DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect mass air ¯ow sensor har-
ness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V1and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
+Harness connectors
M52,F7+Harness for open or
short between mass air
¯ow sensor and ECM
+Harness for open or
short between mass air
¯ow sensor and ECCS
relay
If NG, repair harness or
connector.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Loosen and retighten engine ground
screws.
3. Check harness continuity between ter-
minal
V2and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
E106,M88+Harness connectorsM51,F6+Harness for open or
short between mass air
¯ow sensor and ECM
+Harness for open or
short between mass air
¯ow sensor and TCM
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK INPUT SIGNAL CIRCUIT.
1. Disconnect ECM harness connector.
2. Check harness continuity between ter-
minal
V3and ECM terminalV35.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK COMPONENT
(Mass air ¯ow sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace mass air ¯ow sen-
sor.
Disconnect and reconnect harness con-
nectors in the circuits. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF713V
SEF736V
SEF676V
SEF737V
SEF738V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-77
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modi®es a voltage signal from the
ECM. The modi®ed signal returns to the ECM as the engine cool-
ant temperature input. The sensor uses a thermistor which is sen-
sitive to the change in temperature. The electrical resistance of the
thermistor decreases as temperature increases.
Engine coolant tempera-
ture
ÉC (ÉF)Voltage*
(V)Resistance
(kW)
þ10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.3 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and measured between ECM terminal
V19(Engine coolant temperature sensor) and ECM terminalV43(ECCS ground).
Diagnostic
Trouble Code
No.Malfunction is detected when ...Check Items
(Possible Cause)
13+An excessively high or low voltage from the sensor is
entered to ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Engine coolant temperature sensor
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 5 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'' and wait at least 5 seconds.
2) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
3) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF594K
SEF012P
SEF741V
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)
EC-79
DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector
and combination meter harness con-
nector.
3. Check harness continuity between ECM
terminal
V26and meter terminalV26.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
M52,F7
+Joint connectorM79
+Harness for open or
short between ECM and
combination meter
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK SPEEDOMETER FUNCTION.
Make sure that speedometer functions
properly.
OK
cNG
Check the following.
+Harness connectors
M86,E104(LHD mod-
els)
+Harness connectors
M21,E127(RHD mod-
els)
+Harness connectors
E70,E201
+Harness for open or
short between combina-
tion meter and vehicle
speed sensor
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
Check vehicle speed sen-
sor and its circuit.
Refer to EL section.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF742V
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``VEHICLE SPEED SEN'' (DTC 14)
Vehicle Speed Sensor (VSS) (Cont'd)
EC-86
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
15+An excessively high or low voltage from the sensor is
detected by ECM.
...........................................................................................
+An improper voltage signal from the sensor is
detected by ECM during engine running.+Harness or connectors
(The control sleeve position sensor circuit is open or
shorted.)
+Control sleeve position sensor
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and run it for at least 2 seconds at idle
speed.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and run it for at least 2 seconds at idle
speed.
2) Turn ignition switch ``OFF'', wait at least 5 seconds and
then ``ON''.
3) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF714V
TROUBLE DIAGNOSIS FOR ``CONT SLEEV POS SEN'' (DTC 15)
Control Sleeve Position Sensor (CSPS) (Cont'd)
EC-88
DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector
and electronic fuel injection pump har-
ness connector.
3. Check harness continuity between ter-
minal
V2and ECM terminalsV53,V57.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK INPUT SIGNAL CIRCUIT.
Check harness continuity between sensor
terminal
V3and ECM terminalsV63,V67.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT-I.
Check harness continuity between sensor
terminal
V6and ECM terminalsV62,V66.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT-II.
1. Loosen and retighten engine ground
screws.
2. Check harness continuity between ter-
minal
V4and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Joint connector
F19
+Harness for open or
short between control
sleeve position sensor
and engine ground
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
jA
SEF679V
SEF744V
SEF745V
SEF746V
SEF676V
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``CONT SLEEV POS SEN'' (DTC 15)
Control Sleeve Position Sensor (CSPS) (Cont'd)
EC-90
Adjustment Resistor
The adjustment resistor is used to achieve uniform pump charac-
teristics.
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
46 Y Adjustment resistor Ignition switch ``ON''
Approximately 0 - 4.6V
(Voltage varies with part
number of adjustment
resistor.)
50 B Sensors' groundEngine is running.
(Warm-up condition)
Idle speedApproximately 0V
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ...Check Items
(Possible Cause)
17+An excessively high or low voltage from the resistor is
detected by ECM.+Harness or connectors
(The adjustment resistor circuit is open or shorted.)
+Adjustment resistor
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 5 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'' and wait at least 5 seconds.
2) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
3) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF681V
SEF748V
TROUBLE DIAGNOSIS FOR ``ADJUST RESISTOR'' (DTC 17)
EC-92
Electric Governor
The electric governor is built into the electronic fuel injection pump.
It moves the control sleeve to increase or decrease the amount of
fuel injected.
When current ¯ows through the coil, a magnetic force is produced,
rotating the rotor. The rotor shaft is installed to the control sleeve
via a ball pin which is eccentrically situated in relation to the rotor
shaft. With this arrangement, the control sleeve can be moved in
relation to rotor rotation.
The rotor's rotating angle is determined by a balanced condition of
magnetic force (generated by current ¯ow regulated by means of
the ECM) and tension of return spring (installed to rotor). The larger
the current ¯ow through the coil, the greater the rotor's rotating
angle. This means that the control sleeve moves to the right,
increasing the amount of fuel injected.
The ECM regulates the current ¯ow through the coil by changing
the duty ratio which controls the ON-OFF operation of the electric
governor grounding circuit.
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
4 B/Y ECCS relay (Self-shutoff)Ignition switch ``ON''
Ignition switch ``OFF''
For a few seconds after turning ignition switch
``OFF''0 - 1.5V
Ignition switch ``OFF''
A few seconds passed after turning ignition
switch ``OFF''BATTERY VOLTAGE
(11 - 14V)
101
107R/B Electric governorEngine is running.
Idle speedBATTERY VOLTAGE
(11 - 14V)
SEF632S
SEF633S
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
EC-96
Injection Timing Control Valve
The injection timing control valve is built into the electronic fuel
injection pump. It controls the timer piston to change the fuel injec-
tion timing.
The timing control valve is a solenoid valve located in the line
between high-pressure chamber and low-pressure chamber. It
changes fuel pressure in the high-pressure chamber.
When current ¯ows through the solenoid (the solenoid turns ON),
the timing control valve opens, advancing fuel injection timing.
When current does not ¯ow through it, the timing control valve
closes, retarding injection timing.
The ECM emits an ON-OFF duty signal. The longer the OFF-
duration, the greater the advance angle. The longer the
ON-duration, the greater the retard angle. This means that chang-
ing the ON-OFF duty ratio makes it possible to achieve an optimal
advance angle and accurately control fuel injection timing.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
ACT INJ TIMG+Engine: After warming up
+Air conditioner switch: ``OFF''
+Shift lever: ``N''
+No-loadIdle þ9.5 to þ12.0É
2,000 rpm þ10.0 to þ15.5É
INJ TIMG C/V+Engine: After warming up, idle the engine. Approx. 50%
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
104
11 0L/WInjection timing control
valveEngine is running.
(Warm-up condition)
Idle speedBATTERY VOLTAGE
(11 - 14V)
SEF729V
Engine is running.(Warm-up condition)
Engine speed is 2,000 rpm.BATTERY VOLTAGE
(11 - 14V)
SEF730V
SEF638S
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
EC-101