Network, generic

U0137 Lost Communication With Trailer Brake Control Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0137 means the trailer brake control module, which energises a towed trailer’s electric brakes in step with the tow vehicle's braking, is missing on the bus. Ford uses the code widely: on 2022 F-150 trucks without that module the ABS unit may store U0137 by mistake, and it can then be ignored (SSM 50418); on F-150, Expedition, Navigator and Ranger of 2021–2024 the IPC, BCM or PSCM log it together with a warning that the trailer brake module has failed, solved by disconnecting the battery and module and reprogramming the trailer module (SSM 53236). Ram 1500–3500 with integrated trailer brake module can show Park Assist System Disabled with U0137 (FCA 9004253). Invalid data from this module is U0438. Check the trailer brakes before towing.

Likely causes

Trailer or ABS module software, fixed by reprogramming (Ford SSM 53236, 50418)
Improperly seated connector, damaged harness or water intrusion at the module (FCA 9004253)
Module retrofitted or configured incorrectly (dealer-installed tow package)
Trailer brake control module internally faulty

Symptoms

  • Trailer brake fault message in the cluster
  • Trailer brakes not applied or gain control inoperative
  • Park assist disabled on some Ram trucks

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–900
Time0.3–3 h

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

Parts involved

trailer brake modulecan bus wiring

Related codes

U0438U0121U0140

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