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.
Basic Diagnostic Procedure: Procedure
- CHECK ENGINE START FAILURE
.
- Ask the customer when and how the trouble occurred using the interview check list. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>CHECK LIST FOR INTERVIEW .
- Turn the ignition switch to ON.
- Navigate to Inspection Mode for measuring Exhaust Gas. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>WORK SUPPORT>OPERATION>SERVICE MODE
.NOTE:
If it is necessary to run the engine for 10 minutes or more, fasten the driver's seat belt .
- Start the engine.
Does the engine start?
Yes: Go to 2.
No: Inspection using "Diagnostics for Engine Starting Failure". Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>DIAGNOSTICS WITH PHENOMENON .
- CHECK ILLUMINATION OF MALFUNCTION INDICATOR LIGHT
.
Check the illumination status of malfunction indicator light. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>WARNING LIGHT ILLUMINATION PATTERN .
Does the malfunction indicator light illuminate?
Yes: Go to 3.
No: Check using "Diagnostics with Phenomenon". Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>DIAGNOSTICS WITH PHENOMENON .
- CHECK COMMUNICATION STATUS
.
- Turn the ignition switch to OFF.
- Connect the Subaru Select Monitor or general scan tool to the data link connector.
- Turn the ignition switch to ON, and run the Subaru Select Monitor or general scan tool.NOTE:
- SUBARU SELECT MONITOR
.
For detailed operation procedures, refer to "Help" of application
- General scan tool
.
For detailed operation procedures, refer to the general scan tool operation manual
- SUBARU SELECT MONITOR
.
Does Subaru Select Monitor or general scan tool communicate with vehicle normally?
Yes: Go to 4.
No: Inspection using "Basic Diagnostic Procedure" of LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS) (HEV)>BASIC DIAGNOSTIC PROCEDURE .
- CHECK DTC
.
Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC for [Engine] displayed? (Current malfunction)
Yes: Save DTC and freeze frame data, then repair the trouble cause. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to COMMON (DIAG)>FREEZE FRAME DATA .
After repair, go to the next step.
Go to 5.
No: Repair the related parts.
NOTE:If DTC is not shown on display although the malfunction indicator light illuminates, perform the diagnosis of malfunction indicator light circuit or combination meter . Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>WARNING LIGHT ILLUMINATION PATTERN .
- FINAL CHECK
.
- Connect all connectors.
- Using the Subaru Select Monitor or a general scan tool, perform the clear memory of [Engine]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
- Execute the inspection mode. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>INSPECTION MODE .
- Read the readiness code of [Engine] using Subaru Select Monitor and check that the concerned DTC is completed. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>ALL READINESS DIAGNOSTIC CODE(S) .
- Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC for [Engine] displayed? (Current malfunction)
Yes: Check the connection of connector. If there is no faulty connector, perform the diagnosis for the displayed DTCs. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .
No: Finish the diagnosis.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.