P0073
DTC P0071-P0073
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.
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
Diagnostic Fault Information
Circuit/System Description
The Hybrid/EV Powertrain Control Module 2 supplies the ambient air temperature sensor with a low reference circuit and 5 V signal circuit. The Hybrid/EV Powertrain Control Module 2 determines the voltage drop across the sensor, which is proportional to temperature. As the air temperature increases, the sensor resistance decreases. As the air temperature decreases, the sensor resistance increases.
Conditions for Running the DTC
Vehicle in Service Mode.
Conditions for Setting the DTC
The Hybrid/EV Powertrain Control Module 2 detects the ambient air temperature sensor signal circuit is less than -35°C (-39°F) or more than 85°C (185°F) for more than 15 seconds.
Action Taken When the DTC Sets
* The DIC will display SERVICE A/C SYSTEM.
* The system operates using a default value.
Conditions for Clearing the DTC
* The DTC will become history if the Hybrid/EV Powertrain Control Module 2 no longer detects the condition that set the DTC.
* The history DTC will clear after 100 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
Automatic HVAC Description and Operation HVAC - Automatic
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearningfor scan tool information
Circuit/System Testing
1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B23 ambient air temperature sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohm between the low reference circuit terminal B and ground.
• If 10 ohm or greater
1. Vehicle OFF, disconnect the harness connector at the K114A Hybrid/EV powertrain control module 2.
2. Test for less than 2 ohm in the low reference circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K114A Hybrid/EV powertrain control module 2.
• If less than 10 ohm
3. Vehicle in Service Mode.
4. Verify the scan tool Ambient Air Temperature Sensor parameter is less than -35°F.
• If -35°F or greater
1. Vehicle OFF, disconnect the harness connector at the K114A Hybrid/EV powertrain control module 2.
2. Test for infinite resistance between the signal circuit terminal A and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K114A Hybrid/EV powertrain control module 2.
• If less than -35°F
5. Install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B.
6. Verify the scan tool Ambient Air Temperature Sensor parameter is greater than 240°F.
• If 240°F or less
1. Vehicle OFF, disconnect the harness connector at the K114A Hybrid/EV powertrain control module 2, vehicle in Service Mode.
2. 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
3. Vehicle OFF
4. Test for less than 2 ohm in the signal circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K114A Hybrid/EV powertrain control module 2.
• If greater than 240°F
7. Test or replace the B23 ambient air temperature sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Ambient Air Temperature Sensor Replacement Service and Repair
* Control Module References Programming and Relearningfor Hybrid/EV Powertrain Control Module 2 replacement, programming and setup