B1B42

Code

LAND ROVER B — Body

front left internal sensor

Brand: LAND ROVER

Type: B — Body

Views: UK: 31 EN: 1,832 RU: 33

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Page language: EN

Causes

Failed front-left internal sensor
Open, short or intermittent wiring/harness to the sensor
Corroded or loose connector pins at the sensor or control module
Loss of sensor reference power or ground
Water ingress or physical damage to the sensor
Faulty control module or software/configuration issue

Symptoms

Instrument cluster warning or message indicating sensor fault
Loss or degradation of the affected system function (dependent on which system uses the sensor)
Stored code(s) and possible related faults in other modules
Intermittent operation or intermittent warning illumination
System may default to safe mode or reduced functionality

What to check

Read freeze-frame and full fault list with a Land Rover-compatible scan tool; note related codes and timed conditions
Identify exact sensor location and obtain wiring diagrams for the front-left sensor circuit
Visually inspect sensor and connector for damage, corrosion, water ingress or debris
Check that connector is fully seated and locking tab engaged
Backprobe connector to measure reference supply (typically 5V or vehicle-specific), signal and ground with ignition on
Perform continuity check and resistance measurement between the sensor connector and the controlling module

Signal parameters

Reference supply: typically a regulated reference (commonly ~5 V) — verify exact value from wiring diagram
Signal output: typically a varying 0–5 V or switched/serial output depending on sensor type — check live data values for plausibility
Ground: near 0 V; high resistance or voltage on ground indicates poor ground
Resistance (passive sensors): refer to service data; an open circuit or short to ground/power indicates failure
Communication sensors: check for expected bus activity (CAN/LIN) if sensor communicates digitally

Diagnostic algorithm

Connect a compatible diagnostic scan tool and capture the B1B42 code along with freeze-frame and any related codes.
Confirm the exact sensor name/location and review the vehicle service manual and wiring diagram for the sensor circuit.
Perform a visual inspection of the front-left sensor, mounting, and harness; note damage, corrosion, or water ingress.
With ignition on, backprobe the sensor connector and measure reference power, signal voltage and ground reference. Compare to factory values.
If voltages are abnormal, trace wiring to the module checking for continuity, shorts to ground/power and connector pin condition. Repair as required.
If wiring and power/ground are good, test sensor resistance or function per manufacturer procedure. Replace sensor if it fails bench or in-circuit tests.
If sensor and wiring test good, inspect the controlling module for stored communication faults and update software/ECU if applicable.
After repair or replacement, clear codes, perform relearns or calibrations required by the service manual, then road test and re-scan to confirm the fault is resolved.

Likely causes

Damaged/chafed wire in the harness near the front-left corner (common moving/chassis contact points)
Connector contamination or corrosion causing poor contact
Sensor internal component failure due to age or impact
Poor ground at local chassis/ground point affecting sensor readings
Aftermarket changes or recent repairs where connector was not seated

Fault status

⚠️ Status

Front-left internal sensor circuit fault — sensor reading out of range, no communication, or electrical fault. Requires wiring, connector and sensor checks.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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Repair manuals

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Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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