ignition ISUZU TF SERIES 2004 Workshop Manual

6E–276 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
8 Repair the open circuit between the “Stop Lamp fuse
(15A)” and brake switch 1.
Is the action complete?—Verify repair—
9 Using the DVM and check the brake switch 1 circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type B. (ECM
connected) Ref. Page 6E-103
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 brake switch 1 and
check the circuit for open or short to voltage
circuit.
Was the problem found?
Pedal is not
stepped on:
Less than 1V
Pedal stepped
on: 10-14.5V Go to Step 12Fix ed at 10-
14.5V: Go to
Step 10
Fix ed at less
than 1V: Go to
Step 11
10 Repair the short to voltage circuit between the brake
switch 1 connector and ECM.
Is the action complete?
—Verify repair—
11 Repair the open circuit between the brake switch 1
connector and ECM.
Is the action complete?
—Verify repair— Step Action Value(s) Yes No
105Breaker Box
V
V
2 C-44
230C-56
C-44
230C-56
C-44

6E–278 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0703 (Symptom Code B) (Flash Code 25)
Brake Switch 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 P0703 (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 P0703 (Symptom Code B) 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 brake 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 brake switch 2.
1. Ignition “Off”, engine “Off”.
2. Remove the brake switch connector at the brake
pedal.
3. Check the brake switch 2.
Was the DVM indicated specified value?
Pedal is not
stepped on:
No continuity
Pedal stepped
on: Continuity Go to Step 6Replace pedal
switch and
verify repair
653
4 C-56 C-44




Brake Switch

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–279
6 Using the DVM and check the brake switch 2 power
supply circuit.
1. Ignition “On”, engine “Off”.
2. Remove the brake switch connector from the
brake 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 brake switch 2.
Is the action complete?—Verify repair—
8 Using the DVM and check the brake switch 2 circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type B. (ECM
connected)
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 brake switch 2 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 11Fix 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
3C-44
65Breaker Box
V
V
4 C-44

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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–285
DIAGNOSTIC TROUBLE CODE (DTC) P1105 (SYMPTOM CODE 1)
(FLASH CODE 86) BAROMETRIC PRESSURE SENSOR CIRCUIT HIGH INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1105 (SYMPTOM CODE 2)
(FLASH CODE 86) BAROMETRIC PRESSURE SENSOR CIRCUIT LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM monitors the barometric pressure signal at
inside of the ECM. If the sensor with malfunction, DTC
P1105 (Symptom Code 1) or P1105 (Symptom Code 2)
will be stored.
Diagnostic Aids
If the DTC P1105 is stored, sensor or circuit of ECM
inside is failed.
Diagnostic Trouble Code (DTC) P1105 (Sy mptom Code 1) (Flash Code 86)
Barometric Pressure Sensor Circuit High Input
Diagnostic Trouble Code (DTC) P1105 (Sy mptom Code 2) (Flash Code 86)
Barometric Pressure Sensor Circuit Low Input
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
86 P1105 1 ON Ba rome tric Pressure Se nsor
Circuit High InputBa rome tric pressure senso r
output voltage is more than
4.4V.ECM use s 1013hpa condition
as substitute .
2 ON Ba rome tric Pressure Se nsor
Circuit Lo w InputBa rome tric pressure senso r
output voltage is below 1.5V.
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 P1105 (Symptom Code 1) or P1105
(Symptom Code 2) 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 P1105 (Symptom Code 1) or P1105
(Symptom Code 2) stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 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 5

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–289
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 1) 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 1) 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 TPS or ECM
connector. If a poor/faulty connection is found, repair
as necessary.
Was the problem found?
—Verify repair Go to Step 5
5 Visually check the TPS.
Was the problem found? —Go to Step 12Go to Step 6 Step Action Value(s) Yes No
4939
57
23 1C-56
E-22

6E–290 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the TPS.
1. Ignition “Off”, engine “Off”.
2. Disconnect TPS connector.
3. Measure the resistance of TPS.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 7Go to Step 12
7 Using the DVM and check the TPS power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for short to voltage circuit.
Was the DVM indicated specified value?
Approx imately
5.0V Go to Step 9Go to Step 8
8 Repair the short to voltage circuit between the ECM
and TPS.
Was the problem solved?
—Verify repair Go to Step 14 Step Action Value(s) Yes No
Measurement
Te r m i n a lRe sista nce (
)
1 - 2Approximately 0.4k
a t idle po sitio n
Approximately 4.0k
at WOT
2 - 3Approximately 4.3k
a t idle po sitio n
Approximately 0.8k
at WOT
1 - 3Approximately 4.6k
a t idle po sitio n &
WO T
TPS
123
1
23
V3 E-22
57
3 C-56
E-22

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–291
9 Using the DVM and check the TPS signal circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 10Repair faulty
harness and
verify repair
10 Using the DVM and check the TPS ground circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector .
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 11Repair faulty
harness and
verify repair Step Action Value(s) Yes No
V
2 E-22
V1E-22

6E–292 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
11 Using the DVM and check the TPS ground circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Ref. Page 6E-103
3. Disconnect the TPS connector.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the TPS connector and ECM
connector.
3. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 14
12 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 13Go to Step 14
13 Replace the TPS.
Is the action complete?—Verify repair—
14 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 15
15 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
E-2249Breaker Box




49
1C-56
E-22