2007 ISUZU KB P190 engine

ENGINE DRIVEABILITY AND EMISSIONS 6E–91
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
StepAction 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 . A t t e m p t t o d i s p l a y “ E n g i n e D a t a ” 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
Chart Go to Step 6
6 Compare typical scan data values displayed on the Tech 2 “Engine Data” and “O
2 Sensor Data”.
Are the displayed values within the range? —Refer to
SYMPTOM
DIAGNOSIS Refer 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

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ISUZU KB P190 2007

6E–92 ENGINE DRIVEABILITY AND EMISSIONS
9 Using the DVM and check the data link connectorground 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-582
C-56(J2)
ΩΩ
B-58230

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–93
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 —
Step
Action Value(s) Yes No

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6E–94 ENGINE DRIVEABILITY AND EMISSIONS
NO CHECK ENGINE LAMP (MIL)
Circuit Description
The check engine lamp should be illuminated and
steady for about five seconds with the ignition “ON” and
the engine stopped. Ignition feed voltage is supplied to
the check engine lamp bulb through the meter fuse.
The Engine Control Module (ECM) turns the check
engine lamp “ON” by grounding the check engine lamp
driver circuit.
Diagnostic Aids
An intermittent check engine lamp may be cased by a
poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check for the
following items:
• Inspect the ECM harness and connections for improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
• If the engine runs OK, check for a faulty light bulb, an open in the check engine lamp driver circuit, or an
open in the instrument cluster ignition feed.
• If the engine cranks but will not run, check for an open ECM ignition or battery feed, or a poor ECM to
engine ground.
No Check Engine Lamp (MIL)
Step Action Value(s) Yes No
1 Check the “Meter” fuse (15A). If the fuse is burnt out, repair as necessary.
Was the problem found? — Verify repair Go to Step 2

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–95
2 Using the DVM and check the “CHECK ENGINE”lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Ignition “On”.
4. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 5Go to Step 3
3 Check the “CHECK ENGINE” lamp bulb. If the bulb is burnt out, repair as necessary.
Was the problem found? — Verify repair Go to Step 4
4 Using the DVM and check the “CHECK ENGINE” lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and ECM connector.
3. Check the circuit for open circuit.
Was the problem found?
— Verify repair Go to Step 5
5 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 6
6 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
V
32C56(J2)
3217C56(J2)B24

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ISUZU KB P190 2007

6E–96 ENGINE DRIVEABILITY AND EMISSIONS
CHECK ENGINE LAMP (MIL) “ON” STEADY
Circuit description
The check engine lamp should always be illuminated
and steady for about five seconds with ignition “ON” and
the engine stopped. Ignition feed voltage is supplied
directly to the check engine lamp indicator. The Engine
Control Module (ECM) turns the check engine lamp
“ON” by grounding the check engine lamp driver circuit.
The check engine lamp should not remain “ON” with the
engine running and no DTC(s) set. A steady check
engine lamp with the engine running and no DTC(s)
suggests a short to ground in the check engine lamp
driver 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 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.
Check Engine Lamp (MIL) “ON” Steady
Step Action Value(s) Yes No
1 1. Ignition “Off”, engine “Off”. 2. Disconnect the ECM connector.
3. Ignition “On”.
Was the “CHECK ENGINE” lamp turned on? — Go to Step 2Go to Step 4

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–97
2 Using the DVM and check the “CHECK ENGINE”lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and ECM connector.
3. Check the circuit for short to ground circuit.
Was the problem found?
— Verify repair Go to Step 3
3 Replace the meter assembly. Is the action complete? — Verify repair —
4 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 5
5 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
32C56(J2)

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ISUZU KB P190 2007

6E–98 ENGINE DRIVEABILITY AND EMISSIONS
FUEL METERING SYSTEM CHECK
Some failures of the fuel metering system will result in
an “Engine Cranks But Will Not Run” symptom. If this
condition exists, refer to the Cranks But Will Not Run
chart. This chart will determine if the problem is caused
by the ignition system, the ECM, or the fuel pump
electrical circuit.
Refer to Fuel System Electrical Test for the fuel system
wiring schematic.
If there is a fuel delivery problem, refer to Fuel System
Diagnosis , which diagnoses the fuel injectors, the fuel
pressure regulator, and the fuel pump.
Followings are applicable to the vehicles with
closed Loop System:
If a malfunction occurs in the fuel metering system, it
usually results in either a rich HO2S signal or a lean
HO2S signal. This condition is indicated by the HO2S
voltage, which causes the ECM to change the fuel
calculation (fuel injector pulse width) based on the
HO2S reading. Changes made to the fuel calculation
will be indicated by a change in the long term fuel trim
values which can be monitored with a Scan Tool. Ideal
long term fuel trim values are around 0%; for a lean
HO2S signal, the ECM will add fuel, resulting in a fuel
trim value above 0%. Some variations in fuel trim values
are normal because all engines are not exactly the
same. If the evaporative emission canister purge is 02
status may be rich condition. 02 status indicates the
lean condition, refer to DTC P1171 for items which can
cause a lean HO2S signal.
FUEL INJECTOR COIL TEST PROCEDURE
AND FUEL INJECTOR BALANCE TEST
PROCEDURE
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Relieve the fuel pressure by connecting 5-8840- 0378-0 T-Joint to the fuel pressure connection on the
fuel rail.
Caution: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the
fuel pressure connection. The towel will absorb
any fuel leakage that occurs during the
connection of the fuel pressure gauge. Place the
towel in an approved container when the
connection of the fuel pressure gauge is
complete.
Place the fuel pressure gauge bleed hose in an
approved gasoline container.
With the ignition switch OFF open the valve on the
fuel pressure gauge.
3. Record the lowest voltage displayed by the DVM after the first second of the test. (During the first
second, voltage displayed by the DVM may be
inaccurate due to the initial current surge.)
Injector Specifications:
• The voltage displayed by the DVM should be within the specified range.
• The voltage displayed by the DVM may increase throughout the test as the fuel injector windings
warm and the resistance of the fuel injector
windings changes. Resistance Ohms
Voltage Specification at
10°C-35°C (50°F-95°F)
11.8-12.6 5.7-6.6

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