
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
Note: If DTC 18, 22, 25 and DTC 15 are displayed, perform
TROUBLE DIAGNOSIS FOR DTC 15. (See EC-87.)
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and warm it up to normal operating tem-
perature.
3) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and warm it up to normal operating tem-
perature.
2) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
Note: If a malfunction occurs intermittently, conduct suitable
driving pattern for 10 minutes. This makes it possible to
determine DTC.SEF751V
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-98

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

ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
21+Injection timing feedback system does not operate
properly. (This system consists essentially of ECM,
injection timing control valve and needle lift sensor.)+Harness or connectors
[Injection timing control valve, needle lift sensor,
crankshaft position sensor (TDC) circuits]
+Injection timing control valve
+Needle lift sensor
+Crankshaft position sensor (TDC)
+Air in fuel line
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
Note: If both DTC 21 and 34 or 47 are displayed, perform
TROUBLE DIAGNOSIS FOR DTC 34 or 47. (See EC-126
or EC-144.)
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and warm it up to normal operating tem-
perature.
3) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and warm it up to normal operating tem-
perature.
2) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
Note: If a malfunction occurs intermittently, conduct suitable
driving pattern for 10 minutes. This makes it possible to
determine DTC.
SEF751V
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
Injection Timing Control Valve (Cont'd)
EC-102

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

Accelerator Switch (F/C)
The accelerator switch is installed to the accelerator pedal assem-
bly. The switch senses accelerator position and sends an ON-OFF
signal to the ECM. The ECM uses the signal to control the fuel cut
operation at deceleration for better fuel efficiency.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
ACCEL SW (FC)+Ignition switch: ON
(Engine stopped)Accelerator pedal: released CLOSE
Accelerator pedal: slightly open OPEN
DECELER F/CUT+Engine: After warming upIdle OFF
When accelerator pedal is
released quickly with engine
speed at 3,000 rpm or more.ON
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)
29 R/L Accelerator switch (F/C)Ignition switch ``ON''
Accelerator pedal fully releasedBATTERY VOLTAGE
(11 - 14V)
Ignition switch ``ON''
Accelerator pedal depressedApproximately 0V
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
23+The OFF signal (short) is sent to the ECM for a cer-
tain period of time even when the accelerator pedal is
not being depressed.+Harness or connectors
(The switch circuit is shorted.)
+Accelerator switch (F/C)
SEF687V
TROUBLE DIAGNOSIS FOR ``ACCEL POS SW (F/C)'' (DTC 23)
EC-106

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Depress and release accelerator pedal once for 15 sec-
onds.
3) Repeat step 2 for 26 times.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON''.
2) Depress and release accelerator pedal once for 15 sec-
onds.
3) Repeat step 2 for 26 times.
4) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
5) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF756V
TROUBLE DIAGNOSIS FOR ``ACCEL POS SW (F/C)'' (DTC 23)
Accelerator Switch (F/C) (Cont'd)
EC-107

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK OVERALL FUNCTION.1. Turn ignition switch ``ON''.
2. Check ``ACCEL SW (F/C)'' in
``DATA MONITOR'' mode with
CONSULT.
Accelerator pedal released:
OFF
Accelerator pedal depressed:
ON
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
1. Turn ignition switch ``ON''.
2. Check voltage between ECM
terminal
V29and ground.
Voltage:
Accelerator pedal released
Battery voltage
Accelerator pedal depressed
Approximately 0V
NG
cOK
INSPECTION END
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Loosen and retighten engine ground
screws.
3. Disconnect accelerator switch (F/C) har-
ness connector.
4. Check harness continuity between termi-
nal
V3and engine ground.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Check the following.
+Harness connectors
M51,F6(RHD mod-
els)
+Joint connector
F18+Harness for open or
short between accelera-
tor switch (F/C) and
engine ground
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 ECM
terminal
V29and terminalV1.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Check the following.
+Harness connectors
F6,M51(RHD mod-
els)
+Harness for open or short
between ECM and accel-
erator switch (F/C)
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
[Accelerator switch (F/C)].
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace accelerator pedal
assembly.
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
SEF688V
SEF589S
SEF590S
SEF591S
SEF592S
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``ACCEL POS SW (F/C)'' (DTC 23)
Accelerator Switch (F/C) (Cont'd)
EC-109

Engine Control Module (ECM)-ECCS-D Control
Module
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The unit controls the engine.
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Item
(Possible Cause)
27, 31+ECM calculation function is malfunctioning.+ECM
(ECCS-D control module)
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 2 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON''.
2) Wait at least 2 seconds.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEC220B
SEF748V
TROUBLE DIAGNOSIS FOR ``ECM 1'' (DTC 27), ``ECM 2'' (DTC 31)
EC-111