2007 ISUZU KB P190 ECO mode

ENGINE DRIVEABILITY AND EMISSIONS 6E–159
DIAGNOSTIC TROUBLE CODE (DTC) P0134 O2 SENSOR NO ACTIVITY
DEFECTED (BANK 1 SENSOR 1)
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) high and low circuits. The oxygen
sensor varies the voltage within a range of about 1000
mV when the exhaust is rich, down through about 10
mV when exhaust is lean. The ECM constantly monitors
the HO2S signal during “Closed Loop” operation and compensates for a rich or lean condition by decreasing
or increasing injector pulse width as necessary. If the
Bank 1 HO2S 1 voltage remains at or near the 450 mV
bias for an extended period of time, Diagnostic Trouble
Code P0134 will be set, indicating an open sensor
signal or sensor low circuit.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
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. “Open Loop” fuel control.

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ISUZU KB P190 2007

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–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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ISUZU KB P190 2007

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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ISUZU KB P190 2007

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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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–175
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 P0325 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 P0325 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 knock 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 knock sensor. Was the problem found? — Go to Step 10Go to Step 6
6 Listen to the engine noise while raising and lowering the engine speed.
Is a knock or audible noise present? — Go to Step 7Go to Step 8
7 Repair the mechanical engine problem or a loose bracket or component.
Is the action complete? — Verify repair —
Step
Action Value(s) Yes No
32
3
E-60(J1)
E-84

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ISUZU KB P190 2007

6E–178 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0327 Knock Sensor Circuit
StepAction 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 P0327 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 P0327 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 knock 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 knock sensor. Was the problem found? — Go to Step 9Go to Step 6
6 Using the DVM and check the knock sensor circuit. 1. Ignition “Off”, engine “Off”.
2. Disconnect the knock sensor connector and ECM connector.
3. Check the circuit for short to sensor ground or ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 7
32
3
E-60(J1)
E-84
E-84
2
1

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–181
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 poor
terminal-to-wire connection. • Damaged harness - Inspect the wiring harness for
damage; shorts to ground, shorts to battery positive
and open circuits. If the harness appears to be OK,
disconnect the ECM, turn the ignition on and observe
a voltmeter connected to the 58X reference circuit at
the ECM harness connector while moving connectors
and wiring harnesses related to the ECM. A change
in voltage will indicate the location of the fault.
Diagnostic Trouble Code (DTC) P0336
Crankshaft Position Sensor Circuit Range/performance (58x)
Diagnostic Trouble Code (DTC) P0337
Crankshaft Position Sensor Circuit Low Input (58x)
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 P0336 or P0337 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 P0336 or P0337 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 CKP sensor or ECM connector. If a poor/faulty connection is found,
repair the faulty terminal.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the CKP sensor. If a faulty installation i s f o u n d , r e p a i r a s n e c e s s a r y.
Was the problem found? — Verify repair Go to Step 6
21
61
E-60(J1)
E-59

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ISUZU KB P190 2007