The OBD2 code P0074 indicates a problem with the Ambient Air Temperature Sensor Circuit being intermittent. This means that the sensor, which measures the temperature of the air outside the vehicle to help adjust engine operations for optimal performance, is sometimes losing its connection or sending erratic signals.
These intermittent issues can be tricky because they come and go, making diagnosis and resolution a bit more challenging than a constant fault.
P0074 quick overview
| Meaning | P0074: Ambient Air Temperature Sensor Circuit Intermittent |
| Is it serious? | Moderately, as it can affect engine performance and fuel efficiency, but the vehicle will generally remain operable. |
| Possible causes | – Loose or damaged wiring harness connector – Corrosion at the sensor connector – Physical damage to the sensor – Intermittent fault in the sensor circuit |
| How to diagnose? | Check the wiring harness for damage or loose connections. Inspect the ambient air temperature sensor for physical damage or corrosion. Test the sensor circuit with a multimeter for intermittent connectivity issues. Compare sensor readings to actual ambient temperatures for accuracy. Clean, secure, or replace the necessary components based on findings. |
P0074 Meaning
If your car’s check engine light flickers on and off and you’re told it’s due to a P0074 code, it means there’s an occasional hiccup in how your car is reading the outside temperature. This sensor’s job is to tell your car’s brain the temperature outside so it can adjust things like how much fuel to use. When there’s a hiccup, your car might not adjust these settings perfectly.
Think of it as your car sometimes wearing a winter coat on a warm day because it thinks it’s colder than it actually is. Fixing it involves making sure all the connections to this sensor are snug and clean, or replacing parts if they’re damaged.
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
How to fix P0074 – learn from mechanics
I looked into P0074 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Chrysler P0074
Vehicle information
2006 Chrysler Pacifica Touring 3.5L
Issue + repair history
- Check engine light on
- Error codes: P0080 (Exhaust Valve Control Solenoid Circuit High), P0074 (Ambient Air Temperature Sensor Circuit Intermittent), P0420 (Catalyst System Efficiency Below Threshold Bank 1), P2000 (NOx Trap Efficiency Below Threshold Bank 1), P00C0 (Undefined), P1080 (Undefined)
- Previous repair: catalytic converter replaced 6 months ago for P0420 code
- Despite multiple attempts, unable to clear codes permanently
- Suspected wiring problem due to undefined codes and unsuccessful attempts to resolve
Other OBD2 Codes + Test Results
- P0080 – Exhaust Valve Control Solenoid Circuit High
- P0074 – Ambient Air Temperature Sensor Circuit Intermittent
- P0420 – Catalyst System Efficiency Below Threshold Bank 1
- P2000 – NOx Trap Efficiency Below Threshold Bank 1
- P00C0 – Undefined
- P1080 – Undefined
Mechanic suggestions
- Check all grounds at PCM and connectors at PCM
- Investigate possible shutdown of voltage supply to sensors, particularly those exposed to heat
- Consider OEM catalytic converter replacement due to short lifespan of aftermarket converters
- Utilize Chrysler’s website for factory code information and diagnostic assistance
- Verify VIN in PCM and use an alternative scanner to confirm code existence and obtain accurate code definitions
- Monitor upstream and downstream O2 sensors for efficiency
- Clean or replace post-catalytic converter O2 sensor
- Inspect spark plugs for proper gap and condition
Final fix
Replacement of EGR valve resolved the issue, despite multiple unrelated error codes.
Case #2: Ford P0074
Vehicle information
2010 Ford Fusion SE 2.5L
Issue + repair history
- Check engine light on
- Error code: P0074 (Ambient Air Temperature Sensor Circuit Intermittent)
- No previous repair history related to this code
- Car runs normally, but check engine light persists despite attempts to clear code
Other OBD2 Codes + Test Results
- P0074 – Ambient Air Temperature Sensor Circuit Intermittent
Mechanic suggestions
- Check wiring harness for damage or loose connections
- Inspect ambient air temperature sensor for physical damage or corrosion
- Verify sensor operation by comparing ambient temperature readings to actual temperatures
- Test sensor circuit using a multimeter to check for intermittent connectivity issues
Final fix
Replaced damaged wiring harness connector for ambient air temperature sensor, resolving intermittent circuit connectivity issue.
Case #3: Toyota P0074
Vehicle information
2015 Toyota Camry LE 2.5L
Issue + repair history
- Check engine light on
- Error code: P0074 (Ambient Air Temperature Sensor Circuit Intermittent)
- No previous repair history related to this code
- Vehicle exhibits normal performance, but check engine light remains illuminated
Other OBD2 Codes + Test Results
- P0074 – Ambient Air Temperature Sensor Circuit Intermittent
Mechanic suggestions
- Check for loose or corroded connections at ambient air temperature sensor
- Inspect sensor and wiring harness for physical damage or signs of wear
- Test sensor circuit using a multimeter to detect intermittent faults
- Compare sensor readings to actual ambient temperature to verify accuracy
Final fix
Cleaned and secured loose connector at ambient air temperature sensor, eliminating intermittent circuit issue and resolving check engine light concern.
How to diagnose P0074
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect wiring harness and connections | Look for any damage, wear, or loose connections that could cause intermittent signals. |
| Check for physical damage or corrosion | Examine the sensor and its connector for any signs of physical damage or corrosion that might interfere with its operation. |
| Test sensor circuit for continuity | Use a multimeter to check the sensor circuit for intermittent faults, ensuring consistent connectivity. |
| Verify sensor accuracy | Compare the sensor’s temperature readings against actual ambient temperatures to check for accuracy. |
| Secure or replace connections as needed | Clean and secure loose connectors, or replace damaged wiring harness connectors to resolve the issue. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko