
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
102
108G/Y Electric governor groundEngine is running.
Idle speedApproximately 10V
SEF727V
Engine is running.
Engine speed is 2,000 rpm.Approximately 10V
SEF728V
11 6
11 7W Power supply for ECM Ignition switch ``ON''BATTERY VOLTAGE
(11 - 14V)
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
18, 22, 25+Fuel injection feedback system does not operate prop-
erly. (This system consists essentially of ECM, electric
governor and control sleeve position sensor.)+Main power supply circuit (ECM terminals
11 6,11 7)
and fuse
+Harness or connectors
(Electric governor and control sleeve position sensor
circuit)
+Electric governor
+Electronic fuel injection pump
+ECM
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-97

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
Refer to EC-63.
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
V1and ECM terminals101,107.
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.
Check harness continuity between termi-
nal
V5and ECM terminals102,108.
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
(Electric governor).
Refer to ``COMPONENT INSPECTION''
below.
OK
cNG
Take proper action.
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness con-
nector. Reconnect ECM harness connector
and retest.
INSPECTION END
COMPONENT INSPECTION
Electric governor
1. Disconnect electronic fuel injection pump harness connector.
2. Check continuity between terminals
V1andV5.
Resistance: Approximately 0.68W[at 23ÉC (73ÉF)]
If NG, take proper action.
SEF679VA
SEF752V
SEF753V
SEF684V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-100

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

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK FOR AIR IN FUEL FILTER.
1. Move priming pump up and down to
purge air from fuel ®lter.
2. Perform ``DIAGNOSTIC TROUBLE
CODE CONFIRMATION PROCE-
DURE''.
NG
cOK
INSPECTION END
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect injection timing control valve
harness connector.
3. Turn ignition switch ``ON''.
4. Check harness continuity between ter-
minal
V2and ground with CONSULT or
tester.
Voltage: Battery voltage
OK
cNG
Check the following.
+Harness connectors
M51,F6
+Electronic fuel injection
pump harness connector
F3
+10A fuse
+Harness for open or
short between injection
timing control valve and
fuse
If NG, repair harness or
connectors.
CHECK OUTPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector.
3. Check harness continuity between ter-
minal
V1and ECM terminals104,
11 0.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Electronic fuel injection
pump harness connector
F3
+Harness for open or
short between injection
timing control valve and
ECM
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Injection timing control valve).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace injection timing
control valve.
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness con-
nector. Reconnect ECM harness connector
and retest.
INSPECTION END
SEF670V
SEF685V
SEF754V
SEF755V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
Injection Timing Control Valve (Cont'd)
EC-104

COMPONENT INSPECTION
Injection timing control valve
1. Reconnect injection timing control valve harness connector.
2. Disconnect electronic fuel injection pump harness connector.
3. Check resistance between terminals
V3andV7.
Resistance: Approximately 11W[at 20ÉC (68ÉF)]
If NG, replace injection timing control valve.
SEF686V
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
Injection Timing Control Valve (Cont'd)
EC-105

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK FOR AIR IN FUEL FILTER.
1. Move priming pump up and down to
purge air from fuel ®lter.
2. Perform ``DIAGNOSTIC TROUBLE
CODE CONFIRMATION PROCEDURE''.
NG
cOK
INSPECTION END
Loosen and retighten engine ground
screws.
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector and
needle lift sensor harness connector.
3. Check harness continuity between termi-
nal
V1and ECM terminalV34.
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.
Check resistance between terminal
V2and
engine ground.
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 NO. 1 INJECTION NOZZLE FOR
CLOGGING.
Refer to ``SPRAY PATTERN TEST'', ``Test
and Adjustment'', ``INJECTION NOZZLE'',
EC-26.
OK
cNG
Replace No. 1 injection
nozzle.
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness con-
nector. Reconnect ECM harness connector
and retest.
INSPECTION END
SEF670V
SEF676V
SEF692V
SEF766V
SEF767V
.
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``NEEDLE LIFT SEN'' (DTC 34)
Needle Lift Sensor (NLS) (Cont'd)
EC-129

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY FOR ECM.
Check power supply circuit. Refer to
EC-63.
OK
CHECK OUTPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``ON''.
2. Select ``FUEL CUT SOL/V'' in
``ACTIVE TEST'' mode with
CONSULT.
3. Touch ``ON'' and ``OFF'' alter-
nately.
4. Check that operating sound is
emitted.
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness con-
nector and electronic fuel injec-
tion pump harness connector.
3. Check harness continuity
between terminal
V4and ECM
terminals
11 3,11 5.
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
(Fuel cut solenoid valve).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace fuel cut solenoid
valve.
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
SEF860S
SEF682VA
SEF768V
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``FUEL CUT S/V 1'' (DTC 36),
``FCV SHORT'' (DTC 37), ``FUEL CUT S/V 2'' (DTC 38)
Fuel Cut Solenoid Valve (Cont'd)
EC-133

Fuel Temperature Sensor (FTS)
The fuel temperature sensor is used to detect the fuel temperature
in the injection pump. The sensor modi®es a voltage signal from the
ECM. The modi®ed signal returns to the ECM as the fuel tempera-
ture input. The sensor uses a thermistor which is sensitive 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)
þ20 (þ4) 4.6 13.67 - 16.37
20 (68) 3.5 2.306 - 2.568
60 (140) 1.8 0.538 - 0.624
80 (176) 1.2 0.289 - 0.344
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)
10 P Fuel temperature sensor Engine is running.
Approximately 0 - 4.8V
Output voltage varies with
fuel temperature.
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)
42+An excessively high or low voltage from the sensor is
detected by ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Fuel 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.
SEF666S
SEF012P
SEF748V
TROUBLE DIAGNOSIS FOR ``FUEL TEMP SENSOR'' (DTC 42)
EC-135