Air intakeGeneric OBD-II codeUrgency: Garage soon
Code P0070: ambient temperature sensor: circuit fault
P0070 means: ambient air temperature sensor circuit.[1][2][3] The engine control unit has detected a fault in the ambient air temperature sensor circuit, the one that measures the outside air temperature. According to CarParts, that data is used to display the outside temperature and to adjust the operation of the automatic climate control; according to Autodoc, the control unit also needs it to calculate the air-fuel mixture.[1][2][3]
What code P0070 means
The engine control unit has detected a fault in the ambient air temperature sensor circuit, the one that measures the outside air temperature. According to CarParts, that data is used to display the outside temperature and to adjust the operation of the automatic climate control; according to Autodoc, the control unit also needs it to calculate the air-fuel mixture.[1][2][3]
CarParts explains when it triggers: if the information from the ambient sensor differs greatly from that of the intake air temperature (IAT) and coolant (ECT) temperature sensors, the control unit takes it as an inconsistency and logs P0070. It is the general code of the P0070–P0074 series: according to TaT and CarParts, the neighbouring codes are P0071 (range or performance), P0072 (low signal), P0073 (high signal) and P0074 (intermittent).[2][3]
It should not be confused with the intake air temperature (IAT) sensor, which measures the temperature in the intake duct and which the control unit uses to adjust the mixture and the ignition.[3][4]
It is a generic OBD-II code (it starts with P0), not specific to a make, so its definition is the same on any car; what changes from one engine to another is the most likely cause.[5]
Original definition (SAE J2012): Ambient Air Temperature Sensor Circuit[1][2][3]
Causes of P0070
From most to least likely, according to the sources.
- 1Faulty ambient temperature sensor: this is the first cause cited by Autodoc and CarParts.[1][3]
- 2Problems in the sensor circuit: damaged or corroded wiring, loose or dirty connectors, a short circuit in the sensor wire or an interrupted earth.[1][3]
- 3Sensor overheated by engine heat or dirty or blocked, according to Autodoc.[1]
- 4Faulty control unit (ECM/PCM): this is the least likely cause.[1][3]
Symptoms
- Engine warning light on in the instrument cluster.[1][3]Engine warning light: faults that cause it
- Air conditioning or automatic climate control that does not work properly.[1][3]
- Wrong outside temperature in the instrument cluster or on the roof console.[3]
- Difficulty starting in extreme temperatures, according to Autodoc.[1]Hard to start: faults that cause it
- Uneven idle, according to Autodoc.[1]Vibrations: faults that cause it
- Increased fuel consumption, according to Autodoc.[1]Uses more fuel: faults that cause it
- Reduced engine power, according to Autodoc.[1]Less power: faults that cause it
How to diagnose P0070
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the code with diagnostic equipment, clear it and check whether it comes back.[1]
- 2On the diagnostic equipment, compare the ambient air, intake air and coolant temperatures with the car having been parked for three or four hours: they should be similar, and a large difference of the ambient sensor from the other two is exactly what triggers the code.[3]
- 3Inspect the sensor, its connector and the wiring: damage, dirt, corroded terminals or loose connections.[1]
- 4With a multimeter, measure the voltage at the sensor and check the continuity of the wiring and connectors.[1]
- 5Only when the circuit is fine, replace the sensor. The control unit is the last thing to suspect.[1][3]
Can I keep driving with P0070?
Garage soon
The sources do not agree on the extent of the fault. Autodoc states that you can keep driving in the short term, but that it can increase consumption and that in extreme temperatures there may be starting problems, so it asks for it to be repaired promptly. CarParts, by contrast, only mentions effects on the warning light, the air conditioning and the outside temperature displayed, and does not say whether you can drive. As a precaution, it is best to have it checked soon.[1][3]
Documented faults related to P0070
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
What is the ambient temperature sensor for?
It measures the outside air temperature and sends the data to the control unit. According to CarParts, it is used to display the outside temperature and to adjust the automatic climate control; according to Autodoc and TaT, the control unit also uses it in engine management, such as calculating the air-fuel mixture.[1][2][3]
Can I drive with code P0070?
Yes, in the short term, according to Autodoc, but it is best to repair it soon: it can increase consumption and, in extreme temperatures, make starting difficult. CarParts only cites the warning light, the air conditioning and the wrong outside temperature, and does not say whether you can drive.[1][3]
Is it the same as the intake air temperature sensor?
No. The ambient sensor measures the outside air temperature, and the intake (IAT) sensor measures that of the air in the intake duct. The control unit compares them with each other and with the coolant temperature sensor: if the ambient sensor's data deviates greatly from the other two, it logs P0070.[3][4]
How is P0070 diagnosed?
You start by reading and clearing the code and seeing whether it comes back; then the sensor, connector and wiring are inspected and the voltage is measured with a multimeter. CarParts also recommends comparing the ambient air, intake air and coolant temperatures on the diagnostic equipment with the car having been parked for three or four hours.[1][3]
Does P0070 mean the same on all makes?
Yes. Codes starting with P0 are generic OBD-II codes and have the same definition across all manufacturers.[5]
Will I pass the MOT with code P0070?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[6]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- Código OBD2 P0070: causas, síntomas y cómo corregirloAutodoc Club · Technical documentation · consulted 4 October 2026 · in Spanish
- P0070 — Ambient Air Temperature Sensor CircuitThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- P0070 Code: Ambient Air Temperature Sensor CircuitCarParts.com · Technical documentation · consulted 4 October 2026
- Intake-air temperature sensor - checking & faultsHELLA Tech World · Manufacturer · consulted 4 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 4 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish