2004 ISUZU TF SERIES engine

6E –248 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0500 (Symptom Code B) (Flash Code 24)
Vehicle Speed Sensor Incorrect Signal
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 P0500 (Symptom Code B) 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 P0500 (Symptom Code B) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Perform test drive and check the speed meter. Does the speed meter indicate correct vehicle speed. —Go to Step 5 Go 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 17 Go to Step 7
6 Check for poor/faulty connection at the VSS, TCM (A/ T 2WD) and meter connectors. If a poor/faulty
connection is found, repair the faulty terminal.
Was the problem found?
— Verify repair Go to Step 8
13
2
9 10
10 B-24
C-94(10) E-44

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –249
7 Check for poor/faulty connection at the ECM and
other connectors. If a poor/faulty connection is found,
repair the faulty terminal.
Was the problem found?
— Verify repair Go to Step 9
8 Remove the VSS from the housing case and visually
check.
Was the problem found? —Go to Step 10 Go to Step 9
9 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 si gnal
at each connector connection. Does the oscilloscope
indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
17 Refer the table
10 Replace the VSS. Is the action complete? —Verify repair
Step Action Value(s) Yes No
68
C-56
Me asure ment Position Vo lta ge (V)
(AC Range) If No
Go od
VSS terminal 3 & GND Approximately 6.0 V at 20km/h Go to
St e p 1 0
TCM C94 conne ctor 10 &
GND (A/T 2WD) Go to
Step 11
Meter B24 connector 9 &
GND Go to
St e p 1 2
Meter B24 connector 10 &
GND Go to
St e p 1 4
ECM C56 connector 68 &
GND Go to
St e p 1 5
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

6E –250 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
11 Replace the TCM.
Is the action complete?
IMPORTANT: The replacement TCM must be
programmed. “SPS (Service Programming System)
is necessary. ” —Verify repair —
12 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 13 Repair faulty
harness and verify repair
13 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 —
14 Replace the speed meter. Is the action complete? —Verify repair —
Step Action Value(s) Yes No
9
V
B-24
3
9
E-44
B-24

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –251
15 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 16 Repair faulty
harness and verify repair
16 Using the DVM and check the VSS signal 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 meter connector.
4. Check the circuit for open or shot to ground circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off ”, engine “Off ”.
2. Disconnect the meter connector and ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
— Repair faulty
harness and verify repair Go to Step 17
Step Action Value(s) Yes No
10
V
B-24
68
Breaker BoxB-24




68
10
B-24
C-56

6E–252 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
17 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 18
18 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–253
DIAGNOSTIC TROUBLE CODE (DTC) P0560 (SYMPTOM CODE 1)
(FLASH CODE 35) SYSTEM VOLTAGE TOO HIGH
DIAGNOSTIC TROUBLE CODE (DTC) P0560 (SYMPTOM CODE 2)
(FLASH CODE 35) SYSTEM VOLTAGE TOO LOW
DIAGNOSTIC TROUBLE CODE (DTC) P0560 (SYMPTOM CODE A)
(FLASH CODE 35) SYSTEM VOLTAGE MALFUNCTION
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM and PSG monitors the system voltage on the
ignition feed terminal to the ECM or PSG. The systemvoltage to the ECM excessively high or low, DTC P0560
(Symptom Code 1) or P0560 (Symptom Code 2) will be
stored. The system voltage to the PSG ex cessively high
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
35 P0560 1 OFF System Voltage Too High System voltage is more than
20V.ECM use s 9V co nditio ns a s
substitute.
2 OFF System Voltage Too Low System voltage is below 7V.
A OFF System Voltage Malfunction System voltage of PSG
(pump co ntrol unit) is below
4.5V or more than 27V.PSG uses default voltage as
substitute.

6E–254 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
or low, DTC P0560 (Symptom Code A) 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 and PSG-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 “System Voltage” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0560 (Symptom Code 1) (Flash Code 35)
System Voltage Too High
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 P0560 (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 P0560 (Symptom Code 1) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Was the battery jump start cable incorrectly
connecting?—Verify
procedure Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “System Voltage” in the data display.
3. Load the electrical system by turning on the
headlights, etc..
Does the Tech 2 indicate correct ignition voltage? 10 - 14.5V Go to Step 6Check the
charging
system
6 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 7

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–255
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— Step Action Value(s) Yes No