AC(diag)-3
General Description
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
2. General Description
A: CAUTION
1) Never connect the battery in reverse polarity.
•Auto A/C control module may be destroyed in-
stantly.
2) Do not disconnect the battery terminals while the
engine is running.
•A large counter electromotive force will be gener-
ated in the generator, and this voltage may damage
electronic parts such as auto A/C control module
etc.
3) Before disconnecting the connectors of each
sensor and the auto A/C control module, be sure to
turn the ignition switch to OFF.
•Auto A/C control module may be damaged.
4) Every A/C-related part is a precision part. Do not
drop them.
5) Airbag system wiring harness is routed near the
A/C control panel and junction box.
CAUTION:
•For airbag system, yellow-colored wiring har-
ness and connectors are all used. Do not use
the electrical test equipment on these circuits.
•Be careful not to damage the airbag system
wiring harness when servicing the A/C control
panel and junction box.
B: INSPECTION
Before performing the diagnosis, check the follow-
ing items which might affect A/C system problems.
1. BATTERY
1) Measure the battery voltage and specific gravity
of electrolyte.
Standard voltage: 12 V
Specific gravity: 1.260 or more
2) Check the condition of the fuses for A/C system
power supply and other fuses.
3) Check the condition of harness and harness
connector connections.
2. ASPIRATOR HOSE
1) Turn the ignition switch to ON, and press the A/
C switch.
2) Turn the temperature control dial to maximum
hot position.
3) Turn the air flow control dial to “DEF” position.
4) Turn the fan speed control dial to 4th position.
5) Put a strip of paper close to the front side of in-
vehicle sensor suction port (A) located in the driv-
er’s side console side panel, and check that air is
being sucked into the port by seeing the paper
moving towards the port.
NOTE:
Be careful not to let the paper get sucked into the
port.
6) If the paper does not move at all, remove the
driver’s side console side panel
connection of the aspirator hose, in-vehicle sensor
and heater unit, and repair them if necessary.
3. A/C LINE
Check the connection for A/C line (A) and lower
side high-pressure pipe.
AC-01323
AC-01324
(A)
EN(H6DO)(diag)-5
General Description
ENGINE (DIAGNOSTICS)
3. General Description
A: CAUTION
1) Airbag system wiring harness is routed near the
ECM, main relay and fuel pump relay.
CAUTION:
•All airbag system wiring harnesses and con-
nectors are colored yellow. Do not use electri-
cal test equipment on these circuits.
•Be careful not to damage the airbag system
wiring harness when servicing the ECM, TCM,
main relay and fuel pump relay.
2) Never connect the battery in reverse polarity.
•The ECM will be destroyed instantly.
•The fuel injector and other parts will be dam-
aged.
3) Do not disconnect the battery terminals while the
engine is running.
A large counter electromotive force will be generat-
ed in the generator, and this voltage may damage
electronic parts such as ECM etc.
4) Before disconnecting the connectors of each
sensor and ECM, be sure to turn the ignition switch
to OFF. Perform the clear memory mode after con-
necting the connectors.
5) Poor contact has been identified as a primary
cause of this problem. Measure the voltage or re-
sistance of individual sensor or all electrical control
modules using a tapered pin with a diameter of less
than 0.64 mm (0.025 in). Do not insert the pin more
than 5 mm (0.20 in) into the part.
6) Remove the ECM from the located position after
disconnecting two cables on battery.
Otherwise, the ECM may be damaged.
CAUTION:
When replacing the ECM, be careful not to use
the wrong spec. ECM to avoid any damage on
the fuel injection system.
7) Connectors of each sensor in the engine com-
partment and the harness connectors on the en-
gine side and body side are all designed to be
waterproof. Even if the connectors are waterproof,
take care not to allow water to get into them when
washing the vehicle, or when servicing the vehicle
in rainy weather.
8) Use ECM mounting stud bolts as the grounding
point to chassis when measuring voltage and resis-
tance in the passenger compartment.
9) Use the engine ground terminal or engine as-
sembly as the grounding point to chassis when
measuring the voltage and resistance in engine
compartment.
10) Every MFI-related part is a precision part. Do
not drop them.
11) Observe the following cautions when installing
a radio in MFI equipped models.
CAUTION:
•The antenna must be kept as far apart as pos-
sible from control unit. (The ECM is located un-
der the steering column, inside of the
instrument panel lower trim panel.)
•The antenna feeder must be placed as far apart
as possible from the ECM and MFI harness.
•Carefully adjust the antenna for correct
matching.
•When mounting a large power type radio, pay
special attention to the three items mentioned
above.
•Incorrect installation of the radio may affect
the operation of ECM.
12) Release the pressure in the fuel system before
disconnecting the fuel hose. If engine starts during
this operation, run it until it stops.
13) For the model with ABS, the ABS warning light
may illuminate when performing driving test with
jacked-up or lifted-up condition, but this is not a
system malfunction. The reason for this is the
speed difference between the front and rear
wheels. After diagnosis of engine control system,
perform the ABS memory clear procedure of self-
diagnosis function.
B: INSPECTION
Before performing diagnostics, check the following
item which might affect engine problems.
1. BATTERY
1) Measure the battery voltage and specific gravity
of electrolyte.
Standard voltage: 12 V
Specific gravity: Above 1.260
2) Check the condition of the main and other fuses,
and harnesses and connectors. Also check for
proper grounding.
2. ENGINE GROUND
Make sure the engine ground terminal is properly
connected to engine.
EN-02473
WI-3
Basic Diagnostic Procedure
WIRING SYSTEM
1. Basic Diagnostic Procedure
A: BASIC PROCEDURES
1. GENERAL DESCRIPTION
The most important purpose of diagnostics is to
quickly determine which part is malfunctioning, to
save time and labor.
2. IDENTIFICATION OF TROUBLE SYMP-
TOM
Determine what the problem is based on the symp-
tom.
3. PROBABLE CAUSE OF TROUBLE
Look at the wiring diagram and check the system’s
circuit. Then check the switch, relay, fuse, ground,
etc.
4. LOCATION AND REPAIR OF TROUBLE
1) Using the diagnostics, narrow down the causes.
2) If necessary, use a voltmeter, ohmmeter, etc.
3) Before replacing certain component parts
(switch, relay, etc.), check the power supply,
ground, for open wiring harness, poor connectors,
etc. If no problem is encountered, check the com-
ponent parts.
5. SYSTEM OPERATION CHECK
After repairing, ensure that the system operates
properly.
B: BASIC INSPECTION
1. VOLTAGE MEASUREMENT
1) Using a voltmeter, connect the negative lead to a
good ground point or negative battery terminal and
the positive lead to the connector or component ter-
minal.
2) Contact the positive lead of the voltmeter on
connector (A). The voltmeter will indicate a voltage.
3) Shift the positive lead to connector (B). The volt-
meter will indicate no voltage.
4) With the test set-up held as it is, turn the switch
ON. The voltmeter will indicate a voltage and, at the
same time, the light will come on.
5) The circuit is in good order. If a problem such as
a light failing to illuminate occurs, use the proce-
dures outlined above to track down the malfunc-
tion.
2. CIRCUIT CONTINUITY CHECKS
1) Disconnect the battery terminal or connector so
there is no voltage between the check points.
Contact the two leads of an ohmmeter to each of
the check points.
If the circuit has diodes, reverse the two leads and
check again.
2) Use an ohmmeter to check for diode continuity.
When contacting the negative lead to the diode
positive side and the positive lead to the negative
side, there should be continuity.
When contacting the two leads in reverse, there
should be no continuity.
3) The symbol“ — ” indicates that continuity
exists between two points or terminals. For exam-
ple, when a switch position is at “3”, continuity ex-
ists among terminals 1, 3 and 6, as shown in the
table below.
WI-02739
To powerFUSEsupplySwitchLight
V
(A)(B)
WI-02740
Continuity No continuity