U0154

Universal

Lost Communication With Restraints Occupant Sensing Control Module

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
High Severity

The restraint system has detected that it cannot communicate with the occupant sensing control module. That module provides occupant-related information used by the vehicle’s restraint system. The cause may be a power, wiring, network, or module issue; this code alone does not prove that the module has failed. An SRS warning may appear, and some occupant-sensing or restraint functions may be affected. Some vehicles may show no obvious symptoms.

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⚠️ Before You Begin (Safety First)

Treat this as a safety-system fault and arrange diagnosis promptly. Restraint or occupant-sensing behavior may be affected, so do not assume the system will respond normally in a crash. Do not probe, disconnect, or bypass SRS wiring or connectors; have that work performed by a qualified technician. The code alone does not mean the vehicle must be stopped immediately, but stop if the vehicle shows other signs that make it unsafe to drive.

Common Symptoms

  • The SRS or airbag warning light may be on because the restraint system has detected a communication fault.
  • The passenger-airbag status indicator or occupant-related restraint behavior may be affected, depending on the vehicle’s design.
  • A related warning message may appear, or other restraint-system functions may be limited.
  • There may be no noticeable symptoms even though the system has stored the communication code.

Common Causes

  • Loss of power or ground to the occupant sensing control module.
  • Damaged, loose, corroded, or otherwise faulty wiring or connections in the module’s power, ground, or communication circuits.
  • A fault elsewhere on the vehicle communication network that prevents messages from reaching or leaving the module.
  • Low or unstable vehicle voltage that interrupts module communication.
  • An internal occupant sensing control module fault; this should be considered only after circuit and network checks.

Diagnostic Steps

  1. Note any SRS warnings and record other stored codes before clearing anything; related codes can help distinguish a local module issue from a broader power or network problem.
  2. Check the vehicle battery condition and visible battery connections using safe, vehicle-appropriate procedures; low or unstable voltage can interrupt module communication.
  3. With the vehicle safely parked and switched off, look for obvious damage to accessible wiring, without pulling on or disconnecting SRS connectors or wiring.
  4. Check the owner’s manual for the meaning of any restraint-system warning and arrange prompt professional diagnosis if the warning remains on.
  5. Do not attempt to bypass the occupant sensing system or probe airbag, squib, or other SRS circuits; leave those checks to a qualified technician.

When to Call a Professional

Scan all accessible modules for related communication and SRS codes, then follow model-specific service information to check the occupant sensing module’s power, ground, connectors, and network communication. Check for low-voltage or battery-related history where relevant. Avoid testing airbag or occupant-sensing circuits by guesswork; use approved procedures and equipment.

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Commonly Asked Questions

Does U0154 prove that the occupant sensing control module is bad?

No. It identifies a loss of communication with that module. A power, ground, wiring, connector, network, or voltage problem can cause the same detected condition.

Can the vehicle have this code without obvious symptoms?

Yes. The code may be stored even when the driver notices no change. The restraint system may still have a limitation that is not obvious during normal driving.

Is it safe to keep driving?

The code alone does not establish that the vehicle is unsafe to move, but it indicates a possible restraint-system limitation. Arrange diagnosis promptly and follow any warning messages and vehicle-specific guidance.

Can I unplug connectors to find the problem?

Do not disconnect or probe SRS or occupant-sensing connectors as a DIY test. Incorrect handling can create additional faults or safety risks; a qualified technician should use the vehicle-specific procedure.

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