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DTC codes / U01xx · Lost communication with a control module / U017E

U017ELost Communication With Seat Belt Pretensioner Module A

U017E is a generic network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has stopped receiving valid messages from the seat belt pretensioner module designated as 'A'. The detecting module, often the airbag control unit or body control module, sets this code when the expected periodic CAN frames from the pretensioner module are missing or corrupted for a calibrated time period.

SystemNetwork
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaLost communication with a control module

Symptoms you may notice

  • Airbag or supplemental restraint system (SRS) warning light illuminated on the instrument cluster
  • Seat belt warning light stays on or flashes even when the belt is buckled
  • Pretensioner may not deploy in a collision, compromising occupant restraint
  • Other unrelated warning lights may appear if the module shares a bus segment with other systems
  • Often no symptoms besides the warning light, with the vehicle driving normally

Common causes, most likely first

  1. Open, shorted, or chafed wiring in the CAN bus circuit between the pretensioner module and the network
  2. Corroded or loose electrical connector at the pretensioner module or at a CAN bus junction point
  3. Failed seat belt pretensioner module due to internal electronics fault or water intrusion
  4. Blown fuse or poor power/ground connection supplying the pretensioner module
  5. CAN bus termination resistor fault or network-wide communication issue affecting multiple modules
  6. Aftermarket accessories or improper prior repairs splicing into the SRS or CAN wiring

How to diagnose and fix it

  1. Connect a scan tool and record all stored codes in every module to confirm U017E is current and identify any companion communication codes
  2. Inspect the pretensioner module connector and surrounding wiring for corrosion, looseness, or damage, and clean or reseat as needed
  3. Check the fuse and relay supplying power to the pretensioner module, and verify ground integrity with a multimeter
  4. Measure CAN bus resistance and voltage at the pretensioner module connector to confirm bus integrity and rule out wiring faults
  5. Perform a wiggle test on the harness while watching live data for the pretensioner module to expose intermittent connections
  6. If wiring and power are confirmed good, substitute a known-good pretensioner module or perform a module communication test to verify the fault
  7. Clear codes and verify repair by cycling the ignition and confirming the module communicates and no codes return

Why the pretensioner module goes silent

  • A seat belt pretensioner module that loses communication often does so because of a poor ground connection at the module mounting point, not because the module itself has failed.
  • U017E can be set by a low battery or voltage spike during engine cranking, and the code may be historical rather than indicating a current fault.
  • Some vehicles route the pretensioner module on a sub-bus or LIN network, so a fault in the gateway module can mimic a pretensioner communication failure.
  • After a collision, the pretensioner module may enter a locked state and stop communicating until it is replaced or reset, which sets U017E without any wiring fault.
  • Technicians sometimes replace the pretensioner module only to find the real fault is a chafed harness behind the seat or under the carpet where it flexes.

Can I keep driving with U017E?

Because the seat belt pretensioner may not deploy in a crash, the vehicle should not be driven until the fault is diagnosed and repaired; if you must move it, drive directly to a repair facility and avoid any situation where a collision is likely.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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