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 WRX BaseFACTORY OEM SERVICE PROCEDURE
Unit Registration (Verification): Inspection
| Error message | Cause | Corrective action |
|---|---|---|
| Diagnostic Communication Error. End processing An Error occurred in the following ECUs. ECM***, ECM***••• |
Attempted to establish communication while the indicated ECM was not connected. | Perform the basic diagnosis for the indicated ECM, and then perform the procedure again from the beginning. If the error persists, replace the indicated ECM. |
| Attempted to establish communication while the indicated ECM was not able to communicate. | Turn the ignition switch OFF → ON, and then perform the procedure again from the beginning. If the error persists, perform the basic diagnosis for the indicated ECM. If the same error still persists, replace the indicated ECM. | |
| It is not a target vehicle for Unit Registration. End processing. | A central gateway control module with a wrong part number which does not support MAC authentication was installed. | Replace the central gateway control module with the correct part number and perform registration from the beginning.
NOTE:
The wrongly-installed central gateway control module is not affected. It can be used again as a service part for another vehicle.
|
| Attempted to verify the key for a wrong vehicle which is not subject to MAC authentication. | No corrective action.
NOTE:
The wrongly-operated vehicle is not affected. It is OK to proceed to the next operation directly.
|
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| 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 verification of MAC Key. End processing. ECM***: Success ECM***: Verification failed *** |
Key verification failed on the indicated ECM. | Reconnect the indicated ECM connector, and then perform the procedure again. If the error persists, perform module registration (update and verification) 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 and verification). |
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.