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U0336 Software Incompatibility With Restraints Control Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The restraints control module reads the crash sensors and triggers airbags and belt tensioners according to a calibration written for one body style and equipment level. U0336 means a connected unit rejects the software or configuration of this module. Ford's 2014 code interpretation lists U0336 without the MIL marker. Jaguar Land Rover shows why the software level matters: replacement RCMs for the Range Rover Evoque came with software older than the factory level, the tester picked its update from the module content instead of the as-built data, and the unit stored B0002-13 until a manual patch fixed the choice (SSM74259). On 2013 Jaguar XJ AWD cars a generic RCM calibration failed FMVSS 208, leading to recall J040. U0151 is lost contact, U0452 invalid data. The airbag lamp stays on.

Likely causes

Replacement airbag module delivered with an older software level and not brought up to the vehicle level
Calibration for another body style, drive or equipment loaded
Used module from another vehicle installed

Symptoms

  • Airbag warning lamp stays on
  • Further restraint codes such as airbag circuit faults stored
  • Code appears right after airbag module replacement

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–1,000
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

restraints control module

Related codes

U0151U0452

References: performanceparts.ford.com, static.nhtsa.gov, static.nhtsa.gov.