Circuit ISUZU KB P190 2007 Workshop Repair Manual

6E–160 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:
• Poor connection or damaged harness - Inspect the harness connectors for backed-out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
Diagnostic Trouble Code (DTC) P0134
O
2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)
Step Action Value(s) Yes No
1 Was 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 By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P0134 stored as “Present Failure”? — Go to Step 3Refer 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 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P0134 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the O
2 sensor 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 O
2 sensor circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
Approximatly 450mV Go to Step 7Go to Step 6
C56(J2) E77
31 216
V
21
E77

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–161
6 Using the DVM and check the O2 sensor circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM disconnected) Refer to 6E-88 page.
3. Disconnect the O
2 sensor.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the O
2 sensor connector and ECM
connector.
3. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 13
7 1. Using the Tech 2, ignition “On” and engine “On”. 2. Monitor the “Manifold Absolute Pressure” in thedata display.
Does the Tech 2 indicate correct “Manifold Absolute
Pressure” in accordance with engine speed or
acceleration? — Go to Step 9Go to Step 8
8 Remove the MAP sensor and check for the following conditions.
• Objects blocking the air cleaner.
• Objects blocking the MAP sensor.
• Objects blocking the throttle valve.
• Vacuum leaking at intake duct.
• Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found? — Verify repair Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “On”. 2. Select the “Miscellaneous Test” and perform the“IAC Control” in the “IAC System”.
3. Operate the Tech 2 in accordance with procedure.
Was the engine speed changed, when the IAC valve
is operating step by step? — Go to Step 11Go to Step 10
Step
Action Value(s) Yes No
J2-6J2-21
Breaker Box
E-77
21
ΩΩ
1
2
21
6C56(J2) E77

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–163
DIAGNOSTIC TROUBLE CODE (DTC) P0135 O2 SENSOR HEATER CIRCUIT
(BANK 1 SENSOR 1)
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
Heated oxygen sensors are used to minimize the
amount of time required for “Closed Loop” fuel control
operation and to allow accurate catalyst monitoring. The
oxygen sensor heater greatly decreases the amount of
time required for fuel control sensors Bank 1 HO2S 1 1
to become active. Oxygen sensor heaters are required
by catalyst monitor sensors Bank 1 HO2S 2 to maintain
a sufficiently high temperature which allows accurate
exhaust oxygen content readings further from the engine.
The engine control module (ECM) will run the heater
test only after a cold start (determined by engine coolant
and intake air temperature at the time of start-up) and
only once during an ignition cycle. When the engine is
started the ECM will monitor the HO2S voltage. When
the HO2S voltage indicates a sufficiently active sensor,
the ECM looks at how much time has elapsed since
start-up. If the ECM determines that too much time was
required for the Bank 1 HO2S 1 to become active, a
Diagnostic Trouble Code P0135 will set.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0135 A O
2 SensorHeater Circuit (Bank 1 Sen-
sor 1) 1. No DTC relating to MAP sensor and ECT
sensor.
2. Engine coolant temperature is more than 60 deg. C.
3. Engine run time is longer than 20 seconds.
4. MAP sensor output is more than 70kPa.
5. O
2 sensor bank 1 heater current more than
10mA. No fail-safe function.

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6E–164 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
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; shorts to ground, shorts to battery positive
and open circuits.
Diagnostic Trouble Code (DTC) P0135
O
2 Sensor Heater Circuit (Bank 1 Sensor 1)
Step Action Value(s) Yes No
1 Was 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 By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P0135 stored as “Present Failure”? — Go to Step 3Refer 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 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P0135 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the O
2 sensor or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the O
2 sensor.
Was the problem found? — Go to Step 11Go to Step 6
6 Using the DVM and check the O
2 sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect O
2 sensor connector
3. Measure the resistance of heater.
Was the tester indicated specified value?
Approximately
12.5 Ω at 20°C Go to Step 7Go to Step 11
3431
C56(J2) E77
34
1234
O2 Sensor

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ENGINE DRIVEABILITY AND EMISSIONS 6E–165
7 Using the DVM and check the heater power supplycircuit for the affected cylinder.
1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 9Go to Step 8
8 Repair the open or short to ground circuit between the “O
2 Sensor” fuse (10A) and O2 sensor.
Is the action complete? — Verify repair —
9 Using the DVM and check the heater ground circuit. Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM disconnected) Refer to 6E-88 page.
3. Disconnect the O
2 sensor connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the O
2 sensor 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 10
Step
Action Value(s) Yes No
4
V
E77
J2-31Breaker BoxE-77
3
ΩΩ
331E56(J2)E77

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6E–166 ENGINE DRIVEABILITY AND EMISSIONS
10 Using the DVM and check the heater ground circuit.1. Ignition “On”, engine “Off”.
2. Disconnect the O
2 sensor connector.
3. Check the circuit for short to voltage circuit.
Was the DVM indicated voltage?
—Repair faulty
harness and verify repair Go to Step 12
11 Replace the O
2 sensor.
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 —
Step
Action Value(s) Yes No
3
V
E77

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ENGINE DRIVEABILITY AND EMISSIONS 6E–167
DIAGNOSTIC TROUBLE CODE (DTC) P0201 INJECTOR 1 CONTROL CIRCUIT
DIAGNOSTIC TROUBLE CODE (DTC) P0202 INJECTOR 2 CONTROL CIRCUIT
DIAGNOSTIC TROUBLE CODE (DTC) P0203 INJECTOR 3 CONTROL CIRCUIT
DIAGNOSTIC TROUBLE CODE (DTC) P0204 INJECTOR 4 CONTROL CIRCUIT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) has four individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the ECM, the injector is activated. The ECM monitors the current in each driver
circuit. The ECM measures a voltage drop through a
fixed resistor and controls it. The voltage on each driver
is monitored to detect a fault. If the voltage is not what
the ECM expects to monitor on the circuit, a Diagnostic
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0201 A Injector 1 Control Circuit 1. Engine is running.
2. Engine speed is more than 1000rpm.
3. Injector voltage does not meet to the bat- tery voltage when the injector is com-
manded Off or does not meet to the 0V
when the injector is commanded On. No fail-safe function.
P0202 A Injector 2 Control Circuit
P0203 A Injector 3 Control Circuit
P0204 A Injector 4 Control Circuit

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6E–168 ENGINE DRIVEABILITY AND EMISSIONS
Trouble Code is set. This Diagnostic Trouble Code is
also set if an injector driver is shorted to voltage.
Diagnostic Aids
An injector driver circuit that is open or shorted to
voltage will cause a Diagnostic Trouble Code P0201 to
set. It will also cause a misfire due to an inoperative injector. A misfire Diagnostic Trouble Code will also be
set indicating which cylinder is inoperative.
Long term and short term fuel trims that are excessively
high or low are a good indication that an injector is
faulty.
Use Fuel Injector Coil Test Procedure to check for faulty
injectors.
Diagnostic Trouble Code (DTC) P0201 Injector 1 Control Circuit
Diagnostic Trouble Code (DTC) P0202 Injector 2 Control Circuit
Diagnostic Trouble Code (DTC) P0203 Injector 3 Control Circuit
Diagnostic Trouble Code (DTC) P0204 Injector 4 Control Circuit
Step Action Value(s) Yes No
1 Was 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 By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P0201, P0202, P0203 or P0204 stored as
“Present Failure”? — Go to Step 3Refer 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 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P0201, P0202, P0203 or P0204 stored
in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the injector or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the injector for the affected cylinder. Was the problem found? — Go to Step 11Go to Step 6
22
89
11
E-60(J1)
E-6/E-7/E-8/E-9

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6E–170 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the injector power supplycircuit for the affected cylinder.
1. Ignition “On”, engine “Off”.
2. Disconnect the injector connector for the affected cylinder.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 9Go to Step 8
8 Repair the open or short to ground circuit between the “IGN” fuse (15A) and injector for the affected cylinder.
Is the action complete? — Verify repair —
Step Action Value(s) Yes No
V
1
E-6
No.1 Cylinder
V
1
E-7
No.2 Cylinder
V
1
E-8
No.3 Cylinder
V
1
E-9
No.4 Cylinder

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ENGINE DRIVEABILITY AND EMISSIONS 6E–171
9 Using the DVM and check the injector signal circuit forthe affected cylinder.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM disconnected) Refer to 6E-88 page.
3. Disconnect the injector connector for the affected cylinder.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 10
Step
Action Value(s) Yes No
J1-9Breaker Box2
ΩΩ
No. 1 Cylinder
E-6
J1-22Breaker Box2
ΩΩ
No. 2 Cylinder E-7
J1-8Breaker Box
ΩΩ
No. 3 Cylinder
E-82
J1-11Breaker Box2
ΩΩ
No. 4 Cylinder E-9

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