Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) Diesel Injector
Cross-Reference & Technical Specs
Authoritative technical specifications, verified Bosch part numbers, control valve stamping codes, nozzle spray orifices, and hold-down tightening torque for the Subaru Boxer 2.5L Turbo DOHC 1 diesel engine family.
All Verified Part Numbers for Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255)
The following 1 common-rail injector assembly is calibrated for this engine family. Click the SKU to view individual test bench flow curves, sister cross-references, and vehicle applications.
12-Hole High-Flow Micro-Atomization DirectorNozzle Code: See Product Detail| Part Number (SKU) | Primary OE Reference | Control Valve | Nozzle Code |
|---|---|---|---|
| 16611-AA72A, FJ942, 195500-4430 | 12-Hole High-Flow Micro-Atomization Director | See Product Detail |
Verified Vehicle Compatibility
| Make / Manufacturer | Vehicle Model & Platform | Engine Specification | Model Years |
|---|---|---|---|
| Subaru | WRX STI GRB/GVB/VAB | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2007-2021 |
| Subaru | Impreza WRX / Forester XT | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2008-2014 |
| Subaru | Legacy GT / Outback XT | Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) | 2008-2012 |
Installation, Tightening Torque & Re-torque Protocol
Strict torque compliance is mandatory on Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) common-rail cylinder heads. Over-torquing stretches the injector body or strips the head clamping threads, while under-torquing allows combustion blow-by past the copper sealing washer:
- Hold-down clamp bolt: 19 N·m (cold state). Always clean the cylinder head recess with an injector seat reamer.
- High-pressure rail flare nut: 25-30 N·m using a dedicated 17 mm line wrench.
- Return leak-off banjo bolt: 9-12 N·m with fresh copper washers on both sides of the banjo union.
After fitting replacement injectors on Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255), generate or program the cylinder-specific IMA calibration code into the engine ECU using an OEM-level scan tool (Bosch KTS, Renault CLIP, or VAG-COM) to prevent cylinder power imbalance and rough idle.
Technical Diagnostics FAQ for Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255)
What DTC fault codes indicate a failing injector on Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255)?
The most frequent fault codes are P0201 through P0204 (Injector Circuit Malfunction on Cylinders 1-4), P2146/P2149 (Injector Group Supply Voltage Error), and P0087 (Fuel Rail Pressure Low due to excessive internal leak-off). Measure solenoid coil resistance across the pins (0.5-1.5 Ω) and perform a graduated-bottle dynamic leak-back test to pinpoint the leaking cylinder.
Can sister SKUs within the Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) family be interchanged?
Not unless explicitly confirmed on the vehicle build plate. While sister SKUs share the same physical outer envelope and 12-Hole High-Flow Micro-Atomization Director control valve, they differ in nozzle spray orifice angle and factory IMA flow calibration. Mixing sister SKUs on the same engine block can trigger rough idle, elevated exhaust gas temperatures (EGT), and MOT emissions failure.
Which specific Bosch injectors fit the Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) engine?
The verified genuine Bosch common-rail injectors engineered for the Subaru Boxer 2.5L Turbo DOHC 16-Valve Horizontal-Opposed 4-Cylinder (EJ257, EJ255) engine family are:
- Bosch 16611-AA720 Common Rail Injector → (OE: 16611-AA72A, FJ942, 195500-4430) — Control Valve: 12-Hole High-Flow Micro-Atomization Director,