The P0071 trouble code is a diagnostic trouble code (DTC) that indicates a problem with the Ambient Air Temperature (AAT) sensor range or performance. This code is triggered when the vehicle’s Powertrain Control Module (PCM) detects that the input from the AAT sensor does not align with readings from other temperature sensors, such as the Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensors. Understanding this code is crucial for vehicle owners and DIY mechanics, as it can affect various vehicle functions, including air conditioning and engine performance.
| P0071 Code Meaning | P0071 Code Common Causes |
|---|---|
| Ambient Air Temperature Sensor Range/Performance Issue | Faulty Ambient Air Temperature Sensor |
| Inconsistent Sensor Readings | Wiring Issues (shorts, breaks, corrosion) |
| Malfunctioning Climate Control System | Failed Powertrain Control Module (PCM) |
| Inaccurate Outside Temperature Display | Electrical Connector Problems |
Symptoms of P0071 Code
When the P0071 code is triggered, several symptoms may manifest in your vehicle:
- Malfunction Indicator Light (MIL): The check engine light will typically illuminate on the dashboard.
- Air Conditioning Issues: The air conditioning system may not function correctly, leading to inadequate cooling.
- Inaccurate Temperature Readings: The instrument cluster may display incorrect outside temperature readings.
- Overhead Console Malfunction: The overhead console may also fail to display the correct outside temperature.
Technical Explanation of P0071 Code
The Ambient Air Temperature sensor plays a vital role in providing the PCM with real-time data about the ambient air temperature. This information is essential for various functions, including fuel metering and climate control. When the PCM detects that the AAT sensor’s readings do not correlate with those of the IAT and ECT sensors, it sets the P0071 code.
How the AAT Sensor Works
The AAT sensor operates by sending a voltage signal to the PCM, which reflects the ambient air temperature. If this signal deviates significantly from expected values—especially when compared to other temperature sensors—the PCM interprets this as a malfunction and triggers the P0071 code.
Step-by-Step Diagnosis of P0071 Code
Diagnosing the P0071 code requires a systematic approach to identify and resolve underlying issues.
Step 1: Retrieve Diagnostic Trouble Codes
Using an OBD-II scanner, retrieve all stored DTCs. This will provide insight into whether additional codes are present that could indicate related issues.
Step 2: Record Freeze Frame Data
Capture freeze frame data associated with the P0071 code. This data can provide context regarding engine conditions at the time of the fault.
Step 3: Inspect Wiring and Connectors
Visually inspect the wiring harness and connectors leading to the AAT sensor. Look for signs of:
- Shorts or breaks in wiring
- Corrosion or burn marks on connectors
- Loose connections
Step 4: Test AAT Sensor Functionality
Using a multimeter, test the resistance of the AAT sensor. Compare its readings against manufacturer specifications. If readings are out of spec, replace the sensor.
Step 5: Check PCM Functionality
If all previous tests pass but the code persists, consider checking for PCM issues. This may require professional diagnostic equipment.
Step 6: Clear Codes and Test Drive
After addressing any identified issues, clear the DTCs using your scanner and take the vehicle for a test drive to ensure that no codes return.
Solution Methods for P0071 Code
Resolving a P0071 code typically involves one or more of the following actions:
Replace Faulty Ambient Air Temperature Sensor
If diagnostics confirm that the AAT sensor is faulty, replacing it is often necessary. Ensure you disconnect the battery before replacement and follow manufacturer instructions for installation.
Repair Wiring Issues
If wiring or connectors are found to be damaged during inspection, repair or replace these components as needed. Use electrical contact cleaner on corroded terminals and apply electrical grease for protection.
Consult Professional Help for PCM Issues
If you suspect that the PCM is malfunctioning but cannot confirm it through testing, consult a professional mechanic. Replacing or reprogramming a PCM requires specialized knowledge and equipment.
The cost of repairs associated with a P0071 trouble code can vary significantly based on several factors:
- Ambient Air Temperature Sensor Replacement: $50 – $200 depending on vehicle make and model.
- Wiring Repairs: $100 – $300 depending on labor rates and extent of damage.
- PCM Replacement/Repair: $500 – $1500 depending on whether reprogramming is required.
Warnings and Recommendations
- Professional Diagnosis Recommended: If you are unsure about diagnosing or repairing electrical issues, it’s best to seek professional assistance to avoid further damage.
- Regular Maintenance: Regularly inspect your vehicle’s electrical systems and components to prevent potential issues from developing into more significant problems.
Closing Paragraph
Understanding and addressing the P0071 trouble code is essential for maintaining your vehicle’s performance and reliability. By following systematic diagnostic steps and being aware of common symptoms and causes, vehicle owners can effectively troubleshoot this issue. Whether you’re a DIY mechanic or seeking professional help, taking action promptly can save time and money while ensuring your vehicle operates efficiently.
Frequently Asked Questions About P0071
- What does P0071 mean?
P0071 indicates an issue with the Ambient Air Temperature Sensor range or performance. - How serious is a P0071 code?
This issue can affect engine performance and climate control but is generally not immediately serious. - Can I drive my car with a P0071 code?
While it’s possible to drive with this code, it’s advisable to address it promptly to avoid further complications. - How much does it cost to fix a P0071 code?
The cost can range from $50 for sensor replacement to over $1500 if PCM replacement is needed. - What are common symptoms of P0071?
Common symptoms include an illuminated check engine light, malfunctioning air conditioning, and inaccurate temperature readings. - Can I diagnose P0071 myself?
Yes, using an OBD-II scanner can help you diagnose this issue effectively. - What should I do if I can’t find any problems?
If diagnostics do not reveal any issues but codes persist, consult a professional mechanic. - Is replacing an AAT sensor easy?
Replacing an AAT sensor can be straightforward; however, ensure you follow proper procedures to avoid damaging other components.