Ambient Air Temperature Sensor Circuit Malfunction
The P0070 code indicates a problem in the ambient air temperature sensor circuit. This sensor measures outside air temperature and is used by the engine control module (ECM) for various functions, including automatic climate control and engine performance adjustments. A fault can cause inaccurate temperature readings, leading to improper HVAC operation or minor driveability issues.
1. Most Common Causes
- Faulty ambient air temperature (AAT) sensor
- Open, short-to-ground, or short-to-voltage in the sensor circuit wiring
- Corroded, oxidized, or damaged pins in the sensor connector
- Faulty engine control module (ECM/PCM) processing the signal
- Excessive resistance in circuit connections due to poor crimps or loose terminals
2. Symptoms You Will Notice
- Incorrect outside temperature display on dashboard
- Automatic climate control may not work properly
- Check Engine Light illuminated
- Possible minor impact on fuel economy or engine performance
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Visually inspect the ambient air temperature sensor and its wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance with a multimeter and compare to manufacturer specifications.
Step 4: Check for voltage and ground at the sensor connector with the ignition on.
Step 5: If sensor and wiring are okay, test the circuit at the ECM connector to rule out an ECM issue.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive with a P0070 code. The vehicle will remain operational, but the outside temperature display and automatic climate control may not function correctly.
How much does it cost to fix?▼
The cost to fix a P0070 code typically ranges from $50 to $150, including parts and labor. The sensor itself is inexpensive, and labor is minimal if it's easily accessible.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.