B1853

Code

LAND ROVER B — Body

Climate control in the engine air temperature sensor - failure of circuit

Brand: LAND ROVER

Type: B — Body

Views: UK: 13 EN: 24 RU: 18

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Page language: EN

Causes

Open or short in the sensor wiring (broken wire, chafing, pinched harness)
Corroded, loose, or contaminated connector or terminal
Failed air temperature sensor (NTC thermistor or similar)
Poor or missing ground or reference supply to the sensor
Water ingress or physical damage to the sensor
Climate control module or ECU input driver fault (less common)

Symptoms

Incorrect ambient/engine air temperature reading on HVAC display
Automatic climate control not regulating temperature correctly
Blower/AC cycling or running continually in unusual ways
Illumination of HVAC or climate system warning or related dash message
Possible stored related HVAC/engine module fault codes

What to check

Read freeze frame and full DTC list with a diagnostic scanner; record live sensor values
Visually inspect sensor and connector for corrosion, water, or damage
Wiggle harness/connectors while watching live data for intermittent changes
Check for correct reference voltage (usually ~5 V) at the sensor connector
Measure sensor signal voltage and compare to expected range and temperature
Measure sensor resistance vs. ambient temperature (if NTC type)

Signal parameters

Sensor type: usually NTC thermistor (resistance varies with temperature)
Typical reference supply: ~5 V (confirm with OEM data)
Expected signal voltage: roughly 0.5–4.5 V depending on temperature and sensor design
Typical resistance examples (NTC): ~10 kΩ at 25°C is common for many IAT/ambient sensors — consult factory spec
Open-circuit: infinite resistance / signal near supply or 0 V (vehicle-specific)
Short-circuit: near 0 Ω or signal stuck at reference or ground depending on short

Diagnostic algorithm

Verify code and check for other related DTCs. Note live data for the engine air/climate air temperature sensor.
Inspect sensor and connector for visible damage, corrosion, or moisture. Repair or dry and clean as needed.
With ignition ON, back-probe the sensor connector: verify reference voltage (typically ~5 V) and ground presence.
Measure sensor signal voltage while changing sensor temperature (blow on sensor with breath or warm gently with a heat gun, do not exceed safe temperatures). Observe live data change; no change suggests open/failed sensor or wiring fault.
If a thermistor, disconnect sensor and measure resistance across sensor pins; compare to expected resistance for ambient temp (consult service data).
Check continuity and resistance of the harness between sensor and climate control module; repair any opens or shorts. Check for short to battery or ground where applicable.
If wiring and connectors are good but signal is out of range, replace the sensor and re-test.
If fault persists after sensor and wiring replacement, suspect control module input driver fault; verify with OEM module tests or consult dealer-level diagnostics before replacing module.
After any repair, clear codes and perform a functional test and road/operation test to confirm the fault does not return.

Likely causes

Wiring damage at engine harness where it flexes or contacts hot/abrasive parts
Corroded connector at the sensor (water/debris entry)
Failed thermistor-type sensor due to age/high heat exposure
Weak or missing 5 V reference or ground from control module

Fault status

⚠️ Status

Climate control engine air temperature sensor circuit fault detected — signal out of range, open, or short. Sensor reading unreliable for automatic climate control functions.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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B1853 — Climate control in the engine air temperature sensor - failure of circuit