engine ISUZU TF SERIES 2004 Workshop Manual

6E–234 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
10 Replace the EGR EVRV.
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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –235
Diagnostic Trouble Code (DTC) P0400 (Symptom Code 5) (Flash Code 32)
Exhaust Gas Recirculation Flow Insufficient Detected
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 P0400 (Symptom Code 5) 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 P0400 (Symptom Code 5) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step 4
4 Visually check the EGR control vacuum hose. If the hose is clogged or disconnected, repair as
necessary.
Was the problem found? —Verify repair Go to Step 5
5 Using the DVM and check the EGR EVRV. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the EGR EVRV connector.
3. Measure the resistance of EGR EVRV solenoid coil.
Does the tester indicate standard resistance?
Approx imately 14
at 20 °C Go to Step 8 Go to Step 6
6 Substitute a known good EGR EVRV and recheck. Was the problem solved? —Go to Step 7 Go to Step 8
7 Replace the EGR EVRV. Is the action complete? —Verify repair —
1
2
EGR EVRV
1
2

6E–236 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
8 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:
3. Using the Tech 2, ignition "On" and engine "On".
4. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
5. 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 or
Go to Step 10 Go to Step 9
9 Inspect the EGR valve.
1. Remove the EGR valve from the engine.
2. Inspect the EGR valve whether pintle valve is
stuck or damaged.
If ex cessive carbon deposit is found, clean up the
EGR valve and inspect damage of the pintle and seat.
Was the problem found?—Verify repair or
Go to Step 10 Go to Step 11
10 Replace the EGR valve.
Is the action complete?—Verify repair - Step Action Value(s) Yes No

Vacuum Pump Small Window

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –237
11 Check for poor/faulty connection at the MAF sensor or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 12
12 Visually check the MAF sensor. Was the problem found? —Go to Step 14 Go to Step 13
13 Using the DVM and check the MAF sensor signal circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the MAF sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 16 Repair faulty
harness and verify repair
14 Substitute a known good MAF & IAT sensor assembly and recheck.
Was the problem solved? —Go to Step 15 Go to Step 16
15 Replace the MAF & IAT sensor assembly. Is the action complete? —Verify repair —
16 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 17
17 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
92
88 83
2 3
4
5
C-116
C-57(B)
5
V
C-116

6E –238 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0400 (Symptom Code 8) (Flash Code 32)
Exhaust Gas Recirculation Circuit Short to Battery
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 P0400 (Symptom Code 8) 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 P0400 (Symptom Code 8) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids
4 Check for poor/faulty connection at the EGR EVRV 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 EGR EVRV. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the EGR EVRV connector.
3. Measure the resistance of EGR EVRV solenoid coil.
Does the tester indicate standard resistance?
Approx imately 14
at 20 °CGo to Step 6Go to Step 8
9712
C-115
C-57
1
2
EGR EVRV
1
2

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –239
6 Using the DVM and check the EGR EVRV circuit.
1. Ignition “Off ”, engine “Off ”.
2. Remove the EGR EVRV connector and ECM connector.
3. 3. Check the circuit for short to voltage circuit.
Was the DVM indicated specified value?
No continuity Go to Step 10Go to Step 7
7 Repair the short to voltage circuit. Is the action complete? —Verify repair —
8 Substitute a known good EGR EVRV and recheck. Was the problem solved? —Go to Step 9 Go to Step 10
9 Replace the EGR EVRV. 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
11 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
1
2
C-115

6E–240 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (SYMPTOM CODE 1)
(FLASH CODE 24) VEHICLE SPEED SENSOR CIRCUIT HIGH INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (SYMPTOM CODE A)
(FLASH CODE 24) VEHICLE SPEED SENSOR INPUT SIGNAL FREQUENCY
TOO HIGH
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (SYMPTOM CODE B)
(FLASH CODE 24) VEHICLE SPEED SENSOR INCORRECT SIGNAL

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–241
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The VSS is a magnet rotated by the transmission output
shaft. The VSS uses a hall element. It interacts with the
magnetic field treated by the rotating magnet. It outputs
pulse signal. The 12 volts operating supply from the
meter fuse.
The engine control module (ECM) calculates the vehicle
speed by VSS.
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 DTC P0500 display on the Tech2 while moving
connectors and wiring harnesses. A change in the
display will indicate the location of the fault.
Diagnostic Trouble Code (DTC) P0500 (Symptom Code 1) (Flash Code 24)
Vehicle Speed Sensor Circuit High Input
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
24 P0500 1 ON
at next
ignitio n
cy cleVehicle Spe ed Se nsor Circuit
High InputVehicle speed is more than
200km/h.ECM uses v ehicle spe ed 5km/
h condition as substitute.
AON
at next
ignitio n
cy cleVehicle Speed Sensor Input
Signal Frequency Too HighInput signal frequency is too
high.ECM uses v ehicle spe ed 5km/
h condition as substitute.
BON
at next
ignitio n
cy cleVehicle Spe ed Se nsor Inco r-
re ct Signal1. Engine speed is more than
3200rpm (4JA1-TC) o r
3600rpm (4JH1-TC).
2. Fuel injection quantity is
more than 30mg/strk
(4JA1-TC) or 41mg/strk
(4JH1-TC).
3. Vehicle speed is below
1.5km/h.Fuel injection quantity is
re duced.
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 P0500 (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 P0500 (Symptom Code 1) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4

6E–242 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
4 Perform test drive and check the speed meter.
Does the speed meter indicate correct vehicle speed.—Go to Step 5Go to Step 6
5 Perform test drive and use the Tech 2.
Monitor the “Vehicle Speed” in the data display.
Does the Tech 2 indicate correct vehicle speed as
same as the speed meter indication in the instrument
panel?—Go to Step 15Go to Step 7
6 Remove the VSS from the housing case and visually
check.
Was the problem found? —Go to Step 8Go to Step 7
7 Using the DVM and check the VSS signal.
1. Ignition “On”, vehicle “Run (lift up)”.
2. Measure the VSS output voltage at sensor, TCM
(A/T 2WD), meter and ECM.
Does the tester indicate specified value?
If a oscilloscope is available, monitor the VSS signal
at each connector connection. Does the oscilloscope
indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
15Refer the table
8 Replace the VSS.
Is the action complete?—Verify repair
9 Replace the TCM.
Is the action complete?
IMPORTANT: The replacement TCM must be
programmed. “SPS (Service Programming System)
is necessary.” —Verify repair— Step Action Value(s) Yes No
Me asure ment Position Vo lta ge (V)
(AC Range)If No
Go od
VSS terminal 3 & GND Approximately 6.0
V at 20km/hGo to
Step 8
TCM C94 conne ctor 10 &
GND (A/T 2WD)Go to
Step 9
Meter B24 connector 9 &
GNDGo to
St e p 1 0
Meter B24 connector 10 &
GNDGo to
St e p 1 2
ECM C56 connector 68 &
GNDGo to
St e p 1 3
Ve hicle Spee d Sensor (VSS) Refe re nce Wav e Fo rm
0V
Mea sure me nt Terminal: 68(+) GND(-)
Mea sure me nt Scale: 5V/div 50ms/div
Measurement Condition: Approximately 20km/h

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –243
10 Using the DVM and check the VSS signal circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the meter connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 11 Repair faulty
harness and verify repair
11 Using the DVM and check the VSS signal circuit. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the VSS connector and meter connector.
3. Check the circuit for open or short to ground circuit.
If a open or short to ground circuit is found, repair the
faulty harness and verify repair.
Is the action complete?
— Verify repair —
12 Replace the speed meter. Is the action complete? —Verify repair —
13 Using the DVM and check the VSS signal circuit. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the meter connector and ECM connector.
3. Ignition “On ”.
4. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 14 Repair faulty
harness and verify repair
Step Action Value(s) Yes No
9
V
B-24
3
9
E-44
B-24
10
V
B-24