Subaru EJ25 2.5L Engine Full Workshop Manual

This manual contains complete technical information about the Subaru EJ25 engine. Includes:

🔹 DTC (Diagnostic Trouble Codes) – list of errors and their decoding.

🔹 Wiring Diagram – electrical diagrams for diagnostics and repair.

🔹 Maintenance and Repair – recommendations for troubleshooting.

🔹 Features of the engine management system – sensors, fuel and ignition.

Ideal for mechanics and Subaru owners who want to understand the EJ25 device.

• Subaru All Engine>>

📌 Cars with EJ25 Engine:

🔹 Subaru Forester

SF5 (1998–2002) – EJ25D (DOHC, naturally aspirated)

SG5 (2002–2008) – EJ253 (SOHC, naturally aspirated)

SH5, SH9 (2008–2013) – EJ255 (DOHC, turbo)

SJ5, SJG (2013–2018) – EJ255 (DOHC, turbo)

🔹 Subaru Outback

2nd generation (1999–2003, Legacy Outback) – EJ251, EJ252

3rd generation (2003–2009) – EJ253

4th generation (2009–2014) – EJ253

🔹 Subaru Legacy

2nd generation (1994–1999) – EJ25D

3rd generation (1998–2003) – EJ251, EJ252

4th generation (2003–2009) – EJ253, EJ255 (GT, turbo)

5th generation (2009–2014) – EJ253

🔹 Subaru Impreza

GD, GG (2001–2007, WRX STI) – EJ255, EJ257 (turbo)

GH, GE, GR (2007–2014, WRX STI) – EJ255, EJ257

🔹 Subaru Baja

2003–2006 – EJ253

1️⃣ Problems with cylinder head gaskets

🔹 Overheating, oil and coolant leakage.

🔹 Most common on EJ251, EJ252, EJ253.

🔹 How to avoid? Use high-quality antifreeze, check the coolant level, install reinforced gaskets during repairs.

2️⃣ Increased oil consumption

🔹 Especially on EJ255 and EJ257 (turbo).

🔹 The reason is wear of piston rings and design features.

🔹 How to avoid? Use high-quality oil, change every 5-7 thousand km, do not overheat the engine.

3️⃣ Knocking liners (Knock Knock)

🔹 Typical for turbo versions with aggressive driving.

🔹 Due to lack of lubrication, the connecting rod bearings may turn.

🔹 How to avoid? Monitor oil pressure, do not skimp on lubrication, do not turn the engine when cold.

4️⃣ Failure of ignition coils and sensors

🔹 Crankshaft sensor, camshaft position sensor - common problems.

🔹 Symptoms: misfires, unstable engine operation.

🔹 How to avoid? Use only original spare parts, regularly check for DTC errors (OBD-II)

🛠 How to properly service the EJ25?

✅ Oil - change every 5,000 - 7,000 km (5W-30, 5W-40, 10W-40 - depending on the condition of the engine).

✅ Antifreeze - change every 3-4 years, use Subaru Super Coolant.

✅ Timing belt (belt) – change every 90,000 – 100,000 km together with rollers and pump.

✅ Spark plugs – change every 30,000 – 50,000 km (iridium for turbo).

✅ Flush radiator and cooling system – once every 2-3 years.

✅ Check OBD-II errors – monitor sensors, coils and injectors.