AI DamageU3018 code: Control Module Input Power Circuit A/B Correlation
Code U3018 is named in 3 US owner complaints. Models: 3, model years 2021–2024.
What the code means
Control Module Input Power Circuit A/B Correlation. Generic meaning per SAE J2012 (the same for all makes).
How to read U3018: the letter U means network communication between modules; the second digit 3 marks a generic SAE code shared by all makes; the last three characters 018 identify the specific fault.
Lost communication codes (U0xxx) mean one module cannot hear another on the data bus. The cause can be the module itself, its power or ground, or a damaged wiring harness. After a crash this is a typical trace: the impact tears wiring in the rail, fender or rocker and modules drop off the network.
Key figures
- Complaints with this code
- 3
- Models
- 3
- Model years
- 2021–2024
Which models and years
Models whose owners name this code (3). Years link to the model year problems page.
Components named together with the code
Component as the owner filed it (one complaint can list several).
Complaints by model year
What to do if an auction car has this code
- Check wiring harnesses in the impact zone: rail, fender, rocker, pillar.
- Check the battery and grounds: low voltage triggers false lost communication codes.
- Budget a network scan: a missing module may be intact while its wiring is damaged.
What owners report
Excerpts of owner complaints in the original wording. Owner statements not verified by the regulator; personal data removed.
Third-party diagnostic scanning revealed network power codes U3018, U3505, P00FF, and P0700, indicating a total loss of power to the Body Control Module (BCM). This is the second life-threatening incident with this vehicle I have experienced following a previous highway engine stall due to engine recall.
The dealer replaced the starter; it now restarts but continues to stall every ~10 miles. A dealer diagnostic scan recorded numerous "Lost Communication" codes across nearly all control modules, plus control-module input-power codes showing low voltage and power-circuit correlation faults (e.g., U3505, U3018, U3007)…
Following a full engine replacement performed by the dealer under this safety recall, the vehicle has suffered a catastrophic electrical compromise. The vehicle is currently throwing codes P2534 (Low Ignition Voltage) and U3018 (BCM Communication).
Related codes
- U3000Control Module
- U0073Control Module Communication Bus A Off
- U0140Lost Communication With Body Control Module
- U3003Battery Voltage
- U0001High Speed CAN Communication Bus
- U0422Invalid Data Received From Body Control Module
- U0002High Speed CAN Communication Bus Performance
- U0146Lost Communication With Serial Data Gateway…
- U0141Lost Communication With Body Control Module A
- U3006Control Module Input Power A Circuit/Open
- U0010Medium Speed CAN Communication Bus
- U0029Vehicle Communication Bus A Performance
Sources: public official US data (owner complaints) and the SAE J2012 standard. Complaints are owner statements not verified by the regulator. A code from a complaint does not replace a scan tool diagnosis. Data updated 2026-11-10.