Lost CAN Communication with Occupant Detection Module
The U0154 code indicates that the powertrain control module (PCM/ECM) has lost Controller Area Network (CAN) communication with the Restraints Occupant Sensing Control Module. This module manages seat occupancy sensors (presence and classification) that determine if a seat is occupied and by what type of occupant (adult, child, object), which is critical for airbag deployment decisions. Loss of communication prevents the airbag system from receiving valid occupancy data, potentially disabling certain airbags or causing them to deploy with default safety parameters.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty occupant detection module (OCM or SOCM)
- Open or short circuit in the CAN bus (high or low line)
- Corrosion, damage, or disconnection in wiring harness connectors
- Failed CAN bus termination resistor
- Low voltage or power supply failure to the occupant detection module
- Moisture or liquid damage to the module or occupancy sensors
- Faulty airbag control module (SDM) acting as communication gateway
3. Symptoms You Will Notice
- Airbag warning light illuminated on the dashboard
- Airbag system may be partially or fully disabled
- Seat occupancy detection may not function (e.g., passenger airbag off indicator may not display correctly)
4. Step-by-Step Diagnosis
Scan for all stored codes and check for related CAN bus communication codes
Inspect the CAN bus wiring and connectors for damage, corrosion, or loose connections
Check power and ground supplies to the occupant detection module
Test CAN bus termination resistance at the module connector
Verify communication by monitoring CAN bus signals with an oscilloscope or scan tool
If wiring and power are okay, suspect a faulty occupant detection module or airbag control module
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended because the airbag system may not deploy correctly in a crash, increasing injury risk. Have the vehicle diagnosed and repaired as soon as possible.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on the cause. A simple wiring repair may be on the lower end, while replacing an occupant detection module can cost $300–$600 including labor.