U0140 code meaning
Lost Communication With Body Control Module
Network system Generic code U01xx codes Check engine light
What U0140 means
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.
U0140 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0140
- 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)
Common causes of U0140
- Most likelyBCM fuse, power feed or ground missing or corroded
- PossibleChafed bus line or loose, wet connector between BCM and the listening modules
- PossibleWeak battery, jump start or voltage dip leaves a stored history code
- PossibleBCM or listener software or configuration out of date (Ford SSM 47040, FCA 18-013-22)
- Less likelyBCM internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Body control moduleCAN bus wiring
What each part of U0140 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 40 | The exact fault in that area. |
What to do next
- Note U0140 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0140
What does U0140 mean?
U0140 means "Lost Communication With Body Control Module". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U0140?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0140 fail an emissions test?
U0140 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0140 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U0140 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.