B1A64

Code

LAND ROVER B — Body

Front Passenger Occupancy Sensor Circuit - Fault

Brand: LAND ROVER

Type: B — Body

Views: UK: 13 EN: 20 RU: 16

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Page language: EN

Causes

Damaged or chafed wiring harness between front passenger seat sensor and airbag/RCM module
Corroded, loose, or contaminated connector pins at the seat sensor or control module
Faulty passenger occupancy sensor mat/module under the seat cover
Water or moisture ingress into the seat cushion or connector
Aftermarket seat covers, cushions or repairs interfering with the sensor operation
Blown fuse or poor ground in the SRS/occupant detection circuits

Symptoms

SRS/Airbag warning lamp illuminated on dash
Passenger airbag status incorrectly disabled or not available
Occupant classification/airbag status message displayed (e.g., 'Passenger Airbag Off')
Possible inability to register occupant presence (seat appears always empty or always occupied)
Diagnostic trouble codes related to occupant detection stored in module

What to check

Read and record all SRS/airbag and occupant detection DTCs with a capable scan tool (note freeze frame and live data)
Visually inspect the passenger seat area for water ingress, debris, or aftermarket covers
Inspect seat-to-floor wiring harness for chafe points, broken insulation, or pinched sections (inspect under trim and seat rails)
Disconnect and inspect connectors (seat sensor and module) for corrosion, bent pins or contamination
Check fuses, power and ground circuits for the airbag/occupant detection system
Observe live occupancy sensor data using scan tool while sitting in the seat and during wiggle tests

Signal parameters

Reference supply typically a low-voltage reference (commonly 5 V) — verify stable reference at seat sensor connector with respect to vehicle ground
Signal line should change state when weight is applied/removed — expected to move from an ‘empty’ value to an ‘occupied’ value (varies by model, typically within 0–5 V signal range)
Open circuit: infinite/very high resistance between sensor connector and module pins or no signal on scanner
Short to ground: very low resistance (< a few ohms) from signal to ground indicates short
Short to battery: signal stuck near supply voltage (close to reference) indicates short to Vb
Module data: occupancy status codes should toggle between empty/occupied when a person sits and leaves — if unchanged, sensor circuit or sensor mat likely faulty

Diagnostic algorithm

Safety first: follow manufacturer SRS precautions. Disable battery negative terminal and wait required time (consult service manual) before disconnecting airbag/seat wiring.
Connect a diagnostic scan tool with SRS/occupant detection capability. Read and record DTCs, freeze frame, and live occupant sensor parameters.
Clear the code and attempt to replicate fault by sitting in seat and performing realistic seat adjustments; see if code returns and note conditions.
Visually inspect seat upholstery, seams and sensor mat for signs of damage, moisture or foreign objects. Remove seat trim per procedure if necessary.
Inspect connectors at the seat sensor and airbag/RCM module. Unplug, inspect pins and apply contact cleaner if contaminated. Reconnect and retest.
With ignition on (and SRS safety followed), backprobe harness at sensor connector to verify reference voltage and signal behavior while sitting/standing. Compare to expected ranges.
Perform continuity and resistance checks from sensor connector pins to module connector pins to detect opens or shorts. Wiggle harness and connectors to reproduce intermittent faults.
If wiring and connectors are good, test or replace the occupant sensor mat/module. If a known-good spare seat/sensor is available, swap to confirm.
If fault persists after sensor/harness replacement, inspect module power/ground and consider module fault. Consult wiring diagrams and module diagnostics; reflash/update software if applicable.
After repairs, clear codes, perform occupant detection calibration (if required by manufacturer), and verify correct operation with scan tool and functional checks.

Likely causes

Broken/chafed wiring at seat harness (most common with seat movement or previous repairs)
Contaminated/corroded connector at seat occupancy sensor (common with moisture)
Defective sensor mat assembly due to age or physical damage
Intermittent connection caused by poor pin fit or partial break
Incorrectly installed aftermarket seat cover altering sensor readings

Fault status

⚠️ Status

Stored fault: Front Passenger Occupancy Sensor Circuit malfunction. May disable passenger airbag or set SRS warning; investigate wiring, connector, sensor mat, and module.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours

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B1A64 — Front Passenger Occupancy Sensor Circuit - Fault