Drain Plug (Water) Locations

[theonlyBuster]

I'll try to keep this short, but if more info is needed, feel free to ask.

The "Check Engine" light as well as all the Driver Assist lights illuminated on my dash. According to my dealership, the problem is very likely a (semi-)clogged drain port. The mechanic who diagnosed the issue told me I could fix the problem at home in about 20-minutes with a shop vac which I'm totally fine doing.

 

My question is where are the drain ports located on a 15 Legacy?

I imagine, once I find the drain port, I simply blow air through them to clean them out? Speaking of blowing air, would air from an air compressor be OK or would it be too pressurized and cause further problems?

 

I roamed around YouTube but didn't really find any videos that I felt were helpful with this issue -- but then again I wasn't exactly sure what to look for.

[ammcinnis]

The "Check Engine" light as well as all the Driver Assist lights illuminated on my dash. According to my dealership, the problem is very likely a (semi-)clogged drain port.

We need more information. What specific Diagnostic Trouble Codes (DTCs) were set? I'm not aware of any "plugged drain" condition that will set a DTC and illuminate the Check Engine light.

 

The only "drains" I know of on the Gen 6 Legacy that may occasionally get plugged are: 1) the A/C condenser drain, 2) the sunroof drain(s), and 3) the windshield cowl drains ... probably in that order ... and none of them set DTCs or the CE light.

[PATS4LIFE]

How about the EGR drain filter?

Part# 42072AL00A

[theonlyBuster]

We need more information. What specific Diagnostic Trouble Codes (DTCs) were set? I'm not aware of any "plugged drain" condition that will set a DTC and illuminate the Check Engine light.

 

The only "drains" I know of on the Gen 6 Legacy that may occasionally get plugged are: 1) the A/C condenser drain, 2) the sunroof drain(s), and 3) the windshield cowl drains ... probably in that order ... and none of them set DTCs or the CE light.

I'll go back to the dealership and inquire.

 

To give more back story, I brought it to the dealership regarding the issue. I mentioned that I got my O2 sensor replaced a week prior. The mechanic connected his OBD scanner and said it had nothing to do with the O2 sensor. He said the code specified "drain port" (or maybe "drain valve") was the issue. He went on to say that this was fairly common when there's a heavy rain, driving through high water, or spider makes a web. Well there was a heavy rain the day before. He cleared the error and sent me on my way. That was just over a week ago.

A week later and a morning after a night of heavy rain, the "problem" is back.

 

Honestly, I think the mechanic and intake-representative were just trying to discourage me from leaving the vehicle at the service center because they have a full backlog. The next available appointment was almost 3 weeks.

 

I don't have a sunroof and rarely run my AC, so the AC condenser drain may have been what he meant. If not, I guess the windshield and rear window will be my next focus if I can't get a straight/helpful answer from the mechanic when I go back.

[iyalla]

If you dont have a code reader go to an autozone or similar and have them read the code for you. That will at least help point us, and more importantly you, in the right direction.

[MoleMan]

This brings up fond memories of growing up in Miami and driving through the rainstorms with the high water. I actually lost a A3 VW Golf from hydrolock from driving in heavy rains.

 

So back to the issue. I noticed when I spray water from my hose while washing my 6th gen the drain holes tend to be in the back of the engine bay closest to where the backside of the front wheels are located.

 

You could try to put the car up on ramps and then spray water on the car or have someone spray water on the front of the car to find the drain holes and see if they are clogged etc... however as ammcinnis has referenced a clogged drain normally does not set off a CEL. In my case with my Infiniti the drain holes on the battery tray were clogged causing the main wiring loom that someone thought at Nissan was a great idea to cause shorting etc.. problem was solved when I removed the battery and tray only to find the real culprit which was debris buildup from a tree all lodged in and the car was fine after that.

 

 

You could try to remove the battery and look under the tray and see if you have any debris that’s maybe causing a clog. Even if that is not the issue I was going to suggest pulling the negative and positive cables and letting the computer reset itself and see if that fixes the issue.

[theonlyBuster]

Well in usual fashion, when I returned to the dealership and connected the ODB scanner, it read Code P0456. This was done by the same mechanic as previous and he confirmed/noted that this wasn't the same code as the previous 2 instances.

 

The error was cleared and I'll see what happens in the coming days and week. If I get warning lights again, I'll bring it to my previous dealership in the next county and have them look into it and fix it. But as it seems, there may be two very different problems to be addressed here.

 

 

This brings up fond memories of growing up in Miami and driving through the rainstorms with the high water. I actually lost a A3 VW Golf from hydrolock from driving in heavy rains.

 

So back to the issue. I noticed when I spray water from my hose while washing my 6th gen the drain holes tend to be in the back of the engine bay closest to where the backside of the front wheels are located.

 

You could try to put the car up on ramps and then spray water on the car or have someone spray water on the front of the car to find the drain holes and see if they are clogged etc... however as ammcinnis has referenced a clogged drain normally does not set off a CEL. In my case with my Infiniti the drain holes on the battery tray were clogged causing the main wiring loom that someone thought at Nissan was a great idea to cause shorting etc.. problem was solved when I removed the battery and tray only to find the real culprit which was debris buildup from a tree all lodged in and the car was fine after that.

 

 

You could try to remove the battery and look under the tray and see if you have any debris that’s maybe causing a clog. Even if that is not the issue I was going to suggest pulling the negative and positive cables and letting the computer reset itself and see if that fixes the issue.

Hydro locking is never fun. Thankfully I learned this lesson with a rental vehicle as opposed to my own.

 

I would try the spray method to clean any drain holes -- though my problem is I don't know where they are. Never really had this type issue before.

 

Though I may try the battery trick to clear future P0456 codes. I just hate doing it because I always have to re-program my windows, give the transmission time to re-learn itself, and other little annoyances.

Edited November 23, 2021 by theonlyBuster

[ammcinnis]

You could try to remove the battery and look under the tray and see if you have any debris that’s maybe causing a clog.

There is no drain below the battery, just a shallow plastic tray that nests in the support bracket.

[silverton]

P0456 is a small evap leak, did you research it at all? Likely means you got a broken vacuum line somewhere. code will re-set every two drive cycles when/if cleared til the issue is found and resolved.

 

I'd say take a look at the gas cap, but i can't remember if that has its own code like other manufacturers.

[Painless]

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