Buick Regal: DTC P0097, P0098, or P0099
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
DTC P0097
Intake Air Temperature (IAT) Sensor 2 Circuit Low Voltage
DTC P0098
Intake Air Temperature (IAT) Sensor 2 Circuit High Voltage
DTC P0099
Intake Air Temperature (IAT) Sensor 2 Circuit Intermittent
Diagnostic Fault Information
IAT Sensor 2
Typical Scan Tool Data
IAT Sensor 2
Circuit/System Description
The intake air temperature (IAT) sensor 1 is a variable resistor that
measures the temperature of the air in
the sensor bore. The engine control module (ECM) supplies 5 V to the IAT sensor
1 signal circuit and a
ground for the IAT sensor 1 low reference circuit. The signal varies with inlet
air temperature and is
displayed by the scan tool as ºC (ºF).
The IAT sensor 2 produces a frequency signal based on the inlet air temperature
very close to the
humidity sensor within the sensor bore. The signal varies with inlet air
temperature and is displayed by
the scan tool as ºC (ºF) and Hertz (Hz). The ECM applies 5 V to the circuit.
The signal circuit is
shared by the IAT sensor 2 and the humidity sensor. Ignition voltage and ground
circuits are also
supplied to the multifunction intake air sensor's internal circuits for these
sensors:
- IAT sensor 2
- Humidity sensor
- Mass Air Flow (MAF) sensor
The multifunction intake air sensor houses the following:
- IAT sensor 1
- IAT sensor 2
- Humidity sensor
- MAF sensor
- BARO pressure sensor
IAT Sensor 1 - Temperature, Resistance, Voltage Table
IAT Sensor 2 - Temperature, Frequency Table
Conditions for Running the DTCs
P0097, P0098, and P0099
- The ignition is ON, or the engine is running.
- The Ignition 1 voltage is at least 11 V.
- The DTCs run continuously within the enabling conditions.
- Where P0099 is used, the DTC runs continuously within the enabling
conditions.
Conditions for Setting the DTCs
P0097
NOTE: The scan tool display range is between -40 and +150ºC (-40 and
+302ºF).
The ECM detects that the IAT sensor 2 signal is less than 13 Hz, colder than
-60ºC (-76ºF), for
greater than 5 s.
P0098
The ECM detects that the IAT sensor 2 signal is greater than 390 Hz, warmer
than 150ºC (302ºF),
for greater than 5 s.
P0099
Where P0099 used, the ECM detects that the IAT sensor 2 signal is
intermittent or has abruptly changed
for longer than 5 s.
Action Taken When the DTC Sets
- DTCs P0097, P0098, and P0099 are Type B DTCs - North America and Korea.
- DTCs P0097, P0098, and P0099 are Type C DTCs - Except North America and
Korea.
- The ECM commands the cooling fans ON.
Conditions for Clearing the MIL/DTC
- DTCs P0097, P0098, and P0099 are Type B DTCs - North America and Korea.
- DTCs P0097, P0098, and P0099 are Type C DTCs - Except North America and
Korea.
Diagnostic Aids
- With the ignition ON, the engine OFF, if the engine is cold, a properly
functioning IAT sensor 2
will gradually increase the scan tool IAT Sensor 2 parameter. This is due to
the heat that is
generated by the MAF sensor heating elements.
- The humidity sensor and the IAT sensor 2 signals are sent to the ECM on
the same circuit. If the
IAT Sensor 2 parameter displays the values: 10 Hz; -40ºC (-40ºF), and
there are also Humidity
Sensor DTCs, check for a circuit problem.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Powertrain Component Views
Powertrain Component Views
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL-38522-A Variable Signal Generator
For equivalent regional tools, refer to Special Tools (diagnostic tools) and
Special Tools (Mechanical Tools).
Circuit/System Verification
1. Ignition ON.
2. Verify that DTC P0641, P0651, P0697, P06A3, or P06D2 is not set.
- If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further
diagnosis.
- Go to next step: If none of the DTCs are set
NOTE: To minimize the effects of residual engine heat and sensor
internal
heating elements, perform Steps 3 and 4 of this verification
procedure only if the ignition has been OFF for 8 hours or more.
3. Ignition ON.
4. Verify the following scan tool parameters are within 30ºC (54ºF) of each
other.
- Start-Up IAT Sensor 1
- IAT Sensor 2
- IAT Sensor 3; where equipped
- If not within 30ºC (54ºF)
Refer to Circuit/System Testing.
- Go to next step: If within 30ºC (54ºF)
5. Engine idling, verify the following scan tool parameters are between:
between -38 and +149ºC
(-36 and +300ºF).
- IAT Sensor 1
- IAT Sensor 2
- IAT Sensor 3; where equipped
- If not between: -38 and +149ºC (-36 and +300ºF)
Refer to Circuit/System Testing.
- Go to next step: If between: -38 and +149ºC (-36 and +300ºF)
6. Operate the vehicle within the conditions for running the DTC. You may
also operate the vehicle
within the conditions that you observed from the freeze frame/failure records
data.
7. Verify the DTC does not set.
Refer to Circuit/System Testing.
- Go to next step: If the DTC does not set
8. All OK
Circuit/System Testing
NOTE: You must perform the Circuit/System Verification before
proceeding with
Circuit/System Testing.
1. Ignition OFF, and all vehicle systems OFF, it may take up to 2 min. for
all vehicle systems to
power down. Disconnect the harness connector at the B75C Multifunction Intake
Air sensor.
2. Test for less than 2 Ω between the low reference circuit terminal 3 and
ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open or high resistance in the
circuit.
- If less than 2 Ω replace the K20 Engine Control Module.
- Go to next step: If less than 2 Ω
3. Ignition OFF, all vehicle systems OFF, test for less than 2 Ω between the
ground circuit terminal 7
and ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open or high resistance in the
circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 2 Ω
4. Ignition ON, verify that a test lamp illuminates between the ignition
circuit terminal 5 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the test lamp and remove the fuse for the ignition
voltage circuit.
- Test for less than 2 Ω in the ignition voltage circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage
at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, remove the test lamp and remove the fuse for the ignition
voltage circuit.
- Test for infinite resistance between the ignition voltage circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, test all components connected to the
ignition circuit, replace as
necessary.
- Go to next step: If a test lamp illuminates
5. Ignition ON, test for 4.8 - 5.2 V between the intake air temperature
sensor 2 signal circuit terminal
8 and ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
NOTE: If the signal circuit is shorted to a voltage the engine
control
module or the sensor may be damaged.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Ignition ON, test for less than 1 V between the signal circuit and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If between 4.8 - 5.2 V
6. Determine if EL-38522-A Variable Signal Generator or equivalent is
available.
- EL-38522-A, Variable Signal Generator; or equivalent is not available
- Test or replace the B75C Multifunction Intake Air sensor.
- Operate the vehicle within the Conditions for Running the DTC. You may
also operate the
vehicle within the conditions that you observed from the freeze
frame/failure records data.
- Verify the DTC does not set.
Replace the K20 Engine Control Module.
- Go to next step: If no DTCs set
- All OK.
- Go to next step: EL-38522-A, Variable Signal Generator; or equivalent
is available
7. Ignition OFF, connect the leads of the EL-38522-A Variable Signal
Generator as follows:
- Red lead to the signal circuit terminal 8 at the harness connector
- Black leads to ground
- Battery voltage supply lead to B+
8. Set the EL-38522-A Variable Signal Generator to the following
specifications.
- Signal switch to 5 V
- Duty Cycle switch to 50 % (Normal)
- Frequency switch to 30 Hz
9. Ignition ON, verify the scan tool IAT Sensor 2 parameter is between 28 -
32 Hz.
- If not between 28 - 32 Hz
Replace the K20 Engine Control Module.
- Go to next step: If between 28 - 32 Hz
10. Test or replace the B75C Multifunction Intake Air sensor.
Component Testing
Multifunction Intake Air Sensor
1. Test the IAT Sensor 2 by varying the sensor temperature while monitoring
the air temperature
with a thermometer. Compare the readings with the scan tool IAT Sensor 2
parameter. The values
should be within 5%.
- If not within the specified range
Replace the B75C Multifunction Intake Air Sensor.
- Go to next step: If within the specified range
2. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Mass Airflow Sensor with Intake Air Temperature Sensor Replacement for
multifunction
intake air sensor replacement
- Control Module References for engine control module replacement,
programming, and setup.
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
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crashes that occur with moving
vehicles in the side blind zone (or
spot) areas or with vehicles rapidly
approaching these areas from behind. The LCA warning display
will light up in the corresponding
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Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Refer to Diagnostic System
Check - Vehicle
Review the description of Strategy Based Diagnosis:Strategy Based
Diagnosis
An overview of each diagnostic category can be found here: Refer to