U0170 Lost communication with restraints system sensor A

Lost communication with passenger presence (occupant sensing) module

U0170 in short

U0170 means a module lost contact with restraints system sensor A. On GM cars dealers read it as the passenger presence (occupant sensing) module in the front passenger seat. Causes include a loose seat connector or a failed module. The airbag light comes on and an airbag may not deploy, so have it checked soon.

U0170's title is lost communication with restraints system sensor A. A 2011 Traverse readout gives that title, and Pontiac G8 and Cadillac ELR dealers read it as lost communication with the passenger presence module. That module senses whether someone is in the front passenger seat so the airbag system knows whether to use the passenger airbag.

Pontiac G8 owners report U0170 together with B0081 (passenger presence system), and dealers replaced the passenger presence module. A Traverse owner traced the same pair to a seat connector whose locking tab had broken during earlier seat work. Cadillac ELR owners report the module is discontinued.

U0170 can also appear among many lost-communication codes when a whole network drops out. GM's 15-NA-004 for the 2013-2016 Acadia and bulletin 4142 for 2007 trucks list it with U0140, U0151 and others. Airbags are safety-critical, so the repair belongs with a professional.

Most likely causes

  1. Failed passenger presence (occupant sensing) module

    Supported by vehicle data
    Why it ranks here
    Pontiac G8 dealers read U0170 with B0081 and replaced the passenger presence module, and a Cadillac ELR dealer traced U0170 to the same module.
    What would change this
    Rises if U0170 comes with B0081 and the seat wiring and connectors are intact. Falls if a connector is loose or damaged.

  2. Loose or damaged connector or wiring under the passenger seat

    Common general cause
    Why it ranks here
    Network codes are usually wiring. A Traverse owner found the locking tab on the connector under the right front seat broken after seat work, letting it slip apart.
    What would change this
    Rises if the seat was recently removed or adjusted, or the code comes and goes with seat movement. Falls if the connectors are locked and the wiring is intact.

  3. Network fault affecting several modules (some GM models)

    Supported by vehicle data
    Why it ranks here
    GM's 15-NA-004 (2013-2016 Acadia) and 4142 (2007 trucks) list U0170 among many lost-communication codes with no-crank and cluster symptoms.
    What would change this
    Rises if many U-codes and other symptoms appear together. Falls if U0170 shows only with B0081.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Have the airbag system and all modules scanned, and note whether U0170 comes with B0081 or with many other U-codes.

    Low riskTool: scan tool that reads airbag codes

  2. Have a shop inspect the connectors and wiring under the front passenger seat, then test the passenger presence module's power, ground and network circuits.

    Best left to a shopTool: scan tool, multimeter, wiring diagram

    Warning:Airbags are safety-critical. Do not unplug or probe airbag or seat sensor connectors yourself; leave this to a professional.

Symptoms

  • Airbag light on or flashing
  • Service Airbag or Air Bag Fault message
  • Passenger seat not detecting an occupant

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

  • passenger presence module:Some Pontiac G8 repairs listed both the module and a seat sensor. Cadillac ELR owners report the module is discontinued. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Pontiac

  • 2008–2009 · G8

    Supported by vehicle data

    Owners report the airbag light with U0170 and B0081; dealers read it as the passenger presence module and replaced it. Owner reports, not verified.

Cadillac

  • 2016 · ELR

    Supported by vehicle data

    A Cadillac dealer traced the airbag light to U0170, lost communication with the passenger presence module; owners report the part is discontinued. Owner report, not verified.

GMC

  • 2013–2016 · Acadia

    Supported by vehicle data

    GM 15-NA-004: U0170 among many U-codes with no crank and erratic cluster. Whether it is still current is not verified.

  • 15-NA-004Status unverified

    Intermittent no crank, radio and HVAC inoperative, erratic cluster

    2013–2016acadia · issued · NHTSA 10126348

    Repair information for a network fault that sets U0170 with U0140, U0151, U0155 and other U-codes.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • U0151Lost communication with the restraints (airbag) control module

    Shares causes Supported by vehicle data

    GM's 15-NA-004 and 4142 list U0170 and U0151 together when a network drops out.

  • U0155Lost communication with the instrument panel cluster

    Shares causes Supported by vehicle data

    GM's 15-NA-004 lists U0170 with U0155, and 16-NA-237 ties U0155 on the ATS and CTS to timing with the passenger presence system.

  • U0140Lost communication with the body control module

    Shares causes Supported by vehicle data

    GM's 15-NA-004 and 4142 list U0170 with U0140 in the same network dropout.

All Module network (CAN bus) communication codes

U0170 questions

Do my airbags work with U0170 set?

Possibly not. GM dealers told Pontiac G8 owners the airbag system will not work while this code is set. Treat the airbag light as a reason to get the car checked soon.

Sources and review

  1. NHTSA complaint 10583422: 2009 Pontiac G8 airbag light, U0170 and B0081 — NHTSA Office of Defects Investigation
  2. NHTSA complaint 11632989: 2016 Cadillac ELR airbag light, U0170 — NHTSA Office of Defects Investigation
  3. 2023 Integra Owner's Manual: Indicators — American Honda Motor Co.
  4. NHTSA complaint 10678862: 2009 Pontiac G8 passenger presence module replaced, U0170 — NHTSA Office of Defects Investigation
  5. ASE L1 study guide: Network U-codes — Open Exam Prep
  6. NHTSA complaint 10788150: 2011 Chevrolet Traverse Service Air Bag, U0170 and B0081 — NHTSA Office of Defects Investigation
  7. GM 15-NA-004: Intermittent no crank, radio and HVAC inoperative, erratic cluster — General Motors / NHTSA ,
  8. GM 4142: No crank, no start, no communication on low-speed GMLAN — General Motors / NHTSA ,
  9. GM 16-NA-237: What sets U0155 (IPC and PPS timing) — General Motors / NHTSA ,
  10. NHTSA complaint 10549703: 2009 Pontiac G8 flashing SRS light, U0170 and B0081 — NHTSA Office of Defects Investigation
  11. NHTSA complaint 11164627: 2008 Pontiac G8 passenger seat not registering, U0170 — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
Editorial review
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