Airbags

U0151 — Lost Communication with Restraints Control Module (Airbag/SRS)

Severity: high Drive with care, to a shop

What U0151 means

U0151 means a control module, or your scan tool, lost communication with the Restraints Control Module (RCM, the airbag module) on the CAN bus. Normally the RCM constantly exchanges data with other modules, sharing system status and receiving crash sensor, seat belt and seat inputs. When that exchange stops, the airbag system may be disabled and the SRS warning light comes on.

Symptoms

  • Airbag/SRS warning light on
  • Seat belt or pretensioner warnings
  • Scan tool cannot communicate with the RCM
  • Warning message or chime on the dash
  • Horn or steering wheel controls not working (clock spring damage)
  • Several warning lights on at once

Possible causes

  1. Open or shorted CAN bus wiring between the RCM and other modules
  2. Loose, corroded or damaged connectors at the RCM
  3. Failed Restraints Control Module
  4. No power or ground supply to the RCM
  5. Damaged impact sensor wiring or a faulty clock spring
  6. Aftermarket seat swap without a resistor/emulator
  7. Another faulty module loading down the bus

How to diagnose

  1. Scan all modules and map which ones respond and which are missing
  2. Check the fuses and relays that feed the RCM
  3. Inspect the RCM connector for corrosion, bent pins or moisture
  4. Look over the harness under the seats and along the center console for chafing or past repairs
  5. Measure power and ground at the RCM
  6. Check CAN bus resistance at the diagnostic connector; CAN-H to CAN-L should read about 60 ohms
  7. If seats or the steering column were serviced, verify their sensor and clock spring connections
  8. Disconnect suspect modules one at a time only per a documented factory procedure, with the battery disconnected and the capacitor discharge time observed

Common fixes

  • Repair or replace damaged CAN wiring and connectors
  • Clean and secure the RCM connectors
  • Restore power and ground to the RCM
  • Replace the clock spring or faulty sensors
  • Replace or reprogram the RCM if everything else checks out

U0151 on different brands

Ford · manuals
On Ford, U0151 may be logged by other modules, such as the power steering control module on the Explorer, when they get no response from the restraints module; the exact meaning depends on model and year.

Questions and answers

Can I drive with U0151?

The car will drive, but the airbags and pretensioners may not work in a crash. Get it diagnosed as soon as you can.

Why is the airbag light on with U0151?

The RCM isn't responding on the CAN bus, so the system can't confirm it's working. The light warns that the airbags may be disabled.

Can I just clear the code?

Clearing it only helps briefly. If the cause is wiring, a connector or the module, the code will return and the system stays in doubt.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.