Parts Cannon of the SENTRA! - Part 1 (No Start, No 5V Ref?) 

I love how you showed the pre-game process on this one. Very insightful. cheers.

Having shops contact you for help despite you being so far away must be a really good feeling.

A couple of points: When probing those bulk connectors, it's sooooo easy to make mistakes comparing the connector diagram to the connector, getting it backwards, upside down etc, especially if you're not sure whether the diagram represents the plug or the socket. Yes you can check the colors of the wires you're probing, that's good. But I note that the plug was labelled with row and column letters and numbers. It would be good to inspect the corner wires, correlate those to the diagram, and mark up the diagram with letters and number matching the connector. In other cases, you can use a marker to pen some representative numbers onto the connector. This small preparation step saves having to puzzle out each pin individually and accidentally probing a wrong pin, getting a result that sends you off in the wrong direction. A second point -- as usual, Ivan consistently recites what he expects to happen and what different results will mean, before performing a test. This saves you from the problem that if you haven't thought through what results you expect, when you observe the results your interpretation of them may be colored by some pet theory you have in mind already. This can lead you astray. Good job Ivan tracking down the problem with relentless rigor!

What I really liked in this video is how you planned and then took the time to show and explain to viewers why you did this. One thing to keep in mind is some or all of this plan is subject to change when you get to the vehicle. But since you took the time to locate the wiring diagram, you are way ahead in your diagnostic strategy. You're on the right path to success, can't wait to see part two!

Plan the work then work the plan. I like the systematic approach. Much better than going in blind and wasting a bunch of time. Having the wiring diagram is a valuable tool that most shops don't take advantage of.

Ivan. Am loving your weekend multi part episode format. Thanks for all your RU-vid effort. Keep it up.

I like the way you show the average DIY mechanic how to set about tackling a situation, you become the ECM, monitoring the 5v reference.

Your method of locating a short circuit in the wiring with the DC amp clamp is super clever. I have never seen that trick before.

What a fantastic case on how to troubleshoot for shorts on connect circuits. Always learning from your process Ivan. Thank you for being who you are and sharing your knowledge.

Really appreciate that your're training us as you diagnose. Super helpful. Thanks Ivan!

There are at least 200 problems I am thoroughly prepared for, if they ever happen on my car. Thanks to Ivan! I like the split into part 1&2 to give time to think about it, rather than just a quick video to watch.

Hi Ivan, I like how you create your plan of attack by researching possible causes. Saves a lot of time out in the field. Looking forward to your discovery with that harness in part 2. You and your family stay safe.

Ivan I learned so much on troubleshooting watching your channel.Thanks

Love the way you show your planning on how to execute the problem and how you are executing the plan very interesting and very cool thank you so much

Having an action plan is the way to go, not just for away trips, but also for whatever you are looking at in the workshop. obviously having an action plan for away trips is an absolute must do, we all know working in a different location can mess with your thought process simply because you are away from one of your comfort zones.

I do some mobile outboard repair. I also study before I go into the field. I have to be careful not to drop customers parts or my tools in the water. 🤞

You explaining your prep work is priceless!

Always excited to watch your videos Ivan

👍 Proper planning can save a whole bunch of time and headaches. 👍

I still view sections several times, but it is the beginning of understanding. Thank you.

Good job to do some homework before you attack the problem. Your diagnostic flow chart in your brain is impressive...Thank you for sharing this diagnosis.

Ivan, an excellent video teaching us the way its done. Looking forward to Part 2 and the sound of that car coming back to life. Thanks for Sharing!

These videos are gold to the beginner,mid level, and expert techs. Endless testing procedures to have in the arsenal along with the best part! The unveiling of the problem circuit. My assumption is the catalyst is plugged getting stupid hot and the wires inside that corrugated metal oven loom got so hot it took the insulation off the wires which caused the ckp sig wire to short either against another bare wire or that loom itself? Another great one Ivan!

This is a great diag! Hopefully the engine wasnt overheated and melted those wires... Time to watch part 2!

Ivan I like your videos and more importantly that you are open to share your experiences and knowledges. Others channels don't which is sad independently if they get a small cut. On today's video you detailed some process that are helpful to understand problem solving, so an educational video showing the issues with battery, harnesses, lights, etc will be great.

This is a norm with these Nissan. I have replaced the jack or harness for this type of vehicle numerous times.The exhaust heat tends to make the jack brittle and crack when removing. Very easy to cross up the wiring and get the P0335 dtc. I saw a guy blew an ECU because of that. Never got the 5v ref circuit short so this was new for me to see the outcome. Thanks again

I don't know how you guys do it til I heard you say "ok lets get into the field and have some fun".....Then it sunk in....

DEAR SIR IVAN: IMPRESSIVE EVAULATIONS OF THE FULL PICTURE OF DIAGNOSTICS. RIGHT ON THE MONEY. YOU ARE #1 DIAGNOSTIC TECH. GARAGE OWNER IS SUPER LUCKY TO SEEK YOUR EXPERT KNOWLEDGE. YOU ARE THE BIGGEST SUCCESS IN THE AUTOMOTIVE REPAIR INDUSTRY. KEEP UP THE GOOD WORK. THANKS A MILLION.

as ivan mentioned in a video that you have to love what you do for living..golden quote..i had one toyta yaris 2007 and it was collapsing on its face after hour or so.it came from a so called technician.problem was near firewall from wiring lome it had a 5volts reference wire broken so dumb tech added a LM7805 near ckp and provided 5volts to the wire which carry for all sensors so after 7805 was getting overtemp it was shuting down reference volts.can you imagine how these techs made problems worse

Brother, you made that look so easy!! I wonder how many people watching realize how difficult this problem would be to isolate without the very specific techniques you are using here! I’m pretty sure I personally would not have been able to target the fault on this one. A wire to wire short to ground on a 5volt ref circuit is INCREDIBLY UNCOMMON, and to not end up a needle in a haystack situation, requires techniques that I did not have in my tool bag until now. You could go a career in a shop and never see this problem! Super well done man! Thanks for the education! That was awesome!!

A very professionally done diagnosis. Planning is so important, and I would be planning what to check/do nearly all night (couldn't sleep). I know how it feels to have this kind of responsibility. To attempt to answer your question, the wires got hot in the beginning because of the heat from the exhaust. This heat melted the wires together, nearly shorting them together (estimating 0.2 Ohms between them, if correct, drawing or trying to draw about 25 Amps from the 5V Ref), causing a large current draw, which added considerably to the heating. Good job Ivan, and the explanation in the beginning is a great addition. Thanks for making the video. Omegaman

Great planing! Has to be much easier to look stuff at home than in the field with unknown weather, cell service, customer over should etc. etc. Looking forward to part 2.

Thank you for the behind the scene preparations on those call out diag jobs and the background work needed (if it can be done with the available information like here) along with the breakdown of fault finding. 👍👍👍

Really nice to see the homework phase of the diag. Thanks for sharing Ivan.

My guess from past experience on the meltdown , “someone” was in there before for something and did not put things back as they should have, but probably made out on the flat rate time. Nice work Ivan.👍

I kind of doubt that's just poor wire routing, as much as I'd like to blame Nissan. Seems more likely that someone was in there before and failed to route stuff as factory and left something too close to the manifold. OR.....someone was playing torch the fastener (something stuck) and was very sloppy.

Ivan, AWESOME approach and thought process appreciate the time and effort to show and explain ur method of diagnosing such a hard problem to solve as always learning from the best thank you.

An excellent video, showing all of the work that you have to do before you can leave for the client.

Great diagnosis and insight in how your thought process works. Research and resources are key.

Ivan, i like your game plan and see what's the diagnosis before you work on a car. I like your thinking!! It's like surgery to find the right wire lol!! Getting there!! Great video!!

I like your approach Ivan. Great video! Here's a challenge for you or any seasoned tech: Try and diagnose an electrical problem without looking at a wiring diagram. One must have a solid understanding of electrical theory and operation and precisely how components work. I have actually done this to challenge myself and make myself better. I had to map out the suspect circuits. Took plenty of notes and was successful. Try it! Thanks for sharing your knowledge and experience Ivan.

Ivan, in the Aerospace industry we use a Time Domain Reflectometer (TDR) to pinpoint exactly how far down the connector the Open/Short is located. Saves lots of time and money hunting down wiring problems.

Great video and brilliant insight into how you go about preparing before you're on site Ivan!

I remember a Sentra from around 83 that was a nice car, not fancy but but roomy and elegant none the less

Very interesting video. That is a very unusual problem. Great Troubleshooting!

This pre-game analysis was very interesting, and obviously prepared you well for the job. My guess on why there is a Part 2 is that after the 5V reference circuit is restored, there will be some complications when those new sensors come alive, since the answer to "are they OEM" was something like "not sure". I'm looking forward to seeing Part 2.

i cant wait part-2, hurry-up , its interresting for me

Lovely rd and trees .

Cliffhanger! I anxiously await part two 👍

Routing wires close to exhaust is called PFIR in service departments. Planned Future Income Repairs.

I don't think they teach the Binary Search algorithm in "Technician 101" programs at the local dealership unfortunately. "Factory Trained" basically means little. My buddy who worked for a dealer told me that they literally go out to new cars on the lot to salvage parts for troubleshooting. Unlimited parts cannon, and if that doesn't work they simply replace harnesses until they find the right combination!

When you said AC pressure was on the circuit, I remembered a crashed Nissan from the body shop, a no start that had pinched the AC sensor wires and had the same issue. Yours in on the Crank sensor itself, but that is possibly a repaired vehicle I wonder as well?

I also order the AC clamp on your link above. Like in many things in life, Research is critical it can make it easy or hard depends on how well you do it! Great video by the way!

I went ahead and ordered that clamp meter through your link. I was going to buy it before, but it was like $50.. but now it has dropped to $30, and I do need a DC amp clamp, so that's a steal.

This situation is “Heating up” !

simple but brilliant

Hi Ivan. Absolutely love your testing methods. Could you possibly do a video on how to find which way in the harness the short is with your amp metre. Still trying to work out how you know which direction it is. Also I noticed that brown pcm connector is a delphi 48 pin female connector. I tried to depin one recently and gave up 😂. How do you depin them? Maybe a separate video on depinning connectors would be massively appreciated. I searched RU-vid on that Dephi connector and not one single video on that specific connector. Cheers. Michael C

And you're still having fun!

Great lesson on job planning, Ivan! Also, great approach to finding the short without dismantling the whole wire loom. Molten plastic means temperatures too high around it - too close to the exhaust pipe? Poor design, or incorrectly placed in a previous job? Now waiting for Part 2 - this is very interesting :-)

After reading the customer request, and using a diagram, where the DTC's showing have a common dependence of a 5 Volt reference, the 'unplug' sequence is the next step. I am more likely to measure a perceived load with the ohm-meter (Rx10 scale) on each sensor, and note it (comparison between OEM and non-OEM), but still think the light is just as effective to find a short to ground in the wiring loom. It is quite possible that some mechanical work was done without checking the 'hot' spaces around the exhaust manifold, and perhaps leaving a heat shield uninstalled. I eagerly await 'Part 2'...

Not all heros wear a cape. But defo going prepared for the win! Do you add this preparation time to your charges? You need Eric O’s wire nose / ability to sniff out those breaks/shorts😝

Thanks for another video PHAD!

At least grumpy called the right person

cliffhanger!!!

The wire loom likely broke away, or someone helped it, from it's OEM attachment. Or, there was something else that broke away or got too close to the looms that was hot enough to damage them, exhaust or EGR tubes etc. Could be collateral damage from something in the past too. This vehicle has about 150,000 miles on it so it made it that long without issues which is suggesting to me, the issue was human related or a material failure. It's still early but, if the CPS isn't OEM, may as well put one in now since everything is accessable.

Parts cannons always cause more problem for absolutely everything in life

This is better than Sherlock Holmes.

I’m just a DIY but for several years I’ve owned an ES 687 amp clamp with a narrow beak which I think is better suited for automotive work. The specs aren’t lab scope specs but for this type of troubleshooting they’re fine. The wide jaw ones I keep thinking it’s an electrician’s clamp.

Hot exhaust? Either things weren't in the proper location, or the engine has been running lean for some reason.

Dorman sensors, could very well be the problem, since Dorman products arent good with sensors, I believe one may have carried too much current/voltage and shorted with wire next to it. Cant wait for part 2.

I would tred lightly putting a 12 volt power source to a sensor that is expecting 5 volts supply ...unless module has voltage regulation built in this can be an issue. Invest in a 12 v to 5 vdc converter...also good to have pin pushers to rule out short in connector ...

I have an Early 1990 Nissan Sentra with the last 3 Vin numbers of 666. Believe Me it lived up to those Numbers. If You are interested in it and You are not afraid of those Numbers, let Me know. I live near Asheboro North Carolina. Some Garage that My Dad took it to used an impact wrecnch on one of the spark plugs and the gasoline is probably dead in it by now.

Arrgh! Left us hanging...

He f up the car going part's at it to sell parts 😂😂😂😂😂

Right when it was getting good! dang..

it could be beacuse of that heat shield around wire gets hot and melted all wire and connect all together to the shield itself.

Be waiting on part 2 .

well done Mate i love it

Harness looks like it got a little too hot, exhaust heat or excessive current ? A lot of times with an in harness short I will run a new wire to save time for ripping the harness up to find the short. Not always easy to access especially in 60 of 120 wire harnesses. Like the mini test bulb.

I used to like Nissan Sentra's, but they have gone down hill over the last few years. It doesn't matter because I don't drive anymore.

All I can say is WOW

my life story, wires shorted in the middle of no-mans land of harness. now find the problem with no diagrams/schematics and minimal tools or none. 🤣

How is it that current remains @ 24:43 but then goes away @ 26:55 when the battery voltage is removed on the same exact green/red wire within a foot of each other? What is the "Theory Of Operation" ? 😊

Brillliant!

When you're doing the amp draw test to find the culprit how do you still get current flow when you remove the test light clamp from battery positive? [24:40] I thought that was your only source of power for this testing. Did you go key on somewhere and I missed it?

Great video, Ivan. I have never thought of using an amp clamp to find a short in this manner, I’m going to have to try it out! When will we get to see the Maserati diag?

Ivan, does it surprise you at times when another independent shop ask for your expertise? The only time in my entire career did I have to require additional assistance was on my 01 Chevrolet Cavalier, the 5 volt reference was all kinds of crazy and the scan tool while the car was running had the following values on the data pids, the car while in park registered a maximum speed of 100 mph, load was at 89 percent, it was jumping from closed to open loop, and other values like long-term and short-term fuel trims were unsteady. I had to have an actual engineer from GM come in and help me, the wiring harness that travels underneath the lower core support had a couple wires shorted out, my wife hit a concrete curb while attempting a left turn at a stoplight, a stray car ran the red light causing her to eat the curb by where the yield concrete pad was located, she hit it so hard it blew the pcm fuse but unbeknownst to me she severed some critical wiring, this was back when I was a greenhorn around 2003 and that expensive experience I NEVER FORGOT and now that I'm a veteran of the trade I have a particular process I always follow regardless the evidence present unless it's really obvious that the problem is right in front of me. My wife treated that Cavalier like a red headed stepchild, I watched her go Dukes of Hazard one morning at my former job at the only Ford dealership I've ever worked for, I cringed every time she was abusive towards my car but deep down she knew I was capable of fixing it even though I didn't always want to be fixing my stuff 24/7/365 due to the politics and burnout that seemed to reach a boiling point until I checked out for one of my week vacations. The Navistar 6.0 diesel engine was most of my grief back then, between the coolant causing pits to the deck of the block,heads, or both. The EGR cooler was junk, Fords program was shit while Navistar had ABSOLUTELY NO PROBLEMS from the 6.0 engines in International trucks, I hated that engine due to its willingness to blow up while being on the highway, it would toss out 7 and 8 rods but still run with the added crunch, crunch sounds. The 6.4 was no better either, I actually watched a video of this F350 with that baffled exhaust tip shooting out flames burning the car next to it's paint!!!! I knew i was in for another nightmare but being able to get through the 6.0 made my job a touch easier until Ford and Navistar started a lawsuit in regards to techs and Dealerships get the monetary shaft from Navistar for credit for cores or warranty time not being paid, (post approved) mechanic time to disassemble ambulances and remove emergency lights and sirens, normal warranty pay was jerked around due to International Navistar piss poor way of playing hardball but nevertheless Navistar ate that two time crap sandwich and Ford left them behind by building their own Diesel engine and it was a dream to work on even though the EPA micromanaged the full process including the def fluid to the regen process for them trucks that never reached the proper temperature to burn off the soot in the Dpf, I always had a F250 or above come in at half power requiring regen to be performed, I would find a cool spot without no flammable materials near the truck since the exhaust temperatures were getting ready to head up to the level of causing grass fires or oil fires if the engine was a leaking oil. Rarely did I have to replace the DPF system due to the ignorance of the elderly customer who had been oblivious no thanks to the lack of education being provided to the salesman about what to do and not do with these trucks, I always say that if you are not going to travel over 40 plus miles to ensure that the regen during regular driving operation conditions is accomplished, just driving to Wal-Mart or Food lion will NOT CLEAR and Clean the DPF.

I do the same when I am asked to do a mobile diag. Homework develop a plan then follow the plan. I am concerned about you and I though. I think there is something wrong with us. We both find this fun and satisfying when we solve the problem. On my side I think it's a mental illness. I can speak for you though. 😆😆😆

Sad part is that the customer pays for them to play “mechanic.”

Hi Ivan At the field or in the workshop the auto-electrician would need wiring diagrams for the specific car that has a trouble. Next day you will face a different car and so on. How you get instant reliable wiring diagrams for all such cars. Is there a contract with e.g. Michel 1 to enable you to download any wiring diagram you would need for different cars and how much we have to pay Michel 1 to sign such contract and get any drawing for any car any time. Please advise. Thanks

Instead of unwrapping the darn thing and showing us where the short existed, YOU ROLLED THE CLOSING CREDITS! (Not even any bonus footage.) That is O.K. the Marquis has laid down and I need to get it running. I went to a local restaurant and had to call for a tow. It wouldn't even click; I tried jumping it from my F-350 to no avail. The tow company sent a roll-back and I got that thing home and rolled it off the truck right into my garage bay. My dad had a battery tester that simulates a load, so, the battery was good when I checked it. I got my test light out and had power to the starter. When I finally got those 3 10mm bolts out there is this thick copper wire that goes from the solenoid inside the starter that has NO insulation on it that contains many green crusties that is burned in half. Well, THERE IS YOUR PROBLEM LADY! I guess I'll need to wait for part 2. Great video!

How dare you! When is part 2 👍

what, a Datsun(lol-nissan) with actually useful schematics and diagrams!

Great diagnosis Ivan. Quick question for you. How were you able to decipher/understand the amp clamp readings to figure out where the short was located Werner it was upstream or downstream? I’ve never seen that method used

Wires may have gotten hot because of an exhaust leak perhaps.

Nissans are picky. I have a 94 Altima I'm still using as a DD for work. Great car.

cliffhanger

Why do people throw away original parts. Unless its proven that it was at fault the parts should be stored for the customer.

WHY NOT poke the accelerstor pedel and look for voltage variances on the scan tool? Doesn't that (-1-) validate operational sensor; (-2-) good ref V to sensor; (-3-) good ground? BRILLIANT! clamp on current test to rule out a connector short. And excellent to use clamp current probe at select points... I wouldn't have thought to... I'm WORRIED that you are seemingly so close to finding the short but that there's a PART 2... so are there more mysteriea to come?? YIKES! BAD ECM TOO from the short?

Do you know if the astro amp clamp measures down to 20-50 milliamps pretty accurately? As in testing for a battery drain.