Powertrain, generic (extended)

P27B1 Internal Control Module Transmission Range Select Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P27B1 belongs to a family of codes raised by an independent supervision layer in the transmission or powertrain module. That layer repeats key transmission decisions in parallel and flags the main software when both results disagree, as a guard against unintended vehicle motion. Ford's 2024 OBD summary places P27B1 only in its table for the TR9070 dual-clutch transmission, filed as UDS P0701_96 for a safety-goal violation tied to the clutch shafts; the 2020–2023 issue does not list it. No other manufacturer documents the code publicly. P27B2 to P27B6 cover range control, gear selection, direction, ratio and speed sensing. Because the trigger is usually software or an implausible input rather than a broken part, updates and the related sensor codes are checked first.

Likely causes

Supervision or main software calibration in the module
Implausible clutch shaft speed or position input
Internal fault in the transmission control module

Symptoms

  • Transmission warning or wrench light
  • Restricted gear selection or default gear

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€0–1,500
Time0.3–4 h

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

Parts involved

tcmexternal range sensor

Related codes

P27B2P27B3P27B4P27B5P27B6P0701

References: fordservicecontent.com, law.cornell.edu.