DTC U0284, Additional Diagnostics Added – 2017-2019 Subaru Impreza

NHTSA ID Number: 10150933

Manufacturer Communication Number: 07-140-18

Summary

This bulletin announces an additional troubleshooting step to follow when diagnosing a DTC U0284: “LOST COMMUNICATIONWITH ACTIVE GRILLE SHUTTER MODULE “A”. Water intrusion into the harness wiring leading to connector B63 for the Active Grille Shutter (AGS) may lead to corrosion of the harness wiring and/or connector terminals and result in a communication loss with the ECM.

 

3 Affected Products

Vehicle

SUBARUeBay logoIMPREZA2017-2019

 


INTRODUCTION:

This bulletin announces an additional troubleshooting step to follow when diagnosing a DTC U0284: “LOST COMMUNICATIONWITH ACTIVE GRILLE SHUTTER MODULE “A”. Water intrusion into the harness wiring leading to connector B63 for the Active Grille Shutter (AGS) may lead to corrosion of the harness wiring and / or connector terminals and result in a communication loss with the ECM.

 

PRODUCTION CHANGE INFORMATION:

The installation method of the corrugated plastic harness protection tube was changed to prevent damage starting with the following VINs:

  • 4-door: J3624930
  • Wagon: J3751997

 

SERVICE PROCEDURE / INFORMATION:

REMINDER:  Customer satisfaction and retention starts with performing quality repairs.

Always refer to the applicable Service Manual and review the full requirements of the repair being performed.  The Service Manual procedures contain information critical to performing an effective repair the first time and every time.  This includes but is not limited to: important SAFETY precautions, proper inspection criteria, necessary special tools, required processes and related onetime-use parts needed for a complete and lasting repair.

The AGS harness connector B63 is located at the end of the AGS assembly in the l/front as shown below.

 

IMPORTANT:  Before proceeding with any other electrical testing as directed by the current Service Manual diagnostics, access and disconnect the AGS harness connector.  The photos below show both sides of the harness connection with corrosion present.  If corrosion or an open circuit in the wiring is identified, replace both the bulkhead wiring harness and AGS assembly following the procedure outlined in the applicable Service Manual.

NOTE:  Do not attempt to repair the wiring or clean the connector terminals.  If there is no corrosion in either connector, check the wiring to the harness connector and confirm there is not an open circuit, broken wire as shown below or unexpected high resistance to indicate corrosion in the wiring.  If no wiring or connector damage is identified, proceed with electrical testing Steps 3 to 6 as outlined in the applicable Service Manual for DTC U0284.

The related Service Manuals will be updated with this new initial diagnostic step.



NUMBER: 07-140-18
DATE: 10/09/18

https://www.nhtsa.gov/recalls?nhtsaId=10150933
https://static.nhtsa.gov/odi/tsbs/2018/MC-10150933-9999.pdf

 


NUMBER: 07-140-18
DATE: 10/09/18

https://www.nhtsa.gov/recalls?nhtsaId=10150908
https://static.nhtsa.gov/odi/tsbs/2018/MC-10150908-9999.pdf

 


 

SaleBestseller No. 1
ANCEL AD310 Classic Enhanced Universal OBD II Scanner Car Engine Fault Code Reader CAN Diagnostic Scan Tool, Read and Clear Error Codes for 1996 or Newer OBD2 Protocol Vehicle (Black)
  • CEL Doctor: The ANCEL AD310 is one of the best-selling OBD II scanners on the market and is recommended by Scotty Kilmer, a YouTuber and auto mechanic. It can easily determine the cause of the check engine light coming on. After repairing the vehicle's problems, it can quickly read and clear diagnostic trouble codes of emission system, read live data & hard memory data, view freeze frame, I/M monitor readiness and collect vehicle information.
  • Sturdy and Compact: Equipped with a 2.5 foot cable made of very thick, flexible insulation. It is important to have a sturdy scanner as it can easily fall to the ground when working in a car. The AD310 OBD2 scanner is a well-constructed mechanic tool with a sleek design. It weighs 12 ounces and measures 8.9 x 6.9 x 1.4 inches. Thanks to its compact design and light weight, transporting the device is not a problem. The buttons are clearly labelled and the screen is large and displays results clearly.
  • Accurate Fast and Easy to Use: The AD310 scanner can help you or your mechanic understand if your car is in good condition, provides exceptionally accurate and fast results, reads and clears engine trouble emission codes in seconds after you fixed the problem. This device will let you know immediately and fix the problem right away without any car knowledge. No need for batteries or a charger, get power directly from the OBDII Data Link Connector in your vehicle.
  • OBDII Protocols and Car Compatibility: Many cheap scan tools do not really support all OBD2 protocols. AD310 scanner as it can support all OBDII protocols such as KWP2000, J1850 VPW, ISO9141, J1850 PWM and CAN. This device also has extensive vehicle compatibility with 1996 US-based, 2000 EU-based and Asian cars, light trucks, SUVs, as well as newer OBD2 and CAN vehicles both domestic and foreign. Pls confirm with our customer service whether it is compatible with your vehicle before purchasing.
  • Home Necessity and Worthy to Own: This is an excellent code reader to travel or home with as it weighs less and it is compact in design. You can easily slide it in your backpack as you head to the garage, or put it on the dashboard, this will be a great fit for you. The AD310 is not only portable, but also accurate and fast in performance. Moreover, it covers various car brands and is suitable for people who just need a code reader to check their car.
SaleBestseller No. 2
BlueDriver Pro Next Gen OBD2 Scanner – No Subscription, Bluetooth Car Code Reader for iPhone & Android – Diagnose 8000+ Issues, ABS SRS TPMS, Repair Reports, Vehicles 1996+
  • [Diagnose Like a Pro] BlueDriver Pro Next-Gen is a professional OBD2 scanner and diagnostic tool that helps you scan, understand, and clear vehicle trouble codes with confidence. Turn your phone into a powerful car diagnostic scanner—no guesswork, no unnecessary repairs.
  • [Read and Clear More Codes Than Ever] Read and clear more codes than basic car code readers. Access enhanced diagnostics for Check Engine, ABS, SRS, Airbag, TPMS, Transmission, and more on supported vehicles, including expanded coverage on newer model years.
  • [Verified Fixes and Real-Time Data] Get unlimited, technician-verified repair reports matched to your VIN, with definitions, causes, and confirmed fixes. Monitor live vehicle data as you drive, view freeze frames, check smog readiness, and analyze Mode 6 test results.
  • [Expanded Make & Model Coverage] Optimized for today’s vehicles with strong support for GM, Ford, Stellantis (RAM, Jeep, Chrysler), Toyota, Honda, Nissan, Mazda, SubarueBay logo, Hyundai, Mercedes-Benz, BMW, and VW. Enhanced communication on select 2024+ Nissan and Mazda models (see compatibility chart).
  • [Gas Vehicles 1996+ & Select Light-Duty Trucks] Works with all gas-powered vehicles made in 1996 or newer, plus select light-duty trucks and diesels, including F-250, RAM 2500, Silverado, and Sierra. Built for daily drivers, family vehicles, and real-world truck use.
SaleBestseller No. 3
GEARWRENCH Professional Bi-Directional Diagnostic Scan Tool | GWSMARTBT
  • OE-Level diagnostics on your smart device
  • FREE Software updates - No subscriptions, no fees – EVER
  • Full bi-directional control, live actuation test
  • Supports 23 vehicle reset/relearn functions, including throttle matching, ABS bleeding, TPMS reset, etc.
  • Live data mapping and freeze frame capturing
Bestseller No. 4
Innova 5610 OBD2 Bidirectional Scan Tool - Understand Your Vehicle, Pinpoint What's Wrong, and Complete Your Repairs with Less Headache, Updates Included, US-Based Technical Support
  • MAINTAIN PEAK PERFORMANCE AND SAFETY ON THE ROAD - Easily find and fix the problem with your vehicle using the INNOVA 5610 bidirectional scan tool. This OBD2 scanner diagnostic tool provides real-time solutions to troubleshoot issues. Access OBD2 and OEM live data with ease, making it an essential car scanner diagnostic tool. Perfect for those seeking reliable car diagnostic scanner and code readers & scan tools for vehicles.
  • PRO-LEVEL FUNCTIONALITIES - Use the INNOVA 5610’s Enhanced Data Stream to view live data for advanced systems like ABS, SRS, transmission, and engine. The Special Reset Function lets you use dealership-level re-learn procedures. This car diagnostic scanner is ideal for those needing a bidirectional scan tool or mechanic tools automotive for professional repairs. Compatible with select vehicle makes and models; not universal.
  • COMMAND WITH BIDIRECTIONAL CONTROLS - The INNOVA 5610 bidirectional scan tool sends commands to test functions such as fuel pump on/off or retracting the electronic parking brake. With this car scanner diagnostic for all cars, you can operate like a pro. Ideal for those seeking a car code reader and reset tool or advanced fixd car diagnostic tool capabilities. Compatible with select vehicle makes and models; not universal.
  • EASY TO USE - The INNOVA 5610 OBD2 scanner diagnostic tool supports English, Spanish, and French. Easily use this scanner for car on most 1996 - 2023 (2024 coming soon) OBD2 vehicles to verify repairs. Designed for ease of operation, it’s a dependable code reader for cars and trucks and check engine code reader. To confirm vehicle coverage, please utilize Innova's Coverage Checker.
  • BUY AND DRIVE WITH CONFIDENCE - Backed by ASE-Certified support, this car scanner pairs with the RepairSolutions2 app, trusted by 4M users, for wireless OBD scanner functionality. With free updates and no subscription fees, this durable car computer diagnostic reader ensures you’re prepared for any repair. A must-have diagnostic scanner for vehicles.
SaleBestseller No. 5
ANCEL AD410 PRO OBD2 Scanner and Battery Tester, 2-in-1 Car Diagnostic Tool, Check Engine Light, EVAP Test, Live Data, 12V Battery Analyzer with Cranking & Charging System Test for Car Motorcycle
  • 【2-IN-1 Engine Diagnostic & Battery Tester】: Upgraded from ANCEL’s best-selling AD310/AD410 series, the AD410 PRO obd2 scanner not only offers deeper, more accurate engine fault diagnosis but also covers battery health assessment, starter motor testing, and charging system evaluation. Skip buying separate tools—save money and space while eliminating the hassle of switching between different diagnostic scan tool
  • 【Silence the Check Engine Light】: Panicked when the check engine light suddenly pops on? This car code reader decodes 42,000+ SAE DTCs in seconds (e.g. “P0300 – Multiple Cylinder Misfire”)—no confusing jargon. Read codes, understand the issue, then clear the light after fixing—so you avoid guesswork and unnecessary shop fees. NOTE: It DOESN'T support ABS, SRS, or Transmission systems
  • 【Comprehensive Battery System Test】: Stop guessing why your car struggles to start—is it the battery, starter, or alternator? AD410 PRO goes beyond a voltage-only check by performing battery health, cranking, and charging system tests to pinpoint where the issue is coming from. Prevent unnecessary replacements and costly repeat repairs—know what's wrong and fix it right, without the guesswork
  • 【Avoid a Smog Re-Test】: No more panic before emissions tests! The dedicated I/M Readiness mode of this professional obd2 scanner diagnostic tool instantly shows your vehicle’s compliance status (green = ready, yellow = incomplete). It covers core monitoring items (misfire, fuel system, catalyst, etc.) — fix potential issues in advance so you know you’re ready before you go, avoiding wasted time and extra inspection fees
  • 【Live Data for Instant Vehicle Insights】: Don’t just read codes—see what your engine is doing in real time with this car scanner. Track 50+ key live readings with visual dashboards and waveform graphs to spot overheating, sensor issues, or fuel/air issues early. Freeze frame replays the exact moment a fault happened (speed/load/temp), so you know what triggered the check engine light—no more guessing

This product presentation was made with AAWP plugin.

Leave a Comment

Share to...