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Service bulletin WQW-58R

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10131644
Published by NHTSA2018-04-02
Manufacturer's numberWQW-58R
Manufacturer's date2016-09-27
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

Subaru of America, Inc. has determined that vehicles affected by this Service Program require ECM reprogramming. This bulletin includes the service procedure for diagnosis and repair of customer concerns involving engine idle roughness or, in some cases, engine noise and/or damage resulting from spark knock (pre-ignition). The Engine Control Module logic has also been optimized requiring the ECM reprogramming. The new logic optimizes the ECM for control of the following parameters: * Change to Fuel Cut control when fuel level is extremely low / near empty * Change to improve idle smoothness / quality * Change to boost pressure control under wide-open throttle (WOT) conditions. Under certain high engine load driving conditions, spark knock can occur which results in elevated cylinder temperatures and pressures. Over time, excessive erosion of the spark plugs and possible damage to the pistons can be consequences of continued operation with these conditions present.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Vehicles listed
SUBARU FORESTER2014, 2015
SUBARU WRX2015

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
16V1620002016-03-21. ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER
20161222016-03-17. Engine

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
02-193-24R2026-07-02. Service bulletin. This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers). (This is an revised version of the original bulletin.)
09-74-21R2026-07-02. Service bulletin. This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers). (This is an revised version of the original bulletin.)
02-193-24R2026-06-01. Service bulletin. This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers).
15-300-22R2026-02-02. Service bulletin. This Bulletin provides the diagnostic procedure for the STARLINK® Remote Engine Start (RES).
09-74-21R2026-01-06. Service bulletin. This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers).
18-226-25R2026-01-06. Service bulletin. This Service Information Bulletin provides the Service Manual Correction to the diagnostic procedure for DTC B2A16 (Immobilizer Key Collation Diagnosis).
18-228-25R2026-01-06. Service bulletin. This bulletin announces the diagnostic procedures to be used when DTCs P2096 (POST CATALYST FUEL TRIM SYSTEM TOO LEAN BANK 1) and P2097 (POST CATALYST FUEL TRIM SYSTEM TOO RICH BANK 1) are detected by the Engine Control Module (ECM).
18-228-252025-12-01. Service bulletin. This bulletin announces the diagnostic procedures to be used when DTCs P2096 (POST CATALYST FUEL TRIM SYSTEM TOO LEAN BANK 1) and P2097 (POST CATALYST FUEL TRIM SYSTEM TOO RICH BANK 1) are detected by the Engine Control Module (ECM).
07-235-252025-10-02. Service bulletin. In the interest of customer satisfaction Subaru of America, Inc. (SOA) is extending the New Car Limited Warranty coverage in the models listed. The extension will address instances of “phantom braking” or the EyeSight/RAB systems causing unnecessary stoppage/slowing of the vehicle.
02-193-24R2025-09-02. Service bulletin. This bulletin provides updated parts information and a service procedure to follow for removing accumulated carbon deposits from fuel injectors and internal engine components (e.g. intake valves and / or manifold, and combustion chambers).