Intake sensor ISUZU TROOPER 1998 Service Repair Manual

6E±25 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
Serviceability Issues
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Accordingly, if commercially sold sensor
or switch is installed, it makes a wrong diagnosis and turn
on the MIL (ªCheck Engineº lamp).
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (ªCheck
Engineº lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted oil filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a ªnon-vehicle
faultº, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD system diagnostics will not run if the
ECM detects a fault on a related system or component.
Visual/Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:

Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.

Inspect hoses that are difficult to see behind other
components.

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the ªClass IIº communication system.
Each bit of information can have one of two lengths: longor short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait.
On this vehicle the Tech 2 displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The diagnostic test has passed during the current
ignition cycle.

The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The fault identified by the diagnostic test is currently
active.

The fault has been active during this ignition cycle.

The operating conditions at the time of the failure.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to operate engine properly.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable. Accel
Position (AP) sensor that indicates high throttle position
at low engine loads or MAP voltage. Input components
may include, but are not limited to the following sensors:

Intake Air Temperature (IAT) Sensor

Crankshaft Position (CKP) Sensor

Intake throttle Position (ITP) Sensor

Engine Coolant Temperature (ECT) Sensor

Camshaft Position (CMP) Sensor

Manifold absolute Pressure (MAP) Sensor

Accel Position Sensor

Fuel Temp Sensor

Rail Pressure Sensor

Oil Temp Sensor

EGR Pressure Sensor

Vehicle Speed Sensor

6E±26
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Output Components:
Output components are diagnosed for proper response to
control module commands. Components where
functional monitoring is not feasible will be monitored for
circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not
limited to, the following circuit:

EGR VSV

EGR EVRV

Electronic Transmission controls

Injector

Intake throttle

Glow plug

MIL control
Refer to ECM and Sensors in General Descriptions.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors a
vehicle system or component. Conversely, an active test,
actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test.
Intrusive Diagnostic Tests
This is any on-board test run by the Diagnostic
Management System which may have an effect on
vehicle performance or emission levels.
Warm-Up Cycle
A warm-up cycle means that engine at temperature must
reach a minimum of 70
C (160
F)
and rise at least 22
C
(40
F) over the course of a trip.
Freeze Frame
Freeze Frame is an element of the Diagnostic
Management System which stores various vehicle
information at the moment an emissions-related fault is
stored in memory and when the MIL is commanded on.
These data can help to identify the cause of a fault. Refer
to
Storing And Erasing Freeze Fame Data for more
detailed information.
Failure Records
Failure Records data is an enhancement of the OBD
Freeze Frame feature. Failure Records store the same
vehicle information as does Freeze Frame, but it will store
that information for any fault which is stored in on-board
memory, while Freeze Frame stores information only for
emission-related faults that command the MIL on.
Common OBD Terms
Diagnostic
When used as a noun, the word diagnostic refers to any
on-board test run by the vehicle's Diagnostic
Management System. A diagnostic is simply a test run on
a system or component to determine if the system or
component is operating according to specification. There
are many diagnostics, shown in the following list:

EGR

engine speed

vehicle speed

ECT
MAP

VSV

IAT

ITP

AP

FT (Fuel Temp)

RP (Rail Pressure)

OT (Oil Temp)

EGR EVRV

Idle SW

Brake SW
The Diagnostic Executive
The Diagnostic Executive is a unique segment of
software which is designed to coordinate and prioritize
the diagnostic procedures as well as define the protocol
for recording and displaying their results. The main
responsibilities of the Diagnostic Executive are listed as
follows:

Commanding the MIL (ªCheck Engineº lamp) on and
off

DTC logging and clearing

Freeze Frame data for the first emission related DTC
recorded

Current status information on each diagnostic
Diagnostic Information
The diagnostic charts and functional checks are designed
to locate a faulty circuit or component through a process
of logical decisions. The charts are prepared with the
requirement that the vehicle functioned correctly at the
time of assembly and that there are not multiple faults
present.
There is a continuous self-diagnosis on certain control
functions. This diagnostic capability is complemented by
the diagnostic procedures contained in this manual. The
language of communicating the source of the malfunction
is a system of diagnostic trouble codes. When a
malfunction is detected by the control module, a
diagnostic trouble code is set and the Malfunction
Indicator Lamp (MIL) (ªCheck Engineº lamp) is
illuminated.
Malfunction Indicator Lamp (MIL)
The Malfunction Indicator Lamp (MIL) looks the same as
the MIL you are already familiar with ªCheck Engineº
lamp.
Basically, the MIL is turned on when the ECM detects a
DTC that will impact the vehicle emissions.

When the MIL remains ªONº while the engine is
running, or when a malfunction is suspected due to a
driveability or emissions problem, a Powertrain
On-Board Diagnostic (OBD) System Check must be
performed. The procedures for these checks are
given in On-Board Diagnostic (OBD) System Check.
These checks will expose faults which may not be
detected if other diagnostics are performed first.
DTC Types
Characteristic of Code

6E±34
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Fuel Injection System
060RW178
Legend
(1) ECM
(2) Meter Panel
(3) Battery
(4) Oil Temp Sensor
(5) Rail Pressure Sensor
(6) Glow Relay
(7) Oil Rail
(8) Tech±2
(9) A/C Comp Relay
(10) RPCV
(11) Intake Air Temp Sensor
(12) Engine Coolant Temp Sensor
(13) MAP Sensor
(14) EGR Valve
(15) EGR Pressure Sensor(16) High Pressure Oil Pump
(17) Fuel Pump
(18) VSV
(19) EXH Throttle VSV1
(20) EXH Throttle VSV2
(21) EVRV
(22) Engine Harness Connector
(23) QWS Relay
(24) APS
(25) T.O.D
(26) ECT
(27) OBD
(28) TDC
(29) Injector
(30) Edge Filter

6E±39 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Engine Control Module ECM
Diagnosis
To read and clear diagnostic trouble codes, use a Tech 2.
IMPORTANT:Use of a Tech 2 is recommended to clear
diagnostic trouble codes from the ECM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition ªOFFº and disconnecting the battery power
from the ECM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the ECM will cause
all diagnostic information in the ECM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the ECM can have a failure which may affect only
one circuit, following the diagnostic procedures in this
section will determine which circuit has a problem and
where it is.
If a diagnostic chart indicates that the ECM connections
or the ECM is the cause of a problem, and the ECM is
replaced, but this does not correct the problem, one of the
following may be the reason:

There is a problem with the ECM terminal
connections. The terminals may have to be removed
from the connector in order to check them properly.

The problem is intermittent. This means that the
problem is not present at the time the system is being
checked. In this case, refer to the
Symptoms portion
of the manual and make a careful physical inspection
of all components and wiring associated with the
affected system.

There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned ªONº and ªOFFº by
the ECM using internal electronic switches called
drivers. A shorted solenoid, relay coil, or harness will
not damage the ECM but will cause the solenoid or
relay to be inoperative.
Multiple ECM Information Sensor
DTCS Set
Circuit Description
The Engine Control Module ECM monitors various
sensors to determine the engine operating conditions.
The ECM controls fuel delivery, spark advance,
transmission operation, and emission control device
operation based on the sensor inputs.
The ECM provides a sensor ground to all of the sensors.
The ECM applies 5 volts through a pull-up resistor, and
determines the status of the following sensors by
monitoring the voltage present between the 5-volt supply
and the resistor:

The fuel temperature (FT) sensor

The engine coolant temperature (ECT) sensor

The Intake air temperature (IAT) sensor
The ECM provides the following sensors with a 5-volt
reference and a sensor ground signal:

The Intake throttle position sensor

The manifold absolute pressure sensor

The rail pressure sensor

The accelerator position sensor

The oil temperature sensor
The camshaft position sensor

The crankshaft position sensor

The EGR pressure sensor
The ECM monitors the signals from these sensors in
order to determine their operating status.
Diagnostic Aids
IMPORTANT:Be sure to inspect ECM and engine
grounds for being secure and clean.
A short to voltage in one of the sensor input circuits may
cause one or more of the following DTCs to be set:

P0337

P0342

P1193

P1404

P1405

P1488
IMPORTANT:If a sensor input circuit has been shorted
to voltage, ensure that the sensor is not damaged. A
damaged sensor will continue to indicate a high or low
voltage after the affected circuit has been repaired. If the
sensor has been damaged, replace it.
An open in the sensor ground circuit between the ECM
and the splice will cause one or more of the following
DTCs to be set:

P0337

P0342

P0117
A short to ground in the 5-volt reference A or B circuit will
cause one or more of the following DTCs to be set:

P0112

P0117

P0182

P0197
An open in the 5-volt reference circuit A, between the
ECM and the splice will cause one or more of the following
DTCs to be set:

P0107

P0405

P1194

P0122
An open in the 5-volt reference circuit B, between the
ECM and the splice will cause one or more of the following
DTCs to be set:

P1485
Check for the following conditions:

Poor connection at ECM. Inspect the harness
connectors for backed-out terminals, improper
mating, broken locks, improperly formed or damage
terminals, and a poor terminal-to-wire connection.

Damaged harness. Inspect the wiring harness for
damage. If the harness is not damaged, observe an
affected sensor's displayed value on the Tech 2 with
the ignition ªONº and the engine ªOFFº while you
move the connectors and the wiring harnesses
related to the following sensors:

ECT Sensor

6E±40
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS

MAP Sensor

CMP Sensor

CKP Sensor

EGR Pressure Sensor

EGR VSV

RPCV

IAT Sensor
Intake Throttle Motor

Fuel Temperature Sensor

Oil Temperature Sensor

Rail Pressure Sensor
Multiple ECM Information Sensor DTCs Set

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Turn the ignition ªOFF,º disconnect the ECM.
2. Turn the ignition ªON,º check the 5 volt reference D
circuit for the following conditions:

D poor connection at the ECM.

An open between the ECM connector and the
splice.

D short to ground.

D short to voltage.
Is there an open or short?
ÐGo to Step 3Go to Step 4
3Repair the open or short.
Is the action complete?
ÐVerify repairÐ
4Check the sensor ground circuit for the following
conditions:

A poor connection at the ECM or the affected
sensors.

An open between the ECM connector and the
affected sensors.
Is there an open or a poor connection?
ÐGo to Step 5Go to Step 6
5Repair the open or the poor connection.
Is the action complete?
ÐVerify repairGo to Step 6
6Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
Ð
Go to OBD
System
Check
Ð

6E±41 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
EGR (Exhaust Gas Recirculation)
Diagnosis

A diagnosis of the EGR system is covered by DTC
P1403.

EGR VSV circuit diagnosis is covered by DTC P1404.

EGR pressure sensor diagnosis is covered by DTC
P405 and/or P406.

EGR EVRV circuit diagnosis is covered by DTC
P1405. Refer to the DTC charts.
Tech 2 Data Definitions and Ranges
A/C CLUTCH±Tech 2 Displays ON or OFF±
Indicates whether the A/C has commanded the A/C
clutch ON.
MAP kPa Ð Tech 2 Range 10-105 kPa/0.00-5.00
Volts Ð
The manifold absolute pressure reading is determined
from the MAP sensor signal monitored during key up and
wide open throttle (WOT) conditions. The manifold
absolute pressure is used to compensate for altitude
differences and is normally displayed around ª61-104º
depending on altitude and manifold absolute pressure.
CMP ACT. COUNTER ±Cam Position
DESIRED IDLE Ð Tech 2 Range 0-3187 RPM Ð
The idle speed that the ECM is commanding. The ECM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.
ECT Ð (Engine Coolant Temperature) Tech 2
Range ±40
C to 151
C (±40
F to 304
F) Ð
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the ECM. The ECM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the ECM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the ECM will interpret
the lower voltage as a warm engine.
ENGINE RUN TIME Ð Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec Ð
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.
ENGINE SPEED Ð Range 0-9999 RPM Ð
Engine speed is computed by the ECM from the 57X
reference input. It should remain close to desired idle
under various engine loads with engine idling.Air Intake Valve meter POSITION Ð Tech 2 Range
0-100 % Ð
IAT (INTAKE AIR TEMPERATURE)Ð Tech 2 Range
±40
C to 151
C (±40
F to 304
F) Ð
The ECM converts the resistance of the intake air
temperature sensor to degrees. Intake air temperature
(IAT) is used by the ECM to adjust fuel delivery and spark
timing according to incoming air density.
MAP Ð Tech 2 Range 10-105 kPa (0.00-4.97 Volts)Ð
The manifold absolute pressure (MAP) sensor measures
the change in the boost pressure.
MIL Ð Tech 2 Displays ON or OFF Ð
Indicates the ECM commanded state of the malfunction
indicator lamp.
AP Ð Tech 2 Range 0%-100% Ð
AP (Accelerator position) angle is computed by the ECM
from the AP sensor voltage. AP angle should display
ª0%º at idle and ª100%º at wide open throttle.
AP SENSOR Ð Tech 2 Range 0.00-5.00 Volts Ð
The voltage being monitored by the ECM on the AP
sensor signal circuit.
VEHICLE SPEEDÐTech 2 Range 0-255 km/h (0-155
mph)±
The vehicle speed sensor signal is converted into km/h
and mph for display.
Typical Scan Data Values
Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly. Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing. The typical scan data values represent
values that would be seen on a normally-running engine.
NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer. Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.
Only the parameters listed below are referred to in this
service manual for use in diagnosis. For further
information on using the Tech 2 to diagnose the ECM and
related sensors, refer to the applicable reference section
listed below. If all values are within the typical range
described below, refer to the
Symptoms section for
diagnosis.
Test Conditions
Engine running, lower radiator hose hot, transmission in
park or neutral, accessaries off, brake not applied and air
conditioning off.

6E±54
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
ECM Diagnostic Trouble Codes
The following table lists the diagnostic trouble codes
supported a Tech 2 and to flash.If any DTCs not listedhere are displayed by a Tech 2, the Tech 2 data may be
faulty; notify the Tech 2 manufacturer of any DTCs
displayed that are not included in the following table.
ECM Diagnostic Trouble Codes
DTC
using a
Tech 2
Flash DTCDescriptionMIL
P010734MAP Sensor Low VoltageON
P010834MAP Sensor High VoltageON
P011223Intake Air temp Sensor Low VoltageON
P011323Intake Air temp Sensor High VoltageON
P011714Engine Coolant Temp Sensor Low VoltageON
P011814Engine Coolant Temp Sensor High VoltageON
P012133Accel Position Sensor RationalityON
P012221Accel Position Sensor Low VoltageON
P012321Accel Position Sensor High VoltageON
P018215Fuel Temp Sensor Low VoltageON
P018315Fuel Temp Sensor High VoltageON
P019263Rail Pressure Sensor Low VoltageON
P019363Rail Pressure Sensor High VoltageON
P119364RPCV Circuit Open/ShortÐ
P119461Rail Pressure System Low VoltageON
P119561Rail Pressure System High VoltageON
P119662Rail Pressure System High WarningON
P019716Oil Temp sensor Low VoltageON
P019816Oil Temp sensor High VoltageON
P020151Injector #1 Circuit FaultON
P020252Injector #2 Circuit FaultON
P020353Injector #3 Circuit FaultON
P020454Injector #4 Circuit FaultON
P021722High Coolant Temp WarningON
P121736High Oil Temp WarningON
P021911Engine Over Speed WarningON
P033643Crank Position Sensor Out of SyncroON
P033743Crank Position Sensor No SignalON
P034141Cam Position Sensor Out of SyncroON
P034241Cam Position Sensor No SignalON
P038066Glow Relay Circuit Open/ShortÐ
P038167Glow Lamp Circuit Open/ShortÐ
P140332EGR EVRV FaultÐ
P140431EGR VSV CircuitÐ
P040526EGR Pressure Sensor Low VoltageON
P140537EGR EVRV Circuit Open/ShortÐ
P040626EGR Pressure Sensor High VoltageON

6E±55 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC
using a
Tech 2Flash DTCDescriptionMIL
P047571EXH #1 VSV Circuit Open/ShortÐ
P147571EXH #2 VSV Circuit Open/ShortÐ
P148574Intake Throttle Position Sensor Low VoltageON
P148674Intake Throttle Position Sensor High VoltageON
P148773Intake Throttle System Circuit Open/ShortON
P148872Intake Throttle Motor Control Circuit Signal GapÐ
P050224Vehicle Speed Sensor No SignalON
P051075Idle SW Malfunction, Open CircuitON
P151075Idle SW Malfunction, Short CircuitON
P056235System Voltage Too LowON
P156235System Voltage Too Low at CrankingON
P158725Brake SW Malfunction [B]Ð
P158825Brake SW Malfunction [A]ON
P060155ECM Checksum ErrorON
P162656Immobilizer No SignalON
P163156Immobilizer Wrong SignalON
P164856No Security Code EnteredON
P164956Immobilizer Function not ProgrammedON
P065077Check Engine Lamp Circuit Open/ShortÐ
P065427Techometer Circuit Open/ShortÐ
P165517Thermo Relay Circuit Open/ShortÐ
P165776ECM Main Relay Circuit Open/ShortÐ
P158947TransMission SW Circuit Open/ShortÐ

6E±56
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0107 (Flash DTC 34)
MAP Sensor Circuit Low Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively low, DTC P0107
will be set.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0107 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:

Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.

Check for intermittent codes.

The MAP sensor shares a ground with the ECT sensor,
and the Transmission Fluid Temperature sensor.

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. 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.
If DTC P0107 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0107 Diagnostic Chart may isolate
the cause of the fault.

6E±58
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0108 (Flash DTC 34)
MAP Sensor Circuit High Voltage
060RW134
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum).
The ECM monitors the MAP signals for voltages outside
the normal range of the MAP sensor. If the ECM detects a
MAP signal voltage that is excessively high, DTC P0108
will be set.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0108 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:

Turn on the ignition switch and stop the engine. At this
time, the boost pressure will be equal to the
atmospheric pressure and the signal voltage will
increase.

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. 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.
If DTC P0108 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set. If
it is determined that the DTC occurs intermittently.