Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2024 Subaru Outback BaseFACTORY OEM SERVICE PROCEDURE
Module Registration (Verification)
| Error message | Cause | Corrective action |
|---|---|---|
| Diagnostic Communication Error. End processing An Error occurred in the following ECUs. ECM***, ECM***••• | Attempted to communicate with the corresponding ECM when it was not connected. | Perform the basic diagnosis of the corresponding ECM, and repeat the procedure from the beginning. If the fault is not fixed, replace the corresponding ECM. |
| Attempted to communicate with the corresponding ECM when it was in a situation where communication was not possible. | Turn the ignition switch OFF → ON, and then perform the procedure again from the beginning. If the fault is not fixed, perform the basic diagnosis of the corresponding ECM. If the fault still exists, replace the corresponding ECM. | |
| Battery voltage is low. Check the condition of the vehicle and try again. End processing. | The vehicle power supply voltage is 10 V or less. (control module for voltage measurement: Central gateway control module) | Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE . |
| The Ignition is OFF. After confirming that the Ignition is ON, please press the Rerun Button. | Attempted to update or verify the key with the ignition switch OFF. | Perform the procedure again with the ignition switch ON. |
| Failed to update MAC Key. End processing. ECM***: Success ECM***: Verification failed••• |
Key verification failed on the indicated ECM. | Reconnect the corresponding ECM connector and repeat the procedure. If the fault is not fixed, perform module registration (update & verify) again. |
| There is an ECU that has detected a Key update failure DTC. End processing. ECM***: Not detected ECM***: Detected••• |
The communication key of the central gateway control module does not match other ECMs during key verification. | Perform the diagnosis of DTCs B1E00, C1E00 and P1E00. Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC B1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT . Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC C1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT . Ref. to CENTRAL GATEWAY (DIAGNOSTICS)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P1E00 REGISTRATION FAULT OF AUTHENTICATION UNIT . |
| MAC key update has not been performed. MAC key verification can be performed after MAC key update. End processing. | Key verification was performed before key update was performed. | Perform module registration (update & verify). |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.