Code
B0068
HUMMER
B — Body
Occupant Classification Sensor (OCS) Circuit Malfunction
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring in the OCS harness (under/around passenger seat)
- Corroded, loose or contaminated connector at the OCS sensor or SRS control module
- Faulty occupant classification sensor (seat mat/sensor pad) or sensor module
- Poor or lost power or ground to the OCS circuit
- Water intrusion or debris in seat or connector
- Intermittent connector contact from seat movement or seat track rubbing harness
Symptoms
- SRS/Airbag warning lamp illuminated on dash
- Passenger airbag status indicator shows incorrect or 'OFF' when occupied
- Diagnostic scan tool shows B0068 stored (may be accompanied by related OCS codes)
- Passenger presence may be misreported or ignored (false OFF/ON)
- Possible disablement of passenger airbag deployment
What to check
- Connect a professional scan tool and read SRS/airbag module codes and freeze-frame data
- Record the passenger airbag status and any related SRS codes
- Visually inspect passenger seat, underside, and seat tracks for damaged wiring or pinched harness
- Inspect the OCS connector(s) for corrosion, bent pins, contamination or water intrusion
- Verify proper battery voltage to the vehicle and SDM (check before and during tests)
- Perform wiggle test on seat wiring and connectors while watching live data/scan tool for changes
Signal parameters
- OCS supply voltage (key ON): typically ~5 V reference (refer to service data for exact value)
- OCS ground continuity: near 0 Ω to chassis ground
- Sensor output: varies with applied load/seat occupation — expected to change smoothly with occupant weight
- Circuit resistance: seat mat sensor pad resistance varies by design — compare to service manual specifications
- Communication/update rate: OCS data typically updates several times per second to SDM; look for intermittent or missing data on scan tool
Diagnostic algorithm
- Retrieve and record all SRS codes and freeze-frame data with a capable scan tool. Note any other SRS or communication codes.
- Follow OEM SRS safety procedure: disable battery and wait the specified time before touching airbag/seat wiring or connectors.
- Perform a visual inspection of the passenger seat underside, seat track, and connector areas for chafing, pinching, water, or obvious damage. Repair any obvious issues.
- Reconnect battery per procedure and confirm SRS lamp behavior. Re-scan for codes. If B0068 persists, proceed.
- With scan tool showing live OCS data, wiggle the seat wiring and connectors while observing for changes or intermittent faults. Repair any intermittent connections.
- Measure OCS circuit supply voltage and ground at the sensor connector with key ON. Compare to manufacturer specs. Repair open/shorts if out of range.
- Measure continuity/resistance of the OCS sensor circuit (per service manual). If sensor resistance/characteristics are out of spec, replace the seat sensor pad/module.
- If wiring and sensor check good, inspect/verify SDM power, ground, and communications. Check for other modules reporting U-codes that could affect OCS.
- If wiring and module power/grounds are correct and the sensor is known good, consider SDM/software fault — consult service info for reprogramming or module replacement.
- After repairs, clear codes, perform system self-tests and confirm proper passenger airbag status with known occupant loads. Road test and re-scan to ensure fault does not return.
Likely causes
- Corroded/loose connector at passenger seat (most common)
- Broken/chafed harness under seat from seat travel or mounting hardware
- Failed occupant classification sensor pad or sensor element
- Open/shorted power or ground for the OCS circuit
- Fault in SDM or module communication after wiring/sensor checks
Fault status
Status
Occupant Classification Sensor (OCS) Circuit Malfunction. SRS control module has detected an open/short/intermittent or out-of-range signal in the passenger OCS circuit. Passenger airbag enable/disable may be incorrect and the SRS warning lamp will be illuminated.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Repair manuals
Manual library for HUMMER
138
Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
HUMMER
-
HUMMER: 2009
-
HUMMER: 2008
-
HUMMER: 2007
-
HUMMER: 2005
-
HUMMER: 2004
-
HUMMER: 2000
-
HUMMER: 1999
-
HUMMER: 1994
-
HUMMER: 1993
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email