Page 665 of 1833
Wiring Diagram
YEC676A
DTC P0120 ACCEL POS SENSORTD27Ti
EC-390
http://vnx.su/
Page 666 of 1833

Diagnostic Procedure
ACCELERATOR POSITION SENSOR
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch to ªLOCKº position.
2. Disconnect accelerator work unit har- ness connector.
3. Turn ignition switch to ªONº position.
4. Check voltage between accelerator work unit connector terminal q
2and
engine ground with CONSULT-II or
tester.
Voltage: Approximately 5V
OK
ENG Check the following:
IHarness for open or
short-circuit between
ECM and accelerator
work unit.
If NG, repair harness or
connectors.
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch to ªLOCKº position.
2. Loosen and retighten engine ground screws.
3. Check harness continuity between accelerator work unit connector termi-
nal q
4and ECM connector terminal
434. Refer to wiring diagram.
Continuity should exist.
If OK, check harness for short-circuit.
OK
ENG Check the following:
IHarness for open-circuit
between ECM and
accelerator work unit
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal
425and accelerator
position sensor connector terminal q
3.
Refer to wiring diagram.
Continuity should exist.
If OK, check harness for short-circuit.
OK
ENG Repair harness or connec-
tors.
CHECK COMPONENT
(Accelerator position sensor).
Refer to ªCOMPONENT INSPECTIONº on
page EC-394.
OK
ENGReplace accelerator pedal
assembly.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
NEF700
NEF591
YEC698A
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DTC P0120 ACCEL POS SENSORTD27Ti
EC-391
http://vnx.su/
Page 667 of 1833

ACCELERATOR POSITION SWITCH
The accelerator position switch detects OFF-accelerator switch sig-
nal and Full-accelerator switch signal and sends these signals to
the ECM. The ECM will then determine engine idle conditions.
These signals are also used for diagnosing the accelerator position
sensor.
INSPECTION START
CHECK OVERALL FUNCTION.
With CONSULT-II
1. Turn ignition switch to ªONº position.
2. Select ªFULL ACCELL SWº and ªOFF ACCEL SWº in ªDATA MONITORº mode
with CONSULT-II.
3. Check ªFULL ACCEL SWº and ªOFF ACCEL SWº signal under the following
conditions.
OFF ACCEL SW:Accelerator pedal released
ÐON
Accelerator pedal depressed
Ð OFF
FULL ACCEL SW: Accelerator pedal fully depressed
ÐON
Without CONSULT-II
1. Turn ignition switch to ªONº position. 2. Check voltage between ECM terminal
435
and body ground under the following condi-
tions:
Voltage: Accelerator pedal releasedApproximately 0V
Accelerator pedal fully depressed Approximately 5V
NG
EOK INSPECTION END
qA
MEC969D
MEC955D
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DTC P0120 ACCEL POS SENSORTD27Ti
Diagnostic Procedure (Cont'd)
EC-392
http://vnx.su/
Page 668 of 1833

qA
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch to ªLOCKº position.
2. Disconnect accelerator work unit har- ness connector and ECM harness con-
nector.
3. Check harness continuity between accelerator work unit terminal q
3and
ECM terminal
435. Refer to wiring
diagram.
Continuity should exist.
Check harness for short-circuit.
OK
ENG Check the following:
I10A fuse in fuse box
I 75A fusible link in fusible
link box
I Harness continuity
between ECM relay and
battery positive supply
I Harness for open or
short-circuit between
ECM relay and accelera-
tor position switch.
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch to ªLOCKº position.
2. Disconnect ECM harness connector.
3. Check harness continuity between accelerator work unit connector termi-
nal q
1and ECM connector terminal
426. Refer to wiring diagram.
Continuity should exist.
If OK; check harness for short-circuit.
If OK, re-connect harness connectors.
OK
ENG Repair harness or connec-
tors.
CHECK COMPONENT.
(Accelerator position switch.)
Refer to ªCOMPONENT INSPECTIONº on
page EC-394.
OK
ENGReplace accelerator pedal.
Disconnect and reconnect harness con-
nectors in the circuits. Then retest.
Trouble is not fixed
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF628S
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DTC P0120 ACCEL POS SENSORTD27Ti
Diagnostic Procedure (Cont'd)
EC-393
http://vnx.su/
Page 669 of 1833
Component Inspection
ACCELERATOR POSITION SENSOR
1. Disconnect accelerator work unit harness connector.
2. Make sure that resistance between terminalsq
3andq4changes
when opening throttle valve manually.
Throttle valve conditions Resistance [at 25ÉC (77ÉF)]
Completely closed Approximately 1.2 kW
Partially open 1.2 - 1.9 kW
Completely open Approximately 1.9 kW
If NG, replace accelerator pedal assembly.
CAUTION
I Do not disassemble accelerator pedal assembly.
ACCELERATOR POSITION SWITCH
1. Disconnect accelerator work unit harness connector.
2. Check continuity between terminals q
5andq6.
Conditions
Continuity
Accelerator pedal released No
Accelerator pedal depressed Yes
If NG, replace accelerator pedal assembly.
CAUTION:
IDo not disassemble accelerator pedal assembly.
YEC699A
YEC700A
DTC P0120 ACCEL POS SENSORTD27Ti
EC-394
http://vnx.su/
Page 670 of 1833

Component Description
FUEL TEMPERATURE SENSOR (FTS)
The fuel temperature sensor is used to detect the fuel temperature
in the injection pump. The sensor modifies a voltage signal from the
ECM. The modified 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.
The sensor is built into the inside electrical circuit of the injection
pump.
On Board Diagnosis Logic
DTCMalfunction is detected when ... Check Items
(Possible Cause)
P0180
0402 I
An excessively high or low voltage from the sensor is
detected by ECM. I
Harness or connectors
(The sensor circuit is open or short-circuited.)
I Fuel temperature sensor
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch to ªONº position.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
WITHOUT CONSULT-II
1) Turn ignition switch to ªONº position and wait at least 5 sec-
onds.
2) Turn ignition switch to ªLOCKº position, wait at least 5 seconds and then turn to ªONº position.
3) Perform ªDiagnostic Test Mode IIº (Self-diagnostic results).
DTC P0180 FUEL TEMP SENSORTD27Ti
EC-395
http://vnx.su/
Page 671 of 1833
Wiring Diagram
YEC677A
DTC P0180 FUEL TEMP SENSORTD27Ti
EC-396
http://vnx.su/
Page 672 of 1833

Diagnostic Procedure
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch to ªLOCKº position.
2. Disconnect electrical fuel injection pump harness connector.
3. Turn ignition switch to ªONº position.
4. Check voltage between electronic con- trol fuel injection pump (Fuel tempera-
ture sensor) harness connector termi-
nal q
6and engine ground with CON-
SULT-II or tester.
Voltage: Approximately 4.9V
OK
ENG Check the following:
IHarness for open or
short-circuit between
ECM and electronic con-
trol fuel injection pump
(fuel temperature sen-
sor)
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch to ªLOCKº position.
2. Check harness continuity between electronic control fuel injection pump
(fuel temperature sensor) connector
terminal q
5and ECM connector
terminal
335. Refer to wiring dia-
gram.
Continuity should exist.
If OK, check harness for short-circuit.
OK
ENG Check the following:
IHarness for open or
short-circuit between
ECM and electronic con-
trol fuel injection pump
(fuel temperature sen-
sor).
If NG, repair harness or
connectors.
CHECK COMPONENT
[Electronic control fuel injection pump
(Fuel temperature sensor)].
Refer to ªCOMPONENT INSPECTIONº on
page EC-398.
OK
ENG Have the injection pump
assembly serviced by an
authorised service repre-
sentative.
Disconnect and reconnect harness con-
nectors in the circuits. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
YEC248A
YEC254A
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DTC P0180 FUEL TEMP SENSORTD27Ti
EC-397
http://vnx.su/