Fault code P0070 – a step-by-step guide to diagnosing and fixing it

Error code P0070 is displayed and the check engine light is on - what does this mean?

The OBD system detects a fault in the ambient temperature sensor circuit, which reports an abnormal voltage or a signal failure. This DTC P0070 affects the engine control unit, which requires the outside temperature for optimum fuel/air mixture calculation. For various manufacturers, this trouble code can also be referred to as "Ambient Air Temperature Sensor Circuit".

What causes can this error code have?

• Defective ambient temperature sensor
• Damaged or corroded cable connections to the sensor
• Short circuit in the sensor wiring
• Interrupted ground connection of the sensor
• Defective engine control unit (ECM/PCM)
• Loose or oxidized plug connections
• Overheating of the sensor due to engine heat
• Contamination or blockage of the sensor

What symptoms occur in parallel with fault code P0070?

• Check engine light: Permanent activation of the check engine light
• Starting problems: Difficult starting at extreme temperatures
• Uneven idling: Engine runs unevenly at idle speed
• Increased fuel consumption: Poor engine efficiency due to incorrect mixture formation
• Air conditioning: Faulty control of the automatic air conditioning system
• Loss of power: Reduced engine power at cold or hot outside temperatures

How can the problem with fault code P0070 be rectified?

• Repairing fault code P0070 requires a systematic approach to identify the exact cause.
• Sensor replacement: Replace the defective ambient temperature sensor with an original part from the vehicle manufacturer, as replica parts often provide inaccurate readings
• Cable repair: Check and repair damaged cables between sensor and control unit, including insulation and ground connections
• Clean connectors: Clean all connectors with contact spray and make sure they are tight and corrosion-free
• Check sensor position: Make sure the sensor is mounted correctly and is not affected by engine heat or dirt
• ECU reset: Clear the EOBD fault code after the repair and perform a test drive to confirm proper function
• Professional diagnosis: Have a full system diagnosis carried out in the event of recurring problems, as the engine control unit may be defective