P0070

Code

MITSUBISHI P — Powertrain

Ambient air temperature sensor

Brand: MITSUBISHI

Type: P — Powertrain

Views: UK: 14 EN: 23 RU: 19

AI status

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Page language: EN

Causes

Faulty ambient air temperature (AAT) sensor (thermistor)
Open, shorted or corroded wiring or connector between sensor and ECU/BCM
Poor connector contact or water intrusion at sensor
ECU/BCM internal fault or incorrect reference/pull‑up circuit
Aftermarket parts or recent repairs that disturbed the harness

Symptoms

Malfunction Indicator Lamp (MIL) or check engine light ON
Incorrect ambient temperature shown on dash or climate control display
Climate control behavior may be incorrect or in default mode
Possible minor drivability effects under certain control strategies (cold/hot start compensation)
Code may be stored with no noticeable driveability symptoms

What to check

Retrieve freeze frame and freeze data; note ambient temp PID and related sensors
Visually inspect sensor location (front bumper/air intake area) and wiring for damage or contamination
Backprobing: view ambient temp sensor PID on a scan tool while changing sensor temperature (warm with hand/air, cool with cold air) and confirm the value moves smoothly
Measure sensor connector voltage and/or resistance with reference to service manual
Wiggle test wiring while monitoring PID or voltage to find intermittent faults
Check for other stored codes that could affect temperature inputs or communication

Signal parameters

Sensor type: usually a 2‑wire NTC thermistor (resistance decreases as temperature rises)
Typical signaling: voltage at ECU input changes with ambient temperature (0–5 V domain depending on vehicle); mid-range ambient often near midscale
Expected behavior: smooth, monotonic change in resistance/voltage when sensor is warmed/cooled; no sudden jumps
Refer to vehicle service manual for exact resistance vs. temperature table and expected voltages

Diagnostic algorithm

Confirm code P0070 and any related codes using a scanner; record freeze frame data.
Visually inspect sensor, harness, and connector for damage, corrosion, water ingress or pin deformation; repair as needed.
With ignition ON (engine off), backprobe the sensor connector and monitor the ambient temp PID or sensor voltage while changing sensor temperature. Verify the signal changes smoothly.
Remove sensor and measure its resistance at known ambient temperature; compare to manufacturer specification (or verify resistance changes when warmed/cooled).
Check continuity between sensor connector and ECU connector; check for shorts to battery positive, ground, or other circuits.
If wiring and connector are good but sensor out of spec, replace the ambient air temperature sensor and clear codes.
After repair, erase codes and perform a test drive or allow the system to reach operating conditions to confirm the code does not return.
If problem persists with known-good sensor and wiring, consider ECU/BCM diagnostics or module replacement per manufacturer procedures.

Likely causes

Corroded terminal or loose connector at the ambient temp sensor
Broken or chafed wire causing intermittent open or short to ground/power
Failed ambient temperature sensor (thermistor out of spec)
Connector contaminated with moisture causing wrong voltage/resistance
Less likely: control module fault

Fault status

⚠️ Status

Ambient air temperature sensor circuit malfunction — control module detects implausible or out‑of‑range ambient temperature signal (open/short/intermittent).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P0070 — Ambient air temperature sensor