A weak or failing 12-volt battery that drops voltage during cranking or under load, disrupting network communication.; Corroded, loose, or damaged ground connections at the BCM 'E' mounting point or chassis ground studs.; Faulty or chafed wiring in the CAN bus circuit between the ECM and the BCM 'E', including open circuits or shorts to ground.; A failed BCM 'E' module itself, often due to water intrusion, internal component failure, or a blown internal fuse.; Blown fuse or poor connection in the power feed circuit that supplies the BCM 'E'.; Software incompatibility or a failed module configuration after battery replacement or component swapping.; A network fault elsewhere on the same bus that prevents the BCM 'E' messages from reaching the ECM.

DTC codes / U01xx · Lost communication with a control module / U0145

U0145Lost Communication With Body Control Module 'E'

Q: What does code U0145 mean?

Lost Communication With Body Control Module 'E'. U0145 means the vehicle's main computer, usually the engine control module (ECM), has stopped receiving regular data messages from a specific body control module (BCM) designated 'E' on the communication network. The ECM sets this code when the expected controller area network (CAN) messages from that module are missing for a calibrated period, indicating a communication breakdown rather than a direct fault in the BCM itself.

U0145 means the vehicle's main computer, usually the engine control module (ECM), has stopped receiving regular data messages from a specific body control module (BCM) designated 'E' on the communication network. The ECM sets this code when the expected controller area network (CAN) messages from that module are missing for a calibrated period, indicating a communication breakdown rather than a direct fault in the BCM itself.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaLost communication with a control module

Symptoms you may notice

Illumination of the check engine light or service vehicle soon message on the dashboard.
Often no symptoms besides the warning light, with all accessories and body functions working normally.
Intermittent or complete failure of non-critical body features such as interior lighting, remote keyless entry, or power windows.
A no-start condition if the BCM 'E' is responsible for immobilizer or ignition authorization messages.
Multiple unrelated warning lights or module communication codes stored in other controllers.
Erratic operation of convenience features that share the same network segment as the affected module.

Common causes, most likely first

A weak or failing 12-volt battery that drops voltage during cranking or under load, disrupting network communication.
Corroded, loose, or damaged ground connections at the BCM 'E' mounting point or chassis ground studs.
Faulty or chafed wiring in the CAN bus circuit between the ECM and the BCM 'E', including open circuits or shorts to ground.
A failed BCM 'E' module itself, often due to water intrusion, internal component failure, or a blown internal fuse.
Blown fuse or poor connection in the power feed circuit that supplies the BCM 'E'.
Software incompatibility or a failed module configuration after battery replacement or component swapping.
A network fault elsewhere on the same bus that prevents the BCM 'E' messages from reaching the ECM.

How to diagnose and fix it

Perform a battery load test and check charging system output; low voltage is the most common root cause of communication codes.
Inspect and clean all ground connections for the BCM 'E' and the ECM, including chassis grounds and engine block grounds.
Check the fuse and relay that supply power to the BCM 'E', and verify voltage at the module connector with the key on.
Use a scan tool to read live data and confirm whether the BCM 'E' is communicating at all, then perform a network integrity test if available.
Disconnect the battery and inspect the CAN bus wiring between the ECM and BCM 'E' for continuity, shorts, and corrosion; repair any damaged sections.
If wiring and power are good, substitute a known-good BCM 'E' or reflash the module with the latest software before condemning it.
After repairs, clear codes and perform a road test with a scan tool connected to verify that communication is restored and no codes return.

Why body module communication codes mislead

A failing battery or alternator often sets U0145 before any starting complaint appears, so voltage testing should always precede module replacement.
The BCM 'E' designation refers to a specific module on the network, not necessarily the main body control module, and misidentifying it leads to replacing the wrong part.
Water leaks into the passenger compartment or trunk can corrode BCM connectors and cause intermittent communication loss that only appears in damp weather.
A single failed module on the CAN bus can disrupt messages from other modules, so U0145 may be accompanied by codes for systems that are actually fine.
After replacing a BCM, many vehicles require programming or relearning, and skipping that step will leave U0145 stored even with a good module.

Can I keep driving with U0145?

The vehicle is generally safe to drive if the only symptom is a warning light and all body functions work, but avoid long trips and have it diagnosed promptly. If the engine cranks but does not start, or if safety systems like lights or wipers fail, stop driving and arrange a tow.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.