Description

Subaru IMPREZA 2001 Service Manual

You ever pull a head bolt off a Subaru boxer engine using a spec you found on a forum? I have. Once. That head gasket leaked inside 500 miles because the torque sequence was wrong. The 2001 Subaru IMPREZA Service Manual sitting here on the bench is the only thing that keeps that from happening again. 2186 pages. Factory-issued by Fuji Heavy Industries. This is the same binder that dealer techs used when these cars were new. If you are doing anything inside the Subaru IMPREZA 2001 Service Manual – camshaft timing, valve clearance, fuel system diagnostics – you need the original spec, not a translation somebody made in a basement.

CAMSHAFT Timing Belt Service – Factory Procedure

Page numbers for the camshaft drive belt service are in the PERIODIC MAINTENANCE SERVICES chapter under “CAMSHAFT DRIVE BELT”. The manual spells out the tensioner preload, the alignment marks on the sprockets, and the specific rotation direction. I have seen guys use a pry bar to “seat” the belt. That’s how you bend a valve. The factory procedure lists the tools required – the belt tension gauge part number is in the back. Do not guess the belt routing; the illustration on the belt cover section is drawn to scale. If your IMPREZA has a 2.0L or 2.5L, the steps are identical per the manual, but the tension values differ. Check the SPECIFICATIONS chapter for your exact engine code.

Valve Clearance Adjustment – Why the Spec Matters

The “VALVE CLEARANCE” entry under ENGINE SECTION gives the intake and exhaust clearance in thousandths of an inch. Intake: 0.006–0.009 in. Exhaust: 0.008–0.010 in. Cold. Use a feeler gauge that is not bent. The manual also tells you which camshaft lobe to rotate to for each cylinder. I have watched a junior tech shove a feeler in at TDC on the wrong stroke and get a reading that was off by 0.003. Then he tightened the lock nut wrong and stripped the adjuster screw. The factory manual has a warning note about that exact mistake. Do not skip the “NOTE” page in the GENERAL INFORMATION SECTION – that page lists fasteners that must be replaced, not reused. Page 20 of the PDF bookmarks has that note.

What This 2186-Page Manual Actually Covers

The manual is split into sections: GENERAL INFORMATION, ENGINE, TRANSMISSION/TRANSAXLE, DRIVELINE/AXLE. The ENGINE section alone runs hundreds of pages. It includes FUEL INJECTION (FUEL SYSTEMS) with every sensor – crankshaft position, camshaft position, knock sensor, throttle position, intake manifold pressure. The EMISSION CONTROL section walks through the front and rear catalytic converters, purge control solenoid, fuel tank pressure sensor. The MECHANICAL chapter covers compression testing, idle speed adjustment, ignition timing. If you are rebuilding the cylinder head, the “CYLINDER HEAD ASSEMBLY” section includes the valve spring compressor tool number. The manual is not a quick reference; it is the full diagnostic and repair sequence. Compared to aftermarket books, this one does not combine multiple model years into one book. This is year-specific. SUBARU IMPREZA 1993 Service Manual – Section: Electrical Section is a different document – do not use that for your 2001 fuel injection wiring.

Engine Mechanical: Compression and Idle Speed Data

The “COMPRESSION” subsection gives standard compression pressure: 170–190 psi at 250 RPM. Minimum: 142 psi. Difference between cylinders: 7 psi. Idle speed: 700 ± 100 RPM (manual transmission). The manual also lists the ignition timing: 10° BTDC at idle. These numbers are stamped into the ECU calibration, but the manual lets you verify without a scan tool. For the camshaft position sensor testing, the manual shows a resistance check across pins 1 and 2: 1.0–1.5 kΩ. If you get open circuit, the sensor is dead. That is page 68 of the ENGINE SECTION bookmarks.

Who Needs This Manual?

If you own a 2001 Subaru IMPREZA and you are replacing the engine mounts, doing a timing belt job, or chasing a misfire code, this is for you. DIY guys who have lifted the engine out of the car will use the “ENGINE ASSEMBLY” chapter to reinstall with the correct mount torque (22 ft-lb for the bracket nuts). Beginners should read the “PRECAUTION” chapter first – it covers SRS system disabling and fuel line pressure relief. I tell every home garage enthusiast: use the OEM manual, not a Haynes. The aftermarket book I saw for the 2001 IMPREZA had the wrong valve clearance for the DOHC engine because they copied data from the 2000 model. Don’t trust that. Subaru Impreza Service Manual is also available on this site, but verify the year matches your car. SUBARU Impreza 1994 Service Manual – Section: Engine Sction will not help you with the 2001 Camshaft Position Sensor pinout.

Source Validity: OEM vs Aftermarket

This is a factory Fuji Heavy Industries publication. It includes the same illustrations, torque specs, and diagnostic procedures that Subaru dealers received. The OCR excerpt from page 1 says: “This service manual has been prepared to provide SUBARU service personnel with the necessary information and data for the correct maintenance and repair.” That means it was written for mechanics who get paid by the job, not for hobbyists who have time to experiment. The aftermarket manuals I have seen reprint the wiring diagrams with colors wrong – red becomes pink, ground wires get mislabeled. This manual uses the actual wire colors. If you need to trace the fuel pump relay circuit, the schematic shows the exact connector view. Automotive Industry Overview cannot help you with Subaru-specific fasteners. The Automotive Industry Overview is a general resource; this manual is the specific one.

FAQ – Subaru IMPREZA 2001 Service Manual

Does this manual cover the 2.5 RS engine?

Yes. The manual includes both 2.0L and 2.5L engine variations. The ENGINE MECHANICAL chapter lists separate specifications for each. Look for the engine code printed on the timing cover.

What is the torque spec for the cylinder head bolts?

Go to the “CYLINDER HEAD ASSEMBLY” section. The spec is listed in a table with step sequence. It gives both ft-lb and Nm. Use a calibrated beam-type torque wrench.

Are wiring diagrams included?

Yes. The ELECTRICAL COMPONENTS LOCATION and ECM I/O SIGNAL sections have full diagrams with connector pin numbers. The manual also includes the OBD-II scan tool procedure for reading codes.

Can I use this for a 2002 model?

No. The 2002 model has different sensor calibrations and a revised intake manifold. Get the correct year-specific manual. Different model years have different torque sequences for the camshaft sprocket.

The 2001 Subaru IMPREZA has been off the dealer lift for years, but you still need the right numbers. Access the Factory Manual from AutoRepairManuals. Print the page you need and take it to the workbench. Do not memorize it – reference it. That is how you keep the head gasket sealed and the cam timing where it belongs.