Buick Regal: DTC P0071-P0074
Diagnostic Instructions
- Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
- Review the description of Strategy Based Diagnosis:Strategy Based
Diagnosis
- An overview of each diagnostic category can be found here: Diagnostic
Procedure Instructions
DTC Descriptors
DTC P0071
Ambient Air Temperature Sensor Performance
DTC P0072
Ambient Air Temperature Sensor Circuit Low Voltage
DTC P0073
Ambient Air Temperature Sensor Circuit High Voltage
DTC P0074
Ambient Air Temperature Sensor Circuit Intermittent
Diagnostic Fault Information
Circuit/System Description
For an overview of the component/system, refer to:Instrument Cluster
Description and Operation.
Conditions for Running the DTC
Ignition - On / Vehicle - In Service Mode
Conditions for Setting the DTC
P0071
The difference between the following parameters is greater than a predefined
value:Outside Ambient Air
Temperature Sensor Signal & Intake Air Temperature Sensor Signal
P0072
Outside Ambient Air Temperature Sensor Signal=Greater than 88ºC (190ºF)
P0073
Outside Ambient Air Temperature Sensor Signal=Less than -40ºC (-40ºF)
P0074
Outside Ambient Air Temperature Sensor Signal=Not Plausible
Action Taken When the DTC Sets
- DTCs listed in the DTC Descriptor Category = Type B DTC
- Air Conditioning Compressor Clutch = Disabled
- The control module uses default replacement values.
Conditions for Clearing the DTC
The conditions for setting the DTC no longer exist.
Diagnostic Aids
The displayed temperature is a filtered value that updates periodically while
driving. The value rarely
changes when the vehicle is parked.
For an overview of the component/system, refer to:Instrument Cluster
Description and Operation.
Reference Information
Schematic Reference
Instrument Cluster Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEW INDEX
Master Electrical Component List
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
Circuit/System Verification
1. Ignition - On / Vehicle - In Service Mode.
2. Verify the scan tool parameter:Ambient Air Temperature=-40 to 88ºC (-40 to
190ºF) and
changes.
- If not between -40 and 88ºC (-40 and 190ºF) or does not change
- Refer to: Circuit/System Testing
- Go to next step: If between -40 and 88ºC (-40 and 190ºF) and
changes
3. All OK.
Circuit/System Testing
NOTE: It may take up to 2 min for all vehicle systems to power down
before
an accurate ground or low reference circuit continuity test can be
performed.
1. Ignition/Vehicle & All vehicle systems - Off.
2. Disconnect the electrical connector: B9 Ambient Air Temperature Sensor.
3. Test for less than 10 ohms between the test points: Low Reference circuit
terminal B(or2) &
Ground.
- Disconnect the electrical connector: K20 Engine Control Module
- Test for less than 2 ohms between the test points:Low Reference circuit
terminal
B(or2)@Component harness & The other end of the circuit
- If 2 ohms or greater - Repair the open/high resistance in the
circuit.
- If less than 2 ohms - Replace the component: K20 Engine Control
Module
- Go to next step: If less than 10 ohms
4. Ignition - On / Vehicle - In Service Mode.
5. Verify the scan tool parameter: Ambient Air Temperature = Less than -34ºC
(-30ºF).
- If -34ºC (-30ºF) or warmer
- Ignition/Vehicle - Off
- Disconnect the electrical connector: K20 Engine Control Module
- Test for infinite resistance between the test points: Signal circuit
terminal
A(or1)@Component harness & Ground
- If less than infinite resistance - Repair the short to ground on the
circuit.
- If infinite resistance - Replace the component: K20 Engine Control
Module
- Go to next step: If -35ºC (-31ºF) or colder
6. Connect a 3 A fused jumper wire between the test points: Signal circuit
terminal A(or1) & Low
Reference circuit terminal B(or2).
7. Verify the scan tool parameter:Ambient Air Temperature = Greater than 143ºC
(290ºF).
- If 143ºC (290ºF) or colder
- Ignition/Vehicle - Off & Remove - Jumper wire(s)
- Disconnect the electrical connector: K20 Engine Control Module
- Ignition - On / Vehicle - In Service Mode
- Test for less than 1 V between the test points: Signal circuit@Component
harness & Ground
- If 1 V or greater - Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
- Ignition/Vehicle - Off
- Test for less than 2 ohms between the test points: Signal
circuit@Component harness & The
other end of the circuit
- If 2 ohms or greater - Repair the open/high resistance in the
circuit.
- If less than 2 ohms - Replace the component: K20 Engine Control
Module
- Go to next step: If 144ºC (291ºF) or warmer
8. Connect the component: B9 Ambient Air Temperature Sensor.
9. Operate the vehicle within the Conditions for Running the DTC.
10. Verify the DTC does not set.
Replace the component: B9 Ambient Air Temperature Sensor
- Go to next step: If the DTC is not set
11. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair:
Diagnostic Repair Verification
- Displays and Gauges Component Replacement Reference
- For control module replacement, programming, and setup refer to: Control
Module References
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
DTC Descriptors
DTC P0521
Engine Oil Pressure Sensor Performance
DTC P0522
Engine Oil Pressure Sensor Circuit Low Voltage.
DTC P0523
Engine Oil Pressure Sensor Circuit High Voltage
Diagnostic Fault In
SEE MORE:
General Description
A crankcase ventilation system is used to consume crankcase vapors in the
combustion process instead of venting
them to atmosphere. Fresh air from the intake system is supplied to the
crankcase, mixed with blow by gases and
then passed through a calibrated orifice into the inta
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.
Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descripto