The audio amplifier has an on-board diagnostic function to facilitate system diagnosis.
The on-board diagnostic function consists of the following functions: A malfunction detection function, which detects overall malfunctions in the audio amplifier-related parts; a memory function, which stores detected DTCs; a display function, which indicates system malfunctions via DTC display.
Malfunction detection function
Detects overall malfunctions in the immobilizer system-related parts.
If a malfunction occurs, the start stop unit records the malfunction as a DTC. A recorded DTC can be read by the Mazda Modular Diagnostic System (M-MDS).
| DTC No. | Warning/indicator light | Description | Fail-safe function | Drive cycle | Self test type*1 | Memory function |
| U0001:88 | — | Module communication error (HS-CAN) | — | — | C | × |
| U2300:54 | — | Configuration error (data not received) | — | — | C | × |
| U2300:55 | — | Configuration error (not configured) | — | — | C | × |
| U2300:56 | — | Configuration error (not configured) | — | — | C | × |
| U2300:64 | — | Configuration error (error value read) | — | — | C | × |
| U3000:49 | — | Audio unit internal malfunction | — | — | C | × |
| U3003:16 | — | Voltage decrease input from battery | — | — | C | × |
| U3003:17 | — | Audio amplifier high power supply voltage input | — | — | C | × |
When related systems or components have failed, the CM stores the DTC of the malfunctioning part in the CM memory, and allows for the retrieval of the store data using scanning tool when necessary. The DTCs are indicated using seven digits. Each digit indicates the following.
The status byte is the two digits (two digits after hyphen (-)) after the seven-digit DTC.
The status byte is a code which indicates the pending code, current/past malfunction status, or warning illumination status.
The status byte can be read by performing a CMDTC self-test using the Mazda Modular Diagnostic System (M-MDS).
For details on the status byte, refer to the explanation on the M-MDS when reading the DTC.
The active command modes are shown below.
| Simulation item | Unit/Operation | Data contents | Output part name |
| EHE | On/Off |
| Audio amplifier |