
VD
Check heated oxygen sensor harness:
1. Turn off engine and disconnect battery ground
cable.
2. Disconnect ECM harness connector from ECM.
3. Disconnect heated oxygen sensor harness con-
nector and connect terminal for heated oxygen
sensor to ground with a jumper wire.
4. Check for continuity between terminal
V19of
ECM harness connector and ground metal on
vehicle body.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Continuity exists ... OK
Continuity does not exist ... NG
OK NG
Repair harness.
cVF
Connect ECM harness connector to ECM.
1. Select ``ENG COOLANT TEMP'' in
``ACTIVE TEST'' mode.
2. Set ``COOLANT TEMP'' at 20ÉC (68ÉF).
--------------------------------------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------------------------------------
lDisconnect engine coolant temperature
sensor harness connector.
lConnect a resistor (2.5 kW) between ter-
minals of engine coolant temperature sen-
sor harness connector.
Start engine and warm it up until engine coolant
temperature indicator points to the middle of gauge.
(Be careful to start engine after setting ``COOLANT
TEMP'' or installing a 2.5 kWresistor.)
Rev engine two or three times under no-load then
run engine at idle speed.
VE
MEF031DB
SEF053U
.
.
.
.
.
.
.
BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-29

CAUTION:
If it becomes necessary to start the engine with a booster
battery and jumper cables,
a. Use a 12-volt booster battery.
b. After connecting battery cables, ensure that they are
tightly clamped to battery terminals for good contact.
c. Never add distilled water through the hole used to check
specific gravity.
How to Handle Battery
METHODS OF PREVENTING OVER-DISCHARGE
The following precautions must be taken to prevent over-dis-
charging a battery.
lThe battery surface (particularly its top) should always be
kept clean and dry.
lThe terminal connections should be clean and tight.
lAt every routine maintenance, check the electrolyte level.
This also applies to batteries designated as ``low mainte-
nance'' and ``maintenance-free''.
lWhen the vehicle is not going to be used over a long period
of time, disconnect the negative battery terminal.
lCheck the charge condition of the battery.
Periodically check the specific gravity of the electrolyte. Keep
a close check on charge condition to prevent over-discharge.
CHECKING ELECTROLYTE LEVEL
WARNING:
Do not allow battery fluid to come in contact with skin, eyes,
fabrics, or painted surfaces. After touching a battery, do not
touch or rub your eyes until you have thoroughly washed
your hands. If acid contacts eyes, skin or clothing, immedi-
ately flush with water for 15 minutes and seek medical atten-
tion.
MEL040F
MEL041F
MEL042F
BATTERY
EL-18

Trouble Diagnoses
Symptom Possible causes Repair order
Radio inoperative (no digital
display and no sound from
speakers).1. 10A fuse
2. Poor radio case ground
3. Radio1. Check 10A fuse (No.
18, located in fuse block). Turn igni-
tion switch ON and verify battery positive voltage is present
at terminal
V10of radio.
2. Check radio case ground.
3. Remove radio for repair.
Radio controls are operational,
but no sound is heard from
any speaker.1. Radio output
2. Radio1. Check radio output voltages.
2. Remove radio for repair.
Radio presets are lost when
ignition switch is turned OFF.1. 7.5A fuse
2. Radio1. Check 7.5A fuse (No.
6, located in fuse block) and verify
battery positive voltage is present at terminal
V6of radio.
2. Remove radio for repair.
Individual speaker is noisy or
inoperative.1. Speaker
2. Radio output
3. Speaker circuit
4. Radio1. Check speaker.
2. Check radio output voltages.
3. Check wires for open or short between radio and speaker.
4. Remove radio for repair.
Radio stations are weak or
noisy.1. Antenna
2. Poor radio ground
3. Radio1. Check antenna.
2. Check radio ground.
3. Remove radio for repair.
Radio generates static noise
with engine running.1. Poor radio ground
2. Loose or missing ground bonding straps
3. Ignition condenser or rear window defogger
noise suppressor condenser
4. Alternator
5. Ignition coil or secondary wiring
6. Radio1. Check radio ground.
2. Check ground bonding straps.
3. Replace ignition condenser or rear window defogger noise
suppressor condenser.
4. Check alternator.
5. Check ignition coil and secondary wiring.
6. Remove radio for repair.
Radio generates static noise
with accessories on (switch
pops and motor noise).1. Poor radio ground
2. Antenna
3. Accessory ground
4. Faulty accessory1. Check radio ground.
2. Check antenna.
3. Check accessory ground.
4. Replace accessory.
SPEAKER INSPECTION
1. Disconnect speaker harness connector.
2. Measure the resistance between speaker terminals
V1andV2.
lThe resistance should be2-4W.
3. Using jumper wires, momentarily connect a 9V battery between speaker terminals
V1andV2.
lA momentary hum or pop should be heard.
ANTENNA INSPECTION
Using a jumper wire, clip an auxiliary ground between antenna and body.
lIf reception improves, check antenna ground (at body surface).
lIf reception does not improve, check main feeder cable for short circuit or open circuit.
RADIO INSPECTION
All voltage inspections are made with:
lIgnition switch ON or ACC
lRadio ON
lRadio connected (If removed for inspection, supply a ground to the case using a jumper wire.)
AUDIO
EL-142

Voltage check method
To help in understanding the diagnosis of open circuits please refer to the previous schematic.
In any powered circuit, an open can be found by methodically checking the system for the presence of volt-
age. This is done by switching the DMM to the voltage function.
1. Connect one probe of the DMM to a known good ground.
2. Begin probing at one end of the circuit and work your way to the other end.
3. With SW1 open, probe at SW1 to check for voltage.
voltage; open is further down the circuit than SW1.
no voltage; open is between fuse block and SW1 (point A).
4. Close SW1 and probe at relay.
voltage; open is further down the circuit than the relay.
no voltage; open is between SW1 and relay (point B).
5. Close the relay and probe at the solenoid.
voltage; open is further down the circuit than the solenoid.
no voltage; open is between relay and solenoid (point C).
Any powered circuit can be diagnosed using the approach in the above example.
TESTING FOR ``SHORTS'' IN THE CIRCUIT
To simplify the discussion of shorts in the system please refer to the schematic below.
Resistance check method
1. Disconnect the battery negative cable and remove the blown fuse.
2. Disconnect all loads (SW1 open, relay disconnected and solenoid disconnected) powered through the
fuse.
3. Connect one probe of the ohmmeter to the load side of the fuse terminal. Connect the other probe to a
known good ground.
4. With SW1 open, check for continuity.
continuity; short is between fuse terminal and SW1 (point A).
no continuity; short is further down the circuit than SW1.
5. Close SW1 and disconnect the relay. Put probes at the load side of fuse terminal and a known good
ground. Then, check for continuity.
continuity; short is between SW1 and the relay (point B).
no continuity; short is further down the circuit than the relay.
6. Close SW1 and jump the relay contacts with jumper wire. Put probes at the load side of fuse terminal
and a known good ground. Then, check for continuity.
continuity; short is between relay and solenoid (point C).
no continuity; check solenoid, retrace steps.
SGI847
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-26

CAUTION:
If it becomes necessary to start the engine with a booster
battery and jumper cables,
a. Use a 12-volt booster battery.
b. After connecting battery cables, ensure that they are
tightly clamped to battery terminals for good contact.
c. Never add distilled water through the hole used to check
specific gravity.
How to Handle Battery
METHODS OF PREVENTING OVER-DISCHARGE
The following precautions must be taken to prevent over-dis-
charging a battery.
lThe battery surface (particularly its top) should always be
kept clean and dry.
lThe terminal connections should be clean and tight.
lAt every routine maintenance, check the electrolyte level.
This also applies to batteries designated as ``low mainte-
nance'' and ``maintenance-free''.
lWhen the vehicle is not going to be used over a long period
of time, disconnect the negative battery terminal.
lCheck the charge condition of the battery.
Periodically check the specific gravity of the electrolyte. Keep
a close check on charge condition to prevent over-discharge.
CHECKING ELECTROLYTE LEVEL
WARNING:
Do not allow battery fluid to come in contact with skin, eyes,
fabrics, or painted surfaces. After touching a battery, do not
touch or rub your eyes until you have thoroughly washed
your hands. If acid contacts eyes, skin or clothing, immedi-
ately flush with water for 15 minutes and seek medical atten-
tion.
MEL040F
MEL041F
MEL042F
BATTERY
EL-18

Trouble Diagnoses
Symptom Possible causes Repair order
Radio inoperative (no digital
display and no sound from
speakers).1. 10A fuse
2. Poor radio case ground
3. Radio1. Check 10A fuse (No.
18, located in fuse block). Turn igni-
tion switch ON and verify battery positive voltage is present
at terminal
V10of radio.
2. Check radio case ground.
3. Remove radio for repair.
Radio controls are operational,
but no sound is heard from
any speaker.1. Radio output
2. Radio1. Check radio output voltages.
2. Remove radio for repair.
Radio presets are lost when
ignition switch is turned OFF.1. 7.5A fuse
2. Radio1. Check 7.5A fuse (No.
6, located in fuse block) and verify
battery positive voltage is present at terminal
V6of radio.
2. Remove radio for repair.
Individual speaker is noisy or
inoperative.1. Speaker
2. Radio output
3. Speaker circuit
4. Radio1. Check speaker.
2. Check radio output voltages.
3. Check wires for open or short between radio and speaker.
4. Remove radio for repair.
Radio stations are weak or
noisy.1. Antenna
2. Poor radio ground
3. Radio1. Check antenna.
2. Check radio ground.
3. Remove radio for repair.
Radio generates static noise
with engine running.1. Poor radio ground
2. Loose or missing ground bonding straps
3. Ignition condenser or rear window defogger
noise suppressor condenser
4. Alternator
5. Ignition coil or secondary wiring
6. Radio1. Check radio ground.
2. Check ground bonding straps.
3. Replace ignition condenser or rear window defogger noise
suppressor condenser.
4. Check alternator.
5. Check ignition coil and secondary wiring.
6. Remove radio for repair.
Radio generates static noise
with accessories on (switch
pops and motor noise).1. Poor radio ground
2. Antenna
3. Accessory ground
4. Faulty accessory1. Check radio ground.
2. Check antenna.
3. Check accessory ground.
4. Replace accessory.
SPEAKER INSPECTION
1. Disconnect speaker harness connector.
2. Measure the resistance between speaker terminals
V1andV2.
lThe resistance should be2-4W.
3. Using jumper wires, momentarily connect a 9V battery between speaker terminals
V1andV2.
lA momentary hum or pop should be heard.
ANTENNA INSPECTION
Using a jumper wire, clip an auxiliary ground between antenna and body.
lIf reception improves, check antenna ground (at body surface).
lIf reception does not improve, check main feeder cable for short circuit or open circuit.
RADIO INSPECTION
All voltage inspections are made with:
lIgnition switch ON or ACC
lRadio ON
lRadio connected (If removed for inspection, supply a ground to the case using a jumper wire.)
AUDIO
EL-142