Dirty MAF Sensor Case Study

2000 Toyota Corolla MAF sensor testing. Using a scanner and labscope.
Trouble code P0171 in memory. How to determine what is causing the engine to run lean.
Symptoms:
- low power
- hesitation
- check engine light with a P0171 fault code
Fix:
- clean dirty MAF sensor
Test procedures shown:
- how to test a mass airflow sensor
- how to use a the oxygen sensor at wide open throttle to test fuel delivery
- before and after cleaning scan data and scope measurements of the MAF sensor
- throttle position sensor will not reach 100% on scan data
- how to clean a MAF sensor
Tools used:
- Lab scope
- Scan tool
- Back-probing pins
- Brake cleaner/MAF cleaner
Related videos:
- How to troubleshoot a faulty MAF sensor
• How to troubleshoot a ...
- How to test a Ford MAF sensor
• How to test a Ford MAF...
- How to identify and clean a dirty MAF sensor
• How to identify and cl...
- How to identify and clean a Dirty MAF Sensor
• How to identify and cl...
- False MAF sensor trouble codes (cracked air intake tube)
• Low power, lean condit...
- MAF and lean codes from a missing air filter (P0171, P0174, P0102) • Cold Air Intake Warnin...
- How to test a 3-wire MAF sensor (wiring and sensor tests)
• Substituted values (Sc...
Playlist:
- (Chapter 12) Mass Airflow Sensor Testing
• (Chapter 12) Mass Airf...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
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On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.

[@PineHollowAutoDiagnostics]

Working on my friend's 2000 Tacoma truck today. Same P0171 code, plus a P1133 (A/F sensor circuit response). Drove around, long term FT topping out at +39% at higher engine loads, but negative at idle. This video instantly came to mind. Checked fuel pressure just to make sure, then went after the MAF. BINGO! A little electronics cleaner and a light brush...truck drives like new now! So why don't these sensors have a self-cleaning burn-off circuit like older MAFs? Once again,you're the man, Paul!

[@ScannerDanner]

Yes. The MAF sensor is actually a mini computer. All of the conversions are done inside of it. All computers need a main power and ground to work. So you can think of the 12v feed and ground on this MAF sensor as the same thing. IT is actually a MAF module.

[@Airman..]

you never over killed a single video on your channel cause your knowledge is priceless

[@ScannerDanner]

thanks so much!

[@mike-yp1uk]

this video is not for amatur mechanics. It is accurate and packed with infomation for trained professionals who may have missed or are trying to deepen there knowledge. You have to watch it a few times to gather all the info and check out other videos and spend some time studying. Great and accurate video as usual. thanks paul.

[@ScannerDanner]

Thanks mike r!

[@ScannerDanner]

@MrMratni Thank you very much and no problem. I am glad you liked it.

[@ScannerDanner]

Good question, as for the vacuum leak issue. I have never seen that effect the baro calculation. Also after cleaning the MAF, you have to reset the KAM or disconnect the battery for awhile to clear the baro calculation in memory.

[@chief455]

just bought a 2001 Corolla with code PO171 thinking O2 sensor, reading some tech found more likely a dirty MAF - this video is awesome! I not only see the how and why it makes sense - but your explaination helped me understand data I have been logging on a racing V8 car as well with fuel problems. this is internet at it's best, thanks for sharing!

[@EP91STARLET]

Had an exact same problem on a 2001 Yaris and this gave me confidence to confirm my repair after I had cleaned the MAF, great videos!

[@ScannerDanner]

@lucky51762 Sorry, it was a snap-on verus and not all MAFs can be cleaned. Just the hot-wire type. Thanks for your comment.

[@kevinemesiobi6169]

Great diagnostic strategy, Using just the scanner to narrow down on the fault, that's a show of in dept knowledge on auto-diagnostic.. Thumps Up......

[@ScannerDanner]

Thank you Kevin!

[@429psi]

This info is absolute gold! Best diagnostic videos on the web hands down. I highely recommend the ebook people, I will be buying the lecture videos also. Thanks for the wealth of info paul, keep up the good work!

[@sebsbae9149]

El Paso TX right here... Keep it up ScannerDanner... this channel is music to my ears...

[@ScannerDanner]

@jdrums5555 Thanks for your comment. I am glad you liked it. For more resources check out my website, its listed on my channel page.

[@ScannerDanner]

@chief455 Thats great! Thanks for your response. It helps to know that this video was clear and useful. It keeps me motivated to keep filming more.

[@ScannerDanner]

I'm ok with the initial drop lean on a rapid snap to WOT(sometimes you see that, sometimes you don't). Just make sure it stays rich the entire time after that.

[@richardashcroft4596]

Thank you Paul for this, my ‘11 Cruze LS has P0171 code. Will be testing this method on my way to work tonight.

[@ScannerDanner]

@GamingJediPwns you are mistaken on that comment. this style of hot wire maf is not damaged by the cleaner i used. its just a heated resistor with a glass covering. I've been cleaning them this way for 15 years with ZERO comebacks

[@jdrums5555]

great videos scannerdanner lots of good info,i just graduated from ATS school in sacramento and i am getting ready to test soi am reading all my books and watching all your videos very helpful thankyou.

[@ScannerDanner]

@03mazpro a dirty mass air flow sensor will not cause a catalytic converter trouble code. if all you have is a converter code and no exhaust leaks then you need to replace it. as for cleaning the mass air flow sensor as long as it is the style in this video then it is cleanable and brake or carb cleaner is fine

[@ScannerDanner]

i believe that is an analog type maf sensor and the signal should read more than 4 volts at wot redline. with a dmm you will need to drive it to see that number as the meter isn't fast enough for a wot snap test in park. You could also look at the stft and see if it tracks positive with a rise in the maf signal, this would also indicate a maf problem.

[@kickblake]

If you're reading the values from a diablosport predator, I believe the output for the "baro hz" isn't the actual hz, its that number converted to "Hg based on a table. So a reading of 30Hz is actually 30"Hg...or approximately sea level.

[@ScannerDanner]

I've seen them set for only one bank but if you look at the trim numbers both banks are affected. It just flags one side because it is worse than the other. (sometimes)

[@ScannerDanner]

@mechanic4yourcar Thank you! With your creditials that means alot. I am glad you liked it. Thanks for watching.

[@ScannerDanner]

don't worry about the STFT with the engine cold and in open loop. The numbers are irrelevant. So do you have positive or negative fuel trim numbers when warm. mainly the LTFT is what I need

[@ScannerDanner]

There are two grounds because the PCM MAF signal circuit actually gets its ground through the MAF sensor. So one ground is PCM to MAF and the second ground is MAF to the block. If the MAF to the block ground is bad, BOTH grounds will be bad. No 5 v ref. on this design.

[@georgedawsonjr450]

Thanks to Paul danner I can't look at vehicals the same anymore. The book he put out is worth every $ your pay. My life has realy changed thank you paul. I can't wait to see more videos and I'm really hoping you put out an other book I know there is more you have discovered to teach us. I soon will have my L1 certificate. Thanks to you again. Keep up all your doing its great.

[@ScannerDanner]

All new stuff right now is in the form of video lessons on my Premium channel. I may write another book someday, but for now, come join my classes! Thanks

[@ScannerDanner]

@import0408 I hesitate to say all but most yes. The older vane airflow meters on some of the cars had high voltage at idle and it would drop under load, so opposite of the others in operating range.

[@higgout]

This is so awesome man. My 98 camry was running lean base on my fairly new plugs having ash like build up and power reduction at increased RPM. found you video and it surely help me to understand a bit more of whats going on. dont have all your test equipment but now know the expected output voltage from the sensor when I do my volt meter test. As an electrician I know the benefits of the right test equipment. great job on the video.

[@ScannerDanner]

@contagiousFX What numbers? Fuel trim should be +/- 10% MAF grams/sec and frequency will depend on year and engine size to name a few. For most of the GMs I look for at least 150 gram/ sec at WOT and a frequency of over 8500HZ, Idle would be around 2.3-2.4khz. But again there are variable.

[@FixItAngel]

friend had a '01 Lexus GS300, P0171 and P0174. Did exactly what you showed on your video with my ETHOS Snap On and figured it out. Thank You!! Though I worked at a dealership for 7 years as a used car tech and graduated UTI, nothing compares to your skill. I hope I can get to your level. Next buy is your book. Thanks again.

[@lyleandres1510]

A trick: you can watch series at flixzone. Been using them for watching a lot of movies recently.

[@karsonali241]

@Lyle Andres Yea, I have been using flixzone} for since december myself :D

[@ScannerDanner]

The car most likely also had some fuel trim trouble codes too. If the MAF is reporting the wrong airflow the a/f ratio will be completely wrong and this can cause misfiring. Usually this is accompanied by lean or rich trouble codes as well.

[@DDR233]

Does the sensor under report or over report when it’s dirty? I get that the O2 shows lean and it’s dumping fuel, but it’s only reading lean because of what the maf is reading. So does that mean the maf is over reporting airflow? If that’s the case why are airflow numbers greater with the clean sensor? I’m just confused as to how the MAF causes the O2 to misread if the calculated air was less with the dirty sensor? Am I misunderstanding and the maf is under reporting and it’s fueling for what the MAF thinks is passing but the actual air charge still passes and leans out the mixture the MAF thinks it is dealing with? Then that causes the pcm to infinitely rich the mixture because it will never record absolute air flow

[@ScannerDanner]

@@DDR233 a dirty MAF will under report airflow under loads. Some will over report at idle only, but both types will under report under loads. This causes the base fuel map to be skewed as the engine load is being under reported too. So positive fuel trim numbers result. Positive trim numbers does NOT mean rich!! It is a rich command caused by a lean condition.

[@MrMratni]

This is the best MAF diagnostic video. All your videos are very informative, thank you so much sir for uploading..

[@ScannerDanner]

if the o2 is switching before the wot run then it is not an 02 problem. it is a fuel delivery problem. low fuel Psi and dirty MAF are the top two. a severe misfire can also cause this

[@LynxStarAuto]

I've had this issue before and although I fixed it with a clean, the sensor eventually failed down the line. I just prefer to replace the sensors now.

[@mike-yp1uk]

that build up is call insulation and insulation traps heat. air coming in is designed to cool sensor but good insulation wont allow that. great case study.

[@W.Khairi]

A few observation here - The PCM didn't throw a MAF performance code e.i P0101 - u didn't look at the load PID or abs-load pid at WOT - I think at WOT injector ms is not calculated using MAF it is calculate based on built in maps, that at least has been my experience, Thanks a lot for information full video as usual.

[@cagonesss]

yes i did the resistance check and found one injector at 5 oms and 3 others at around 9 ohms so i did have shorted injector ,was my starting issue.hey thanks alot for your help i was going crazy with this hard to find issue for 3 weeks .thanks again for sharing knowledge i saved alot of money doing it myself. gm 2.8 fixed good day

[@ScannerDanner]

Thanks! I was having trouble getting a clear shot with this design. Sorry about that

[@cbobcbob100]

great info as always...love the ending with long and short term relearning....bob

[@halleffect1]

haha, Paul's voice sounds like it's straining sometimes, but that's just b/c he's passionate about his work and wants you to hear over the shop noise.

[@ScannerDanner]

not a dumb question. you cannot use the downstream sensor the same way because the cat catches and stores oxygen. there is some diagnostic advantage though but it is not used the same way. check out my o2 fixed lean case study

[@ScannerDanner]

Thank you so much. I truly appreciate the support

[@ScannerDanner]

@lesbirel91 A dirty MAF is not the only cause of a lean exhaust trouble code. If you have my book check out Section 5 page 5. The list on this page address the most common causes for P0171 and P0174 DTCs

[@ScannerDanner]

Did you do the resistance check I showed in part 2 of the one video? This is your only option without a scope, unless you get lucky and the shorted injector is one of the two injectors you can get to without removing the intake. There are other causes of this condition on your car, but lets do a resistance check on the injectors first.

[@oscarrojas4281]

You are awesome I just brought your book and send me here you're the man I'm learning a lot thank you so much

[@ScannerDanner]

Awesome! Thank you so much!

[@Pissed0ffKrzysztof]

Great Video, I can barely see 1 Thermistor (Temperature Thermal Resistor) when it was dirty at 07:30, and you can clearly see both afterword's at 08:56, Everything looks Clean, Dry, and Tight.

[@ScannerDanner]

I don't think there was a problem at all with the scan data. I think this was simply a small engine that doesn't "breath" the same amount as other engines do. Remember every car is different as far as what peak grams per sec will read.

[@ScannerDanner]

No the hissing is tank vapor psi not fuel psi and will have nothing to do with your lean exhaust code. An EVAP code maybe but not a lean exhaust.

[@PineHollowAutoDiagnostics]

haha I actually used a fine-tipped dental pick, but don't tell anyone! A little compressed air helped too. Those wires were pretty gunked up...not to mention his airbox was full of dry leaves lol

[@ScannerDanner]

@JohnMcClane99 Awesome! I'm glad it worked out for you. Extra money in our pockets this time of year is a good thing.

[@luismartinez4198]

I read somewhere, that when you have a fuel related lean code, as you rpms get higher, the fuel trims go high really fast; but for a MAF issue, the fuel trims have a slower increase.

[@abdul-kabiralegbe5660]

Thanks. I was trying to see how to differentiate between the two. This is why I like to read comments on a video.

[@tonylexmark]

Superb video and very informative. To get rid of glare on your screen get a polarizing filter for your camera, cheers.

[@ScannerDanner]

If it was a 2 bank system then yes, a dirty MAF would affect both banks. But this is only a 1 bank 4 cylinder engine. Bank 2 doesn't exist. Great question though, it means your thinking!

[@ScannerDanner]

Rosedale Tech in Pittsburgh Pa is the school and you can get more info. about my eBook on my website listed on my youtube channel page or search "Auto Computers Troubleshooting" on the web. Thanks!

[@ScannerDanner]

I am not sure. I know some guys use this initial spike to determine if the MAF sensor is dirty. I am just not familiar enough with the procedure.

[@onepaa1636]

Great test i like the veruss min max capability however i always use my dvom when reading o2 signals ive just been burnt to much with false readings but overall that was a great test got straight to the root without even having to check fuel pressure

[@ScannerDanner]

Yea, I know I should take it off as I am not showing proper safety procedures with it on. I am super careful of where I put my hand and truthfully I would rather take the chance than take my ring off. It is sacred to me. (I do take it off if I am reaching my hand near a starter motor or alternator that I cannot see very well)

[@ScannerDanner]

Close. Low fuel pressure will also be an under load lean condition just like a dirty MAF

[@ScannerDanner]

holy Crap. that could be the lowest baro reading I've ever seen on a ford. it should be running ultra lean with that number. you have any codes

[@BRILLOPADral]

Really good tutorials, keep up the good work, we need more like these.

[@JoelAutomotiveInaction]

Thank you for your response , so it receive 12 volts external the maf and some way inside the maf it is converted to 5 volts Out put sensir signalto PCM is that rigth?? Because on snap throttle I saw about 4 volts. Thank you , you are a great teacher

[@MihaiF82]

So the O2 being lean initially on the WOT was fine? That was a bit confusing because you said at first that it's not ok and in the end that it is ok.

[@mechanic4yourcar]

The whole video is very good filled with good information.

[@georgen9383]

Danner,great channel buddy. As a hobby mechanic, and a guy who mostly tinkers with *gasp* carbs, I can only dream of having the diagnostic tools and knowledge that you've acquired over the years. But I appreciate you showing us how it really should be done by good, experienced mechanics. Quick question for ya. On my 96 Mustang I had a P0172, if I remember correctly. I chased it for months with new vac hoses, sensors, etc. Ended up being badly arcing plug wires. Does that sound right to you?

[@kenmh7357]

This very informative. Thanks! Have a VW and waiting to get my OBD II Pro to get real data

[@ScannerDanner]

there is no time frame, it is a learned value and will constantly adjust if needed. Every run period there can be small changes with it. After a repair, it will correct back to normal values while driving the vehicle. Watch my video "Understanding ST and LT Fuel Trim"

[@JoelAutomotiveInaction]

Paul do you know how this circuit works (maf sensor) I was working. On 2000 ford focus the maf sensor has 6 wires Pin 1 And 6 are for air sensor . The pin #2 has system voltage ( 12v). On the pin #5 is coming out the sensor signal to PCM at wot about 4 volts . But on pin 3and 4 I have ground . How that works . This was perform on not working maf I did. Not see any signal so I decide ti check power and ground and I did not find any 5 volt reference any way I replace the maf and it fix

[@nGuLozZa]

very nice to see scanner a pro not just out for yourself im from uk cowboys changed my valves after cambelt snapped an bent them [ 1100 pound and car never been right since wish u could help me

[@sivucit]

Thanks for reply. Will there be situation where good working o2 sensor will not switch in closed loop mode because of vacuum leak or fuel issue.

[@hp11208]

how would i test a maf with a multimeter, on a 01 maxima code po171.

[@serchmarc]

do you think the next snap on scanner model(the model using in this video) will clear or fix the processing velocity ,like you explained in the video when you check grams of mass from the maf signal?

[@jcer45]

I have a 1990 Toyota Camry, and i just replaced the Fuel pump, and filter, and spark plugs/battery. The car starts up, and then it idles, and a few seconds later, dies. Does anything ring a bell ? because im about on a blank on whats wrong with it. any tip or help would be appreciated!

[@alb12345672]

Is the Ford computed BARO parameter sensitive to Vacuum leaks? I know it needs a WOT to do a calculation. Would a slightly lower value(149 vs 158) implicate a bad sensor(mine was cleaned). The sensor seems to pass all response tests (shop manual numbers). No Codes.

[@HeyItsLouis18]

I know this is an off topic question for you but i really want a 2003-04 cobra if its modified what do i have to worry about future cost and how do i strip an engine down to the block to get it in the machining shop

[@fabiansotelo836]

Also car does fine no hesitation or anything. I had the injectors cleaned as well with everything there has only been little improvement, please help.

[@IBoughtASupra]

Hey. I have a question. I have a 1998 Corolla VVT-I and it does not have a MAF sensor. Some people said it is on the air box but there is nothing there. I have a P0171 code that is annoying me and I would like to try this first before replacing the 02 sensors. Thanks.

[@stephenhighland6394]

This looks like exactly the right video to help me figure out my 2002 Prius. It gave me two P0171 codes. I borrowed a scanner from a CarQuest shop and the freeze frame data says: Fuel Sys 1 CL Fule Sys 2 NA Calc Load % 48.63 ECT% 72 STFT B1 % 0.00 LTFT B1 % 43.75 ENG RPM 1494 Veh speed 45 IAT (deg C) 12 [I am a complete novice and don't know what most of this is saying.] Does this look like a dirty MAF sensor, too? I am about to attempt cleaning it in my driveway. Yay -- it's above 30 degrees for the first time in weeks, too!

[@ScannerDannerPremium]

Yes it does. An under load lean condition is what your freeze frame data shows. IT will either be a dirty MAF or a low fuel pressure problem. Although this being a hybrid may change things but I am not totally sure.

[@ScannerDanner]

Thank you Joel!

[@sulaimana.abdullah5989]

hi Paul. I love. your instructional videos. they are really very informative. what I need to know now is if my MAF sensor in a Lexus GS 430 could get damaged and how much they cost. cheers

[@ScannerDanner]

Of course you can damage the sensor if you're not careful. Thanks!

[@MihaiF82]

You say in the video that the O2 should never be lean at WOT. You tried it 2 times at it was lean the whole time. Also you say that indicates a fuel delivery problem! So why did you conclude that is was a dirty MAF?

[@dahimediag6977]

if the most causes of lean condition are low fuel pressure dirty MAF vacuum leak then what are the most causes of rich condition ?? I think a stuck open fuel injector is one them

[@ScannerDanner]

deal. and yes I am from PA. That obvious huh? :-) We do take in outside work and I would love to help. are you close? btw I know I use alot of fancy stuff but if you keep watching you will.see that I also like to show other methods when possible.

[@judyskountrykakery]

Hey Danner can you tell me if the MAF on a 2000 Spectra 1.8L is a cleanable MAF, or is it the film type you said not to clean? Thanx

[@lesbirel91]

i have this code coming up on mine the only problem is i have cleaned the sensor 3 times and it still havnt fixed it im thinking is it because of the decat or a lambda sensor ?

[@TelmenTelebe]

Hey ScannerDanner I have question My toyota's Check engine and TRC off and VSC lights are on the engine running good, no problem I think its minor problem

[@flightmaster178]

@ Gerard Garcia WOT stands for "Wide Open Throttle"

[@Maitykgz]

My friend having the same symptoms, his car run lean, and engine runs unstable for a minute or two, I thing ECU trying to correct STFT & LTFT after that time everything's OK, engine runs smoothly. Until next morning start. So i suggested him to clean MAF sensor, but wondering is his MAF cleanable. (Mercedes e230. 1996) Could you help us with this ???

[@03mazpro]

Could a dirty MAF sensor cause a P0420 code? I have a 2000 Corolla that is getting a random P0420 code. I read online where people state that a dirty MAF could throw all other sensor readings off causing an false P0420. I want to start by cleaning the MAF sensor first. I know P0420 codes are common on this generation Corolla. Also, I've read that it is bad to use carb or brake clean on MAF sensors. Many people say to use a special MAF sensor cleaner. Is this true? Thanks for your help.

[@ScannerDanner]

same tests as any other maf. watch my two part gm maf testing videos. in that one i am showing the dmm method. the only difference is the Nissan is an analog signal and u want to see at least 4v at wot.

[@sivucit]

hi, lean can be caused by dirty mass air flow, clogged fuel injector, or fuel pressure or fuel volume. so how did u know it is dirty mass air flow and not anything to do with fuel. please adivse.

[@sivucit]

Sorry anothe question, during WOT if O2 sensor is showing lean instead of rich, how do u determine that it is dirty MAF, it could be O2 sensor itself, is that right.. i got the same situation in my car, not sure where to go O2 or MAF, otherwords can i assume my o2 is good when i see swing from rich to lean and vice versa.

[@jimmywells33]

I'm surprised being only a .05-.06 volt low could cause a disturbance. Could this also have been diagnosed by checking the voltage numbers of the MAF via DVM while manually throttling to higher RPMS?

[@ScannerDanner]

I think I showed that with the lab scope. The DVOM may not be fast enough to catch peak voltage in park, but would be under load on a test drive

[@RusaiAkaCrispy]

hi, wondering if you would be able to tel me why I can't sync any of my scanners to a 2002 Rav4 and a 2002 Avensis Verso both have the 1AZ engine? I have a n Autel AL419, Autocom CDP+ and also an ELM327 off eBay, none of these scanners will connect to the ECU under any circumstance, except the Autocom but only if I set it to Rav4 02 Model with Diesel engine, and even then it only gives limited access. I'm having an extremely lean burn. Thanks

[@trublue2319]

Am a tech these videos help me out when diagnosising

[@propertarian485]

Will a dirty MAF still show decent readings at idle? I suspect my MAF is dirty but I’m still getting 2-2.5 g/s at idle

[@morganmyers9082]

Hello, I have a mustang 4.0 v6 that is getting 0.00g/s, which makes it go into "Limp home mode". would this be caused by a dirty MAF or something else?

[@carrotecnicatreinamentosau7217]

Excelente estudo de caso. Obrigado!!

[@cagonesss]

thnx for the reply,the 2.8 gm starts once in the morning for a bit then stumbles n stalls i did check injector with noid light and it does pulsate when it starts but when it dont it does not pulsate,when i try start it no pulsation on light so i have eather bad injectors or bad computer?there is power to them tho but no pulsation like in your shorted injector vid.

[@ScannerDanner]

oh and 149hz may be normal where you live dependent on elevation.

[@Mrdubomb]

Great video, after working in the field for many years now, it would have been nice to learn this from a more experienced mechanic instead of having to teach myself. Is that a ring on your finger? they make great electrical conductors, and turn your finger into a crisp hotdog. J