sensor ISUZU TROOPER 1998 Service Repair Manual

6E±108
ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. This step verifies that the problem is present at idle.4. A voltage reading of less than 4 or over 5 volts at the
MAF sensor signal circuit indicates a fault in the
wiring or a poor connection.
5. This verifies that ignition feed voltage and a good
ground are available at the MAF sensor.
DTC P0102 ± MAF Sensor Circuit Low Frequency

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine.
2. With the engine idling, monitor ªMAF Frequencyº
display on the Tech 2.
Is the ªMAF Frequencyº below the specified value?
3 g/SecGo to Step 4Go to Step 5
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0102.
Does the Tech 2 indicate DTC P0102 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFF.º
2. Disconnect the MAF sensor connector.
3. Ignition ªON,º engine ªOFF.º
4. Using a DVM, measure voltage between the MAF
sensor signal circuit and battery ground.
Is the voltage near the specified value?
5 VGo to Step 5Go to Step 8
5Connect a test light between the MAF sensor ignition
feed and ground circuits at the MAF sensor harness
connector.
Is the test light ªON?º
ÐGo to Step 13Go to Step 6
6Connect a test light between the MAF sensor ignition
feed circuit and battery ground.
Is the test light ªON?º
ÐGo to Step 12Go to Step 7
71. Check for a poor connection at the MAF sensor.
2. If a poor connection is found, replace the faulty
terminal(s).
Was a poor connection found?
ÐVerify repairGo to Step 11
81. Ignition ªOFF.º
2. Disconnect the MAF sensor.
3. Disconnect the PCM connector for the MAF signal
circuit.
4. Ignition ªON,º engine ªOFF.º
5. With the DVM, measure the voltage between the
MAF signal terminal at the PCM and battery ground.
Is the voltage under the specified value?
4 VGo to Step 9Go to Step 10

6E±109 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0102 ± MAF Sensor Circuit Low Frequency

 
StepNo Ye s Value(s) Action
91. Ignition ªOFF.º
2. Disconnect the PCM white connector.
3. Ignition ªON.º
4. Check the MAF sensor signal circuit for a short to 5
volts.
Is the action complete?
ÐVerify repairÐ
101. Ignition ªOFF.º
2. Disconnect the PCM white connector.
3. Ignition ªON.º
4. Check the MAF sensor signal circuit between the
PCM and the MAF sensor for an open, short to
ground, or short to the MAF ground circuit.
Is the action complete?
ÐVerify repairGo to Step 13
11Locate and repair the open in the ground circuit to the
MAF sensor.
Is the action complete?
ÐVerify repairÐ
12Locate and repair the open in the ignition feed circuit to
the MAF sensor.
Is the action complete?
ÐVerify repairÐ
13Replace the MAF sensor.
Is the action complete?
ÐVerify repairGo to Step 14
14Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±110
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0103 MAF Sensor Circuit High Frequency
T321122
Circuit Description
The mass air flow (MAF) sensor measures the amount of
air which passes through it into the engine during a given
time. The powertrain control module (PCM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations. A large quantity
of air entering the engine indicates an acceleration or high
load situation, while a small quantity of air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which can
be monitored using a Tech 2. The frequency will vary
within a range of around 2500 Hz at idle to around
9000 Hz at maximum engine load. DTC P0103 will be set
if the signal from the MAF sensor is above the possible
range of a normally operating MAF sensor.
Conditions for Setting the DTC

The engine is running above 500 RPM for more than
10 seconds.

System voltage is above 11.5 volts.

MAF signal frequency is above 10,000 Hz (10.0 kHz)
for a total of 50 percent of the last 200 samples
monitored. A sample is taken every cylinder event.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM calculates an airflow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.

The PCM 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 P0103 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
If DTC P0103 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. This step verifies that the problem is present at idle.
4. A frequency reading with the MAF sensor connector
disconnected indicates an electromagnetic
interfernce (EMI) related fault.

6E±111 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0103 ± MAF Sensor Circuit High Frequency

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0103.
Does the Tech 2 indicate DTC P0103 failed this
ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Start the engine.
2. With the engine idling, monitor ªMAF Frequencyº
display on the Tech 2.
Is ªMAF Frequencyº above the specified value?
219 g/SecGo to Step 4Go to Step 7
41. Ignition ªOFF.º
2. Disconnect the MAF sensor connector.
3. Ignition ªON,º engine idling.
4. Using a Tech 2, monitor ªMAF Frequency.º
Does the Tech 2 indicate a ªMAF Frequencyº at the
specified value?
0.0 g/SecGo to Step 5Go to Step 6
5Replace the MAF sensor.
Is the action complete?
ÐVerify repairGo to Step 8
61. Check the MAF harness for incorrect routing near
high voltage components (solenoids, relays,
motors).
2. If incorrect routing is found, correct the harness
routing.
Was a problem found?
ÐVerify repairGo to Step 7
71. With the engine idling, monitor ªMAF Frequencyº
display on the Tech 2.
2. Quickly snap open throttle to wide open throttle
while under a road load and record value.
Does the Tech 2 indicate ªMAF Frequencyº above the
specified value?
219 g/SecGo to Step 5Go to Step 8
8Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±112
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0107 MAP Sensor Circuit Low Voltage
D06RW102
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP sensor signal voltage to the powertrain control
module (PCM) varies from below 2 volts at idle (high
vacuum) to above 4 volts with the ignition ªON,º engine
not running or at wide-open throttle (low vacuum).
The MAP sensor is used to determine manifold pressure
changes while the exhaust gas recirculation (EGR) flow
test diagnostic is being run (refer to
DTC P0401), to
determine engine vacuum level for some other
diagnostics and to determine barometric pressure
(BARO). The PCM monitors the MAP signals for voltages
outside the normal range of the MAP sensor. If the PCM
detects a MAP signal voltage that is excessively low, DTC
P0107 will be set.
Conditions for Setting the DTC

No TP sensor DTCs present.

Engine is running.

Throttle angle is above 1% if engine speed is less than
1000 RPM.

Throttle angle is above 2% if engine speed is above
1000 RPM.

The MAP sensor indicates manifold absolute pressure
at or below 11 kPa for a total of approximately 10
seconds over a 16-second period.

Ignition voltage more than 11 volts.
Action Taken When the DTC Sets

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

The PCM will default to a BARO value of 79.3 kPa.

The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Check for intermittent codes.

The MAP sensor shares a 5 Volt reference with the
Rough Road Sensor. If these codes are also set, it
could indicate a problem with the 5 Volt reference
circuit .

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

Poor connection at PCM ± 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

6E±113 ENGINE DRIVEABILITY AND EMISSIONS
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 indetermining 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.
DTC P0107 ± MAP Sensor Circuit Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. With the throttle closed, observe the MAP value
displayed on the Tech 2.
Is the MAP value near the specified value?
11 kPa at sea
level
Go to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªSpecific DTCº info for DTC
P0107.
Does the Tech 2 indicate DTC P0107 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFF.º
2. Disconnect the MAP sensor electrical connector.
3. Jumper the 5 volt reference ªAº circuit and the MAP
signal together at the MAP sensor harness
connector.
4. Ignition ªON.º
5. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value?
5 V 104 kPaGo to Step 10Go to Step 5
51. Disconnect the jumper.
2. Connect a test light between B+ and the MAP
sensor signal circuit at the MAP sensor harness
connector.
3. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value.
5 V 104 kPaGo to Step 6Go to Step 8
61. Ignition ªOFF.º
2. Disconnect the PCM and check the 5 volt reference
ªAº circuit for an open or short to ground.
3. If the 5 volt reference ªAº circuit is open or shorted to
ground, repair it as necessary.
Was the 5 volt reference ªAº circuit open or shorted to
ground?
ÐVerify repairGo to Step 7
7Check the 5 volt reference ªAº circuit for a poor
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 11
81. Ignition ªOFF.º
2. Disconnect the PCM, and check the MAP signal
circuit for an open, short to ground, or short to the
sensor ground circuit.
3. If the MAP sensor signal circuit is open or shorted to
ground, repair it as necessary.
Was the MAP signal circuit open or shorted to ground?
ÐVerify repairGo to Step 9

6E±114
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0107 ± MAP Sensor Circuit Low Voltage

 
StepNo Ye s Value(s) Action
9Check the MAP sensor signal circuit for a poor
connection at the PCM and the MAP sensor; replace
the terminal if necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 11
10Replace the MAP sensor.
Is the action complete?
ÐVerify repairÐ
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify repairÐ

6E±115 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0108 MAP Sensor Circuit High Voltage
D06RW102
Circuit Description
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP sensor signal voltage to the powertrain control
module (PCM) varies from below 2 volts at idle (high
vacuum) to above 4 volts with the key ªON,º engine not
running or at wide-open throttle (low vacuum).
The MAP sensor is used to determine manifold pressure
changes while the linear EGR flow test diagnostic is being
run (refer to
DTC P0401), to determine engine vacuum
level for some other diagnostics and to determine
barometric pressure (BARO). The PCM monitors the
MAP signals for voltages outside the normal range of the
MAP sensor. If the PCM detects a MAP signal voltage
that is excessively high, DTC P0108 will be set.
Conditions for Setting the DTC

No TP sensor DTCs present.

Engine is running for more than 10 seconds.

Throttle position is below 3% if engine speed is below
1000 RPM.

Throttle position is below 10% if engine speed is above
1000 RPM.

The MAP sensor indicates an intermittent manifold
absolute pressure above 80 kPa for a total of
approximately 10 seconds over a 16-second period.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM will default to a BARO value of 79.3 kPa.

The PCM 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 PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at PCM ± 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,
performing the DTC P1108 Diagnostic Chart may isolate
the cause of the fault.

6E±116
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0108 ± MAP Sensor Circuit High Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. If the engine idle is rough, unstable or incorrect,
repair the idle problem before using this chart. Refer
to
Symptoms section.
2. With the engine idling, note the MAP value on the
Tech 2.
Is the MAP reading above the specified value?
90 kPaGo to Step 4Go to Step 3
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªSpecific DTCº info for DTC
P0108.
Does the Tech 2 indicate DTC P0108 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFF.º
2. Disconnected the MAP sensor electrical connector.
3. Ignition ªON.º
4. Note the MAP sensor voltage displayed on the Tech
2.
Is the MAP sensor voltage at the specified value?
0.0 V 11 kPaGo to Step 5Go to Step 6
5Probe the sensor ground circuit with a test light to B+.
Is the test light ªON?º
ÐGo to Step 7Go to Step 9
61. Check the MAP signal circuit for a short to voltage or
a short to the 5 volt reference ªAº circuit.
2. If the MAP sensor signal circuit is shorted, repair
circuit as necessary.
Was the MAP sensor signal circuit shorted?
ÐVerify repairGo to Step 11
71. Check for a poor sensor ground terminal connection
at the MAP sensor electrical connector.
2. If a problem if found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 8
8Check for a plugged or leaking vacuum supply to the
MAP sensor.
Is the vacuum supply plugged or leaking?
ÐVerify repairGo to Step 12
91. Check for a poor sensor ground terminal connection
at the PCM.
2. If a problem is found, replace the faulty terminal.
Did the terminal require replacement?
ÐVerify repairGo to Step 10
101. Check the continuity of the MAP sensor ground
circuit.
2. If the MAP sensor ground circuit measures over 5
ohms, repair open or poor connection.
Was a condition found and corrected?
ÐVerify repairGo to Step 11

6E±117 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0108 ± MAP Sensor Circuit High Voltage

 
StepNo Ye s Value(s) Action
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?ÐVerify RepairÐ
12Replace the MAP sensor.
Is the action complete?
ÐVerify repairÐ