECK
(a) Check the battery positive voltage.
Standard: 11 to 14 V (Engine stopped)
(b) Visually check the wire harness, connectors and fuses for open and short, etc.
(c) Warm up the engine to the normal operating temperature.
(d) Confirm the problem symptoms and conditions, and check for DTCs according to the related chart.
OK Go to step 5
NG
4 DTC CHART
(a) Check the results obtained in step 3, then confirm the inspection procedures for the system or part
using the DTC chart.
Go to step 6
5 PROBLEM SYMPTOMS CHART
(a) Check the results obtained in step 3. Confirm the inspection procedures for the system or part using
the problem symptoms table.
6 CIRCUIT INSPECTION OR PARTS INSPECTION
(a) Confirm the circuit in the system or the part that should be checked using the problem symptoms table
or the results obtained in step 4.
Page 2237 of 2572
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01-29
29 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE
HINT:
The diagnostic system in the HIGHLANDER has various functions.
The first function is the Diagnostic Trouble Code (DTC) check. A DTC is a code stored in the ECU
memory whenever a malfunction in the signal circuits to the ECU occurs. In a DTC check, a previous
malfunction's DTC can be checked by a 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 functions, the problem areas can be narrowed down and troubleshooting is more effec-
tive. Diagnostic functions are incorporated in the following systems in the HIGHLANDER:
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnotis Test Mode
(Active Test)
SFI System
(with Check Mode)
ABS with EBD & BA & TRAC & VSC System
Electronic Controlled Automatic Transaxle [ECT]
(with Check Mode)
Air Conditioning System
Supplement Restraint System
Power Window Control System
Power Door Lock Control System
Wireless Door Lock Control System
Engine Immobiliser 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: 1 still
occurring, or 2 occurred in the past but has since returned to normal. In addition, the DTC should be
compared to the problem symptom to see if they are related. For this reason, DTCs should be checked
before and after confirmation of symptoms (i.e., whether or not problem symptoms exist) to determine
current conditions, as shown in the table below.
Never skip the DTC check. Failure to check DTCs may, depending on the case, result in unnecessary
troubleshooting for systems operating normally or lead to repairs not pertinent to the problem. Follow
the procedures listed above in the correct order.
A flow chart showing how to proceed with troubleshooting using the DTC check is shown below. Direc-
tions from the flow chart will indicate should be performed DTC troubleshooting or to the troubleshoot-
ing of each problem symptom.
1 DTC CHECK
2 MAKE A NOTE OF DTCS DISPLAYED AND THEN CLEAR THE MEMORY
3 SYMPTOM CONFIRMATION
aSymptoms exist
bNo symptoms exist
a Go to step 5
Page 2239 of 2572
B71602
Vibrate Slightly
Shake Slightly
Vibrate
Slightly
D25084
Malfunction
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS01-31
31 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
SYMPTOM SIMULATION
HINT:
The most difficult case in troubleshooting is when no problem symptoms occur. In such cases, a thorough
customer problem analysis must be carried out. A simulation of the same or similar conditions and environ-
ment in which the problem occurred in the customer's vehicle should be carried out. No matter how much
skill or experience a technician has, troubleshooting without confirming the problem symptoms will lead to
important repairs being overlooked and mistakes or delays.
For example:
With a problem that only occurs when the engine is cold or occurs as a result of vibration caused by the road
during driving, the problem can never be determined if the symptoms are being checked on a stationary ve-
hicle or a vehicle with a warmed-up engine.
Vibration, heat or water penetration (moisture) is difficult to reproduce. The symptom simulation tests below
are effective substitutes for the conditions and can be applied on a stationary vehicle.
Important points in the symptom simulation test:
In the symptom simulation test, the problem symptoms as well as the problem area or parts must be con-
firmed. First, narrow down the possible problem circuits according to the symptoms. Then, connect the tester
and carry out the symptom simulation test, judging whether the circuit being tested is defective or normal.
Also, confirm the problem symptoms at the same time. Refer to the problem symptoms table for each system
to narrow down the possible causes.
1. VIBRATION METHOD: When vibration seems to be
the major cause.
(a) PART AND SENSOR
(1) Apply slight vibration with a finger to the part of the
sensor considered to be the cause of the problem
and check whether or not the malfunction occurs.
HINT:
Applying strong vibration to relays may 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 device. Check if the
malfunction occurs.
NOTICE:
Do not heat to more than 60C (140F). Exceeding this
temperature may damage components.
Do not apply heat directly to the parts in the ECU.
Page 2240 of 2572
D25085
B02389
ON 01-32
- INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
32 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3. WATER SPRINKLING METHOD: When the malfunc-
tion seems to occur on a rainy day or in highhumidity.
(a) Sprinkle water onto the vehicle and check if the malfunc-
tion occurs.
NOTICE:
Never sprinkle water directly into the engine compart-
ment. Indirectly change the temperature and humid-
ity by applying water spray onto the front of the radia-
tor.
Never apply water directly onto electronic compo-
nents.
HINT:
If the vehicle has or had a water leakage problem, the leakage
may have damaged the ECU or connections. Look for evidence
of corrosion or shorts. Proceed with caution during water tests.
4. HIGH ELECTRICAL LOAD METHOD: When a malfunc-
tion seems to occur when electrical load is exces-
sive.
(a) Turn on all the electrical loads including the heater blower,
headlights, rear window defogger, etc., and check if the
malfunction occurs.
Page 2244 of 2572
ii
Important information about this manual
For safety reasons, this manual indicates
items requiring particular attention with the
following marks.
CAUTION
This is a warning against anything
which may cause injury to people if the
warning is ignored. You are informed
about what you must or must not do in
order to reduce the risk of injury to
yourself and others.
NOTICE
This is a warning against anything
which may cause damage to the ve-
hicle or its equipment if the warning is
ignored. You are informed about what
you must or must not do in order to
avoid or reduce the risk of damage to
your vehicle and its equipment.
INFORMATION
This provides additional information.
Initial screen
When you start the engine or turn the ignition
switch to the ACCº position, the initial
screen appears and the system begins
operating.
CAUTION
When the vehicle is stopped with the
engine running, always apply the park-
ing brake for safety.
After a few seconds, the CAUTIONº screen
appears.
Touch either Englishº or
Fran†aisº to select a language. Read
and follow the instructions.
When you touch the
I Agreeº switch
on the screen, the map screen appears.
You can access this screen when you push
the
INFOº button and touch the Lan-
guageº
switch. Then you can select a lan-
guage.
Page 2249 of 2572
05-1890
- DIAGNOSTICSCOMBINATION METER
2080 Author: Date:
2 READ VALUE OF HAND-HELD TESTER(ENGINE SPEED SIGNAL)
(a) Operate the hand-held tester according to the steps on the display and select the ºDATA LISTº.
METER:
ItemMeasurement Item/
Range (Display)Normal ConditionDiagnostic Note
TACHO METEREngine speed / Min.: 50 rpm, Max.:
12,750 rpmAlmost same as actual engine
speed (When engine is running)-
OK:
Engine speed displayed on the tester is almost the same as the actual engine speed.
NG Go to step 3
OK
REPLACE COMBINATION METER ASSY(SEE PAGE 71-18)
3 READ VALUE OF HAND-HELD TESTER(ENGINE SPEED SIGNAL)
(a) Operate the hand-held tester according to the steps on the display and select the ºDATA LISTº.
ALL (ECM):
ItemMeasurement Item/
Range (Display)Normal ConditionDiagnostic Note
ENGINE SPDEngine speed / Min.: 50 rpm, Max.:
12,750 rpmAlmost same as actual engine
speed (When engine is running)-
OK:
Engine speed displayed on the tester is almost the same as the actual engine speed.
NG GO TO ENGINE CONTROL SYSTEM
(SEE PAGE 05-5, 05-362)
OK
Page 2250 of 2572
I30440
Wire Harness View:
C12-1
A05138
- DIAGNOSTICSCOMBINATION METER
05-1891
2081 Author: Date:
4 INSPECT COMBINATION METER ASSY
INSPECTION USING OSCILLOSCOPE
(a) Check the input signal waveform.
(1) Remove the combination meter assy.
(2) Connect the oscilloscope to the terminals C12-1
and body ground.
(3) Start the engine.
(4) Check the signal waveform according to the condi-
tion (s) in the table below.
ItemCondition
Tool setting5 V/DIV, 10 ms/DIV
Vehicle conditionEngine idle speed
OK:
As shown in the illustration
NG Go to step 5
OK
REPLACE COMBINATION METER ASSY(SEE PAGE 71-18)
Page 2251 of 2572
I40608
Combination Meter Assy
Wire Harness View: ECM Wire Harness View:
C12-1
E5-5
I40144
E5-5 ECM Wire Harness View:
05-1892
- DIAGNOSTICSCOMBINATION METER
2082 Author: Date:
5 CHECK HARNESS AND CONNECTOR(ECM - COMBINATION METER ASSY)
(SEE PAGE 01-26)
(a) Disconnect the C12 and E5 connectors.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester ConnectionConditionSpecified Condition
C12-1 - E5-5AlwaysBelow 1 W
C12-1 - Body groundAlways10 kW or higher
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
6 INSPECT COMBINATION METER ASSY
(a) Disconnect the E5 connector.
(b) Measure the voltage according to the value(s) in the table
below.
Standard:
Tester ConnectionConditionSpecified Condition
E5-5 - Body groundIgnition switch ON10 to 14 V
NG REPLACE COMBINATION METER ASSY
(SEE PAGE 71-18)
OK
GO TO ENGINE CONTROL SYSTEM(SEE PAGE 05-5, 05-366)
