U0154: Lost Communication with Restraints Occupant Sensing Module

What it means

A control module has stopped receiving expected messages from the restraints occupant sensing module. Occupant classification functions may be limited or unavailable, and the restraint system may display a warning.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

The restraints occupant sensing module reports occupant classification information, which the restraint system uses to determine passenger-airbag status. U0154 sets when another controller stops receiving its expected messages, so passenger classification or airbag status may be unavailable or flagged as faulty.

Common causes

Most likely first.

1. Occupant sensing module power or ground fault
2. Damaged seat wiring or connector
3. Occupant sensing module failure
4. Low system voltage

Symptoms

• Airbag or SRS warning
• Occupant classification or passenger airbag status may be unavailable
• Other communication codes

How to diagnose it

1. Scan all modules and save SRS and communication codes to confirm the missing response is from the occupant sensing module and check whether passenger-airbag status is also flagged.
2. Check the 12-volt battery and charging system for low-voltage faults that could interrupt module communication.
3. With the vehicle off, visually inspect accessible under-seat wiring and connectors for movement, damage, moisture, or corrosion without unplugging or probing restraint circuits.
4. Use the vehicle-specific wiring diagram and safety procedure to verify the occupant sensing module's specified power, ground, and fuses.
5. Test the CAN connection and relevant seat harness circuits using the manufacturer's procedure if the supplies are correct.
6. If wiring checks pass, verify occupant sensing module response and any required calibration using suitable SRS-capable equipment and the specified seat conditions.

Common fixes

• Restore a weak 12-volt battery or repair its charging-system fault.
• Correct a visibly damaged or poorly seated accessible connector using the prescribed restraint-system safety procedure.
• Repair a verified power, ground, CAN, or seat-harness fault.
• Perform the specified occupant-sensing calibration if required after seat or module work.
• Replace the occupant sensing module only after circuit checks and required calibration procedures are confirmed.

Can I keep driving?

Do not assume the passenger airbag will deploy correctly while this fault or an SRS warning is present; occupant classification may be unavailable. Arrange prompt diagnosis and avoid moving or working on under-seat restraint wiring unless following the vehicle's safety procedure.