P0071
Fix when convenientYour vehicle's computer detects an issue with the ambient air temperature sensor's signal, indicating it's out of expected range or performing incorrectly.
Code P0071 means your ambient air temperature sensor has a performance issue. Common causes: Faulty AAT sensor (85%), wiring problems (10%). Drivability: Yes, safe to drive. Repair cost: $30-$100 DIY, $80-$200 professional.
Can I Drive With P0071?
Yes, safe to drive
No restrictions
Stop driving immediately if: No need to stop driving for this code.
Symptoms of P0071
- 1Incorrect outside temperature displayed on dashboard
- 2Air conditioning system not working correctly (e.g., blowing hot air when it should be cold, or vice versa)
- 3Automatic climate control system not maintaining desired cabin temperature
- 4Minor changes in engine performance or fuel economy (less common, but possible as the PCM uses this data for fuel trims)
Common Causes of P0071
Parts most likely causing this code, ranked by probability
The sensor itself has failed internally, sending an inaccurate or no signal to the engine computer.
85% of P0071 cases are fixed by replacing this part
Corrosion, a loose connection, or damaged wiring to the AAT sensor prevents the correct signal from reaching the computer.
10% of P0071 cases are fixed by repairing wiring or connectors
The vehicle's main computer has an internal fault, misinterpreting the AAT sensor's signal or failing to process it correctly.
5% of P0071 cases are fixed by replacing the PCM
Check These First (Before Buying Parts)
- Locate the ambient air temperature sensor (often in the front bumper, grille, or side mirror) and visually inspect it for any obvious damage, dirt, or corrosion.
- Check the electrical connector to the sensor to ensure it's securely plugged in and free of corrosion.
How to Diagnose P0071
- 1Visually inspect the ambient air temperature sensor for physical damage or corrosion.
- 2Check the electrical connector to the AAT sensor for looseness, corrosion, or bent pins.
- 3Inspect the wiring harness leading to the AAT sensor for any signs of fraying, cuts, or damage.
- 4Use a multimeter to test the resistance of the AAT sensor (refer to your vehicle's service manual for specifications).
- 5Use a scan tool to monitor the AAT sensor's live data reading; compare it to the actual ambient temperature.
P0071 on Popular Vehicles
Ford F-150
2004-2024The AAT sensor is often located in the front bumper or behind the grille, making it susceptible to road debris and moisture. Check the connector for corrosion.
90% fixed by replacing the AAT sensor or repairing wiring
Honda Accord
2003-2024On some Accord models, the AAT sensor is integrated into the side mirror assembly or located in the front bumper. Verify the exact location for your year.
85% fixed by replacing the AAT sensor
Toyota Camry
2007-2024The AAT sensor is typically found in the front bumper area, often near the lower grille. Check for physical damage from minor impacts or road debris.
90% fixed by replacing the AAT sensor or repairing wiring
Frequently Asked Questions
What does P0071 mean?
P0071 indicates that your vehicle's computer has detected a problem with the ambient air temperature sensor's signal, meaning it's either out of the expected range or not performing as it should.
Can I drive with P0071?
Yes, you can drive safely with a P0071 code. This code primarily affects your climate control system and the accuracy of the outside temperature display. It does not typically cause immediate drivability issues or engine damage.
Will P0071 clear itself?
No, P0071 will not clear itself. The code will remain stored in the computer until the underlying issue with the ambient air temperature sensor or its circuit is repaired. You will need to clear the code with a scan tool after the repair.
How do I fix P0071 myself?
Start by visually inspecting the ambient air temperature sensor and its wiring for damage. If the sensor looks fine, test its resistance with a multimeter. Most often, replacing the ambient air temperature sensor itself will resolve the P0071 code.
How much does it cost to fix P0071?
Fixing P0071 yourself typically costs $30-$100 for a new ambient air temperature sensor. If you take it to a professional shop, expect to pay $80-$200, which includes parts and labor.
P0071 keeps coming back - why?
If P0071 keeps returning, it indicates the initial repair did not address the root cause. This often means there's a persistent wiring issue, a faulty connector, or less commonly, a problem with the Powertrain Control Module (PCM) itself.
Will P0071 fail emissions/smog test?
Yes, a P0071 code will cause your vehicle to fail an emissions or smog test. Any active Check Engine Light (CEL) or stored diagnostic trouble code (DTC) prevents a passing result in most states.
What's the difference between P0071 and P0070?
P0070 indicates a general circuit malfunction for the ambient air temperature sensor, meaning the computer sees an open or short in the circuit. P0071 specifically points to a range or performance issue, meaning the sensor is sending a signal, but it's outside the expected values or inconsistent.
P0071 on Ford F-150?
On many Ford F-150 models, the ambient air temperature sensor is located in front of the radiator or behind the grille. Due to its exposed location, it's common for the sensor or its wiring to suffer damage from road debris or corrosion, leading to a P0071 code.
Questions to Ask Your Mechanic
Did you check the ambient air temperature sensor's live data with a scan tool?
Good answer: Yes, the sensor was reading -40 degrees Fahrenheit, which is clearly incorrect, indicating a faulty sensor or open circuit.
What did you find when you inspected the wiring and connector to the AAT sensor?
Good answer: I found some corrosion on the pins of the connector, which I cleaned, but the sensor still read incorrectly, so I replaced the sensor.
Repair Cost Estimate
DIY Repair
Parts only
$30-$100
Shop Repair
Parts + labor
$80-$200
Save $50-$100 by doing it yourself
Difficulty
beginner
Time
0.5-1 hour
Beginner-friendly – Replacing the ambient air temperature sensor usually involves unplugging a connector and unbolting a single sensor, making it a simple DIY task.
Cost of Waiting
Ignoring P0071 will not cause engine damage. However, your climate control system may not function correctly, leading to discomfort. In some cases, the engine computer uses ambient temperature for minor fuel trim adjustments, so you might see a slight, negligible impact on fuel economy.
While You're In There...
Cleaning the electrical connector pins can resolve intermittent issues and ensure a solid connection for the new sensor.
Tools You'll Need
- Basic hand tools (screwdriver or small wrench, depending on sensor mounting)
- Multimeter (optional, for testing sensor resistance)
- Scan tool (to confirm repair and clear code)
P0071 is a straightforward code that does not indicate a serious engine problem. The repair is typically inexpensive and easy to perform, restoring your climate control and temperature display.
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Your Next Steps
Step 1: Visually inspect the ambient air temperature sensor and its wiring for any physical damage or corrosion. Clean the connector with electrical contact cleaner.
Step 2: If the visual inspection doesn't reveal an obvious issue, use a scan tool to monitor the live data from the AAT sensor. If it reads an implausible temperature (like -40°F or 250°F), the sensor is faulty.
Step 3: Parts you'll likely need: A new ambient air temperature sensor.