switch ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–281
DIAGNOSTIC TROUBLE CODE (DTC) P0704 (SYMPTOM CODE 6)
(FLASH CODE 57) CLUTCH SWITCH INPUT CIRCUIT MALFUNCTION
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM monitors the clutch switch signal on the feed
terminal to the ECM. If clutch switch circuit with
malfunction, DTC P0704 (Symptom Code 6) will be
stored.
Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Misrouted harness.
Rubbed through wire insulation.Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the “Clutch Switch” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
57 P0704 6 ON Clutch Switch Input Circuit
Malfunctio nClutch signa l do es no t change
between vehicle speed
1.5km/h and 80km/h since
ignitio n switch was tune d on. No fa il-sa fe fun ctio n.

6E–282 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0704 (Symptom Code 6) (Flash Code 57)
Clutch Switch Input Circuit Malfunction
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P0704 (Symptom Code 6) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P0704 (Symptom Code 6) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check for poor/faulty connection at the clutch switch
or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
—Verify repair Go to Step 5
5 Using the DVM and check the clutch switch.
1. Ignition “Off”, engine “Off”.
2. Remove the clutch switch connector at the clutch
pedal.
3. Check the clutch switch.
Was the DVM indicated specified value?
Pedal is not
stepped on:
Continuity
Pedal stepped
on: No
continuity Go to Step 6Replace pedal
switch and
verify repair
311
2
C-56 C-77
Clutch Sw itch



4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–283
6 Using the DVM and check the clutch switch power supply circuit.
1. Ignition “On”, engine “Off”.
2. Remove the clutch switch connector from the clutch switch.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10-14.5V Go to Step 8Go to Step 7
7 Repair the open circuit between the “ECM fuse (10A)” and clutch switch.
Is the action complete? — Verify repair —
8 Using the DVM and check the clutch switch circuit. Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type B. (ECM connected) Ref. Page 6E-104
3. Ignition “On”, engine “Off”.
4. Check the circuit for open or short to voltage circuit.
Was the DVM indicated specified value?
Breaker box is not available: 1. Ignition “On”, engine “Off”.
2. Back probe the DVM to the clutch switch and check the circuit for open or short to voltage
circuit.
Was the problem found?
Pedal is not
stepped on: 10-14.5V
Pedal stepped on: Less than 1V Go to Step 11 Fix ed at 10-
14.5V: Go to Step 9
Fix ed at less
than 1V: Go to Step 10
Step Action Value(s) Yes No
V
1
2
C-77
31Breaker Box
V
V
2
C-77

6E–284 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
9 Repair the short to voltage circuit between the clutch
switch connector and ECM.
Is the action complete?
—Verify repair—
10 Repair the open circuit between the clutch switch
connector and ECM.
Is the action complete?
—Verify repair—
11 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?—Verify repair Go to Step 12
12 Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.—Verify repair— Step Action Value(s) Yes No
312
C-56 C-77
312
C-56 C-77

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–287
DIAGNOSTIC TROUBLE CODE (DTC) P1120 (SYMPTOM CODE 1)
(FLASH CODE 21) PEDAL/THROTTLE POSITION SENSOR CIRCUIT HIGH
INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1120 (SYMPTOM CODE 7)
(FLASH CODE 21) PEDAL/THROTTLE POSITION SENSOR VOLTAGE SUPPLY
CIRCUIT HIGH INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1120 (SYMPTOM CODE 9)
(FLASH CODE 21) PEDAL/THROTTLE POSITION SENSOR VOLTAGE SUPPLY
CIRCUIT LOW INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1120 (SYMPTOM CODE D)
(FLASH CODE 21) PEDAL/THROTTLE POSITION SENSOR BRAKE SWITCH
ERROR
DIAGNOSTIC TROUBLE CODE (DTC) P1120 (SYMPTOM CODE E)
(FLASH CODE 21) PEDAL/THROTTLE POSITION SENSOR IDLE POSITION
SWITCH ERROR

6E–288 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The TPS is a potentiometer connected to throttle shaft
on the throttle body. It is installed to the main TPS and
idle switch.
The engine control module (ECM) monitors the voltage
on the signal line and calculates throttle position. As the
throttle valve angle is changed when accelerator pedal
moved. The TPS signal also changed at a moved
throttle valve. As the throttle valve opens, the output
increases so that the output voltage should be high.
The ECM monitors the TPS supply voltage and TPS
output voltage. The supply voltage is out of range, DTC
P1120 (Symptom Code 7) or P1120 (Symptom Code 9)
will be stored. The output voltage excessively high, DTC
P1120 (Symptom Code 1) will be stored.
If the brake pedal is depressed during accelerator pedal
is depressing, DTC P1120 (Symptom Code D) will be
stored.
If the relation of idle switch and TPS position are
incorrect, DTC P1120 (Symptom Code E) will be stored.
Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Misrouted harness.
Rubbed through wire insulation.
Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the “Throttle Position”, “Idle Switch”, “Brake Switch 1”
and “Brake Switch 2” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P1120 (Sy mptom Code 1) (Flash Code 21)
Pedal/Throttle Position Sensor Circuit High Input
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
21 P1120 1 ON Pedal/Throttle Position Sen-
sor Circuit High InputThrottle position sensor out-
put voltage is more than 4.5V.ECM increa ses idle spe ed up
to 1400rpm.
7 ON Pedal/Throttle Position Sen-
sor Voltage Supply Circuit
High InputThrottle position sensor
power supply voltage is more
than 5.2V.
9 ON Pedal/Throttle Position Sen-
sor Voltage Supply Circuit
Lo w InputThrottle position sensor
power supply voltage is below
4.6V.
D ON Pedal/Throttle Position Sen-
sor Brake Switch Error1. Engine speed is more than
1700rpm.
2. Vehicle speed is more than
1.5km/h.
3. When brake pedal is
depressed during accelera-
tor pe da l is de pre ssing.
E ON Pedal/Throttle Position Sen-
sor Idle Position Switch Error1. Whe n idle switch is turne d
o ff, thro ttle positio n se nsor
wa s be lo w 0.35%.
or
2. Whe n idle switch is tune d
on, throttle position sensor
was more than 7.8%.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check

6E–298 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1120 (Sy mptom Code D) (Flash Code 21)
Pedal/Throttle Position Sensor Brake Switch Error
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1120 (Symptom Code D) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1120 (Symptom Code D) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Visually check the TPS.
Check for the following conditions.
Accelerator pedal sticking.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position”
from 0% to 100% depending on accelerator pedal
operation?—Go to Step 7Go to Step 6
6 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?—Verify repair Go to Step 11
7 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Brake Switch 1” and “Brake Switch 2”
in the data display.
Does the Tech 2 indicate “Inactive” when the brake
pedal was not stepped on?—Go to Step 13Go to Step 8
8 Adjust the brake switch.
Was the problem solved?—Verify repair Go to Step 9
9 Substitute a known good brake switch and recheck.
Was the problem solved?—Go to Step 10Go to Step 13
10 Replace the brake switch.
Is the action complete?—Verify repair—
11 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 12Go to Step 13
12 Replace the TPS.
Is the action complete?—Verify repair—

6E–300 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1120 (Symptom Code E) (Flash Code 21)
Pedal/Throttle Position Sensor Idle Position Switch Error
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1120 (Symptom Code E) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1120 (Symptom Code E) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Visually check the TPS.
Was the problem found? —Go to Step 8Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position”
from 0% to 100% depending on accelerator pedal
operation?—Go to Step 7Go to Step 6Go
to Step 6
6 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?—Verify repair Go to Step 8
7 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Idle Switch” in the data display.
Does the Tech 2 indicate “Inactive” when the
accelerator pedal was stepped on?—Go to Step 10Go to Step 8
8 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 9Go to Step 10
9 Replace the TPS.
Is the action complete?—Verify repair—
10 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?—Verify repair Go to Step 11

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–313
DIAGNOSTIC TROUBLE CODE (DTC) P1520 (SYMPTOM CODE A)
(FLASH CODE 47) NEUTRAL SWITCH ON ERROR
DIAGNOSTIC TROUBLE CODE (DTC) P1520 (SYMPTOM CODE B)
(FLASH CODE 47) NEUTRAL SWITCH OFF ERROR
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM monitors the neutral switch (A/T: N or P
position switch in inhibitor switch) signal on the feed
terminal to the ECM. If the neutral switch with
malfunction, DTC P1520 (Symptom Code A) or P1520(Symptom Code B) will be stored.Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
47 P1520 A ON Neutra l Switch ON Error Neutra l switch signa l is input-
te d “On” thre e times co nsecu-
tively under driving
conditio ns.No fa il-sa fe fun ctio n.
B ON Neutra l Switch OFF Erro r Neutra l switch signa l is input-
te d “Off” three time s co nse cu-
tively under driving
conditio ns.

6E–314 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Misrouted harness.
Rubbed through wire insulation.
Broken wire inside the insulation.
Check for the following conditions:
Poor connection at ECM-Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, andpoor terminal to wire connection.
Damaged harness-Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the “Neutral Switch” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P1520 (Symptom Code A) (Flash Code 47)
Neutral Switch ON Error
Diagnostic Trouble Code (DTC) P1520 (Symptom Code B) (Flash Code 47)
Neutral Switch OFF Error
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1520 (Symptom Code A) or P1520
(Symptom Code B) stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1520 (Symptom Code A) or P1520
(Symptom Code B) stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4