Diagnosing P2647 Rocker Arm Press.Sw. Hi Voltage- But I Have No idea What It Means!

[@keithfarrell9875]

I think your one of the best educator's on KZbin.

[@SchrodingersBox]

Thank you!!

[@wolleyreikivalley]

@@SchrodingersBox you’re my favorite channel

[@FreeKanal]

No doubt !

[@Dr.AymanKamar]

For sure

[@neverstoplearning382]

I agree.

[@reneneron2971]

Matt, the “advanced “ VTEC adjusts valve lift and duration, valve timing, and even the number of intake valves open. Impressive.

[@SchrodingersBox]

Yes as I researched this I found there are all kind of goofy VTEC strategies- even including shutting down half of a V6 engine. It seems like such over-engineering to maybe save not even .1 Mile/gal but I guess if you do 50 things you save a couple more per gallon overall.

[@kayjay4060]

@@SchrodingersBox The cylinder deactivation VCM is a failure. It is all about money and E.P.A. so they can't admit it, and continued to push out these engines knowing they are really bad for the environment. They suck in oil, combust it, clog up the oil passages on the pistons, and gunk up the rings. Cause cylinder wall scratches, and destroy the engines. Especially cylinder 3. You can get devices to stop the ECT from reaching operating temp, and tricking the engine into thinking it is still getting up to temp. This keeps VCM disabled.

[@AGuysGarage]

Hi there rage 73 here long time viewer. Thanks for sharing, good troubleshooting techniques as always. In the future if you use a sketchy meter you can always touch the probes together to see what resistance is there before you measure the part you're measuring then subtract whatever was there when you started that's just for the viewers that don't have multiple; DMMs. PS the VTech kicked in yo, little throwback there to the 90s ricers

[@SchrodingersBox]

Hey Rhage!! (I remember it being with an H- maybe I’m wrong lol). Yes that’s exactly the issue - when touching the leads I get 1/2 ohm. It’s actually my positive lead wire that’s faulty.

[@nokalamaduna2709]

Awesome case study Matt as always, much appreciated.🙏

[@rightconditions2010]

I stay with what you said in the beginning: dont panic, you have the fundamentals, and it is the same system.

[@michaelhomdus4945]

Great video, learned lots. Thanks for bringing us in.

[@neverstoplearning382]

The doctor is back.

[@ashercohen4739]

Thanks for the study, it was interesting and also the way to find the problem, thanks

[@jgeorges3061]

MATT. AWESOME approach and thought process one thing the CODE IN THE SCANNER IS P2647 is deferent from what the video is referring P2467 i think the scanner code is the correct one hahaha thanks for sharing brother. cheeers

[@SchrodingersBox]

Aw dang I didn’t catch that Lol!! Thanks I will fix the title!!

[@HouseCallAutoRepair]

Was wondering who else caught that....

[@JimFinlayson]

Great video. I learn so much about diagnosis.

[@SchrodingersBox]

So do I !! This was a new system for me.

[@DependableAutoTruck]

great job i have a 2007 jeep grand cherokee freon leak coming out of the trans fluid filler tube. it is one of the systems that doesn't have a stick has a sealed fitting that you remove and check with test stick and scanner. was so odd my daughters vehicle kept loosing freon couldn't find any leaks anywhere sniffer always quite. she ask for me to check trans fluid while i was there my helper was still sniffing for the freon leak around evap drain and dryer area when i opened the trans tube sniffer went crazy put plug back in sniffer went silent. come to find out upper portion of condensor is a trans cooler lower portion of the condensor is just a condenser there is a common tube on each side of condensor unit with a block of some kind to keep them from mixing. talked to a friend of mine retired from dodge said they had a lot of problems with that system doing just that

[@michaeldraper6558]

Okay Matt thanks for clearing that up believe it or not I have an electronics degree and during school we always measured measure digital circuits at 5 volts

[@SchrodingersBox]

No worries! yeah anytime I see a messaging or signal circuit I always assume it’s 5V because most of them by far are. But it is absolutely true that some references are 12V. I see that maybe 10% of the time. In fact, on some cars like Volvo they can even be 10V!!! Now that will really throw you off course if you aren’t aware!!!!

[@Dr.AymanKamar]

Very helpful video Good job my friend

[@SchrodingersBox]

Thank you as always Dr Kamar!!

[@ThunderbirdRocket]

Awesome work putting the Official Shrodingers Box Automotive Repair Training Manual together ! Very well presented / articulated & user friendly !! 🎯

[@SchrodingersBox]

Ah you remember!! Yes Ayman did such an amazing job with that. I still can’t believe all the work he did entirely on his own. I didn’t even know about it!!!

[@ThunderbirdRocket]

@@SchrodingersBox Yup 👍🏼 ! Amen to that !! 😃 📖 How could I forget the man on a mission ! And I’ll just say another thanks to you for all that you do Matt ! 🥇 Very dedicated coach !

[@wolleyreikivalley]

oh wow, this was exciting to see. I have a 2006 TL. great car. buncha finicky issues but overall quite reliable. I'm finding a vacuum leak at my EGR valve causing my fuel trims to go down from a high of about 20% when I spray the EGR valve with brake cleaner. I used the autoline smoke tester you recommend as its on an even better sale now to check for vacuum leaks and it leaked profusely, then after replacing, it leaked less but still some. I can't find a straight answer on the internet as to whether or not an EGR leak during a smoke test is normal or an unmetered air leak causing a lean condition. lambda AFR sensors are confusing.

[@bernardaflores1720]

unmetered air can cause lean conditions. An EGR should not be leaking at all

[@SchrodingersBox]

correct however a lot of newer EGRs- especially on fords are “positive pressure” EGR valves. they will not act like regular EGR and appear to be leaking but they aren’t.

[@wolleyreikivalley]

@@SchrodingersBox my autozone EGR is leaking but less than the 185K mile 2006 original Acura EGR valve, also causing less of a lean condition. i ordered a Standard Motor Products EGR valve hoping it leaks not at all

[@bernardaflores1720]

@@SchrodingersBox very interesting design on the EGR.

[@wolleyreikivalley]

@@SchrodingersBox where could i find information as to whether my car (2006 Acura TL with Honda 3.2L V6) has a positive pressure egr?

[@n124lp]

Good video. Thanks. I find myself wondering whether your scan tool can control the VVT solonoid. If so, using that control might have simplified your testing a little.

[@SchrodingersBox]

So actually it can but I edited it out of the video because it was useless. there is indeed a VTEC test however it only works with engine off which is totally useless and even then it didn’t work because of some apparent communication issue with scan tool.

[@rrmech11]

Nice job Matt

[@ThunderbirdRocket]

Super helpful ! Above and beyond ! Logic and reason for everything ! Nice 👍🏼 ! Love it !! Thanks mate . 👊🏼 🔥 💡 🦅

[@SchrodingersBox]

Thanks friend!!

[@nadeemahmed640]

appreciated ....good job sir

[@robertfoilesjr1337]

Excellent class.

[@lmstuber6044]

Brilliant video.

[@pfsantos007]

Posting this in my 5 favorite car diagnostics channels in the faint hope someone will pick it up. I'm just a DIY'er that doesn't want to waste money on the parts cannon. 2013 Mercedes E350 with the M276 3.5L V6 - only way I can afford this car is because I do the work myself and stay away from the dealer. Two codes, P2177 and P2179. System Too Lean Off Idle Bank 1 and 2. Long term fuel trims are ~ +40 Bank 1, +30 Bank 2. Fuel trims stay up at idle (+30, +20 roughly), but not as much as when driving. Short terms trims are up 5-10% when driving, then negative 5-10 when decelerating and then stabilize to 0 at idle. No vacuum leaks at idle - 21 inHg at idle. Changed intake seals (green upper, red lower) and MAF sensor because it was cheap - no change. Car drives perfectly fine, no misfires. Pulled oil cap off, no significant vacuum holding it shut. But if I open a propane bottle into the oil cap hole or dipstick, the fuel trims go down, but not sure if that's normal as the PCV system would suck those fumes, no? I know + fuel trims mean too much air, or not enough fuel. But if it was a fuel issue, wouldn't the problems become worse at a higher load? Because car accelerates fine and has good power. No misfires. Also, capped off the EVAP system and brake booster - no change (at idle at least). No other codes, just the two. Scanner shows MAP, Load, Fuel Pressure all responding normally. I’m lost.

[@pfsantos007]

@@plowe6751 Thanks very much for your reply. I'll go down your list and will try to cross off my list.

[@MarzNet256]

You probably have a vacuum leak somewhere if fuel trims improve with rpm. Do a diagnostic smoke test on the intake. Also, propane into the oil fill hole will get into intake at idle if the PCV system is not working correctly and can also create vacuum leak type symptoms if the valve won't completely close (additional air). Finally, check that the evap canister purge valve is working correctly and does not leak when closed (unplugged from connector), you should not be able to blow through it. That can also affect fuel trims.

[@mtrltoolman]

Good job 👍

[@mandytuning]

Everytime i service that solenoid or switch its also a good time for the VTEC filter/gasket to be replaced and the vtc filter behind p/s pump

[@SchrodingersBox]

I totally agree.

[@airratchetjockey7605]

Trans Am gone? Those pressure switches are also used on the transmission and go bad all the time.

[@SchrodingersBox]

Yes blackbird has been traded in for a black cat!!

[@thewolf61691]

​@@SchrodingersBoxyou'll love the cat, been driving them for 6yrs now!

[@madarzudrins9210]

A bit off topic, but how much do you spend per month to access all these electrical circuits from all these different car brands. and maybe which websites do you prefer to use? I understand that there are many things you can find on the web, but mostly this information is not freely available. Here in Europe in most cases you cant even have access to workshop information if you dont have registered workshop. Great video by the way.

[@SchrodingersBox]

Great question. I subscribe to Mitchell on demand for about $120 a month. I used to use the DIY service which is $20/mo per vehicle but now that I do so many more cars that actually became more expensive than just getting the full subscription.

[@samstvshow]

OK end of video - I would like to see the logic of how the ECM registers a high voltage in the faulty state rather than a low voltage.

[@SchrodingersBox]

The reason is because of ohms law. Voltage is inversely proportional to resistance. When the switch is open you have “infinite” resistance so you see full voltage (as was shown on my volt meter- 13.6 V). When the switch closes you now have no resistance which means you have unlimited current. This drops the voltage. Because the oil switch was stuck open when it should have been closed, the PCM sees voltage when there shouldn’t be any and thus sets the code.

[@m.b.smoshitoa8325]

Hi Matt did you buy a new camera for us . Wow lol Moshitoa south Africa

[@SchrodingersBox]

Hahaha thanks for noticing!! I didn’t buy a new camera however what I did do is start posting in 1080p

[@InsideOfMyOwnMind]

I have the non-V-TEK B18A1 that many have Frankensteined a V-TEC head onto and swapped the ECM but not here in the People's Republik of Kalifornia.

[@SchrodingersBox]

My condolences on living in that 3rd world country lol. I have to travel there for work every 6 weeks and I swear every time I go there it’s noticeably worse.

[@samstvshow]

Place your bets now. 18.40 - the switch is either stuck on or there is insufficient oil pressure.

[@SchrodingersBox]

Impossible for it to be insufficient pressure. It either has to be switch is stuck OFF or there is always oil pressure at all times.

[@dimitrist3561]

Can someone please explain what's happening at 23:15 to someone with a very basic knowledge like me. Is he connected to both signal and ground on the sensor and reading battery voltage due to the signal being 13.5v? Does that mean there's voltage freely running through the sensor? Was there supposed to be no voltage or maybe some?

[@SchrodingersBox]

This confirms there is command voltage to the sensor and a fixed ground. The sensor is bad. Voltage does not run through things. Only current does. Voltage does not flow or move. I have confirmed there is voltage but no current. The sensor must be open.

[@markw4710]

Hi Matt. If your leads are adding a small amount of resistance to your measurements (kzbin.info/www/bejne/ppnHc2N9a9GIp80 ), press the 'Relative' button and the meter will null out that resistance and display zero ohms. Great video, as always.

[@GraditelMacedonia]

17:20 My LOGIC says to me,😊 probably that wire is shorted somewhere to B+ 12 volts in installation.

[@SchrodingersBox]

How can that be when we saw a high voltage code? If we saw a low voltage code I might agree.

[@GraditelMacedonia]

@@SchrodingersBox if understood well, hi voltage means presence of 12 volts, switch is not to ground, or im mistaken...

[@SchrodingersBox]

That’s correct. You can never have voltage drop on an open circuit. It’s impossible. Either switch is open OR wiring is open. It cannot possibly a a short.

[@GraditelMacedonia]

@@SchrodingersBox True, that's i mean it...if 12 volts are constantly, then switch are stuck or ground are shorted to 12 volts. For you are easier because everything is there and can be measured...i, must guessing.

[@SchrodingersBox]

if a ground is shorted to 12V then it will create low voltage because you then have current.

[@calholli]

I bet there was probably an actuation test that could have turned on the V-tec.. So you wouldn't have needed to test drive it. Otherwise, clean diag --- as usual

[@SchrodingersBox]

yes there was an activation test but it kept giving me a communication error and wouldn’t work.

[@sheerwillsurvival2064]

They coming for you cats . Lock your doors lock up your cats 🎵🎵

[@SchrodingersBox]

Hahahaha ok i admit he dropped the ball there. Not that the stories aren't true mind you- the police report regarding geese at the local park is evidence enough for me. But so are dozens of murdered women and children that no one can deny is factual

[@sheerwillsurvival2064]

@@SchrodingersBox I was in Haiti several times in the military on different assignments. They eat anything that they can. They are eating the cats . Guaranteed

[@wrenchposting9097]

Haitians are the ones stealing our catalytic converters? Explains so much!

[@michaeldraper6558]

I guess my fundamentals weren't right I'm going to go back over the video again but you yourself in the video that it would probably read 5 volts

[@SchrodingersBox]

Yes I totally expected it would be 5V but as we saw on the DVoM the reference is indeed 12V. Not sure why that is but I often see 12V references used in other applications too- some wheel speed and crank sensor for example may use 12V instead of 5 for whatever reason.

[@wowyummyyy]

L I K E 👍 👍 👍 👍 👍 🤩 🤩 🤩 🤩 🤩 💯💥 💯💥💯

[@SchrodingersBox]

Hahahaha thanks my friend!!

[@turbobuick33]

When did you get the Hell Cat? Do you still have the Trans am?

[@SchrodingersBox]

I no longer have the trans am, sadly. After waiting 7 months for the cylinder heads to arrive after my blown engine catastrophe, I decided that once I got the car running again I would trade it in for a hellcat. The whole purpose of my efforts on the trans am was to make it match up to a hellcat so I decided to stop trying for that at tremendous expense and just get the hellcat

[@2491kridge]

Diagnostic trees are always back asswards, it will go through 27 different steps of testing every little thing and then step 28 will be like “test the resistance of the component, if it’s open then replace the component”. It’s like yeh sure why isn’t that literally step one and if the components good then I’ll start checking everything else in the system lol. I’ll sometimes browse a diagnostic tree but I take them with a massive grain of salt and typically skip around and do the tests that make sense to me for the particular fault

[@SchrodingersBox]

My experience as well usually. That’s why I find it’s actually faster and easier to learn the system first. Once I learn the system, I can do my own diagnostic process that makes the most sense as opposed to blindly following the flow chart.

[@FreeKanal]

Hahah that 7:00 moment made me laugh, thanks again

[@tomtke7351]

~19:10. Switch is closed?? If V = high then no ground present at 0-MPH, 0-RPM.. Let's continue on...

[@SchrodingersBox]

Come again?

[@tomtke7351]

I reviewed and YES I mis heard.. sorry for my incorrect observation. The FAILED pressure switch is open but S/B closed. BTW... Anymore, today's troubleshooting includes (as you did) significant RESEARCH.

[@SchrodingersBox]

I don’t follow how you come to the conclusion no ground is present from that?

[@tomtke7351]

​​@@SchrodingersBox see my correction of MYSELF. My ear heard wrong. As you laid out: ◇solenoid closed=switch open ◇solenoid open=switch closed

[@SchrodingersBox]

Ok got it. No worries!!

[@georgebell3964]

👍

[@samstvshow]

29.00 - remove the old fault code?

[@SchrodingersBox]

Yes I cleared the fault code prior to driving it because it is a one-trip code so I can easily see if something is still faulty.

[@samstvshow]

@@SchrodingersBox Cheers!

[@76ameer]

How the ECM knew this high voltage situation?

[@SchrodingersBox]

PCM has an internal resistor so when the switch is open there is no voltage drop across that resistor. When the switch closes and creates a ground, there is voltage drop across the resistor and the PCM sees it and knows switch has closed. What is odd to me is why it’s 12v instead of 5v. That’s odd to me.

[@76ameer]

The 12 volts may be due that the oil pressure switch is not a variable resistor being either closed or open and needs 12 volts to operate via the PCM to be able to monitor its operation.@@SchrodingersBox

[@SchrodingersBox]

The voltage doesn’t operate the switch though- the oil pressure does. The voltage drop is not measured across the switch- it has to be across an internal resistor. The real question is Why can’t it do that with 5V instead of 12? That’s the real question.

[@76ameer]

@@SchrodingersBox I would suggest ( hoping its a good idea) you try to activate the switch with 5v to see if it response or it needs 12 volts.

[@SchrodingersBox]

That makes no sense whatsoever. We already saw from the wire diagram there is ALWAYS voltage to that switch at all times and the DVOM showed it is 12V. Look at the wire diagram bud. You are suggesting there is a power side control on a simple switch to actually move the switch!!! ALSO- Exactly how do you suggest I put 12V to a default closed switch without burning it up or blowing a fuse? Good thing the way you suggests how this switch works is impossible or every house in the world would catch fire lol.

[@samstvshow]

Also oil check? Is the oil cooler working? Did the switch get cooked? Why did the switch fail? (stupid manufacturers not doing a good job?)

[@SchrodingersBox]

We can see from the PIDs that oil temperature was normal. These switches are common failures. In fact the same switches are also used for other pressure sensing such as in the transmission and they often fail there too.

[@Scooterdude01]

There not getting my kitty 16:51

[@tiitsaul9036]

I didn't know you guys have roundabouts in America.

[@SchrodingersBox]

Hey Tilt great to see you!!! Yes we do but they are very rare. Usually it’s a disaster because of it. People usually keep stopping at them even when they can go through. And of course they go very very slowly because they aren’t sure who has right of way. But as the video shows if people know how they work they are very efficient!!

[@michaeldraper6558]

with new switch installed voltage should read 5 volts at the switch

[@SchrodingersBox]

How is that possible? We literally measured 12V at the source. Please explain.

[@BblastedD]

All your Hellcats are belong to us.

[@SchrodingersBox]

Hahahahaha I forgot about that meme!!! I wanna say Wing Commander right?

[@hstmob8489]

I got a 2003 Chevy Trailblazer 5.3 L and it turns off when driving and won't turn back on for another 30 minutes

[@SchrodingersBox]

what data do you have?

[@wrenchposting9097]

Haha vtec! Classic 4chan meme

[@hstmob8489]

Please help me 😢

[@dro2204]

I used to enjoy this channel… it’s unfortunate you forgot what being humble is about. You did all that nonessential talking when you have access to Mitchell/ all data. Could have easily followed the TECHNICAL SERVICE BULLETIN put out by actual engineers who put that vehicle together. Oh well… I’ll stick with scanner dancers page.. not a pompous ignoramus that runs this channel.. thanks for all the insight in your earlier and way better videos

[@SchrodingersBox]

Smh lol. EVERYONE has access to AllData. EVERYONE. It’s how I have always done it- $20 one-time fee for a month access for a car. Even so- Follow the TSB hahahahahahahahahahaha. Ok and what happens when replacing the switch per TSB doesn’t work? YOU will just stand there like an idiot with a wrench in your hand drooling like a retard while everyone who watches my videos knows the switch wouldn’t have fixed it in the first place. By the way… the engineers don’t write TSB’s. It seems you don’t know the difference between a TSB and a troubleshooting procedure or flow chart. You are just failing at all fronts man. Good riddance. If that’s your mentality after supposedly watching this channel for a long time, you clearly never learned anything anyway. Stay basic.

[@paulpaquette1961]

Wow, Matt is one of the most humble people on KZbin. Over the many years he has taken advice and help from some of the best Automotive Diagnosticians in America!! This man is doing a service to the DiY audience in showing what it takes to do diagnostics. To the people that think there was a shorter way to arrive at the final answer, your right usually there is if you already know it. A diagnostician does not think like this. We start our evaluation at square one, no matter what anyone says. There are no right steps to take, you take the steps that the data leads you to take. Another great vid Humble Matt!!!

[@SchrodingersBox]

@paulpaquette1961 thank you so much man but I do have to say I don’t think too many would call me humble hahahaha. The swagger is part of the differentiation of the channel. I love my test light btw!! I use it all the time !!

[@paulpaquette1961]

@@SchrodingersBox I heard they weren't making them anymore, the OTC 3633, I ordered 4 more, I can't be without that light!!!

[@SchrodingersBox]

Weird- I thought Scannerdanner was going to have some branded version of this exact light- guess that fell through?