Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / B1A70 — Passenger occupant detection sensor circuit fault

B1A70 — Passenger occupant detection sensor circuit fault

Detailed page for trouble code B1A70.

33,012codes
59brands
10,551generic
22,461specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

B1A70

LAND ROVER B — Body

Passenger occupant detection sensor circuit fault

Brand: LAND ROVER
Type: B — Body
Views: UK: 9 EN: 14 RU: 10
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or disconnected wiring harness to the passenger occupancy sensor or occupant classification module
  • Corroded, bent, or loose connector pins (seat harness, module connector)
  • Failed passenger occupant detection sensor mat (pressure/weight sensor) or sensor elements
  • Faulty occupant classification module / SRS control unit or internal electronics
  • Water/moisture ingress or contamination in seat cushion or connector
  • Previous repair damage, improper routing, or pinched wires (after seat removal)

Symptoms

  • Airbag / SRS warning lamp illuminated on instrument cluster
  • Passenger airbag status displays incorrect or shows 'Deactivated' when seat is occupied
  • Passenger occupant detection not changing state (occupied/unoccupied) or erratic behavior
  • Diagnostic trouble code B1A70 stored in SRS/occupant classification module
  • Possible inability to complete seat occupancy calibration

What to check

  • Scan SRS/occupant classification module for stored codes, freeze frame and occurrence history
  • Verify whether passenger airbag status/information is shown on dash or infotainment (if equipped)
  • Visually inspect seat wiring harness, connectors (under seat), and module connector for damage, corrosion, or loose pins
  • Check for signs of liquid spillage or physical damage to the seat cushion or sensor mat
  • Perform a wiggle test on seat wiring while monitoring live data and watch for changes or code setting
  • Check vehicle service information for module locations, wiring diagrams, connector pinouts and common failure bulletins/TSBs

Signal parameters

  • Reference supply present (typically module provides a reference voltage — commonly 5V or vehicle-specific value) to the sensor circuit
  • Sensor signal should change when weight is applied/removed (measurable voltage or resistance change depending on sensor type)
  • Look for opens (infinite resistance) or shorts to battery/ground on the sensor circuit
  • No excessive ECM/SRS module internal fault counts or communication errors; CAN bus messages for SRS should be present

Diagnostic algorithm

  1. Read and record all SRS/occupant classification codes, freeze frame data and lamp state. Clear codes and see if B1A70 returns immediately or after a specific action. 2. Confirm passenger airbag status using vehicle info screens or a scan tool while testing occupancy (seat empty vs known weight). 3. Perform a visual inspection of the seat area: underside of passenger seat, connector(s) and harness routing for damage, corrosion or water ingress. 4. Backprobe the sensor connector(s) with the harness connected: verify reference voltage, signal (while applying/removing load to the seat) and ground integrity. Compare to manufacturer specs if available. 5. Measure continuity/resistance of the sensor mat wiring (with harness disconnected) to check for open/short. If resistance values are manufacturer-specified, compare; otherwise look for obvious open/infinite resistance. 6. Wiggle harnesses and connectors during live-data monitoring to reproduce the fault. Inspect connector pins for corrosion, bent pins or terminal issues; repair or replace as needed. 7. If harness and connectors are good, bench-test or replace the passenger occupant sensor mat per service procedure. Some mats require specific resistance ranges or self-tests. 8. If sensor mat replacement does not clear the fault, inspect/replace the occupant classification module or repair module power/ground/communication lines. Reprogram or calibrate module after replacement as required by manufacturer. 9. After repairs, perform occupant classification system calibration/initialization per service manual and verify correct operation across weight ranges. Clear codes and confirm no reoccurrence.
  2. similar_codes([

Likely causes

  • Open or shorted sensor wiring between passenger seat and occupant classification module
  • Intermittent connector contact at the seat harness or module connector
  • Failed sensor mat inside the seat cushion (common after seat wear or liquid spill)
  • Fault in occupant classification/airbag control module or its power/ground/reference supply

Fault status

⚠️ Status
Passenger occupant detection sensor circuit fault. Airbag/occupant classification fault stored; passenger airbag function may be affected. Inspection and repair required.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

B1A71 B1A72 B1A73 B1A74 B1603 U0151
HTML Workshop Manuals AI manual library for LAND ROVER Click to show available manuals 1

LAND ROVER 2015 Discovery Sport HSE

HTML Manual
Discovery Sport HSE Years: 2015 Manual in English Sections: 61,541 AI chunks: 61,541
Short description
LAND ROVER · Discovery Sport HSE · 2015
Open manual
Workshop Manuals

Repair manuals for LAND ROVER

3

Land Rover Defender 300Tdi — Workshop Manual (1996 model year)

Workshop Manual
Defender 300Tdi Years: 1996 Manual in English 7.5 MB
Short description

Official workshop manual for the Land Rover Defender 300Tdi (from 1996 model year). Contains specifications, adjustment, fault diagnosis and step-by-step repair and overhaul procedures for engine, transmission, axles, suspension, brakes, electrical and body. Intended for dealer workshops and trained technicians.

199,00 UAH
Contents
Key sections:
  • 01 INTRODUCTION
  • 04 GENERAL SPECIFICATION DATA
  • 05 ENGINE TUNING DATA
  • 07 GENERAL FITTING REMINDERS
  • 09 LUBRICANTS, FLUIDS AND CAPACITIES
  • 10 MAINTENANCE
  • 12 ENGINE Tdi
  • - Description and operation
  • - Fault diagnosis
  • - Adjustment
  • - Repair and overhaul procedures
  • 19 FUEL SYSTEM Tdi
Buy

Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)

Workshop Manual
Defender Years: 1999–2002 Manual in English 7.6 MB
Short description

Workshop Manual Supplement and Body Repair Manual for the Land Rover Defender. Includes general specifications, maintenance schedules, tuning data and step‑by‑step repair procedures for engine, transmission, suspension, brakes, electrical and body repairs. Covers Defender models from 1999 and 2002 model years.

199,00 UAH
Contents
Key sections:
  • 01 - INTRODUCTION
  • - Introduction
  • - Dimensions
  • - References
  • - Repairs and replacements
  • - Poisonous substances
  • - Fuel handling precautions
  • - Synthetic rubber
  • - Recommended sealants
  • - Used engine oil precautions
  • - Accessories and conversions
  • - Wheels and tyres
Buy

Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)

Workshop Manual
Manual in English Pages: 494 7.1 MB
Short description

Land Rover Range Rover Electrical Library (LRL 0453ENG). Comprehensive manual covering fuse details, earth points, system descriptions, diagnostics and connector pin-outs for electrical troubleshooting and repair. Intended for technicians and service workshops.

199,00 UAH
Contents
Key sections:
  • 1 INTRODUCTION
  • 1.1 About this document
  • 1.2 Battery voltage
  • 1.3 Electrical precautions
  • 1.4 Battery disconnecting / charging
  • 1.5 Disciplines / greases
  • 1.6 Abbreviations
  • 1.7 HeVAC, sensors abbreviations
  • 1.8 How to use this document
  • 1.9 Connector detail format
  • 1.10 Fault diagnosis
  • 1.11 Wire colour codes
Buy
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .