Code
P0072
LAND ROVER
P — Powertrain
Air temperature sensor environment - low input circuit
Views:
UK: 10
EN: 20
RU: 12
AI status
Completed
Completed
100%
Causes
- Faulty ambient/air temperature sensor (NTC thermistor)
- Broken or open wiring between sensor and ECU
- Short to ground on the signal wire
- Corroded, pushed-out or water-damaged connector/terminals
- Poor ground or reference voltage at the ECU
- Aftermarket replacement sensor or incorrect sensor fitted
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated and P0072 stored
- Ambient/outside temperature gauge or display incorrect or stuck at cold value
- HVAC and climate control may behave incorrectly (e.g., incorrect fan/recirculation logic)
- Possible influence on automatic systems that use ambient temp input (reduced performance unlikely)
- No obvious drivability symptoms in most cases
What to check
- Retrieve freeze-frame and live data with a diagnostic scanner; note ambient temperature value and reported voltage if available
- Visual inspection of sensor and connector for corrosion, water, damage or disconnection
- Wiggle-test harness while observing live data for intermittent changes
- Measure sensor harness back-probe voltage at key points (ECU connector and sensor connector) with ignition ON
- Measure sensor resistance at the sensor with it removed and compare to the expected resistance vs temperature chart (manufacturer or typical NTC curve)
- Check for continuity between signal wire and ground (short) and between sensor connector and ECU pin (open)
Signal parameters
- Signal type: single wire thermistor or 2/3-wire sensor depending on vehicle (consult wiring diagram)
- Typical signal voltage range: ~0.5–4.5 V (varies by design) — low input is usually
- Typical resistance at ~25°C: commonly in the range of ~2–20 kΩ for many NTC sensors (refer to Land Rover specification)
- Expected behavior: voltage should change smoothly with ambient temperature (no abrupt jumps)
Diagnostic algorithm
- Connect a fully capable OBD-II scan tool. Read freeze-frame and current live data for ambient air temperature and sensor voltage. Note values and any related codes.
- Visually inspect the ambient air temperature sensor, mounting area (grille/bumper), wiring harness and connector for damage, corrosion, water entry, or insect/nest intrusion.
- With ignition OFF, unplug the sensor and inspect connector pins for corrosion, bent/pushed-back pins, or debris. Clean and reseat connector; use dielectric grease after repair if appropriate.
- With sensor connected and ignition ON (engine off), back-probe the sensor signal wire and measure voltage. Compare to expected. If voltage is very low (near 0 V), suspect short to ground or failed sensor.
- Remove the sensor and measure resistance at ambient temperature. Compare to Land Rover spec or a typical NTC chart. If resistance is infinite or out of expected range, replace sensor.
- Check continuity between the sensor signal pin and the ECU pin to confirm no open circuits. Check for short to ground between the signal wire and chassis ground.
- If wiring checks good but signal remains low with known-good sensor fitted, test ECU reference/ground and consult wiring diagrams — swap connector pins to isolate, or bench-test module circuits if qualified to do so.
- Repair or replace damaged wiring/connector or replace sensor. Clear codes and perform a road/park test to confirm code does not return and live data is plausible across temperature changes.
- If code persists after sensor and wiring verified/repaired, consult manufacturer service information for ECU testing or replacement procedures.
Likely causes
- Damaged harness at sensor location (rub-through, crushed, or chafed)
- Water ingress or corrosion at sensor connector (especially bumper/behind grill mounted sensors)
- Sensor failed with open/low output
- Connector pins pushed back or bent preventing good contact
- Shorted signal wire to chassis ground
Fault status
Status
Air temperature sensor environment - low input circuit. The sensor signal is below the expected range — possible short to ground, open or failed sensor, or connector/wiring fault.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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