ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –199
Diagnostic Trouble Code (DTC) P0251 (Symptom Code 7) (Flash Code 53)
Injection Pump Malfunction
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0251 (Symptom Code 7) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0251 (Symptom Code 7) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Was the DTC P0335 (Symptom Code B), P0335 (Symptom Code D) or P1335 (Symptom Code A)
stored at the same time?
— Go to DTC
Chart P0335 (Symptom Code B)
(Symptom
Code D) or P1335
(Symptom Code A) Go to Step 5
5 Check for poor/faulty connection at the ECM or PSG (pump control unit) connector. If a poor/faulty
connection is found, repair the faulty terminal.
Was the problem found?
— Verify repair Go to Step 6
91
8C-57(B) E-6

6E–200 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 If a oscilloscope is available, monitor the CKP sensor
output signal. Does the oscilloscope indicate correct
wav e form?
—Go to Step 13Not available:
Go to Step 7
Fix ed at low:
Go to Step 7
Fix ed at High:
Go to Step 8 Step Action Value(s) Yes No
Cra nksha ft Po sitio n (CKP) Sensor & TDC Output Signal
Reference Wave Form
CH1
0V
CH2
0V
Mea sure me nt Terminal: CH1: 90(+) / CH2: 91(+) GND(-)
Mea sure me nt Scale: CH1: 50V/div / CH2: 10V/div 1ms/div
Mea sure me nt Co ndition: Approx imately 2000rpm

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –201
7 Using the DVM and check the CKP sensor output
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 PSG (pump control unit) connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the ECM connector.
3. Disconnect the PSG (pump control unit) connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
— Repair faulty
harness and verify repair Go to Step 8
8 Using the DVM and check the CKP sensor output circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the PSG (pump control unit) connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 9 Repair faulty
harness and verify repair
Step Action Value(s) Yes No
E-691Breaker Box




918
C-57(B) E-6
8
V
E-6

6E–202 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
9 Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?—Remove the
accessory parts
and verify repair Go to Step 10
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
11 Substitute a known good ECM and recheck.
Was the problem solved?
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. —Go to Step 12Go to Step 13
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—
13 Replace the injection pump assembly.
Is the action complete?—Verify repair— Step Action Value(s) Yes No

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–203
Diagnostic Trouble Code (DTC) P0251 (Symptom Code 9) (Flash Code 53)
Injection Pump 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 P0251 (Symptom Code 9) 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 P0251 (Symptom Code 9) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Replace the injection pump assembly.
Is the action complete?—Verify repair—

6E–204 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0251 (Symptom Code A) (Flash Code 53)
Injection Pump 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 P0251 (Symptom Code A) 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 P0251 (Symptom Code A) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Replace the injection pump assembly.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–205
Diagnostic Trouble Code (DTC) P0251 (Symptom Code B) (Flash Code 53)
Injection Pump 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 P0251 (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 P0251 (Symptom Code B) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Replace the injection pump assembly.
Is the action complete?—Verify repair—

6E–206 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0251 (Symptom Code D) (Flash Code 53)
Injection Pump 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 P0251 (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 P0251 (Symptom Code D) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Replace the injection pump assembly.
Is the action complete?—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–207
Diagnostic Trouble Code (DTC) P0251 (Symptom Code E) (Flash Code 53)
Injection Pump 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 P0251 (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 P0251 (Symptom Code E) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Was the DTC P1650 (Symptom Code A) or P1651
(Symptom Code B) stored at the same time?
—Go to DTC
Chart P1650
(Symptom
Code A) Go to Step 5
5 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 6
6 Substitute a known good ECM and recheck.
Was the problem solved?
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. —Go to Step 7Go to Step 8
7 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—
8 Replace the injection pump assembly.
Is the action complete?—Verify repair—

6E–208 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0335 (SYMPTOM CODE B)
(FLASH CODE 43)CRANKSHAFT POSITION SENSOR CIRCUIT MALFUNCTION
DIAGNOSTIC TROUBLE CODE (DTC) P0335 (SYMPTOM CODE D)
(FLASH CODE 43) CRANKSHAFT POSITION SENSOR MALFUNCTION
DIAGNOSTIC TROUBLE CODE (DTC) P0335 (SYMPTOM CODE E)
(FLASH CODE 43) ENGINE SPEED INPUT CIRCUIT RANGE/PERFORMANCE