Painless

Parsed-out Spark Plug R&R info (includes Ignition Coils) from my '16 Service Manual. It should be similar, if not identical, to your vehicle. I've replaced mine three times so far (twice on my '16 and once on my '19). I remove the battery tray as well to make more room. There are several large bolts holding securing it. One is particularly difficult to remove (wheel well area) and I left it out after the first plug change. It made the second plug change much easier and there is plenty still holding the battery tray securely. I was also able to replace the plugs without disconnecting the ignition coils just by manipulating them around a bit. Drivers-side aft plug was the most difficult. I also recommend a correctly sized magnetic spark plug socket and slightly above average mechanical ability and tooling to get the job done right. (several different 1/4" extensions & swivels). I'm editing together a video of the process and may post it this weekend. 2016 SUBARU LEGACY SERVICE MANUAL - Spark Plugs.pdf

Welcome to the forum! Sorry to hear of your issue. Intermittent faults are the hardest to troubleshoot and easiest for dealerships to dismiss. What has helped me in the past (several times) is to capture it on video. (Describe what you are doing during the recording) It may take a while, but, once you capture it, walk on in and show them. There is a recall related to the fuel pump that may be a culprit but was for '19 models last I checked. https://legacygt.com/forums/showthread.php/2019-legacy-fuel-pump-recall-282976.html?t=282976&highlight=fuel+pump Keep the group posted with your findings and ultimate fix (it helps us all).

Quick peruse through the '16 2.5i manual... ... P0456 EVAP SYSTEM (CPC) LEAK DETECTED (VERY SMALL LEAK) NOTE: For the diagnostic procedure, refer to DTC P0455. <Ref. to EN(H4DO)(diag)-314, DTC P0455 EVAP SYSTEM (CPC) LEAK DETECTED (LARGE LEAK), Diagnostic Procedure with Diagnostic Trouble Code (DTC).> So to troubleshoot the small leak, they want you to follow the "large leak" troubleshoot procedure. Quick & dirty causes: - Gas Cap "Filler Cap" (good call silverton) - Purge Control Solenoid Valve - Evap Emission Control System Line (evap leak) - Canister (located in L/H Wheel well area) - Leak Check Valve Assembly - Fuel Tank - Evap Emission Control System P0456 & P0455.pdf

Had this accident with fully functioning eyesight about a year ago. One thing that will very likely be triggering the "Check Engine" is the active grille being inoperative.

We would all like to help, but, need more data. Year, Trim, Engine, Mileage is a good start. You can look this up online (google VIN decoder) easily using your VIN number (don't post your vin). It's on the drivers side door frame after you open the door or on your insurance card.

miltoney I had what may be similar symptoms (as far as noise is concerned) in my '16 2.5i. Rumbling that increased with engine rpm but seemed to be less loud after the car was warmed-up/driven a bit. We did have an exhaust smell as well though. Turned out to be a crack had formed in the bellows of the front exhaust. It is unfortunately tough to verify for sure as there is shielding and insulation over the entire assembly. Link to my posts for reference: https://legacygt.com/forums/showthread.php/exhaust-smell-recall-wuj-95-281725p5.html See post#73 for my findings. This is a known issue and there is a recall WUJ-95 though they refused to cover mine and I had to replace it myself. Hope this helps.

You may want to check the EGR Control Valve pin resistance called-out page "EC(H4DO)-29". Just to verify the valve is good.

Got two 6th gens. Favorite being the '19 sport. The black grille really brings the tuxedo look together for me. (Still need to black-out the remaining chrome) Things I didn't like about the 7th gen when I was researching: - Direct Injection Engine - Massive Infotainment screen (bigger isn't always better) - Front looking camera - Stop/Start - Facial recognition

Parsed-out (what I feel) are the relevant sections of my 2016 Service Manual which should be pretty close, it not, identical to yours. Making assumptions of engine (2.5) and start options (key). Hope this helps. (corrected attachment) 2016 SUBARU LEGACY SERVICE MANUAL - EGR Info.pdf

Have you plugged an ODB2 scanner/reader to clear the code after you completed your work? Do you have a copy of the full service manual to follow troubleshooting?

Good news. Simple fix and "iyalla" is the winner! Very very dead battery. They were using it to power bluetooth speakers. (ah... College kids) Replaced the battery, provided refresher on jump starting and what not to power bluetooth speakers with.

Greetings all, My daughters 2016 with 210k miles won't start after sitting for two weeks. It does seem to have power as lights and bells come on with first key click. Rotate to start and nothing. Tried a boost pack to jump start and still nothing. Luckily, we are heading down to visit this weekend. I'm bringing the simple stuff, ODB2 Scanner, Volt meter, 7.5a fuse, OEM starter relay, jumper cables, a few hand tools. In reading through the Service Manual Diagnostic for Engine Start Failure EN(H4DO)(diag) I keep coming back to the Inhibitor Switch for some reason. Has anyone had an issue with this switch failing or requiring adjustment?

Mine wasn't that quick though I was only doing about 40mph.

There is a recall for fuel pump impeller failures on 2019 models. Exact scenario happened to me (not on the highway though). Maybe includes your model now? Thread: https://legacygt.com/forums/showthread.php/2019-legacy-fuel-pump-recall-282976.html?t=282976&highlight=fuel+pump https://static.nhtsa.gov/odi/rcl/2020/RCRIT-20V218-7149.pdf

After a quick look through the Service Manual... Looks to me like "Unit IG2-2" is "IG Relay 2"(Ignition Relay 2). Red wire supplies voltage to the Combination Meter. Attached selections for reference. IG2.pdf

Could be just a one-off hiccup. If you want to dig deeper... Quick check through the manual points to the Ambient Sensor (or wiring) fault. Parsed-out the relevant data from my '16 which should apply to your vehicle. You may want to replace the Ambient Sensor (less than $15) as a precaution or at least verify the connector is properly seated and wiring looks ok. I do suggest removing the front bumper cover to make troubleshooting/replacement of the sensor easier. P0072 Code Troubleshooting.pdf

Please be sure to disconnect the Ground (not the positive). See attached for safety. Front Seat & Airbag.pdf

Parsed-out the relevant sections of the '16 manual. Should apply to your model as well. Look for B505 Pressure Sensor. Unfortunately, you may need Subaru Select Monitor (SSM4 = a trip to the Dealership) to properly diagnose using their computer. Best of luck and please post final resolution. REFRIGERANT PRESSURE SENSOR (B505).pdf

My older Legacy results... 2016 Legacy Premium (O'Reilly Super Start Extreme Part# 34EXT Battery) No Load = 12.37 A/C turned on = 14.46

My results... On the 2019 Legacy Sport (original Battery) No Load = 12.27 - 12.17 A/C turned on = 14.22

Only took a few minutes. Not a big deal. Please post your findings once solution is confirmed.

I thought my 50k/year was a lot. Aside from normal maintenance items (wipers, brakes, filters, plugs, etc) 205k on my '16. (2ea) windshields. Shifter assembly. Had to do Recall WUJ-95 (exhaust bellows cracks) myself. Still frustrated with SOA for not covering that. https://legacygt.com/forums/showthread.php/exhaust-smell-recall-wuj-95-281725p5.html 82K in my '19 (1ea) windshield. I'm expecting the same exhaust bellows cracks around 180k. Replacing the tires today.

It may also be an issue with the Body Integrated Unit (BIU). (might explain your FOB not working once fuse is blown) I have attached a few excerpts from the wiring section of the service manual from my '16. It may provide some guidance. You might want to get a handful of 10A fuses and troubleshoot 'old school'. Replace the fuse and note exactly what you are doing when is blows... Opening a door, unlocking the car, etc. Fuse 26 Service Manual Excerpt.pdf

Stop by a local parts place end have them check ODB2 to see of there are any stored codes. B2803 = EPB operation prohibit B2804 = EPB no activity detected

2016 200k+ miles. Always garaged. Illinois summers/winters.