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U0175 — Lost Communication Restraints System Sensor F

Generic OBD-II · all makesNetwork / communication

U0175 means the restraints control module (airbag/SRS module) can no longer communicate with a specific impact sensor designated 'F' on the supplemental restraint system network. When this communication is lost, the system cannot rely on that sensor's crash data and will typically illuminate the airbag warning light and may disable certain restraint functions.

Symptoms

What causes it — most likely first

1. Failed restraint system impact sensor F

The sensor itself can fail internally due to moisture intrusion, physical impact, or circuit degradation, causing it to drop off the network and set the lost-communication code.

2. Wiring or connector fault to sensor F

Open, shorted, pinched, or corroded wires and poor pin connections between the sensor and the harness are common and interrupt both power and data communication.

3. Network bus line problem

Damage, high resistance, or improper termination on the CAN or LIN communication lines shared between the restraints control module and the sensor can prevent reliable data exchange.

4. Power or ground supply issue to sensor F

A blown fuse, corroded ground point, or voltage drop on the sensor's ignition or battery feed circuits can cause the sensor to go offline even though the network wiring is intact.

5. Faulty restraints control module

Although less common than sensor or wiring failures, an internal fault in the restraints control module or its network transceiver can cause it to lose communication with one specific sensor.

How it's diagnosed

  1. Record all stored and pending codes from every module, noting any related lost-communication or restraint sensor codes that point to a broader network issue.
  2. Inspect the connector, terminals, and harness routing to sensor F for corrosion, water intrusion, pin push-out, chafing, or damage from prior collision repair.
  3. Check powers, grounds, and network communication lines at the sensor connector against the vehicle wiring diagram while key-on, looking for correct voltage, ground integrity, and valid bus signals.
  4. If wiring and powers are correct, test or substitute sensor F with a matching known-good unit or compare it to a sister sensor to confirm whether the sensor is the failed component.
  5. Only after the sensor and all wiring are ruled out should the restraints control module software level, calibration, and internal hardware be evaluated as the cause.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make
Related codesU0170 — Lost Communication Restraints System SU0171 — Lost Communication Restraints System SU0172 — Lost Communication Restraints System SU0173 — Lost Communication Restraints System SU0174 — Lost Communication Restraints System SU0176 — Lost Communication Restraints System S

Frequently asked

Is it safe to drive with U0175 stored?

It is not advisable to ignore this code. The airbag or supplemental restraint system may be partially or fully disabled, so the vehicle should be diagnosed and repaired promptly.

Can a U0175 be caused by a dead battery or low voltage?

Severe low voltage during cranking or charging can sometimes set communication codes temporarily, but a persistent U0175 usually indicates a real sensor, wiring, or module problem that remains after voltage is restored.

Should the PCM or engine computer be replaced for U0175?

No. The powertrain control module does not manage restraint impact sensors; the restraints control module does. PCM replacement is usually a misdiagnosis for this code and should not be the first or typical repair.

Will the airbag still deploy if this code is active?

The system may default to a disabled or reduced-capability state, so deployment behavior cannot be guaranteed. The exact strategy depends on the vehicle's restraint calibration and which other sensors remain online.