Network, generic

U0140 Lost Communication With Body Control Module

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0140 is among the most frequent network codes: a listening controller misses the frames of the body control module, which handles lights, locks, wipers and often the power mode that wakes other units. The code sits in the listener, not in the BCM. GM watches it in many nodes; its 2019 ECM tables expect certain BCM frames within 500 ms, others within 10 s, rate the fault Type C without MIL and then assume zero A/C compressor load, whereas the 2025 ECM and brake module count it as Type B with MIL after two trips. Saab lists failure-type bytes 71, 72 and 74 (bad data, counter, checksum). Ford's 2017-18 Escape stored it in the front controls module after incomplete configuration (SSM 47040), FCA's 2021 300 with MIL until a PCM flash. U0141 to U0145 cover further body units.

Likely causes

BCM fuse, power feed or ground missing or corroded
Chafed bus line or loose, wet connector between BCM and the listening modules
Weak battery, jump start or voltage dip leaves a stored history code
BCM or listener software or configuration out of date (Ford SSM 47040, FCA 18-013-22)
BCM internally faulty

Symptoms

  • Lights, central locking, wipers or interior lamps misbehave or fail
  • Radio, climate controls or gauges blank or erratic
  • Same code stored in several modules at once
  • MIL on in some vehicles (GM 2025 Type B, FCA PCM)

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–4 h

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

What to check first

  1. Check BCM fuses and grounds
  2. Check network wiring

Parts involved

body control modulecan bus wiring

Related codes

U0141U0142U0143U0144U0145U0422

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.