2009 Subaru Impreza Factory Service Manual

This factory service manual covers maintenance, repair, and diagnosis for the 2009 Subaru Impreza GE and GH platforms with 2.5L SOHC non-turbo or DOHC turbo engines. Separate H4SO and H4DOTC sections distinguish the engine configurations and their service procedures.

Searchable PDF with System Bookmarks

Text search and diagram detail: Searchable PDF text and embedded bookmarks provide access to the engine, transmission, chassis, body, and wiring sections. Small connector pin numbers and wiring codes require zooming for comfortable reading.

Supplied as one printable, English-language 3,619-page PDF.

Engine Overhaul, AWD Transmission Service and Electrical Diagnosis

These selected topics highlight the main workshop coverage. The manual also contains separate seat-belt and sunroof sections.

• Engine repair: Step-by-step procedures for timing-belt replacement, valve-clearance adjustment, engine removal, cylinder-head service, and cylinder-block disassembly and inspection.

• Fuel and emissions diagnosis: Fuel-pressure testing, injection-system checks, emission-control component service, DTC troubleshooting, and Subaru Select Monitor operating procedures.

• AWD transmissions: Internal 5MT and 4AT service, clutch repair, differential inspection, automatic-transmission pressure testing, and control-valve air bleeding.

• Cooling and lubrication: Coolant replacement and air bleeding, radiator and water-pump service, thermostat inspection, oil-pressure checks, and lubrication-system troubleshooting.

• Suspension and steering: Front and rear alignment procedures, ball-joint inspection, strut and shock-absorber service, and power-steering diagnosis and adjustment.

• Brakes and stability control: Disc and drum brake service, hydraulic bleeding, ABS/VDC fault diagnosis, and system-specific inspection and adjustment information.

• Electrical and body systems: Wiring diagrams, connector views, harness routing, waveform references, and diagnostic procedures for HVAC, airbags, immobilizer, and CAN communication.

The diagnostic routines and internal overhaul work are suited to experienced mechanics with electrical testing skills and access to the specified scan tools, pressure gauges, and workshop equipment.

SOHC and Turbo Engine Procedures

The mechanical sections go beyond routine maintenance, with cylinder-head disassembly, valve-guide inspection, piston and connecting-rod checks, and crankshaft inspection. Component exploded views identify tightening torques, lubrication points, seals, and replacement parts.

Valve-train differences: The SOHC section describes rocker adjustment, while the DOHC turbo section uses measured valve clearances and lifter-thickness selection. These separate procedures help you identify the work and parts required for the engine configuration before disassembly.

The turbo timing-belt chapter explains how incorrect camshaft rotation with the belt removed can bring intake and exhaust valves into contact and bend them.

Maintenance and cooling: Pre-delivery inspections, static checks, road-test items, and periodic maintenance schedules accompany the repair sections. Coolant service distinguishes the turbo coolant filler tank from the non-turbo filling arrangement; engine-oil and transmission-oil service have their own procedures and specifications.

Transmission Testing and Internal Repair

The automatic-transmission section pairs stall, time-lag, line-pressure, and transfer-clutch pressure tests with diagnostic tables. This gives mechanics a way to assess shift complaints and clutch operation before deciding whether internal repair is required.

Control-valve service includes Subaru Select Monitor air-bleeding procedures. The line-pressure test identifies oil-pressure gauge adapter 498897200 and gauge assembly 498575400, allowing the required test equipment to be identified in advance.

The internal repair sections cover the 4AT clutch assemblies and main case, plus 5MT main-shaft, drive-pinion, synchronizer, and differential work. Gear-ratio tables distinguish turbo and non-turbo applications. The torque-converter installation section also addresses oil-pump shaft bushing damage caused by improper contact during installation.

Chassis, Brake and Control-System Diagnosis

Alignment information includes wheel-arch height, camber, caster, toe, steering angle, and thrust-angle checks. Brake coverage distinguishes rear drum and rear disc arrangements and supplies component inspection limits.

ABS and VDC diagnosis is presented separately from conventional brake service. The manual limits disassembly of their control modules and hydraulic units to the specified work; it does not authorize unrestricted internal repair.

Observe the manual’s vehicle-support, fuel-pressure, and airbag precautions before service.

Circuit Diagrams and Fault Tracing

System drawings include Engine Electrical System, AT Control System, Anti-lock Brake System, Vehicle Dynamics Control System, and CAN Communication System. Connector terminal views and harness-location drawings connect circuit references to the vehicle wiring.

DTC charts, general diagnostic tables, sensor voltage and resistance checks, and waveform references support fault tracing. The wiring diagnostic section checks power supplies, grounds, harness continuity, and connector condition before component replacement, providing a practical alternative to replacing parts solely on the basis of a fault code.

A Preview of Oil-Service and Brake Inspection Data

Engine-oil service lists a drain-plug tightening torque of 44 N·m. The 5MT specification gives a transmission gear-oil capacity of 3.5 liters.

Brake specifications include pedal free play of 0.5–2.0 mm when the pedal is pulled upward with less than 10 N of force. Front brake-disc thickness is listed as 24 mm standard, with a 22 mm wear limit.