2007 ISUZU KB P190 engine

ENGINE DRIVEABILITY AND EMISSIONS 6E–123
DIAGNOSTIC TROUBLE CODE (DTC) P0108 MANIFOLD ABSOLUTE PRESSURE CIRCUIT HIGH INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure. The MAP
sensor signal voltage to the engine control module
(ECM) varies from below 2 volts at idle (low manifold
pressure) to above 4 volts with the ignition ON, engine
not running or at wide-open throttle (high manifold
pressure).
A “speed density” method of determining engine load is
used on the 2.4L engine. This is calculated using inputs from the MAP sensor, RPM, CKP Sensor, and the
Intake Air Temperature (IAT) sensor. The MAP sensor is
the main sensor used in this calculation, and measuring
engine load is its main function.
The ECM monitors the MAP signals for voltages outside
the normal range (10-104 kPa) of the MAP sensor. If the
ECM detects a MAP signal voltage that is excessively
high, Diagnostic Trouble Code P0108 will be set.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0108 A Manifold Absolute Pressure Circuit High Input 1. No DTC relating to TPS.
2. Throttle position is below 15% if engine speed is below 2500rpm, or throttle posi-
tion 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. The ECM uses default manifold absolute
pressure value based on engine speed
and throttle position.

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ISUZU KB P190 2007

6E–124 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.
• If these codes are also set, it could indicate a problem with the 5 Volt reference circuit.
• Damaged harness - Inspect the wiring harness for damage; an open circuit, a short to ground, or a short
to voltage. If the harness appears to be OK, observe
the MAP display on the Tech 2 while moving
connectors and wiring harnesses related to the
sensor. A change in the display will indicate the
location of the fault.
Diagnostic Trouble Code (DTC) P0108
Manifold Absolute Pressure Circuit High Input
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 P0108 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 P0108 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 MAP 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 MAP sensor. Was the problem found? — Go to Step 11Go to Step 6
16
31 24E85
E60(J1)

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–125
6 Using the DVM and check the MAP sensor powersupply circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the MAP sensor connector.
3. Check the circuit for short to voltage circuit.
Was the DVM indicated specified value?
Approximately 5.0V Go to Step 8Go to Step 7
7 Repair the short to voltage circuit between the ECM and MAP sensor.
Was the problem solved?
— Verify repair Go to Step 13
8 Using the DVM and check the MAP sensor signal circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the MAP sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 9Repair faulty
harness and verify repair
9 Using the DVM and check the MAP sensor ground circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the MAP sensor connector .
3. 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
Step
Action Value(s) Yes No
V
E85
3
31
3
E85
E60(J1)
V
E85
2
V
E85
1

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6E–126 ENGINE DRIVEABILITY AND EMISSIONS
10 Using the DVM and check the MAP sensor groundcircuit.
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 MAP sensor connector.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available:
1. Ignition “Off”, engine “Off”.
2. Disconnect the MAP 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 11
11 Substitute a known good MAP sensor and recheck. Was the problem solved? — Go to Step 12 Go to Step 13
12 Replace the MAP sensor. Is the action complete? — Verify repair —
13 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 14
14 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
J1-16
Breaker Box
Ω
E-85
1
116E85
E60(J1)

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–127
DIAGNOSTIC TROUBLE CODE (DTC) P0112 INTAKE AIR TEMPERATURE SENSOR LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The engine control module (ECM) applies 5
volts through a pull-up resistor to the IAT sensor. When
the intake air is cold, the sensor resistance is high and
the ECM will monitor a high signal voltage on the IAT
signal circuit. If the intake air is warm, the sensor
resistance is lower, causing the ECM to monitor a lower
voltage. Diagnostic Trouble Code P0112 will set when
the ECM detects an excessively low signal voltage (short to ground) on the intake air temperature sensor
signal circuit.
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, short to ground, short to battery and open
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
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 sec- onds.
4. IAT sensor output is more than 149 deg. C. The ECM uses 20 deg. C condition as
substitute.

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6E–128 ENGINE DRIVEABILITY AND EMISSIONS
circuit. If the harness appears to be OK, observe the
IAT display on the Tech 2 while moving connectors
and wiring harnesses related to the IAT sensor. A change in the IAT display will indicate the location of
the fault.
Diagnostic Trouble Code (DTC) P0112
Intake Air Temperature Sensor Low Input
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 P0112 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 P0112 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 IAT 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 Remove the IAT sensor and visually check. Was the problem found? — Go to Step 8Go to Step 6
C56(J2) C121
1
22

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–129
6 Using the DVM and check the IAT sensor.1. Ignition “Off”, engine “Off”.
2. Disconnect IAT sensor connector.
3. Measure the resistance of IAT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 7Go to Step 8
7 Using the DVM and check the IAT sensor signal 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 IAT sensor connector.
4. Check the circuit for short to sensor ground or ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the IAT sensor 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 10
Step
Action Value(s) Yes No
Temperature (°C) Resistance (Ω) (Approximately)
-20 32500
09 91 0
20 3400
40 1509
60 670
80 329
100 182
120 101
21
IAT Sensor
Ω
12
J2-1J2-22
Breaker Box
Ω
Ω
C56(J2)
122

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6E–130 ENGINE DRIVEABILITY AND EMISSIONS
8 Substitute a known good IAT sensor assembly andrecheck.
Was the problem solved? — Go to Step 9Go to Step 10
9 Replace the IAT sensor assembly. Is the action complete? — Verify repair —
10 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 11
11 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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ISUZU KB P190 2007