power ISUZU TF SERIES 2004 Workshop Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–89
Breaker Box Connection Type B
Breaker box connection type B, check for “short to
power supply circuit” and “power, signal voltage check”
between the engine control module (ECM) and
electrical components.
51
432
(1) Engine Control Module (ECM)
(2) Harness Adapter
(3) Breaker Box(4) Digital Voltage Meter
(5) ECM - Harness Adapter Connection

ENGINE DRIVEABILITY AND EMISSIONS 6E–91
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
Step Action Value(s) Yes No
1 1. Ignition “On”, engine “Off”.
2. Check the “CHECK ENGINE” lamp (MIL).
Does the “CHECK ENGINE” lamp turn “On”?—Go to Step 2Go to No
CHECK
ENGINE Lamp
2 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Attempt to display “Engine Data” w i t h t h e T e c h 2 .
Does the Tech 2 display “Engine Data” and “O
2Sensor Data”? —Go to Step 3Go to Step 7
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select the “Miscellaneous Test” and perform the
“Malfunction Indicator Lamp” in “Lamps”.
3. Operate the Tech 2 in accordance with the Tech 2
instructions.
Does the “CHECK ENGINE” lamp turn “Off”? —Go to Step 4Go to CHECK
ENGINE LAMP
On Steady
4 Attempt to start the engine.
Does the engine start and continue to “Run”?
—Go to Step 5Go to Engine
Cranks But Will
Not Run
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select the “Read DTC Infor By Priority” in
“Diagnostic Trouble Code”.
3. Are any DTCs stored?—Go to DTC
ChartGo to Step 6
6 Compare typical scan data values displayed on the
Te c h 2 “Engine Data” and “O
2 Sensor Data”.
Are the displayed values within the range?—Refer to
SYMPTOM
DIAGNOSISRefer to
TYPICAL
SCAN DATA
7 Using the DVM and check the data link connector
power supply circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 8
8 Using the DVM and check the data link connector
ground circuit.
1. Ignition “Off”, engine “Off”.
2. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 9
V
16
B58
5 4B58

6E–92 ENGINE DRIVEABILITY AND EMISSIONS
9 Using the DVM and check the data link connector
ground circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 10Repair faulty
harness and
verify repair
10 Using the DVM and check the data link connector
communication circuit.
1. Ignition “On”, engine “Off”.
2. Check the circuit for short to power supply circuit.
Was the DVM indicated battery voltage?
—Repair faulty
harness and
verify repair Go to Step 11
11 Using the DVM and check the data link connector
communication circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the 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 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 Step Action Value(s) Yes No
VV
5 4B58
V
B-58

C-56(J2)



B- 58


ENGINE DRIVEABILITY AND EMISSIONS 6E–103
FUEL SYSTEM ELECTRICAL TEST
Circuit Description
When the ignition switch is first turned ON, the engine
control module (ECM) energizes the fuel pump relay
which applies power to the in-tank fuel pump. The fuel
pump relay will remain ON as long as the engine is
running or cranking and the ECM is receiving 58X
crankshaft position pulses. If no 58X crankshaft position
pulses are present, the ECM de-energizes the fuel
pump relay within 2 seconds after the ignition is turned
ON or the engine is stopped.
The fuel pump delivers fuel to the fuel rail and injectors,
then to the fuel pressure regulator. The fuel pressure
regulator controls fuel pressure by allowing ex cess fuel
to be returned to the fuel tank. With the engine stopped
and ignition ON, the fuel pump can be turned ON by
using a command by the scan tool.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:
Poor connection or damaged harness - Inspect the
ECM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.
Caution: To reduce the risk of fire and personal
injury:
It is necessary to relieve fuel system pressure
before connecting a fuel pressure gauge.
Refer to Fuel Pressure Relief Procedure,
below.
A small amount of fuel may be released when
disconnecting the fuel lines. Cover fuel line
fittings with a shop towel before
disconnecting, to catch any fuel that may leak
out. Place the towel in an approved container
when the disconnect is completed.

ENGINE DRIVEABILITY AND EMISSIONS 6E–105
6 Using the DVM and check the fuel pump relay power
supply circuit.
1. Ignition “On”, engine “Off”.
2. Remove the fuel pump relay from the relay box .
3. Check the circuit for open or short to ground
circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 8Go to Step 7
7 Repair the open or short to ground circuit between the
“ECM” fuse (15A) and fuel pump relay.
Is the action complete?—Veri fy repai r—
8 Using the DVM and check the fuel pump relay ground
circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Remove the fuel pump relay from the relay box .
4. Check the circuit for open or short to ground
circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 9
9 Using the DVM and check the fuel pump relay power
supply circuit.
1. Ignition “Off”, engine “Off”.
2. Remove the fuel pump relay from the relay box .
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 11Go to Step 10 Step Action Value(s) Yes No
V
3
X2
4
11C56(J2) X2
V
1X2

6E–106 ENGINE DRIVEABILITY AND EMISSIONS
10 Repair the open circuit between the fuel pump relay
and battery.
Is the action complete?—Veri fy repai r—
11 Using the DVM and check the fuel pump power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the fuel pump connector.
3. Check the circuit for open or short to ground
circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 13Go to Step 12
12 Repair the open or short to ground circuit between the
fuel pump relay and fuel pump.
Is the action complete?—Veri fy repai r—
13 Using the DVM and check the fuel pump ground
circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the fuel pump connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
Continuity Go to Step 15Go to Step 14
14 Repair the open circuit between the fuel pump and
body ground.
Is the action complete?—Veri fy repai r—
15 Replace the fuel pump.
Was the problem solved?—Verify repair Go to Step 16
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 Step Action Value(s) Yes No
V
1
F2
F-2




ENGINE DRIVEABILITY AND EMISSIONS 6E–109
The fuel injector(s).
4. Fuel pressure that drops off during acceleration,
cruise, or hard cornering may case a lean condition.
A lean condition can cause a loss of power, surging,
or misfire. A lean condition can be diagnosed using a
Tech 2 Scan Tool.
Following are applicable to the vehicle with
closed Loop System:
If an ex tremely lean condition occurs, the ox ygen
sensor(s) will stop toggling. The ox ygen sensor
output voltage(s) will drop below 500 mV. Also, the
fuel injector pulse width will increase.
Important: Make sure the fuel system is not
operating in the “Fuel Cut-Off Mode.”
When the engine is at idle, the manifold pressure is
low (high vacuum). This low pressure (high vacuum)
is applied to the fuel pressure regulator diaphragm.
The low pressure (high vacuum) will offset the
pressure being applied to the fuel pressure regulator
diaphragm by the spring inside the fuel pressure
regulator. When this happens, the result is lower fuel
pressure. The fuel pressure at idle will vary slightly
as the barometric pressure changes, but the fuel
pressure at idle should always be less than the fuel
pressure noted in step 2 with the engine OFF.
16.Check the spark plug associated with a particular
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. If
checking the spark plug associated with a particular
fuel injector for fouling or saturation does not
determine that a particular fuel injector is leaking,
use the following procedure:
Remove the fuel rail, but leave the fuel lines and
injectors connected to the fuel rail. Refer to Fuel
Rail Assembly in On-Vehicle Service.
Lift the fuel rail just enough to leave the fuel
injector nozzles in the fuel injector ports.
Caution: In order to reduce the risk of fire and
personal injury that may result from fuel
spraying on the engine, verify that the fuel rail is
positioned over the fuel injector ports and verify
that the fuel injector retaining clips are intact.
Pressurize the fuel system by connecting a 20
amp fused jumper between B+ and the fuel
pump relay connector.
Visually and physically inspect the fuel
injector nozzles for leaks.
17.A rich condition may result from the fuel pressure
being above 376 kPa (55 psi). A rich condition may
cause a 45 to set. Driveability conditions associatedwith rich conditions can include hard starting
(followed by black smoke) and a strong sulfur smell
in the ex haust.
20.This test determines if the high fuel pressure is due
to a restricted fuel return line or if the high fuel
pressure is due to a faulty fuel pressure regulator.
21.A lean condition may result from fuel pressure below
333 kPa (48 psi). A lean condition may cause a 44 to
set. Driveability conditions associated with lean
conditions can include hard starting (when the
engine is cold), hesitation, poor driveability, lack of
power, surging, and misfiring.
22.Restricting the fuel return line causes the fuel
pressure to rise above the regulated fuel pressure.
Command the fuel pump ON with the scan tool. The
fuel pressure should rise above 376 kPa (55 psi) as
the fuel return line becomes partially closed.
NOTE: Do not allow the fuel pressure to exceed 414
kPa (60 psi). Fuel pressure in excess of 414 kPa (60
psi) may damage the fuel pressure regulator.
Caution: To reduce the risk of fire and personal
injury:
It is necessary to relieve fuel system pressure
before connecting a fuel pressure gauge.
Refer to Fuel Pressure Relief Procedure,
below.
A small amount of fuel may be released when
disconnecting the fuel lines. Cover fuel line
fittings with a shop towel before
disconnecting, to catch any fuel that may leak
out. Place the towel in an approved container
when the disconnect is completed.
Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Located on the intake manifold which is at the top
right part of the engine.
3. Start the engine and allow it to stall.
4. Crank the engine for an additional 3 seconds.
Fuel Pressure Gauge Installation
1. Remove the fuel pressure fitting cap.
2. Install fuel pressure gauge 5-8840-0378-0 to the
fuel feed line located on the upper right side of the
engine.
3. Reinstall the fuel pump relay.

ENGINE DRIVEABILITY AND EMISSIONS 6E–111
10 Locate and repair the loss of vacuum to the fuel
pressure regulator.
Is the action complete?—Veri fy repai r—
11 Replace the fuel pressure regulator.
Is the action complete?—Veri fy repai r—
12 1. Run the fuel pump with the Scan Tool.
2. After pressure has built up, turn off the pump and
clamp the supply hose shut with suitable locking
pliers.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant?—Go to Step 13Go to Step 15
13 Visually inspect the fuel supply line and repair any
leaks.
Was a problem found?—Verify repair Go to Step 14
14 Remove the fuel tank and inspect for leaky hose or in-
tank fuel line.
Was a problem found?—Verify repair Go to Step 8
15 1. If the pliers are still clamped to the fuel supply
hose, remove the locking pliers.
2. With suitable locking pliers, clamp the fuel return
line to prevent fuel from returning to the fuel tank.
3. Run the fuel pump with the Scan Tool.
4. After pressure has built up, remove power to the
pump.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant?—Go to Step 11Go to Step 16
16 Locate and replace any leaking fuel injector(s).
Is the action complete?—Veri fy repai r—
17 Is the fuel pressure indicated by the fuel pressure
gauge above the specified limit?376 kPa
(55 psi) Go to Step 18Go to Step 21
18 1. Relieve the fuel pressure. Refer to the Fuel
Pressure Relief.
2. Disconnect the fuel return line from the fuel rail.
3. Attach a length of flex ible hose to the fuel rail
return outlet passage.
4. Place the open end of the flex ible hose into an
approved gasoline container.
5. Run the fuel pump with the Scan Tool.
6. Observe the fuel pressure indicated by the fuel
pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits?290-376 kPa
(42-55 psi) Go to Step 19Go to Step 20
19 Locate and correct the restriction in the fuel return
line.
Is the action complete?—Veri fy repai r—
20 Visually and physically inspect the fuel rail outlet
passages for a restriction.
Was a restriction found?—Verify repair Go to Step 11
21 Is the fuel pressure indicated by the fuel pressure
gauge above the specified value? 0 kPa (0 psi) Go to Step 22Go to Step 23 Step Action Value(s) Yes No

6E–114 ENGINE DRIVEABILITY AND EMISSIONS
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM
Pin No.
P0107 A Manifold Absolute Pressure Circuit Low
Input1. No DTC relating to TPS.
2. Throttle position is more than 0% if engine
speed is below 1000rpm, or throttle
position more than 5% if engine speed is
more than 1000rpm.
3. MAP sensor output is below 12kPa.The ECM uses default manifold
absolute pressure value based on
engine speed and throttle position.MAP sensor output is more than 12kPa. 1. Sensor power supply circuit open or short
to ground circuit.
2. Sensor signal circuit open or short to
ground circuit.
3. Poor connector connection.
4. MAP sensor malfunction.
5. ECM malfunction.J1-24/
J1-31
P0108 A Manifold Absolute Pressure Circuit High
Input1. No DTC relating to TPS.
2. Throttle position is below 15% if engine
speed is below 2500rpm, or throttle
position is below 35% if engine speed is
more than 2500rpm.
3. Engine run time is longer than 10
seconds.
4. MAP sensor output is more than 103kPa.MAP sensor output is below 103kPa. 1. Sensor power supply circuit short to
voltage circuit.
2. Sensor signal circuit short to voltage
circuit.
3. Sensor ground circuit open or short to
voltage circuit.
4. Poor connector connection.
5. MAP sensor malfunction.
6. ECM malfunction.J1-16/
J1-24/
J1-31
P0112 A Intake Air Temperature Sensor Low Input 1. No DTC relating to VSS.
2. Vehicle speed is more than 25km/h.
3. Engine run time is longer than 120
seconds.
4. IAT sensor output is more than 149 deg.
C. The ECM uses 20 deg. C condition
as substitute.IAT sensor output is below 149 deg. C. 1. Sensor signal circuit short to ground
circuit.
2. IAT sensor malfunction.
3. ECM malfunction.J2-22
P0113 A Intake Air Temperature Sensor High Input 1. No DTC relating to VSS & ECT sensor.
2. Vehicle speed is below 70km/h.
3. 3Engine coolant temperature is more than
-8 deg. C.
4. Engine run time is longer than 120
seconds.
5. Mass air flow is below 30g/s.
6. IAT sensor output is below -38 deg. C. IAT sensor output is more than -38 deg. C. 1. Sensor signal circuit open or short to
voltage circuit.
2. Sensor ground circuit open or short to
voltage circuit.
3. Poor connector connection
4. IAT sensor malfunction.
5. ECM malfunction.J2-1/
J2-22
P0117 A Engine Coolant Temperature Sensor Low
Input1. Engine run time is longer than 120
seconds.
2. ECT sensor output is more than 149 deg.
C. The ECM uses default engine
coolant temperature value based
on intake air temperature and
engine run time. ECT sensor output is below 149 deg. C. 1. Sensor signal circuit short to ground
circuit.
2. ECT sensor malfunction.
3. ECM malfunction.J1-27
P0118 A Engine Coolant Temperature Sensor High
Input1. Engine run time is longer than 120
seconds.
2. ECT sensor output is below -38 deg. C. ECT sensor output is more than -38 deg. C. 1. Sensor signal circuit open or short to
voltage circuit.
2. Sensor ground circuit open or short to
voltage circuit.
3. Poor connector connection
4. ECT sensor malfunction.
5. ECM malfunction.J1-27/
J1-32

ENGINE DRIVEABILITY AND EMISSIONS 6E–115
P0122 A Throttle Position Sensor Low Input TPS output voltage is below 0.14V. The ECM uses 0% condition as
substitute.TPS output voltage is more than 0.14V. 1. Sensor power supply circuit open or short
to ground circuit.
2. Sensor signal circuit open or short to
ground circuit.
3. Poor connector connection.
4. TPS malfunction.
5. ECM malfunction.J1-7/
J1-15/
P0123 A Throttle Position Sensor High Input TPS output voltage is more than 4.9V. TPS output voltage is below 4.9V. 1. Sensor power supply circuit short to
voltage circuit.
2. Sensor signal circuit short to voltage
circuit.
3. Sensor ground circuit open or short to
voltage circuit.
4. Poor connector connection.
5. TPS malfunction.
6. ECM malfunction.J1-7/
J1-15/
J1-32
P0131 A O
2 Sensor Circuit Low Voltage (Bank 1
Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. O
2 sensor bank 1 output voltage is below
50mV in “Closed Loop” condition. “Open Loop” fuel control. O
2 sensor bank 1 output voltage is more
than 50mV.1. Sensor harness short to ground circuit.
2. O
2 sensor malfunction.
3. ECM malfunction.J2-6/
J2-21
P0132 A O
2 Sensor Circuit High Voltage (Bank 1
Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. O
2 sensor bank 1 output voltage is more
than 952mV in “Closed Loop” condition. O
2 sensor bank 1 output voltage is below
952mV.1. Sensor harness short to voltage circuit.
2. O
2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. IAC valve malfunction.
6. Incorrect fuel pressure.
7. Injector malfunction.
8. ECM malfunction.J2-6/
J2-21
P0134 A O
2 Sensor Circuit No Activity Detected
(Bank 1 Sensor 1)1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than
60 deg. C.
3. Engine run time is longer than 40
seconds.
4. Mass air flow is more than 7g/s.
5. O
2 sensor bank 1 output voltage is
between 300mV and 600mV.O
2 sensor bank 1 output voltage is below
3 0 0 m V c o n s e c u t i v e l y .
O R
O2 sensor bank 1 output voltage is more
than 600mV consecutively.1. Sensor harness open circuit.
2. O
2 sensor malfunction.
3. MAF sensor output is incorrect.
4. Air intake line malfunction.
5. IAC valve malfunction.
6. Incorrect fuel pressure.
7. Injector malfunction.
8. ECM malfunction.J2-6/
J2-21 Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM
Pin No.