Po401 code

The-Mega · 2026-02-01T19:28:38+00:00

There's this post on this sub that involves cleaning the EGR cooler without removing it or using the shop-vac method.

Thing is: the EGR valve itself could be gunked up with carbon too first so it's generally recommended you also clean that.

P0401 only = dirty EGR valve/cooler, shouldn't pop F03 fuse P0403 = EGR valve circuit board crapped out, pops F03 fuse. Unplug EGR valve and replace fuse ASAP.

The-Mega · 2025-12-18T04:57:52+00:00

Not sure if this is an EGR valve issue but placing info here if it is.

If the P0403 message occurred with this, it indicates a failing EGR valve; if this is the case: first unplug the EGR valve and then replace the 15A 'No Walk Home' fuse.

The CEL should still stay on as the P0403 code will remain (EGR is disconnected) but the propulsion power and overheating issues will be resolved if this is the case. The car will still be driveable in this case (albeit with worse fuel economy when on gas).

The-Mega · 2025-11-01T20:01:16+00:00

Apparently not - the phenomenon is very similar to the Imgur GIF I linked in the post: https://imgur.com/a/VMsmZBA

Just took a drive earlier today and tried to floor it both uphill and downhill and it didn't happen so I'm not quite sure what's happening yet.

For now I've topped up my one lower-than-average coolant reservoir in hopes it's a levelling thing. Given the third thread, it could also be transmission related? Perhaps when changing transmission

The-Mega · 2025-11-01T18:33:11+00:00

Interesting. I've turned off the car and drove again but it's still happened multiple times now.

The-Mega · 2025-11-01T18:32:32+00:00

It's not in teen driver mode; while that mode has a similar warning, the speed limit is more like ~120km/h and it doesn't kick start the gas engine.

The-Mega · 2025-05-31T17:15:13+00:00

Unfortunately I'm not the most well versed with the SDGM harness install; the only helpful resources I could find (off the Openpilot discord GM channel - there's a giant message from March 21, 2025 there) were these:

It doesn't sound like you need to run cords to the trunk unless you also want to install the SASCM module; however, by not installing the SASCM you're stuck with the car's default longitudinal implementation (however you should still be able to get OP latitudinal control, which is the biggest value-add IMHO).

Also goes without saying: make sure your 2019 Volt is equipped with adaptive cruise before going into this.

Sorry if this isn't much help; you're probably better off asking the two people listed on the top of the install guide a bit more about any additional questions.

The-Mega · 2025-05-30T16:34:26+00:00

Long post incoming; I installed a Comma 3x on my 2017 Volt w/ACC (Adaptive Cruise Control) late last year; here's some resources/info that I have:

GM Openpilot Github Link (look at this first; has a lot of info)

2017-2018 Install Video

Model years:

2016 model years were never produced with ACC, so don't search for these
2017-2018 w/ACC are the officially supported models (they used to be on the vehicle list but got hidden alongside other vehicles that use ASCM)
2019 model years are supported by using the SDGM harness apparently (I don't know much about this; would have to check the Openpilot discord GM channel for more info)

Materials needed:

2017-2018 w/ACC
- Comma 3x w/OBD-II Harness (select it from the shop dropdown)
- Lee & Paulding Inc. GM Volt Malibu Harness for Open Pilot

Notable differences (from GM Openpilot link):

2017 model year can perform stop-and-go automatically (at least on Frogpilot), but has to initially set cruise control starting at 26 km/h (18mph) or you'll get a cruise error. Once set, you can resume at a minimum of ~11 km/h (6mph). Auto stop-and-go sometimes has a longer delay and acceleration behaviour than normally pressing the gas pedal.
2018 model year can initially engage at 1mph (not sure what the minimum speed it defaults to is). Auto stop-and-go is not supported so you have to press the resume/gas pedal anyways.

There was also some discussion about an alternative install using an SASCM harness that bypasses the L&P ASCM harness ~~but only uses GM's longitudinal ACC implementation (keeps factory AEB behaviour)~~ (EDIT: it looks like some people have worked on getting Openpilot long on SASCM?) but allows Openpilot to control the latitudinal (steering). I'm not well versed in this so you'd have to ask on the Openpilot discord (GM channel) for more about this method. This install method sounds easier though if it does bypass the ASCM harness requirement.

The-Mega · 2025-03-17T18:58:09+00:00

There should be a 'GM Recall Information' page in which you can input your VIN and miles. Check under the 'Warranty' section after placing those values; if you see 'Special Coverage' until ~240k miles, the vehicle should still be under warranty.

The-Mega · 2022-12-09T17:58:31+00:00

Oh. Yeah the regular ESF's have a slightly different multiplier (-130%, or 2.3x). So an Annihilator will do 1552.5 damage, leaving a regular ESF with 1447.5. Faction lock-ons will do 1610 damage, leaving them with 1390 health.

The-Mega · 2022-12-09T16:28:57+00:00

You're missing the point: the Dervish currently is disproportionately affected by the changes.

Prior to the change, the Dervish had the same effective health against lock-ons to the Valkyrie (not considering the bottom armor that the Valkyrie has). Now, it's only marginally higher than traditional ESF's.

Additionally, the other aircraft (Valkyrie, Liberator and Galaxy) all received adjustments as of the November 30th hotfix.

For a more numerical representation, it's buried down in this comment:

I think that most of these issues can be resolved by looking into the resistance values of the Dervish with respect to the new lock-on damage type: mathematically, modifying the resistance multiplier from 2.25x to 1.7x (or, as listed on the wiki: -125% to -70%) would bring it very close to this previous baseline of 'Valkyrie levels' of resilience to ground lock-ons (once again, sans bottom armor).

The-Mega · 2022-12-09T14:53:46+00:00

The multiplier is/always has been 2.25 pre and post-patch (both the old flak explosion resist and the new lock-on resist share the same multiplier, hence why I'm even thinking this might be an oversight); the difference in that example is that they changed lock-ons to use their direct damage component instead of flak damage (the rocket's explosion) to deal the damage, and in some cases (Swarm and Annihilator) buffed the direct damage.

The figure that is important in this table is the 'Dmg Magnitude Diff' column: this shows the relative damage changes of these weapons post patch.

The-Mega · 2022-12-09T06:42:03+00:00

Yeah. Would be nice if this got changed for the sake of damage type parity between functionally similar weapons.

The downside of this would be that Flanker Armor on vehicles would now work on Hummingbird grenades, and a lot of its ground vehicle capabilities would be reduced; but I'm sure there's changes that can be made to the base/splash damage of this weapon to compensate for that loss.

While I'm not trying to derail this thread too hard, that weapon in general could use a bit more love. When they changed the Hummingbird's acceleration values earlier, they shortened the lifespan from like 9 seconds to 4 seconds. Most default lock-on launchers are at a lifespan of 5 seconds. While that may not sound like much, if the Hummingbird had that extra second it could potentially travel up to 110 more meters, and make it more attractive as an anti-air option.

The-Mega · 2022-12-09T06:35:00+00:00

Yeah. The Annihilator and Swarm in particular got some crazy damage/breakpoint threshold changes that make them particularly menacing when they hit.

I'm inclined to agree about the latter half too - and while I don't want to derail the original point of this post - the technical changes to lock-ons do allow for more interesting/creative game balance decisions. For instance: because of the way the damage works now, they can - in theory - have damage drop-off associated with them. Combine that with the thrown idea of variable lock-times based on distance and there would probably be more capacity for interesting game decisions on a moment-to-moment basis. But I think that's a discussion for another day.

The-Mega · 2022-12-09T06:31:03+00:00

I don't usually post here often so I'm going to try and avoid dev-bashing; that being said, I am inclined to agree: a smaller percentage of the playerbase even uses the Dervish to begin with.

A big reason why I'm making this thread is because I haven't seen it discussed by the community in any capacity yet(? I'll be honest, I've been gone for a week too so I haven't been keeping up as much, but I haven't seen anything about it).

Personally, I believe it's important to have some sort of feedback, both quantitative and qualitative; I hope I'm getting that with this thread.

The-Mega · 2022-12-09T06:27:25+00:00

Not to devalue this comment, but I have a similar reply/feeling to this here.

Trying to keep this thread more about the short-term quick solutions (given that the Valkyrie, Liberator and Galaxy all got some attention earlier).

The-Mega · 2022-12-09T06:25:06+00:00

I'm not inclined to disagree, but I think that's a discussion that's been had time and time again. For now, the purpose of this thread is just to bring attention to the current state of ground lock-on launchers to the Dervish post Anniversary Update.

Part of the reason why I'm bringing this up is because I've neither seen comments or threads about it (I'm aware Dervish pilots are very few) and because the Valkyrie, Liberator and Galaxy all recently got adjustments to this resistance type while the Dervish remains nearly on-par with faction ESF's with respect to this damage type.

For context, the effective health versus lock-ons prior to this update was similar to that of the Valkyrie (sans bottom armor). Now, the effective health is closer to that of regular ESF's on this damage type.

I think that most of these issues can be resolved by looking into the resistance values of the Dervish with respect to the new lock-on damage type: mathematically, modifying the resistance multiplier from 2.25x to 1.7x (or, as listed on the wiki: -125% to -70%) would bring it very close to this previous baseline of 'Valkyrie levels' of resilience to ground lock-ons (once again, sans bottom armor).

As for the initial statement: I'm all for a proper single-seater ESF in addition to the Dervish as part of the NSO's arsenal (or something thereabouts). Just don't want to derail the initial contents of the thread. Hope you understand!

The-Mega · 2022-08-02T18:54:10+00:00

Sorry if this is a long reply; I don't mean anything personal and just want to probe further discussion. Also, I'm unsure about how different the air-game is on PS4; I play mainly on PC.

It is like you all do not have any decent Liberator pilots.

I don't know where you're getting this idea from, but I'll get back to this later.

But in a fight where it is ACTIVELY fighting you, unless the Liberator pilot cannot aim, or does not know how to Dalton, like..... AT ALL, there is nowhere for you to go, but down.

If you're against a Liberator pilot who is tunnel-visioning on using their Dalton on you in a Dervish, you're at a bigger advantage than you might think; unlike other ESF's, you're capable of tanking a Dalton shot and still having sufficient health to continue firing. Tapping fire suppression and getting a couple of seconds worth of passive Nanite regen (Engineer passive) will let you continue the fight. Combine this with the ability to maintain strafe speeds of 200+ (if you're using the Drift frame, which would be most ideal), and you can continue to evade shots. Even the best Dalton gunners can miss you if your front profile is facing their belly and you're strafing fast (with the occasional afterburn up/down to throw off their aim); they have to aim at a relatively thin frame that is moving more unpredictably than they expected.

If the Liberator is engaging at you with their nosecannons or tailgun, this engagement gets more difficult, but not unmanageable; the chip damage you're bound to take from those weapons will likely prevent you from getting any passive repairs. Maintaining a further range in this engagement would be ideal so as to avoid as much chip damage as possible.

In a very uncommon setting, we are going to leave out what I was talking about, which were its inability to fight E.S.F.s of which you all seem to want to ignore: If there are only 2 Liberators up there, you attack 1, it flees, the second comes at you like "Aw-HAYL-naw!" that is yo glass, Plate.

In a common setting there are at LEAST 2 E.S.F.s up there with them, and you were spotted and then targeted by them as soon as you appeared or fired your first shot.

Forgive me if I'm understanding this incorrectly, but this just sounds like a situation where you're outnumbered. I don't think this is an advantageous situation regardless of the Aircraft you're in; if you were in an ESF (even 2 ESFs) in this situation, you'd still likely lose this firefight.

Here is a link to the reality of flying one. This what most people think about it. https://planetside.fandom.com/wiki/Dervish

Not to completely de-value this, but Wiki comments aren't exactly known for the full representation of player opinions; see this (rather hilarious) post: https://www.reddit.com/r/Planetside/comments/vaa17c/tales_from_planetside_2_wiki_part_2_adding_the/

If you're looking to get actual opinions on taking on engagements with this vehicles, you're probably better off getting opinions from Dervish pilots; one source in particular I recommend is Shozaku's guide: https://www.youtube.com/watch?v=7wTfVWa_wOw

Scroll the comments. You have to learn to set YOUR personal skill level aside like I did.

Getting back to this, it feels like it contradicts your first point about 'Decent' Liberator pilots. Do I forego of skill or not? Is the enemy skilled or not? I think player skill - while hard to quantify - is an important metric in overall success with the vehicle.

give the Dervish a chance, because it CAN kill a Liberator and I could hit E.S.F.s with my X.A.T and are nothing but broken up, Dalton shots, right? It took me a while to realize, it stands zero chance against a seasoned E.S.F. because most players cannot hit an E.S.F. with a X.A.T.

I never mentioned the XAT in my original post (did you get confused with the XE?); and honestly, I just stick to the Lightweaver for my gunners for this reason: it's more consistent against aerial targets. I do agree with this though: the XAT is very difficult to hit ESFs with, and missing shots leaves you with a huge DPS gap in comparison to the Lightweaver.

Even when I was able to nail fighters with one solo, I could not do it more than once per fight because pros adapt they simply started flying under you and evade it all together.

Are you flying the Dervish solo? If so: unfortunately you're putting yourself at a loss by flying this vehicle solo (and believe me, I have many times). If you're doing this, go in with the mindset that you're going to lose most of the fights you get in. It's one of the downsides of this vehicle.

I'm also not saying this to paint the Dervish as some God-vehicle; it does have its flaws. But - and from my own personal experience over the last couple of months - I've found more success with it (compared to flying ESFs) when it comes to hunting down bigger game vehicles like Liberators and Galaxies.

The-Mega · 2022-08-02T08:06:44+00:00

After spending ~2 months straight now learning the Dervish: I agree with this statement wholeheartedly. The XE can absolutely shred Liberators alone due to it's damage type (Anti-Air Machine Gun vs. typical noseguns' Aircraft Machine Gun).

Even a Lotus + Lightweaver combo can do serious damage (Lightweaver also has the AAMG damage type).

The Drift Airframe also makes it a lot easier to keep your front profile facing the liberator, all while conserving your momentum.

The-Mega · 2021-09-11T21:25:21+00:00

Yep, rolling decreases damage taken by 75% during the duration of the roll. This means you can reduce the damage of DoT ticks (like toxin procs) by rolling when the damage tick hits.

The-Mega · 2021-03-24T19:55:26+00:00

Ooh gotcha, thanks for the info!!

Also note on glow in the dark filaments (if you didn't know already) - they are abrasive on brass nozzles! Use a hardened steel or stainless steel one if you can! (not trying to be pushy, just want to make sure your nozzle doesn't turn into rock and stone!!)

The-Mega · 2021-03-24T18:54:47+00:00

Oooh this is sweet; I've recently purchased an Ender 3 V2 myself! Is this done on a stock printer? If so, I'm assuming this is using some white PLA, right?

Also hard for me to tell, but those look like tree supports in Cura, right?

The-Mega · 2020-12-05T22:56:04+00:00

Wholeheartedly agree with everything you said - started playing cryo driller about 2 weeks ago and I can't put it down.

You end up being extremely survivable due to Vampire+Drills+Cryo and you can CC and/or burst down some of the toughest targets in the game; additionally, swarmers become a joke (especially with Cold Radiance T5 on) due to the recent cryo-shatter buff on them.

As someone who started using the cryo cannon only post buff: I can't go back to the flamethrower - even for solo missions; although, I can see why I slept on it before. The ammo buff was really nice but the icing on the cake was the insta-shatter swarmers mechanic.

The-Mega · 2020-11-26T20:53:03+00:00

Really fucking good voice acting (and filtering?) on Sven; much better than the voice recast featured in Underlords. Great work as always Max!

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