If your OBD-II scanner displays P0070, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a malfunction in the ambient air temperature sensor circuit.
The generic OBD-II definition for P0070 is:
Ambient Air Temperature Sensor Circuit
Depending on the vehicle manufacturer or scan tool, the description may appear as:
- Ambient Air Temperature Sensor Circuit
- Ambient Air Temperature Sensor Circuit “A”
- Outside Air Temperature Sensor Circuit
- Ambient Temperature Sensor Electrical Fault
- Ambient Air Temperature Sensor Open or Short to Voltage
The ambient air temperature sensor measures the temperature of the air outside the vehicle. The PCM, Body Control Module (BCM), instrument cluster, or climate-control module may use this information to manage engine calculations, automatic climate control, exterior-temperature displays, cooling-fan strategy, emissions monitoring, and cold-weather features.
P0070 is a general circuit-malfunction code. It may be stored when the control module detects an open circuit, short circuit, implausible voltage, failed sensor, damaged connector, or loss of communication with the module supplying the temperature information.
Manufacturer diagnostic logic varies. Ford documentation describes P0070 as an ambient-air-temperature circuit monitor, while Volkswagen and Audi references associate the code with an open circuit, short to battery voltage, or an implausibly cold sensor reading.
Common causes include:
- Failed ambient air temperature sensor
- Broken or disconnected sensor wiring
- Corroded electrical connector
- Sensor circuit shorted to voltage
- Sensor circuit shorted to ground
- Front-end collision damage
- Missing sensor after bumper repairs
- Incorrect sensor installation
- Damaged mirror-mounted sensor
- Shared reference or ground fault
- Body Control Module communication problem
- PCM or BCM software issue
- Failed control module
P0070 may cause an incorrect outside-temperature display, poor automatic climate-control operation, disabled air conditioning, inaccurate cold-start calculations, or a Check Engine Light. In many vehicles, however, there may be no noticeable drivability symptoms.
For additional diagnostic information, visit:
P0070 Quick Facts
| Item | Information |
|---|---|
| OBD-II Code | P0070 |
| Description | Ambient Air Temperature Sensor Circuit |
| Category | Powertrain |
| System | Fuel and Air Metering |
| Main Component | Ambient Air Temperature Sensor |
| Fault Type | General Electrical Circuit Malfunction |
| Severity | Low to Moderate |
| Safe to Drive? | Usually |
| Typical Repair Cost | $50–500 |
What Does P0070 Mean?
P0070 means the control module has detected an electrical problem in the circuit used to monitor outside-air temperature.
The affected circuit may include:
- Ambient air temperature sensor
- Sensor signal wire
- Sensor ground or return circuit
- Electrical connector
- BCM
- Instrument cluster
- PCM
- Communication network
The sensor itself is usually a temperature-sensitive resistor called a thermistor.
As outside temperature changes, the sensor’s resistance changes. The control module converts that resistance into a temperature value.
If the signal voltage is outside the expected range—or if the module cannot receive a valid temperature signal—it may store P0070.
Unlike P0071, which generally indicates a range or performance problem, P0070 is usually treated as a more general electrical circuit malfunction.
What Is an Ambient Air Temperature Sensor?
The ambient air temperature sensor measures the temperature of the air surrounding the vehicle.
It is commonly used for:
- Outside-temperature display
- Automatic climate control
- Air-conditioning operation
- Cold-start fueling calculations
- Cooling-fan strategy
- Emissions monitoring
- Heated mirror operation
- Heated windshield features
- Engine idle adjustments
- Turbocharger or charge-air calculations
- Stop-start system operation
The exact functions vary by vehicle.
Some vehicles use the sensor mainly for the dashboard temperature display.
Others share the signal with:
- PCM
- BCM
- HVAC control module
- Instrument cluster
- Transmission Control Module
- Driver-assistance systems
This means a seemingly harmless outside-temperature sensor can affect more systems than expected.
How the Ambient Air Temperature Sensor Works
Most ambient air temperature sensors use a negative temperature coefficient thermistor, commonly shortened to NTC thermistor.
With an NTC sensor:
- Resistance is high when temperature is low
- Resistance decreases as temperature increases
A typical circuit includes:
- A reference or pull-up voltage supplied by a control module
- The temperature-sensitive sensor
- A sensor-return or ground circuit
- A signal monitored by the module
As sensor resistance changes, the module sees a corresponding voltage change.
The module then converts that signal into a temperature reading.
For example:
- Very cold air may produce high sensor resistance
- Warm air may produce lower sensor resistance
- An open circuit may look like an extremely cold temperature
- A short to ground may look like an extremely hot temperature
The exact direction depends on circuit design, but implausible extremes are useful diagnostic clues.
Where Is the Ambient Air Temperature Sensor Located?
The ambient air temperature sensor is usually mounted where it can sample outside air while avoiding excessive engine heat.
Common locations include:
- Behind the front grille
- In front of the radiator
- Near the front bumper reinforcement
- Behind the lower bumper opening
- Near the hood-latch support
- Inside a side mirror
- Beneath the front fascia
- Near the air-conditioning condenser
- Inside the fresh-air intake duct
On some commercial vehicles and trucks, the sensor may be located in the driver-side mirror. Manufacturer service information confirms that sensor location can vary by model and may include a mirror-mounted design.
Because the sensor is often mounted at the front of the vehicle, it is vulnerable to:
- Road debris
- Water
- Salt
- Snow
- Front-end impacts
- Bumper removal
- Improper collision repairs
- Aftermarket grille or bumper installation
Why Is the Sensor Mounted Away From the Engine?
The sensor must measure outside-air temperature rather than engine-compartment temperature.
Mounting it too close to the:
- Radiator
- Exhaust system
- Engine
- Turbocharger
- Air-conditioning condenser
could cause heat-soak errors.
Even with correct placement, the displayed temperature may rise temporarily when:
- The vehicle is parked
- The engine is hot
- Traffic is moving slowly
- Radiator heat accumulates
- Sunlight heats the front bumper
Many control modules filter or delay temperature changes to prevent the display from reacting instantly to temporary heat sources.
How the PCM Detects P0070
The control module monitors the ambient temperature circuit for voltage, resistance, plausibility, or communication faults.
P0070 may be stored when:
- The signal voltage is outside the permitted range
- The sensor circuit is open
- The circuit is shorted to battery voltage
- The circuit is shorted to ground
- Sensor data is unavailable
- The reported temperature is physically impossible
- The module loses communication with the device supplying the signal
- The fault remains present for a calibrated period
Ford diagnostic documentation shows that some applications run a physical-range check continuously and may set P0070 when the reported ambient temperature exceeds a calibrated threshold. Other manufacturers use P0070 for an open or short-to-voltage fault.
P0070 vs P0071 vs P0072 vs P0073
| Code | Description |
| P0070 | Ambient Air Temperature Sensor Circuit |
| P0071 | Ambient Air Temperature Sensor Range/Performance |
| P0072 | Ambient Air Temperature Sensor Circuit Low |
| P0073 | Ambient Air Temperature Sensor Circuit High |
Generally:
- P0070 indicates a general circuit or communication malfunction.
- P0071 indicates that the reading is plausible electrically but does not agree with expected operating conditions.
- P0072 indicates low circuit voltage.
- P0073 indicates high circuit voltage.
Exact definitions and fault thresholds vary by manufacturer.
Symptoms of P0070
Possible symptoms include:
- Check Engine Light
- Incorrect outside-temperature display
- Outside temperature stuck at one value
- Display reading extremely cold
- Display reading extremely hot
- Blank exterior-temperature display
- Automatic climate control not working correctly
- Air conditioning disabled or limited
- Heater output behaving incorrectly
- Cooling fans operating unexpectedly
- Heated mirrors not operating as expected
- Remote start climate functions working incorrectly
- Stop-start system disabled
- Additional ambient-temperature codes
- No noticeable drivability symptoms
Some vehicles substitute a default ambient-temperature value when the circuit fails.
The dashboard may display values such as:
-40°F-40°C122°F50°C- Dashes instead of a number
The exact fallback value depends on the vehicle.
A suspiciously Arctic dashboard reading during a July traffic jam is usually less of a weather event and more of an open circuit.
Can P0070 Affect Engine Performance?
On many vehicles, P0070 has little or no noticeable effect on engine performance.
However, ambient-temperature information may be used for:
- Cold-start enrichment
- Engine idle control
- Turbocharger calculations
- Cooling-fan operation
- Emissions self-tests
- Diesel glow-plug operation
- Charge-air temperature plausibility
- Transmission strategy
Possible performance symptoms may include:
- Slightly rough cold start
- Longer warm-up
- Incorrect idle speed
- Increased fuel consumption
- Reduced air-conditioning operation
- Emissions monitor failures
Severe drivability problems are uncommon unless related sensor circuits or shared wiring are also affected.
Common Causes of P0070
1. Failed Ambient Air Temperature Sensor
The sensor may fail internally because of:
- Age
- Moisture intrusion
- Corrosion
- Physical damage
- Thermal cycling
- Internal open circuit
- Internal short circuit
A failed sensor may report:
- Extremely low temperature
- Extremely high temperature
- Fixed temperature
- Intermittent values
- No signal
2. Disconnected Sensor Connector
The sensor may have been disconnected during:
- Bumper replacement
- Grille replacement
- Radiator service
- Condenser repair
- Collision repair
- Fog-light installation
- Aftermarket bumper installation
A disconnected sensor often causes an extremely cold displayed temperature because many modules interpret an open circuit as maximum resistance.
Always inspect recent repair areas before ordering parts.
3. Broken Sensor Wiring
Wiring may break because of:
- Front-end impact
- Road debris
- Harness tension
- Incorrect routing
- Sharp bumper brackets
- Repeated vibration
- Rodent damage
- Previous wiring repairs
A broken wire may remain hidden inside insulation that looks undamaged.
4. Corroded Electrical Connector
The sensor’s location exposes the connector to:
- Rain
- Snow
- Road salt
- Car-wash chemicals
- Dirt
- Condensation
- Temperature changes
Inspect for:
- Green corrosion
- White oxidation
- Loose terminals
- Bent pins
- Damaged seals
- Water inside the connector
- Broken locking tabs
5. Sensor Circuit Shorted to Voltage
The signal circuit may contact a powered wire because of:
- Melted insulation
- Crushed harness
- Incorrect splice
- Collision damage
- Improper accessory installation
A short to voltage may cause:
- Extremely cold reading
- Circuit-high code
- P0070
- Communication or plausibility faults
The result depends on circuit design.
6. Sensor Circuit Shorted to Ground
A signal wire touching ground may cause:
- Extremely hot reading
- Circuit-low code
- P0070
- Blown shared fuse in some designs
Inspect the harness where it contacts:
- Radiator support
- Bumper reinforcement
- Hood-latch bracket
- Metal retaining clips
- Aftermarket lighting brackets
7. Front-End Collision Damage
The ambient sensor is commonly located in the same area that absorbs minor parking-lot impacts.
Damage may include:
- Broken sensor
- Severed connector
- Crushed wiring
- Sensor mounted incorrectly
- Missing sensor bracket
- Sensor positioned near radiator heat
- Harness pinched behind the bumper
Even a vehicle with a perfectly repaired bumper cover may still have a sensor harness quietly folded into the wrong place behind it.
8. Sensor Missing After Repairs
The sensor may be:
- Left disconnected
- Removed with the old bumper
- Installed on the wrong bracket
- Tucked behind another component
- Missing entirely
This is common after collision repairs or aftermarket front-end modifications.
9. Incorrect Sensor Placement
The sensor may operate electrically but report inaccurately if mounted:
- Behind the radiator
- Near a cooling hose
- Against a metal heat shield
- Inside the engine compartment
- Too close to the condenser
- Without its factory air shield
Incorrect placement is more likely to trigger P0071, but extreme heat exposure can contribute to P0070 depending on manufacturer logic.
10. Damaged Mirror-Mounted Sensor
On vehicles with the sensor in a side mirror, possible causes include:
- Mirror impact
- Broken mirror harness
- Incorrect replacement mirror
- Missing sensor
- Water intrusion
- Door-module fault
- Mirror connector problem
Some service information notes that mirror-mounted ambient sensors may communicate through the BCM or a door module rather than wiring directly to the PCM.
11. Shared Sensor Ground Fault
The ambient sensor may share a ground or low-reference circuit with other sensors.
A poor shared ground may cause:
- Multiple temperature-sensor codes
- Erratic scan data
- Incorrect readings
- Intermittent warning lights
- P0070
Inspect all related codes before replacing the ambient sensor.
12. Shared Reference or Pull-Up Circuit Problem
Depending on the system, the sensor may rely on a module-provided pull-up voltage.
A circuit failure may be caused by:
- Internal module problem
- Shorted sensor
- Damaged wiring
- Connector corrosion
- Another component on the same circuit
Consult the correct wiring diagram before applying voltage or ground.
13. Body Control Module Communication Fault
The BCM may read the ambient sensor and send the temperature to the PCM through the Controller Area Network.
P0070 may therefore result from:
- BCM failure
- Door-module failure
- Instrument-cluster communication problem
- CAN wiring fault
- Missing sensor message
- Module configuration problem
The sensor circuit may be working correctly while the PCM is not receiving the data.
14. Incorrect Replacement Sensor
An aftermarket sensor with the wrong resistance curve may produce an inaccurate or implausible reading.
Possible issues include:
- Wrong part number
- Incorrect connector
- Different thermistor calibration
- Poor internal sealing
- Sensor designed for a different market
- Generic sensor with incompatible resistance
A sensor can fit physically while speaking an entirely different electrical language.
15. Faulty Instrument Cluster or HVAC Module
Some vehicles route ambient-temperature information through:
- Instrument cluster
- HVAC module
- BCM
- Door control module
A failure in one of these modules may prevent the correct value from reaching the PCM.
16. PCM or BCM Software Issue
Software or configuration faults may cause:
- Incorrect sensor interpretation
- Lost sensor data
- False circuit codes
- Failure to update ambient temperature
- Problems after module replacement
Check for:
- Technical service bulletins
- Calibration updates
- Module programming requirements
- Configuration errors
17. Failed PCM or BCM
An internal control-module fault is possible but uncommon.
Only suspect a module after confirming:
- Sensor resistance
- Wiring continuity
- Connector condition
- Ground circuit
- Signal circuit
- Network communication
- Correct module programming
Replacing a module before checking a two-wire sensor behind the bumper is a remarkably expensive way to discover corrosion.
Is P0070 Serious?
P0070 is generally considered a low- to moderate-severity code.
The vehicle will usually continue to:
- Start
- Run
- Drive
- Accelerate normally
However, the code can affect:
- Automatic climate control
- Air-conditioning performance
- Cold-weather features
- Engine temperature calculations
- Emissions monitoring
- Exterior-temperature display
- Stop-start operation
P0070 should be diagnosed promptly if:
- The air conditioning is disabled
- The defroster does not work correctly
- Cooling fans behave abnormally
- Multiple sensor codes are present
- The wiring is damaged near the radiator fan
- Collision damage is visible
Can You Drive With P0070?
You can usually drive with P0070.
The code typically does not indicate an immediate engine-damage risk.
However, use caution if:
- Automatic defrost is affected
- Windshield visibility is reduced
- Cooling fans operate incorrectly
- The vehicle has additional engine-temperature codes
- Wiring is loose near moving fans or belts
- A front-end collision damaged other components
In most cases, the greatest immediate threat is the dashboard insisting it is minus 40 degrees outside while everyone is wearing shorts.
How to Diagnose P0070
Step 1: Scan for Additional Codes
Check for related codes involving:
- P0071
- P0072
- P0073
- Intake air temperature
- Engine coolant temperature
- BCM communication
- HVAC module communication
- Instrument cluster
- Five-volt reference
- Sensor ground
- CAN communication
Record freeze-frame data before clearing codes.
Important values include:
- Ambient air temperature
- Intake air temperature
- Engine coolant temperature
- Battery voltage
- Vehicle speed
- Ignition status
- Module communication status
Step 2: Compare the Displayed Temperature With Actual Conditions
Compare the scan-tool ambient temperature with:
- Actual outdoor temperature
- Dashboard display
- Intake-air temperature
- Engine coolant temperature after a cold soak
- A reliable thermometer
After the vehicle has been parked for several hours, ambient air, intake air, and coolant temperature should usually be reasonably similar.
A large difference may indicate:
- Failed sensor
- Incorrect sensor calibration
- Wiring fault
- Heat soak
- Communication problem
Step 3: Inspect the Outside-Temperature Display
Look for:
- Extremely low reading
- Extremely high reading
- Fixed reading
- Dashes
- Blank display
- Temperature that changes suddenly
- Different readings between the cluster and scan tool
An extreme negative reading often suggests:
- Open circuit
- Disconnected sensor
- Broken wire
An extreme high reading often suggests:
- Short to ground
- Internally shorted sensor
Manufacturer logic varies, so verify the specific vehicle’s data.
Step 4: Locate the Sensor
Consult service information to identify the sensor location.
Common locations include:
- Behind the grille
- Near the bumper beam
- In front of the condenser
- Beneath the hood-latch support
- Inside a side mirror
Do not assume every small sensor behind the bumper is the ambient sensor.
Parking sensors, airbag impact sensors, active-grille components, and radar hardware may share the same general area and are far less enthusiastic about experimental testing.
Step 5: Inspect for Recent Repair Damage
Ask whether the vehicle recently received:
- Bumper repair
- Grille replacement
- Radiator replacement
- Condenser replacement
- Headlight repair
- Fog-light installation
- Aftermarket bumper
- Front camera installation
- Mirror replacement
Inspect all areas disturbed during the repair.
Step 6: Inspect the Sensor and Bracket
Check for:
- Broken housing
- Missing sensor
- Loose bracket
- Sensor touching hot components
- Road-debris damage
- Incorrect mounting
- Cracked retaining clip
- Contamination
Reposition or replace damaged parts as required.
Step 7: Inspect the Connector
Disconnect the sensor and inspect for:
- Corrosion
- Water
- Bent terminals
- Loose terminal tension
- Broken locking tab
- Damaged seals
- Dirt
- Broken wires at the connector
Repair connector damage before replacing the sensor.
Step 8: Inspect the Wiring Harness
Follow the harness as far as possible.
Look for:
- Cuts
- Chafing
- Pinching
- Crushed insulation
- Exposed copper
- Poor splices
- Missing retaining clips
- Contact with the radiator fan
- Collision damage
Pay special attention to the transition between the bumper harness and main body harness.
Step 9: Measure Sensor Resistance
Disconnect the sensor and measure resistance across its terminals.
Compare the result with:
- Manufacturer resistance chart
- Known ambient temperature
- A known-good sensor
An NTC sensor should generally show:
- Higher resistance when cold
- Lower resistance when warm
Apply gentle temperature changes and watch for smooth resistance movement.
Do not heat the sensor with an open flame.
The goal is diagnosis, not forging a tiny automotive marshmallow.
Step 10: Check the Sensor With a Temperature Change
Place the sensor in controlled conditions such as:
- Cool air
- Room temperature
- Warm air
Monitor resistance or scan data.
The reading should change:
- Smoothly
- Predictably
- Without sudden dropouts
An intermittent sensor may fail only at a particular temperature.
Step 11: Check Circuit Voltage
With the sensor disconnected and ignition on, measure the circuit according to the wiring diagram.
Depending on design, one wire may carry:
- Pull-up voltage
- Reference voltage
- Module bias voltage
The other may be:
- Ground
- Low reference
- Sensor return
Do not assume the circuit uses a standard five-volt reference.
Step 12: Check the Ground or Return Circuit
Measure voltage drop between the sensor-return circuit and battery negative.
Excessive voltage drop may indicate:
- Corroded splice
- Broken wire
- Loose module ground
- Poor connector terminal
- Shared ground failure
A basic continuity test may pass even when the circuit cannot operate correctly under load.
Step 13: Test for an Open Circuit
Disconnect the relevant control module and sensor according to the manufacturer procedure.
Measure continuity through each wire.
Check for:
- Infinite resistance
- Excessive resistance
- Intermittent connection
- Broken wire near the connector
- Open splice
Move the harness gently while monitoring the meter.
Step 14: Test for a Short to Ground
With both ends disconnected, test each signal circuit for unintended continuity to ground.
A short may be caused by:
- Chafed insulation
- Crushed bumper harness
- Incorrect accessory wiring
- Water intrusion
- Damaged connector
Step 15: Test for a Short to Voltage
Check whether the signal circuit is contacting:
- Battery voltage
- Ignition voltage
- Lighting circuit
- Fog-light wiring
- Front-camera wiring
This is especially important after aftermarket lighting installation or front-end repairs.
Step 16: Use a Sensor Simulator When Approved
Some diagnostic procedures use a resistor or sensor simulator to substitute a known temperature value.
If the scan-tool reading becomes correct with the simulator installed:
- Wiring and module may be functional
- Original sensor is likely faulty
Only use the resistance specified by the manufacturer.
Never jumper the circuit blindly.
Step 17: Compare Data Across Modules
Use a capable scan tool to compare ambient-temperature values reported by:
- PCM
- BCM
- HVAC module
- Instrument cluster
- Door module
Possible findings include:
- All modules show the same wrong value: sensor or shared circuit likely
- BCM shows correct value but PCM does not: communication or programming issue
- Cluster differs from scan data: display or cluster issue
- One module has no data: network problem
Step 18: Check CAN Communication
If the sensor connects to another module rather than directly to the PCM, inspect for:
- Communication codes
- Offline modules
- Incorrect module configuration
- CAN wiring faults
- Door-module problems
- Cluster faults
A sensor can operate correctly while the module responsible for sharing its data remains silent.
Step 19: Check Technical Service Bulletins
Search manufacturer service information using:
- VIN
- Model year
- Engine
- P0070
- Ambient temperature symptoms
- Sensor location
- Recent collision repair
Factory information may identify:
- Revised sensor location
- Updated mirror assembly
- Wiring repair
- Software update
- Known connector issue
- Module reprogramming
Step 20: Replace the Confirmed Failed Component
Possible repairs include:
- Reconnecting the sensor
- Cleaning the connector
- Replacing the sensor
- Repairing an open wire
- Repairing a short circuit
- Replacing the connector
- Repositioning the sensor
- Replacing a mirror-mounted sensor
- Updating control-module software
Avoid replacing the PCM unless every external part of the circuit has been verified.
Step 21: Verify the Repair
After completing repairs:
- Clear all diagnostic trouble codes.
- Switch the ignition off.
- Allow the modules to power down.
- Restart the vehicle.
- Compare ambient temperature with actual conditions.
- Monitor the sensor while driving.
- Test automatic climate-control operation.
- Complete the required drive cycle.
- Confirm P0070 does not return.
Some temperature displays update slowly by design.
The reading may require:
- Vehicle movement
- Several minutes of operation
- A key cycle
- Module reset
- Temperature relearn
Do not condemn a successful repair because the dashboard needs a few minutes to emotionally accept the weather.
Common Repairs and Costs
| Repair | Estimated Cost |
| Reconnect sensor or harness | $0–100 |
| Clean electrical connector | $50–150 |
| Replace ambient temperature sensor | $75–250 |
| Repair wiring | $100–450 |
| Replace sensor connector | $75–275 |
| Replace mounting bracket | $50–200 |
| Replace mirror-mounted sensor | $150–600 |
| Replace complete side mirror assembly | $300–1,500 |
| Diagnose network communication fault | $150–500 |
| Update BCM or PCM software | $100–300 |
| Replace BCM or related module | $500–1,500+ |
| Replace PCM | $1,000–2,500+ |
Costs vary depending on:
- Sensor location
- Vehicle design
- Labor rate
- Collision damage
- Whether the sensor is sold separately
- Whether mirror replacement is required
- Wiring accessibility
A $30 sensor behind the grille may be easy to replace.
A $30 sensor permanently integrated into an expensive heated, folding, camera-equipped mirror may arrive with considerably more financial baggage.
Common Diagnostic Mistakes
Avoid these common P0070 diagnostic mistakes:
- Replacing the sensor without inspecting the connector
- Failing to locate the correct sensor
- Ignoring recent bumper or mirror repairs
- Assuming the sensor always connects directly to the PCM
- Missing a broken wire behind the bumper
- Comparing readings before the vehicle has cold-soaked
- Ignoring heat soak after parking
- Replacing the sensor because the display updates slowly
- Installing an incorrectly calibrated aftermarket sensor
- Overlooking BCM or communication codes
- Applying battery voltage to the sensor circuit
- Jumping the connector without a wiring diagram
- Replacing a control module before testing the two-wire circuit
- Confusing the ambient sensor with the intake-air-temperature sensor
The ambient air temperature sensor measures the air outside the vehicle.
The intake air temperature sensor measures air entering the engine.
They may report similar temperatures after a cold soak, but they are not automatically the same sensor.
Vehicles Commonly Affected
P0070 is a generic OBD-II code and may appear on many vehicle brands.
Applications may include certain:
- Audi models
- Volkswagen models
- Ford vehicles
- Ram trucks
- Dodge vehicles
- Jeep models
- Chrysler vehicles
- Chevrolet vehicles
- GMC trucks and SUVs
- Cadillac models
- Mercedes-Benz vehicles
- BMW models
- Volvo vehicles
- Hyundai models
- Kia vehicles
- Mitsubishi models
- Commercial trucks
Failure patterns vary by model.
Examples include:
- Front bumper-mounted sensors
- Grille-mounted sensors
- Mirror-mounted sensors
- BCM-monitored sensors
- Sensors integrated into a separate temperature assembly
Always identify the exact circuit architecture before ordering parts.
P0070 After Front-End Repairs
P0070 commonly appears after work involving the:
- Front bumper
- Grille
- Radiator
- Air-conditioning condenser
- Fog lights
- Headlights
- Active grille shutters
- Front radar sensor
Common repair-related problems include:
- Sensor left disconnected
- Wiring pinched during bumper installation
- Sensor omitted from replacement bumper
- Harness routed across a sharp bracket
- Sensor mounted behind the radiator
- Incorrect bumper harness installed
When P0070 appears immediately after body repairs, begin diagnosis with the area that was disturbed.
The vehicle is often kind enough to provide a clue. Technicians occasionally repay this generosity by replacing an unrelated engine sensor anyway.
P0070 on Vehicles With Mirror-Mounted Sensors
Some trucks and commercial vehicles mount the ambient temperature sensor in a side mirror.
Possible causes include:
- Mirror collision damage
- Broken door harness
- Incorrect aftermarket mirror
- Sensor omitted from replacement mirror
- Door-module failure
- Mirror connector corrosion
- Incorrect module configuration
Service information should be used to determine whether the sensor:
- Connects directly to the BCM
- Connects through a door module
- Shares wiring with mirror functions
- Can be replaced separately
How to Prevent P0070
Reduce the likelihood of P0070 by:
- Securing the sensor after bumper repairs
- Repairing broken connector locks
- Protecting wiring from road debris
- Replacing damaged weather seals
- Avoiding unsealed electrical splices
- Routing bumper wiring correctly
- Inspecting the sensor after front-end impacts
- Using the correct replacement mirror
- Using OEM-quality temperature sensors
- Keeping connectors away from pressure-washer spray
- Reinstalling all harness clips
- Checking sensor operation after collision repairs
Frequently Asked Questions
What does P0070 mean?
P0070 means the PCM or another control module has detected a malfunction in the ambient air temperature sensor circuit.
What does the ambient air temperature sensor do?
It measures the temperature outside the vehicle for the dashboard display, automatic climate control, engine calculations, and other vehicle systems.
Is P0070 serious?
P0070 is usually a low- to moderate-severity code.
The vehicle will normally remain drivable, but climate-control and temperature-dependent functions may be affected.
Can I drive with P0070?
Usually, yes.
Use caution if defrost operation, cooling fans, or other temperature-dependent systems are affected.
What commonly causes P0070?
Common causes include:
- Failed ambient temperature sensor
- Disconnected connector
- Broken wiring
- Corrosion
- Front-end collision damage
- Sensor circuit short
- BCM communication problem
Where is the ambient air temperature sensor located?
It is commonly located:
- Behind the grille
- Near the front bumper
- In front of the condenser
- Near the hood latch
- Inside a side mirror
Consult service information for the exact vehicle.
Can a bumper repair cause P0070?
Yes.
The sensor may be disconnected, damaged, omitted, incorrectly mounted, or have its wiring pinched during bumper repairs.
Why does the outside-temperature display show minus 40?
An extremely low reading often indicates an open circuit, disconnected sensor, or broken wire.
The exact fallback value varies by vehicle.
Why does the outside-temperature display show an extremely high value?
A very high reading may indicate a short to ground, internally shorted sensor, or signal-circuit fault.
Can P0070 affect the air conditioning?
Yes.
Some automatic climate-control systems may limit or disable air-conditioning operation when outside-temperature data is unavailable or implausible.
Can P0070 affect engine performance?
Usually only slightly, if at all.
Some vehicles use ambient temperature for cold-start, emissions, turbocharger, cooling-fan, or idle calculations.
Is the ambient air temperature sensor the same as the intake air temperature sensor?
Not usually.
The ambient sensor measures outside air, while the intake air temperature sensor measures air entering the engine.
Can corrosion cause P0070?
Yes.
The sensor is exposed to water, salt, dirt, and road debris, making connector corrosion a common cause.
Can a faulty BCM cause P0070?
Yes, particularly when the BCM reads the sensor and sends the temperature value to the PCM over the vehicle network.
However, sensor and wiring faults are more common.
Does the new sensor need programming?
Usually not.
Some vehicles may require:
- Code clearing
- Key cycle
- Drive time
- Module reset
- Temperature relearn
A replacement BCM or other module may require programming.
How much does P0070 cost to repair?
A basic sensor replacement may cost $75–250.
Wiring, mirror, communication, or control-module repairs may cost considerably more.
Final Thoughts
The P0070 code means the control module has detected a malfunction in the ambient air temperature sensor circuit.
The most common causes include:
- Failed ambient temperature sensor
- Disconnected connector
- Broken bumper wiring
- Corroded terminals
- Short to voltage
- Short to ground
- Collision damage
- Module communication problem
Start diagnosis by comparing the scan-tool ambient-temperature reading with actual outdoor conditions.
Then:
- Locate the sensor
- Inspect recent repair areas
- Check the connector
- Follow the wiring
- Measure sensor resistance
- Verify circuit voltage and ground
- Compare temperature data across modules
- Check communication codes
Do not replace the PCM because the dashboard believes the vehicle is parked at the North Pole. Most P0070 problems are caused by a small sensor or damaged wiring in one of the harshest locations on the vehicle.
The sensor may be inexpensive. Accessing the two corroded wires hidden behind an elaborately designed bumper is where the vehicle may begin charging admission.
Related Articles
Previous P-Code Articles
- P0068 Code Explained: MAP/MAF–Throttle Position Correlation
- P0069 Code Explained: MAP–Barometric Pressure Correlation
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