What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
U0156:00PCM, CAN communication system, Communication error with CMU (Connectivity Master Unit)Manufacturer communications
12Original wording in English
MAZDA
Reported code forms U0156:00
This Service Alert supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-015/26 05/27/26, 04/20/26, 04/09/26, 03/25/26 and 03/13/26 DESCRIPTION Index Intermittent Globe with a slash icon…
MAZDA
Reported code forms U0156:00
Infotaintment center display and connected vehicle improper operation. This Service Alert supersedes the previously issued SA(s) listed below. The changes are noted in Red. SA-015/26 04/20/26, 04/09/26, 03/25/26 and…
MAZDA
Reported code forms U0156:00
Some customer may experience any of the following: Multiple Warning Lights On • Infotainment center display blank • Engine no start unless the key transmitter is placed near the start button • Interior lights do not…
MAZDA
Reported code forms U0156:00
Some customer may experience any of the following: Multiple Warning Lights On • Infotainment center display blank • Engine no start unless the key transmitter is placed near the start button • Interior lights do not…
MAZDA
Reported code forms U0156:00
Some customers may experience any of the following: Multiple Warning Lights On Infotainment center display blank Engine no start unless the key transmitter is placed near the start button. Interior lights do not…
MAZDA
Reported code forms U0156:00
Some customers may experience a "IN-VEHICLE NETWORK MALFUNCTION" warning message in the instrument cluster with one or more of the following DTC's stored: à ̄‚· B119F:01 TCU - Tel antenna No. 1 malfunctionà ̄‚·…
Check vehicle applicability
25A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Mazda | CX-30 | 2020 |
| Mazda | CX-5 | 2026 |
| Mazda | CX-70 | 2025 |
| Mazda | CX-90 | 2025 |
| Mazda | CX-90 | 2024 |
| Mazda | MAZDA3 | 2020 |
| Mazda | MAZDA3 | 2019 |
| Volvo | S60 | 2015 |
| Volvo | S60 | 2014 |
| Volvo | S60 | 2013 |
| Volvo | S60 | 2012 |
| Volvo | S60 | 2011 |
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.