Reference meaning
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.
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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
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.
Scan worksheet →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
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 • Beep sound near the SOS button and SOS button amber or red LED • Instrument Cluster Master Warning Light illu…
MAZDA
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 03/13/26 DESCRIPTION Index Intermittent Globe with a slash icon • Beep sound near the SOS button and SOS button am…
MAZDA
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 illuminate • DTC P2507:00 - PCM, PCM POWER SYSTEM: (LOW INPUT) stored. • DTC U0156:00 - PCM, CAN communication sys…
MAZDA
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 illuminate • DTC P2507:00 - PCM, PCM POWER SYSTEM: (LOW INPUT) stored. • DTC U0156:00 - PCM, CAN communication sys…
Check vehicle applicability
25A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
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.