fuel ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–341
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 and PSG-Inspect harness
connectors for backed out terminals, improper
mating, broken locks, improperly formed or damaged
terminals, and poor terminal to wire connection.
Diagnostic Trouble Code (DTC) P1630 (Sy mptom Code A) (Flash Code 51) Fuel
Injection Quantity Circuit Malfunction
Diagnostic Trouble Code (DTC) P1630 (Sy mptom Code B) (Flash Code 51) Fuel
Injection Quantity 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 P1630 (Symptom Code A) or P1630
(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 P1630 (Symptom Code A) or P1630
(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—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–349
DIAGNOSTIC TROUBLE CODE (DTC) P1651 (SYMPTOM CODE A)
(FLASH CODE 45) CAN MALFUNCTION
DIAGNOSTIC TROUBLE CODE (DTC) P1651 (SYMPTOM CODE B)
(FLASH CODE 45) CAN RECEIVES ERROR
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The interchange of data between the engine control
module (ECM) and the pump control unit (PSG) is
performed via a CAN-bus system. The individual CAN-
bus systems are connected via two interfaces and can
ex change information and data. This allows control
modules that are connected to different CAN-bussystems to communicate. Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Misrouted harness.
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
45 P1651 A ON CAN Ma lfunction The PSG (pump control unit)
do es not re co gnize CAN sig-
na l from the CAN co ntrolle r.1. MAB (fuel cutoff solenoid
valve) is operated.
2. Desired injection quantity
becomes 0mg/strk.
B ON CAN Ma lfunction The ECM do es not re ad CAN
signal from the PSG (pump
control unit).

6E–362 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
ENGINE CRANKS BUT WILL NOT RUN
DEFINITIONS: Engine cranks, but will not run. (The engine never start.)
NOTE: The vehicle with immobilizer system, this system may be activated. Check the immobilizer system diagnosis.
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. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the fuel amount enough?
—Go to Step 5Add fuel to the
tank
5 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 6
6 Check the “ECM” fuse (10A) and “Engine” fuse (15A).
If the fuse is burnt out, repair as necessary.
Was the problem found?—Verify repair Go to Step 7
7 Visually/physically inspect for the following conditions.
Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system
Check for objects blocking or ex cessive deposits in
the throttle bore and on the throttle plate
Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.
Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 8
8 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Neutral Switch” in the data display.
Does the Tech 2 indicate correct “Neutral Switch”
status depending on any shift positions?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 10

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–363
10 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 11
11 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 12
12 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 13Go to Step 14
13 Replace the CKP sensor.
Is the action complete?—Veri fy repai r—
14 Check the ex haust system for a possible restriction.
Damaged or collapsed pipes or catalytic converter.
Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 16
15 Visually/physically inspect for the following conditions.
Restrict fuel supply system. Check for a pinched
fuel hose/pipe.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 17
16 Replace the fuel filter.
Was the problem solved?—Verify repair Go to Step 18 Step Action Value(s) Yes No

6E–364 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
17 Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.
Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
ex tended maintenance interval.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was the problem found?
—Replace the
eye bolt with
gauze filter and
verify repair Go to Step 18
18 Check the engine compression pressure for each
cylinders.
If a problem is found, repair as necessary.
Was the problem found?
More than 2.1
Mpa (21.0 kg/
cm
2) Verify repair Go to Step 19
19 If the injection pump was replaced, are the timing
gears or injection pump correctly installed?
—Go to Step 20Repair as
necessary Step Action Value(s) Yes No

6E–366 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
HARD START SYMPTOM
DEFINITIONS: Engine cranks, but does not start for a long time. Does eventually start, or may start and then
immediately stall.
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. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 6
5 Visually/physically inspect for the following conditions.
Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system
Check for objects blocking or ex cessive deposits in
the throttle bore and on the throttle plate
Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.
Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 6
6 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 7
7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2 . C h e c k t h e d i s p l a y e d v a l u e .
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 8
8 1. Using the Tech 2, display the FT sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 20Go to Step 9
9 1. Using the Tech 2, ignition “On”.
2. Monitor the “Glow Time Relay” in the data display.
Does the Tech 2 indicate correct “Glow Time Relay”
status depending on the time from ignition switch
“On”?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 20Go to Step 10

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–367
10 1. Using the Tech 2, ignition “On”.
2. Monitor the “Glow Time Relay” in the data display
and then, does the supply voltage correctly supply
to the glow plug?
—Go to Step 11Repair voltage
supply circuit
and verify repair
11 Check the glow plugs for continuity.
If a problem is found, repair as necessary.
Was a problem found?
—Verify repair Go to Step 12
12 Check the ex haust system for a possible restriction.
Damaged or collapsed pipes or catalytic converter.
Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 13
13 Visually/physically inspect for the following conditions.
Restrict fuel supply system. Check for a pinched
fuel hose/pipe.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 14
14 Replace the fuel filter.
Was the problem solved?—Verify repair Go to Step 15 Step Action Value(s) Yes No

6E–368 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
15 Remove the eye bolt with gauze filter from the
injection pump and check for the following conditions.
Objects blocking at the gauze filter. Check for a
condition that causes contaminated fuel, such as
the customer is using an aftermarket fuel filter or
ex tended maintenance interval.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was the problem found?
—Replace the
eye bolt with
gauze filter and
verify repair Go to Step 16
16 Remove the injection nozzles from the engine and
check for the following conditions.
Improper splay condition.
Operating pressure is incorrect.
If a problem is found, repair as necessary.
Was the problem found?
—Replace the
injection nozzle
and verify repair Go to Step 17
17 Check the engine compression pressure for each
cylinders.
If a problem is found, repair as necessary.
Was the problem found?
More than 2.1
Mpa Verify repair Go to Step 18 Step Action Value(s) Yes No
1st Stage 2nd Sta ge
4JA1-TCApproximatly
19.0 MpaApprox ima tly
33.5 Mpa
4JH1-TCApproximatly
19.5 MpaApprox ima tly
33.8 Mpa

6E–370 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTOM
DEFINITIONS: Engine runs unevenly at idle. If severe,
the engine or vehicle may shake. Engine idle speed
may vary in RPM. Either condition may be severe
enough to stall the engine.
X

time rpm
Rough I dle
Stal l
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. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 5
5 1. Check for incorrect idle speed. Ensure that the
following conditions are present.
Engine fully warm.
Accessories are “OFF”.
2. Using a Tech 2, monitor “Desired Engine Idle
Speed” and “Engine Speed”.
Is the “Engine Speed” within the specified values?Desired
Engine Idle
Speed ± 25
rpm Go to Step 7Go to Step 6
6 Visually/physically inspect for the following conditions.
Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system
Check for objects blocking or ex cessive deposits in
the throttle bore and on the throttle plate
Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.
Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 7
7 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 8

6E–374 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
26 Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or ex cessive carbon
deposit.
Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
Solenoid 95%: EGR Valve Open
Solenoid 5%: EGR Valve Close
Vacuum Pump:
1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.
2. Apply vacuum pressure.
Vacuum Apply: EGR Valve Open
Vacuum Release: EGR Valve Close
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 27
27 Check the ex haust system for a possible restriction.
Damaged or collapsed pipes or catalytic converter.
Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 28
28 Visually/physically inspect for the following conditions.
Restrict fuel supply system. Check for a pinched
fuel hose/pipe.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 29
29 Replace the fuel filter.
Was the problem solved?—Verify repair Go to Step 30 Step Action Value(s) Yes No

Vacuum Pump Small Window