Page 1233 of 6000

6E–116
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0108 – MAP Sensor Circuit High Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go 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
Te c h 2 .
Is the MAP reading above the specified value?
90 kPaGo to Step 4Go to Step 3
31. Ignition “ON,” engine “OFF.”
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 “Specific DTC” info for DTC
P0108.
Does the Tech 2 indicate DTC P0108 failed this
ignition?
—Go to Step 4
Refer to
Diagnostic
Aids
41. Ignition “OFF.”
2. Disconnected the MAP sensor electrical connector.
3. Ignition “ON.”
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 “ON?”
—Go 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 “A” circuit.
2. If the MAP sensor signal circuit is shorted, repair
circuit as necessary.
Was the MAP sensor signal circuit shorted?
—Verify 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?
—Verify repairGo to Step 8
8Check for a plugged or leaking vacuum supply to the
MAP sensor.
Is the vacuum supply plugged or leaking?
—Verify 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?
—Verify 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?
—Verify repairGo to Step 11
Page 1234 of 6000
6E–117 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0108 – MAP Sensor Circuit High Voltage
StepNo Ye s Va l u e ( s ) Action
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify Repair—
12Replace the MAP sensor.
Is the action complete?
—Verify repair—
Page 1235 of 6000

6E–118
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0112 IAT Sensor Circuit Low Voltage
D06RW026
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The powertrain control module (PCM) 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
PCM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower, causing the PCM to monitor a lower voltage. DTC
P0112 will set when the PCM detects an excessively low
signal voltage on the intake air temperature sensor signal
circuit.
Conditions for Setting the DTC
The engine has been running for over 2 minutes.
Vehicle speed is greater than 30 mph (48 km/h) .
IAT signal voltage indicates and intake air temperature
greater than 148C (298F) (about 5 volts) for a total
of 12.5 seconds over a 25-second period of time.
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 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 P0112 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM – Inspect harness connectors
for backed-bout 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
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.
If DTC P0112 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. Verifies that the fault is present.
Page 1236 of 6000
6E–119 ENGINE DRIVEABILITY AND EMISSIONS
3. If DTC P0112 can be repeated only by duplicating
the Failure Records condition, refer to the
Temperature vs. Resistance Value table. The table
may be used to test the IAT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be stored above or below
a certain temperature. If this is the case, replace
the IAT sensor. If the IAT sensor appears to be OK,
the fault is intermittent; refer to
Diagnostic Aids.
Intake Air Temperature Sensor
CFOHMS
Temperature vs. Resistance Values
(approximate)
100212177
80176332
60140667
4511 311 8 8
35951802
25772796
15594450
5417280
–52312300
–15521450
–30–2252700
–40–40100700
Page 1237 of 6000

6E–120
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0112–IAT Sensor Circuit Low Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.”
2. Using a Tech 2, monitor the intake air temperature
(IAT).
Is the intake air temperature greater than the specified
value?
148C
(283
F)Go to Step 4Go to Step 3
31. Ignition “ON,” engine “OFF.” Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the “Specific DTC” info for
DTC P0112.
Does the Tech 2 indicate DTC P0112 failed this
ignition?
—
Refer to Te s t
Description
Refer to
Diagnostic
Aids
41. Ignition “OFF.”
2. Disconnect the IAT sensor electrical connector.
3. Ignition “ON.”
4. Observe the intake air temperature on the Tech 2.
Is the intake air temperature below the specified value?
–38C
(–36
F)Go to Step 6Go to Step 5
51. Ignition “OFF.”
2. Disconnect the PCM electrical connectors.
3. Check the IAT sensor signal circuit for a short to
ground.
Is the IAT sensor signal circuit shorted to ground?
—Verify repairGo to Step 7
6Replace the IAT sensor.
Is the action complete?
—Verify repair—
7Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—
Page 1238 of 6000

6E–121 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0113 IAT Sensor Circuit High Voltage
D06RW026
Circuit Description
The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The powertrain control module (PCM) 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
PCM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower causing the PCM to monitor a lower voltage. DTC
P0113 will set when the PCM detects an excessively high
signal voltage on the intake air temperature sensor signal
circuit.
Conditions for Setting the DTC
The engine has been running for over 4 minutes.
Vehicle speed is less than 20 mph (32 km/h).
ECT signal temperature is above 60C (140F).
Mass air flow is less then 20 g/second.
IAT signal voltage indicates an intake air temperature
less than –39C (–38F) for total of 12.5 seconds over
a 25-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 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 P0113 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
The IAT sensor shares a ground with the EGR position
sensor and the TP sensor. Check the ground if these
DTC’s are set.
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
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.
If DTC P0113 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. Verifies that the fault is present.
Page 1239 of 6000

6E–122
ENGINE DRIVEABILITY AND EMISSIONS
3. If DTC P0113 can be repeated only by duplicating
the Failure Records conditions, refer to the
“Temperature vs. Resistance Values” table. The
table may be used to test the IAT sensor at various
temperatures to evaluate the possibility of a
“shifted” sensor that may be open above or below a
certain temperature. If this is the case, replace the
IAT sensor. If the IAT sensor appears to be OK, the
fault is intermittent; refer to
Diagnostic Aids.
Intake Air Temperature Sensor
CFOHMS
Temperature vs. Resistance Values
(approximate)
100212177
80176332
60140667
4511 31188
35951802
25772796
15594450
5417280
–52312300
–15521450
–30–2252700
–40–40100700
DTC P0113 –IAT Sensor Circuit High Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
2Ignition “ON,” engine “OFF.” Observe the “Intake Air
Temp” display on the Tech 2.
Is the “Intake Air Temp” below the specified value?
–38C
(–36
F)Go to Step 4Go to Step 3
31. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data
parameters.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor “Specific DTC” info for DTC
P0113.
Does the Tech 2 indicate DTC P0113 failed?
—
Refer to Te s t
Description
Refer to
Diagnostic
Aids
41. Ignition “OFF.”
2. Disconnect the IAT sensor electrical connector.
3. Jumper the IAT signal circuit and the sensor ground
circuit together at the IAT sensor harness
connector.
4. Ignition “ON.”
5. Observe the “Intake Air Temp” display on the Tech
2.
Is the “Intake Air Temp” at the specified value?
140C
(284
F)Go to Step 6Go to Step 5
51. Jumper the IAT signal circuit at the IAT sensor
harness connector to chassis ground.
2. Observe the “Intake Air Temp” display on the Tech
2.
Is the “Intake Air Temp” at the specified value?
140C
(284
F)Go to Step 7Go to Step 8
Page 1240 of 6000

6E–123 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0113 –IAT Sensor Circuit High Voltage
StepNo Ye s Va l u e ( s ) Action
6Check for poor connections at the IAT sensor and
replace terminals if necessary.
Did any terminals require replacement?
—Verify repairGo to Step 10
71. Ignition “OFF.”
2. Disconnect the PCM, and check the IAT sensor
ground circuit for an open.
3. If the IAT sensor ground circuit is open, repair it as
necessary.
Was the IAT sensor ground circuit open?
—Verify repairGo to Step 9
81. Ignition “OFF.”
2. Disconnect the PCM, and check the IAT signal
circuit for an open.
3. If the IAT sensor signal circuit is open, repair it as
necessary.
Was the IAT signal circuit open?
—Verify repairGo to Step 9
9Check for a poor sensor ground or IAT signal circuit
terminal connection at the PCM and replace
terminal(s) if necessary.
Did any of the terminals need to be replaced?
—Verify repairGo to Step 11
10Replace the IAT sensor.
Is the action complete?
—Verify repair—
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—