check engine ISUZU TF SERIES 2004 Workshop Manual

6E-272 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
11

Using the DVM and check the EGR position sensor
ground circuit.
Breaker box is available:
1. Ignition "Off", engine "Off".
2. Install the breaker box as type A (ECM
disconnected).
Refer to 6E-95 page.
3. Disconnect the EGR valve connector.
4. Check the circuit for open circuit.
Was the problem found?
A22
Breaker Box
E-76






Breaker box is not available:
1. Ignition "Off", engine "Off".
2. Disconnect the EGR valve connector and ECM
connector.
3. Check the circuit for open circuit.
Was the problem found?
E-60(A)
E-76










-

Repair faulty
harness and
verify repair

Go to Step 12
12
Substitute a known good EGR valve and recheck.
Was the problem solved?
- Go to Step 13 Go to Step 14
13
Replace the EGR valve.
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

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-275
CIRCUIT DESCRIPTION
The canister purge solenoid valve is controlled by the
Engine Train Control Module (ECM).
At an appropriate time, the EVAP canister purge
solenoid is “ON," allowing engine vacuum to draw a
small vacuum on the entire evaporative emissions
system.
DIAGNOSTIC AIDS
An intermittent may be caused by the following:
 Poor connections.
 Mis routed 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 fo
r
damage. If the harness appears to be OK, observe
the EVAP purge solenoid display on the Tech 2 while
moving connectors and wiring harnesses related to
the sensor.
A change in the display will indicate the location o
f
the fault. If DTC P0444 or P0445 cannot be
duplicated, the information included in the Failure
Records data can be useful in determined vehicle
mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0444 or P0445 Diagnostic
Chart may isolate the cause of the fault.


Diagnostic Trouble Code (DTC) P0444 EVAP Purge Solenoid
Valve Circuit Low Voltage
Diagnostic Trouble Code (DTC) P0445 EVAP Purge Solenoid
Valve Circuit High Voltage

Step Action Value (s) Yes No
1
Was 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 By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0444 or P0445 stored as "Present
Failure"?
- Go to Step 3 Refer to
Diagnostic Aids
and Go to Step 3
3
1. Using the Tech2, ignition "On" and engine "Off".
2. Select "Clear DTC Information" with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P0444 or P0445 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

6E-276 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
4
Check for poor/faulty connection at the purge solenoid
valve or ECM connector. If a poor/faulty connection is
found, repair as necessary.
Was the problem found?
E-61(B)
E-66




- Verify repair Go to Step 5
5
Using the DVM and check the purge solenoid valve.
1. Ignition "Off", engine "Off".
2. Disconnect purge solenoid valve connector.
3. Measure the resistance of purge solenoid valve
coil.
Does the tester indicate standard resistance?
25 - 30
at
20C
Go to Step 6
Go to Step 9
6
Using the DVM and check the purge solenoid valve
power supply circuit.
1. Ignition "On", engine "Off".
2. Disconnect the purge solenoid valve connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
E-66
V




10-14.5V
Go to Step 8
Go to Step 7
7
Repair the open or short to ground circuit between the
"Engine" fuse (15A) and purge solenoid valve.
Is the action complete?
- Verify repair -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-277
Step Action Value (s) Yes No
8

Using the DVM and check the purge solenoid valve
solenoid signal circuit.
Breaker box is available:
1. Ignition "Off", engine "Off".
2. Install the breaker box as type A (ECM
disconnected).
Refer to 6E-95 page.
3. Disconnect the purge solenoid valve connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
B15
Breaker BoxE-66







Breaker box is not available:
1. Ignition "Off", engine "Off".
2. Disconnect the purge solenoid valve connector and
ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
E-61(B)
E-66











-

Repair faulty
harness and
verify repair

Go to Step 9

6E-278 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
9
Using the DVM and check the purge solenoid valve
signal circuit.
1. Ignition "On", engine "Off".
2. Disconnect the purge solenoid valve connector.
3. Check the circuit for short to battery voltage circuit.
Was the DVM indicated battery voltage?
E-66
V




-
Repair faulty
harness and
verify repair
Go to Step 10
10
Substitute a known good purge solenoid valve and
recheck.
Was the problem solved?
- Go to Step 11 Go to Step 12
11
Replace the purge solenoid valve.
Was the problem solved?
- Verify repair Go to Step 12
12
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 13
13
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 -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-279
DIAGNOSTIC TROUBLE CODE (DTC) P0500 (FLASH CODE 24) VEHICLE
SPEED SENSOR (VSS) CIRCUIT RANGE/PERFORMANCE



RTW46EMF000301

Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
24 P0500 B Vehicle Speed Sensor
Circuit
Range/Performance 1. Engine speed is below 5000rpm.
2. Under fuel cut operation.
3. Vehicle speed sensor output is below 1km/h.
Above conditions are met for 4 seconds. The ECM use 10km/h condition as
substitute.


CIRCUIT DESCRIPTION
The vehicle speed sensor has a magnet rotated by the
transmission output shaft. Attached to the sensor is a
hall effect circuit the interacts with the magnetic field
treated by the rotating magnet. A 12-volt operating
supply for the speed sensor hall circuit is supplied from
the meter fuse. The VSS pulses to ground the 9-vol
t
signal sent from the Engine Control Module (ECM) on
the reference circuit. The ECM interprets vehicle speed
by the number of pulses to ground per second on the
reference circuit.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside
the insulation. Check for:
 Poor connection —Inspect the ECM harness and
connectors for improper mating, broken locks,
improperly formed or damaged terminals, and poo
r
terminal-to-wire connection.
 Damaged harness —Inspect the wiring harness fo
r
damage.

6E-280 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0500 (Flash Code 24) Vehicle Speed Sensor
(VSS) Circuit Range/Performance

Step Action Value (s) Yes No
1
Was 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 By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0500 stored as "Present Failure"?
- Go to Step 3 Refer to
Diagnostic Aids
and Go to Step 3
3
1. Using the Tech2, ignition "On" and engine "Off".
2. Select "Clear DTC Information" with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed This
Ignition" in "F2: DTC Information"
Was the DTC P0500 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
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 5
5
Perform test drive and check the speed meter.
Does the speed meter indicate correct vehicle speed.
- Go to Step 6 Go to Step 7
6
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 25 Go to Step 8
7
Check for poor/faulty connection at the VSS and meter
connectors. If a poor/faulty connection is found, repair
the faulty terminal.
Was the problem found?
B-24E-44







- Verify repair Go to Step 9

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-281
Step Action Value (s) Yes No
8
Check for poor/faulty connection at the immobilizer
control unit (if equipped), ECM and other connectors. If
a poor/faulty connection is found, repair the faulty
terminal.
Was the problem found?
B-68


E-61(B)


- Verify repair Go to Step 10
9
Remove the VSS from the housing case and visually
check.
Was the problem found?
- Go to Step 23 Go to Step 10

6E-282 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
10

Using the DVM and check the VSS signal.
1. Ignition "On", vehicle "Run (lift up)".
2. Measure the VSS output voltage at sensor, meter,
immobilizer control unit (if equipped) and ECM.
Does the tester indicate specified value?

Measurement Position Voltage (V) (AC Range) If No Good
VSS terminal 3 & GND Go to Step 11
Meter B24 connector 9 & GND Go to Step 15
Meter B24 connector 10 & GND Go to Step 17Immobilizer control unit B68 connector 6 & GND
Approximately 6.0 V at 20km/h
Go to Step 18 Immobilizer control unit B68 connector 8 & GND Go to Step 20
ECM E-61 connector 32 & GND
Approximately 4.0 V at 20km/hGo to Step 21
If a oscilloscope is available, monitor the VSS signal.
Does the oscilloscope indicate correct wave form?

Vehicle Speed Sensor (VSS) Reference Wave Form








CH1
0V


CH2
0V




Measurement Terminal: CH1: ECM B32(+) / CH2: VSS 3(+)
GND(-)
Measurement Scale: CH1: 10V/div / CH2: 10V/div 50ms/div
Measurement Condition: Approximately 20km/h
Note: The vehicle is without immobilizer system,
CH1 signal is same as CH2.


-

Refer to
Diagnostic Aids
and Go to Step
25

Refer the table
11
Using the DVM and check the VSS power supply
circuit.

1. Ignition "On", engine "Off".
2. Disconnect the VSS connector.
3. Check the circuit for open or short to ground circuit.
Was the DVM indicated specified value?
E-44
V




10-14.5V
Go to Step 13
Go to Step 12

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-283
Step Action Value (s) Yes No
12
Repair the open circuit between the VSS and meter
fuse.
Is the action complete?
- Verify repair -
13
Using the DVM and check the VSS ground circuit.
1. Ignition "On", engine "Off".
2. Disconnect the VSS connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
E-44
V


Less than 1VGo to Step 14 Repair faulty
harness and
verify repair
14
Using the DVM and check the VSS ground circuit.
1. Ignition "Off", engine "Off".
2. Disconnect the VSS connector.
3. Check the circuit for open circuit.
Was the problem found?
E-44




- Repair faulty
harness and
verify repair Go to Step 23
15
Using the DVM and check the VSS signal circuit.
1. Ignition "On", engine "Off".
2. Disconnect the VSS connector and meter
connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
E-44


B-24
V

V


Less than 1V
Go to Step 16
Repair faulty
harness and
verify repair