B00A0

Code

Generic B — Body

Occupant Classification System

Brand: Generic

Type: B — Body

Views: UK: 28 EN: 190 RU: 33

AI status

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Page language: EN

Causes

Faulty occupant classification sensor (seat mat, weight sensor, or pressure sensor)
Damaged or corroded connector(s) at the seat harness or module
Open, shorted, or intermittent wiring between seat sensors and restraint control module
Low or missing reference supply (typically 5V) or poor ground at sensor/module
Water ingress, foam damage, or contamination of seat sensor/mat
Failed Restraint Control Module (RCM) or internal sensor electronics

Symptoms

Airbag warning light illuminated (SRS/airbag lamp)
Passenger airbag OFF/ON indicator incorrect or locked out
Seat-occupancy/weight readings incorrect or missing in scan-tool live data
Inability to complete OCS calibration or calibration failure message
Related restraint system warnings or DTCs present
Possible seatbelt reminder or indicator anomalies for passenger seat

What to check

Read all SRS/OCS related DTCs and freeze frame data with a capable scan tool
Check for additional communication codes (CAN/Uxxxx) that might affect OCS
Visually inspect passenger seat, seat cushion, carpet, and connectors for signs of water, physical damage, or contamination
Inspect and gently move harnesses and connectors while watching live data for intermittent changes
Verify power (reference) and ground to the occupant sensor module and sensors
Measure occupant sensor outputs while applying known loads (e.g., technician weight) with a scan tool or multimeter

Signal parameters

OCS sensor supply/reference: typically ~5.0 V (nominal) — verify presence and stability
Sensor ground: continuity to chassis ground, expected low resistance (
OCS sensor output voltage swing: typically within ~0.2–4.8 V depending on sensor/load (manufacturer-specific)
Seat mat/resistance values: varies by design — look for open circuit or short to ground/5V (OL or near 0 Ω indicates fault)
CAN bus differential idle voltages ~2.5 V each side (verify communication with restraint/airbag module)
Diagnostic/status flags: module reports sensor open/short/failure bits — check live-status flags in scan tool

Diagnostic algorithm

Safety: follow manufacturer SRS safety procedures before probing or disconnecting connectors (disable battery/DC supply as required and wait specified time).
Scan tool: read and record DTCs, freeze frame, and live OCS data. Note repeatability and related codes. Clear codes and see if B00A0 returns. If intermittent, exercise seat while monitoring.
Visual inspection: inspect passenger seat upholstery, seat mat area, connectors under seat, and harness routing for damage, contamination, or water ingress. Repair visible damage.
Connector/wiring checks: with battery/ignition off and SRS-safe procedure observed, disconnect connectors and inspect pins for corrosion, bent pins, or debris. Re-seat securely.
Power/ground verification: with key on, measure reference supply to the OCS sensors (~5 V) and verify good ground continuity to chassis. Repair as required.
Sensor signal testing: monitor sensor output with scan tool or multimeter while applying weight to the seat. Compare behavior to expected (sensor reading changes smoothly with load). Look for open/short or frozen value.
Wiggle/strain test: while watching live data, move seat tracks, connectors, and harness to locate intermittent faults.
Resistance/continuity: measure resistance of seat mat sensor elements per service manual; confirm not open/short to ground or supply.
Module communication: verify restraint control module communicates on CAN and receives OCS inputs. Check for software updates or known module faults.
Calibration/self-test: attempt OCS calibration following manufacturer procedure. If calibration fails, record the specific failure step.
Replace/repair: replace or repair the faulty sensor, harness, or connector only after confirming failed component. Replace module only if diagnostics point to internal module failure. Ensure any replacement components are compatible and installed per procedure.
Verification: clear codes, perform OCS calibration, and verify proper function with live data and road test if required. Confirm airbag/passenger indicator behavior.

Likely causes

Open/short in seat mat sensor wiring or connector (most common)
Contaminated/damaged seat mat or sensor element from water/foam ingress
Loss of 5 V reference or ground at occupant sensor module
Intermittent connector due to seat position movement or recent seat removal
Module software/configuration mismatch or failed calibration after seat replacement

Fault status

⚠️ Status

Occupant Classification System fault detected — passenger seat sensor or related circuit reporting an error; passenger airbag enable/disable may be affected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 2.5 hours