B1852

Code

LAND ROVER B — Body

Climate control temperature differential - short-circuit to ground

Brand: LAND ROVER

Type: B — Body

Views: UK: 13 EN: 25 RU: 15

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Page language: EN

Causes

Damaged or chafed wiring shorted to chassis ground
Corroded, bent or pushed-out connector pins making contact with ground
Failed temperature sensor (thermistor) with internal short
Poor or missing sensor ground or pin pushed through connector
Water ingress or contamination in sensor connector or harness
HVAC control module or wiring harness connector fault

Symptoms

HVAC system shows incorrect temperature readings or fails to regulate cabin temperature
Climate control blower or modes may behave oddly or go to default safe mode
DTC B1852 logged and possibly related HVAC or comfort system warnings
Reduced or no control of automatic temperature functions

What to check

Scan for B1852 and any related HVAC or sensor codes; view freeze-frame and live data for temperature sensors
Visually inspect sensor connector, wiring harness routing, and nearby chassis ground points for damage or corrosion
Backprobe sensor signal and reference pins with ignition ON and HVAC active; check for expected reference voltage
Measure continuity between the sensor signal wire and chassis ground (expect no direct short)
Unplug the sensor and re-scan: if code changes, suspect sensor; if code persists, suspect wiring or module

Signal parameters

Reference voltage typically 5 V (varies by model); signal should vary with temperature between ~0.5–4.5 V on most systems
Short to ground condition will show signal near 0 V or very low voltage
Open circuit or disconnected sensor may show signal floating toward reference voltage or diagnostic default
Thermistor resistance should change with temperature (check service data for exact ohms @ specific temps)

Diagnostic algorithm

Retrieve full DTC list and live data; note when code sets and any freeze-frame data.
Locate the temperature differential sensor(s) and trace the wiring to the HVAC control module using the factory wiring diagram.
Visually inspect connectors and harness for physical damage, corrosion, water, or pin deformation. Repair or clean as needed.
With ignition ON (engine off per safety), backprobe the sensor connector: verify reference voltage, signal voltage, and ground presence. Compare to known-good values or service data.
Measure resistance from the signal wire to chassis ground. A near-zero reading indicates a short to ground in the wiring.
Disconnect the sensor and monitor codes/live data. If the short remains with the sensor unplugged, isolate and repair wiring between connector and module (check splice points and grommets).
If wiring checks normal and signal still shorted, substitute a known-good sensor or temporarily disconnect harness per service manual to determine if the sensor or module is faulty.
Repair or replace damaged wiring, connectors, or the sensor. Replace HVAC control module only after confirming wiring and sensor are good.
Clear codes and perform functional test of HVAC, monitor live data while cycling temperatures, and road/soak test to confirm repair.

Likely causes

Shorted sensor signal wire to chassis ground (most likely)
Faulty temperature differential sensor (thermistor) internal short
Connector corrosion or water intrusion at sensor or module
Intermittent harness damage where wiring passes through body panels

Fault status

⚠️ Status

B1852 — Climate control temperature differential circuit short to ground detected. Sensor signal is being pulled to chassis ground, preventing valid temperature measurement.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 2.0 hours

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