The OBD2 code P0070 points to an issue with the Ambient Air Temperature Sensor Circuit. This sensor measures the outside air’s temperature and sends the data to the vehicle’s computer system. It plays a crucial role in various engine management functions, such as adjusting the air-fuel mixture and controlling emissions.
Problems with this sensor or its circuit can lead to incorrect readings, affecting the car’s performance and efficiency.
P0070 quick overview
| Meaning | P0070: Ambient Air Temperature Sensor Circuit |
| Is it serious? | It can be, as it may affect engine performance and fuel efficiency. |
| Possible causes | – Disconnected sensor – Damaged sensor or wiring – Incorrect wiring connection |
| How to diagnose? | Check the sensor circuit, including the connection and wiring. Verify sensor functionality and if it has been damaged, especially after a collision. Inspect the wiring for damage or incorrect connections, particularly following body or bumper repairs. Reconnect or replace the sensor if necessary, ensuring correct wiring connections. |
P0070 Meaning
Imagine driving on a chilly morning, but your car thinks it’s a warm day. That’s what can happen if the ambient air temperature sensor isn’t working right. This sensor tells your car’s computer how cold or hot it is outside, which helps the car adjust how it runs to keep performance smooth and fuel usage efficient.
When P0070 appears, it means there’s a hiccup in this process, maybe because the sensor got unplugged during repairs or its wires got damaged. Fixing it helps your car “feel” the right temperature again, ensuring it runs just as it should.
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 P0070 – learn from mechanics
I looked into P0070 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: Mini cooper P0070
Vehicle information
2005 Mini Cooper 1.6L
Issue + repair history
- Check engine light appeared after vehicle was repaired from a major collision
- Only one code found: P0070 (undocumented)
- Code triggered under specific driving conditions
- No information available in AllData or iATN fixes
Other OBD2 Codes + Test Results
- P0070 – Undocumented
Mechanic suggestions
- Check the outside air temperature sensor circuit
- Verify if the sensor has been damaged during the collision
- Consult Mini repair manual for sensor location
Final fix
Discovered the air temperature sensor was unplugged during body repair. Plugged in the sensor to resolve the issue.
Case #2: BMW P0070
Vehicle information
2005 BMW 325Ci 2.5L
Issue + repair history
- Error code P0070 (ambient air temp sensor) detected
- Unable to find information in service manuals
- Replaced broken ambient sensor, but error persisted
- Discovered incorrect wiring connection due to previous bumper damage
Other OBD2 Codes + Test Results
- P0070 – Ambient air temp sensor code
Mechanic suggestions
- Check wiring between temp sensor and DME (Digital Motor Electronics)
- Verify CAN communication faults and reset adaptations in the DME
- Inspect wires to outside temp sensor for damage
- Ensure correct temperature reading displayed by the onboard computer
Final fix
Identified wrong wire connected to the air temp sensor due to bumper damage. Corrected wiring to resolve the issue.
Case #3: BMW P0070
Vehicle information
2005 BMW M3 3.2L
Issue + repair history
- Check engine light on
- Error code P0070 – ambient temp sensor circuit
- Temp sensor located under the front left area of the car
- Missing plastic pieces and potential wire damage observed
- Confusion regarding sensor location between AllData and Mitchell on Demand
- Upon inspection, found 2 broken wires and missing connector in wiring harness
- Installed new connector and repaired wiring
Other OBD2 Codes + Test Results
- P0070 – Ambient temp sensor circuit
Mechanic suggestions
- Check brake duct behind the front bumper airdam for sensor and damaged wires
- If wires are pulled out, splice additional wire and order sensor and connector housing from the dealer
- Check both left and right sides under the splash shields for sensor location
- Be cautious of parking lot curbing to prevent future damage
- Note that Mitchell might refer to the external thermometer, while the actual ambient temperature sensor could be mounted in the air box
Final fix
Repaired wiring harness and installed a new connector, resolving the issue.
How to diagnose P0070
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 |
|---|---|
| Check outside air temperature sensor circuit | Examine the sensor and its circuit for damage, disconnection, or incorrect wiring. |
| Verify sensor condition post-collision | Ensure the sensor wasn’t damaged or disconnected during body repairs. |
| Inspect wiring and connections | Look for damaged wires or incorrect connections, especially after bumper damage. |
| Reconnect or replace sensor as needed | Plug in any disconnected sensors and replace damaged ones to restore proper function. |
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