Troubleshooting a Bad TCM - CAN and Sensor Ground Circuit Problems

What happens to CAN signals on the entire network when one module has a bad ground? Can this problem be missed if the network is not measured a certain way?
How do you isolate which module is causing the problem? When main grounds test good on the affected module, can testing a sensor ground or the 5v ref circuit aid in your diagnosis? Watch this video to answer these questions!
symptoms:
No communication with transmission control module causing a no crank no start condition.
Related video:
Sensor grounds and the 5v reference circuit (a 2016 ScannerDanner Premium video)
• Sensor grounds and the...
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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.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdanner.com/join-sc... There is a 14 day free trial.
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.

[@timwheeler1503]

This video was so cool. Grounds can do some very strange things, especially computer/module grounds. Anytime I see really strange electrical issues the first thing that I check is grounds. I've learned so much from Paul, he is the best teacher hands down and if you can't learn here you may be a parts changer. 🤣🤣🤣 Honestly all you have to do is listen to Paul and apply yourself, you will learn if you watch this channel.

[@mike-yp1uk]

This channel captured my interest years ago. I used to suck with electric work. I watched every free video 2 times. Then I bought the book. Then I watched every premium channel video a few times. This channel absolutely changed my whole life. I hated hitting the brick wall day in day out but I loved working on cars but electric work was painful. Today I am an L-1 certified master tech. I support this channel because of all the extra money I now make. I face electrical problems with a better understanding and not fear. I am very thankful that Paul Danner is here to help us. All you have to do is open your mind and learn.

[@ScannerDanner]

Thank you so much! Props to you for making it happen my friend! For anyone else interested in joining SD Premium you can sign up here. www.scannerdanner.com/join-scannerdanner-premium.html

[@charlesleake930]

@@ScannerDanner All you have to do is open your mind and learn.....mike figure it out : )

[@Viper81766]

Truer words have never been spoken

[@catfishsnagger3284]

What book did you read?

[@jharrison6557]

​@@catfishsnagger3284im sure hes talking about ScannerDanners book, Engine Performance Diagnostics. I have the e-book but theres a paper copy available as well. Very good book to have

[@medicfour9268]

I have watched every single playlist you have multiple times until it clicked in my medically trained brain and the lightbulb lit and I said "Omg THATS how it works, AMAZING and simple!!" Electronic ignitions make sense now. 🤟♥️

[@ScannerDanner]

nice! Thank you

[@jasongrady5035]

As a former medic, looking at the car the way i looked at the human body makes this job much easier. Also danner if he needs a tech im available in the south hills.

[@automedic9781]

This is one of my new favorites. I've been watching your channel, and have been subscribed to premium for years. The amount of knowledge you've given me, the amount of money you've made me, it's unreal. I recently had a Pathfinder that was jumped backwards. Blew the main fuse and a couple other fuses in the IPDM. Also had a COMM code that would randomly come and go in the BCM, and the security light would stay on during cranking. Measured the network and found an erratic signal. Unplugged the BCM (suspected due to the code and also the immobilizer is run through the BCM) and my signal went normal. Checked powers and grounds, and replaced the BCM and called my programmer to program it. Security light turned off, but vehicle still wouldn't start. Performed fuel pressure measurement and found zero with B+ coming out of the fuse box going to the pump during cranking. This gave me the confidence to sell dropping the tank and performing wiring checks at the pump, which ultimately led to me replacing the pump. Vehicle starts and runs now. Has some other problems we're going to be tackling in the coming weeks as the client gets more money, but the fact that I'm at this point that I never thought I would be at, I'm eternally grateful to SD premium and all that you do.

[@ScannerDanner]

Cannot thank you enough for this comment!

[@ScannerDanner]

Isn't is crazy when you have two completely separate issues? Like you and I both had on these cars. It sometimes makes you question yourself doesn't it? Love your story so much and again I appreciate you sharing this.

[@automedic9781]

@@ScannerDanner I question myself all the time. I’m not a confident man by any means, but I follow the process and try to stay calm, and remind myself that I have the readings I do for a reason. Understanding the base engineering of things such as how a computer talks to another, what things like thermistors, Hall effects, and pressure sensors are and how they operate, it all ties into finding the fix. I had another one a few months ago, Dodge Durango that the guy had already replaced his own IAT sensor because Autozone said it was the most likely fix. Backprobed the signal wire at the IAT and found 0v. Moved about 5 inches up the harness and found the 5v ref coming from the computer telling me there was a break in the wire to the connector. De-pinned it, and soldered in a new section of wire with a new terminating lead, and was able to clear the code and read an accurate IAT. All of this due to your teachings. For as long as you’ll make these videos, I’ll be watching.

[@ScannerDanner]

@@automedic9781 heck yeah man, awesome! That open circuit was easy to ID when you understand how the circuit is designed and works. Nice job man

[@faustogonzalez8397]

Yep, ScannerDanner is the Man, without question, I've been a Premium member for years and have never regretted it !!! I watch several other channels, but when I need deep technical diagnostics SCANNERDANNER is the channel. As always Paul keep up the Great Work, it is very appreciated !!

[@Auto209]

Damn these are one of those badass diags that makes you really appreciate how truly hard the industry should be. A lot of parts changers make it seem like the industry is so easy but then you never really solve the issue as a parts changer

[@BigDogDiagnostics]

This whole industry is very thankful for your teaching Paul! Your videos have been a game changer for me personally and I’m sure they have been the same to many many other techs as well! Your knowledge has helped me understand so much. Just even looking at a car like this can be very stressful and intimidating in itself. But with the fundamentals you teach, it makes everything come together! Keep up the good work my friend!

[@ScannerDanner]

Thank you so much!

[@hav2win]

I really like the way you overlay the readout of the scope while you were talking, as well as, highlighting the schematic so I could quickly see which wires you were referring to. It really helps the flow of the entire video. Great job. Thank you, Paul.

[@ScannerDanner]

Glad it was helpful! My son Caleb is my editor and he is really honing in his skills. Thank you so much. We put a lot of work in these

[@ScannerDanner]

What happens to CAN signals on the entire network when one module has a bad ground? Can this problem be missed if the network is not measured a certain way? How do you isolate which module is causing the problem? When main grounds test good on the affected module, can testing a sensor ground or the 5v ref circuit aid in your diagnosis?

[@calholli]

I was hoping that you would open up the TCM and find a broken solder joint.. You even mentioned it there towards the end and got my hopes up. lol.. oh well.

[@fabianrodriguez7219]

Could you isolate which module doing a parasitic draw test??

[@ScannerDanner]

@@fabianrodriguez7219 a module with a bad ground won't cause a drain issue my friend

[@gt3tunecl725]

Incredible the ability to imagine so many ways to proceed in a few seconds and the way he doubts certain particularities, such as the relay, is impressive. Now if I buy the book to learn how to diagnose, I have followed it for more than a year and I was able to start working at Bmw in my country, I can realize how important it is to know how to diagnose well. Great example to follow. Greetings from Chile.

[@ScannerDanner]

Thank you so much!

[@djxtreme1983]

On most control units where the internal ground is bad, you will measure 12v on the Aluminium housing. If that‘s the case you could just ground the housing and your done (for testing purposes, or for driving it to the scrapyard 😂). Grounding a sensor circuit would fry the small trace to the pin instantely as soon as a shift solenoid gets actuated due to it‘s high current.

[@kmanrl3112]

Love you brotha! I just spent this monday chasing can issues on a 2020 F150 and will probably spend tomorrow doing the same. Don't have a picoscope but have a reasonable Chicom facsimilie. The struggle is real, people don't have a clue what we go through!

[@JoeBob79569]

This was great, I really love the logical thinking in problems like this. It certainly beats those garages who just start throwing parts at the car, and then hit you will the bill for all the parts they replaced, that didn't even need replacing.

[@dtandfam8100]

Lovin it! Finding the problem (bad gnd in tcm board) Working past it (supplying a temporary gnd to tcm board) . Achieving the goal! (Getting the car to start and run) get in get out! Get paid! - Good work Danner's!!

[@ScannerDanner]

thank you my friend

[@alrifainidal]

I have been watching your videos for the past couple of years and I have learned so much there are no words to thank you enugh

[@glendekoker3682]

Always love your brother, I lost mine. Dan is a great man helps others.

[@ScannerDanner]

I'm so sorry Glen

[@sohailrabani]

Belive it or not sir..i have fixed one prius2010 learning from your infos recently that car went to many shops but it was just bad spark plug.great to have you out there to help many..cheers

[@ScannerDanner]

awesome, thank you and nice job!

[@nxpapke123]

I have been watching your videos for the past couple of years and I have learned so much, thank you for your knowledge and time.

[@jamescote8991]

Thanks, Paul you just saved my A** tonight. I stopped to grab a bite to eat on the way home - got back in the jeep (05 GC ) went to drive away and noticed a message on the dash "Transmission over Temp" along with all PRND boxed, no reverse lights, among others It wouldn't upshift, It was in Limp mode. I was stuck 115+ miles from home, I have been watching your KZbin videos for quite a while and remembered the one to be honest, I remembered it because of all the junk on the car that had a TCM problem - anyway, I ripped the dash apart and started tapping on the dam thing, turned the key and bam - it was working. I just got home a few minutes ago and put a scope on it before I shut it off. I got a code P1637 EEPROM issue, so I must replace it (at least I was able to make it home and save a tow charge). I have to say TY for all you do, I believe you to be one of if not the best techs I have seen in the last 30 years. Keep up the fantastic job and may god bless.

[@cannbudo]

Thank you so much for the lessons over the years! You've been a big help. Thank you.

[@halwesth0]

Once i opened the video i hit the like button then i start watching because even later on i have to do it , as always i know im gonna enjoy it 👍👌💐

[@richardstockwell4862]

man I am in new york and would love the opportunity to work with you guys absolutely love proving faults. Thank you for another great video paul!

[@stationaryenginesworldwide]

great video Paul and Caleb ...truly enjoy what you do Mr. Danner

[@mike-yp1uk]

I've run into this scenario before so I always make a ground strap and bolt it to the outside of the TCM and bolt it to the body close by. It usually starts. Great video which shows a common problem. I've personally done this about 5 times.

[@PaulysAuto]

Your videos are timeless Paul Danner for eternity. ❤ Thanks for this

[@Lovesermon]

I seriously love the way your video is practical, informative and understanding.... Welcome!!!!!

[@ScannerDanner]

thank you

[@johnlenoir1023]

Love the video thank you so much for all the lessons that you have given out trying to teach the rest of us

[@raviautoscanning]

Thank you too. Great diagnostics and teaching. Your knowledge is so much for us.

[@parochial2356]

Paul, while you were checking the ground at the TCM, I think it should be pointed out that a Phil's Probe uses a tiny set of multiple needles ["bed of nails"] to pierce the insulation [like the Tech's butt sets back in the days of the old POTS phone systems] while other probes like the screw down Pamonas and their knock offs use a single, larger "nail" to pierce the insulation, which can - sometimes - break individual strands in a multi-stand wire, compromising its current carrying capacity. Phil's Probes are superior for these applications, assuming very low current flow through the probe or only for sensing voltage levels. I would not use a Phil's probe to provide a substitute ground on a suspect headlamp bulb circuit, for example. You and Caleb please keep up the stellar work!

[@johnpappas2060]

Bless Tremendous video from many angles. Nice to also see you working with your brother. Thanks 😊

[@englishrifleman6556]

You're A True Tech.. your test procedure was fantastic. 👍👍

[@ScannerDanner]

Thank you!

[@codo7]

Thank you, Mr. Danner. Good learning experience for me.

[@crackone2three]

After the repair the Value of the Car doubled haha, realy nice work !

[@colestowing8695]

Always a treat to watch the process.👍

[@ScannerDanner]

thanks Cole

[@amadorosario-xs4zb]

you are the best .you are a good teacher God bless you and family.

[@advancedleveldiagnostics]

Really great video! Thanks for sharing!

[@williamblack7268]

YOU HAVE A GIFT FROM GOD! WOW TO HAVE THE KNOWLEDGE THEN THE UNDERSTANDING GIVING YOU THE WISDOM. THANKS SO VERY MUCH.

[@ekimbrough1413]

Thanks Paul!!! Fantastic video!

[@isalmankhan1]

Superb👍 Thanks for sharing SD👍 Couldn't learn this knowledge from anywhere else except this channel😍 Thanks A Lot SD😍 Special Thanks to James & Caleb Danner😎 Stay Safe Danner Family❤

[@howlinhog]

When you walked over and turned the radio off, that is so me. It's why I've always preferred working alone. I've worked in shops where there can be multiple radios going on, it's all a huge distraction. When I started my own shop I didn't, don't allow radios. The claim of needing background noise is a complete lie. If you're paying attention to the radio, you are not paying attention to what you are doing. Nobody can divide their attention and then claim that they are giving complete attention anywhere. It can even be maddening when things aren't going well and you've got some idiot on the radio yapping away or music blasting in your ear.

[@robertfrancisco1193]

you are the MASTER MECHANIC love watching your videos!

[@ScannerDanner]

Glad you like them! Thank you

[@artvance8251]

Paul ,great job as usual.

[@terrybarkman3219]

I really really could use one or two of those probes. The premium membership I’m liking too Paul. Helping me be a better tech.

[@ScannerDanner]

Thank you so much Terry!

[@tukwoods2524]

Thanx for the tech tip Mr. Danner with the scanner I’ll remember this if ever stranded. A no cost git er home video, but you have to understand what makes it work and why. Keep it real and yes I do want a probe and I don’t know how to get one from you.

[@ScannerDanner]

You cand find them here www.scannerdanner.com/tools.html On my AESwave affiliate page. Thanks!

[@aamechanic8154]

Last year had a 99 corvette that the dash, hvac, radio would go dead and would go into lImp mode while driving. After some network diag, found the ground for the pass side power window module was bad ( spread female terminal @ door to body harness) same elevated voltage as yours, but in my case it was a class 2 network instead of CAN. Great case study Paul, always a great feeling the moment a no start fires up for the first time 👍

[@Reeeeeee12345]

How would I know what kind of voltages to expect on certain wires? I bought wiring diagram for all systems, but don't know what to look for. Reeee

[@Pablo_Automotive]

Another great video. This time was wonderful read your explanation in the chat

[@thomaspapa3831]

Another great video, can bus still haven't mastered. Wiring diagrams is key.

[@lakesautomotivediagnostics6509]

Nice job,Paul

[@shamessun]

Thank you again guys and thank you Caleb the camera 🎥 man you are making the diag. Prosecutors a life… you making like I am there with you guys…… and thank you guys for this important can diag.

[@chicanesimon]

Great break down for CANBUS probs for noobies Paul , ground-hog day for you at times I'm sure but you still take the time to explain why , Top Dog diagnostics right here

[@simbad909]

One of the most exciting and useful channels i watch 👍

[@ScannerDanner]

Thank you!

[@target-mechanica]

Really great lessons we are getting all the time from your videos thank you very much for your time, efforts, and knowledge you are spreading over the world. Following your from Qatar🇶🇦. I have a question, I have Range Rover 2016 V8 NA with engine misfiring and engine light flashing in cluster. Reading fault codes found misfiring detected on cylinder 6 only. After checking found that firing signal to Cylinder 6 Coil not coming out from PCM not out put from PCM to control Coil which means PCM has internal electrical failure and we estimated to replace PCM. My question is that in this case is there any other solution to do rather than replace PCM especially it is costing too much. Thank you once again Mister Paul Danner

[@ScannerDanner]

@@target-mechanica make sure that coil is not shorted too as this could have damaged the PCM driver. Where is the main switching transistor? Is it is the coil (3 or 4 wire) or inside of the PCM (2 wire)?

[@target-mechanica]

@@ScannerDanner thanks for your reply Mister Paul. Actually the root cause is ground wire short circuited with ignition signal control wire as the wiring is melted and touching each other that’s why the PCM is shorted internally. For the coil is fine because already swapped with other cylinder and working as sparks coming once installed in other cylinder connector. The PCM in order as it is no available in our dealer. Once PCM arrived and programmed I will update here the findings.

[@donniejohnson7499]

awesome video Paul Danner.

[@armory3379]

Thx Caleb good focus vids!

[@jimkillen1065]

Thank you for the videos . I try to watch all of your videos. Great information and I always recommend you when I hear of problems. My friends ask what is going on with this or that .. Most times it's well it's never done this . Yea until it does . So that's not always a good indicator.. Being a parts changer gives mixed results at best.

[@NPCmechanic]

subscribed thanks for the class.

[@sammyd7857]

I wish we had mechanic's with brains like this in AUSTRALIA. I recently put my 2001 turbo beetle into a mechanic because there were no comms. The rat charged 3 hours at 150 per hour to hook up a few scan tools and find no system, then buy a wiring diagram and find the communication module and tell me it was buggered. Then put a scope on the ecu comms and saw that it is working( which I already knew because the thing was running). The main issue was an EPC fault which was the car not revving and going into EPC fault but the mechanic did not look one second at that in 3 hours and it turns out the EPC fault can really only be the throttle control. The fault was the pedal position resistor which I worked out with no comms in the side of the road. The mechanic may not be too smart in his job but because he knew he was only getting paid for diagnosis he just fucked around and did fuck all.

[@rick343]

Yep, fun video, really interesting, love computer diags,

[@labrat6910]

Thanx Paul..Love your content..Respect homie😉

[@bluedeckelectronics]

Great video ! Thank you !

[@hometownautorepair3121]

Good one Paul 👍

[@chasyho]

28:04 bad groud ;). Awesome video, the edits are TV-show level good!

[@ScannerDanner]

Thank you! I'll share this with my son (my editor)

[@Santiago_Ordonez_]

Amazingly wonderful...!!!

[@fabianrodriguez7219]

ScannerDanner 😄👍👌 great job Great Video Thank you for sharing this video and many more .

[@kvcl123]

Great job men!!

[@yosoydpfknr2855]

The best electromechanic in this country hands down

[@slurr4588]

Man awesome! Definitely subscribed.

[@ScannerDanner]

Welcome!

[@MR.KNOWITALL1982]

Hi Teach!! Splendid diagnostics! Nice work with screen blabajaba(scope with you in the foreground) SWEET! I didn't watch the whole hour but I'm sure you got it figured out with that L-scope! When is Picoscope going to come out with an all-in-one tablet scope? Anyway... The shop really cleaned up nicely since the last video I watched! Love the bench space! Organization is key! by for now your pal:)

[@oneilwilliams653]

Great one teacher

[@Steve.191]

Thank you 👍

[@RealSpiit_4rm_Z3]

Ok, you are the ONLY person I've seen, in person or on the internet that know what they're doing. So this is a desperate cry for help. I have a 96 Caprice that I've owned 5 yrs. I haven't even driven it 7 months yet. I've done engine swaps and all. But she will not run long without cutting off or choking. If there's any way I can get her to you or you to her, PLEEEAASE let me know. 🤦🏿‍♂️...And I also live in Atlanta. 🙉🙈🙊..💪🏿💞💯

[@ScannerDanner]

I'm in Pittsburgh PA, I'm sorry your a little far away. But if you can do some testing we can help you on my forum. It's free to join www.scannerdanner.com

[@RealSpiit_4rm_Z3]

@@ScannerDanner thank you so much, I'll see you there later. 😁

[@markraz28]

Ah mate awesome video. Really enjoyed it and learnt a lot. Your brother cracks me up. 😂😂

[@ScannerDanner]

He is fun to be around too my friend, thank you!

[@victorgonza4528]

Epic Danner good video .

[@PaulCTownsend]

You guys are great.❤

[@nukelauncher95]

Hey Paul, these Cobalts were known to have faulty ignition switches. My uncle had one. Some of my friends had them too. The interlocks always break. The column cover actually has a little access panel you can pop out to press the solenoid plunger without ripping the whole cover off. I'm actually surprised you haven't seen this before. It literally affects all Cobalts.

[@scottmahaffey7430]

dfn mm

[@James-fs4rn]

👍Danner team wins again!

[@kevinobrien3063]

Yes I have the book too.

[@michaelproust7891]

Thanks for the excellent camera work and fast flow information. Could you explain why the 12 V waveform out of the TCM shows a bad ground?

[@mph5896]

I had an Impala 4-5 months ago with the same style bad TCM. TCM/PCM sits inside the airbox. Rodents used the box as a nesting area with the TCM as the urinal. TCM was dead, I swapped it out with an identical one from same year/make/model/part number car. Car started, I flashed it anyways just because I already purchased the $40 subscription for the car and I wanted to make sure it was a complete job.

[@ScannerDanner]

While you're waiting for this premier, watch this video Sensor grounds and the 5v reference circuit (a 2016 ScannerDanner Premium video) kzbin.info/www/bejne/Z3_ZqpaVbZ10mLs It is related in certain ways to what we are about to see

[@nathanjamesprouse2769]

Thanks u 👍

[@timharbour4914]

LoL. I was chuckling the whole way through this one. In the background, Up - up, Down - down the old clutch bleed that just won’t cooperate. 😂

[@AdinSLaboy]

U kill it with that video awesome technique 👏 I have a question I have a cura the it was sitting for 5 years in a back yard it was on lean mode at 35k rpm now runs but after a couple minutes running dies dropping the rpm to 0

[@ScannerDanner]

Do you have 5 year old gas in there?

[@michaelproust7891]

Ok, you explained it.

[@nathanjamesprouse2769]

Love one them probes

[@johnnysprocketz]

4:31 ScannerDanner said "It was towed in as a no com, you did trouble shooting and found some bad grounds on the ecm. Was that in checking the ECM wires? and Ole Red Beard replied, "No, it's because I know what I'm doing at this point." 🤣

[@eyesonwashington1]

I’ve got a 99 Honda Accord that I’ve been dealing with a extremely frustrating dreaded EVAP leak p1457 canister filter area. Now, I’ve been dealing with this issue for almost a year and a half so almost everything you can think of, I’ve done to try to remedy the issue. The only thing I haven’t been able to do is put a bi directional scan tool on it to check the system to see if there’s anything to pinpoint the problem. The one screwy thing I believe may be a main cause is the #6 fuse on the passenger side fuse panel isn’t getting any power and as far as I know, it controls the secondary O2 sensor, which could be giving a false reading to the fuel tank pressure sensor and something else is causing low voltage on the light green wire of the same sensor. So I’m stuck and would be extremely grateful for any help to fix the stupid issue I’m having. Tired of only getting a little over 200 miles per tank but still got plenty of power. No drivability issues just extremely crappy gas mileage.

[@fmbfla]

Question : Could the Trans harness have a short to the TFT line internal of the Trans? The solenoid's are 12 volt correct? I didn't see you test that point. I have seen problems in GM , Ford, Chrysler and Mercedes made Chrysler ATX's that required a new Harness. The last 2 are known for wicking ATF to the AT module via the insulation of the wire causing CAN problems Always good to watch you work your magic

[@Autokey_Security_Services]

I agree GM's Techline Connect is a pain in the rear ( with lots of software bugs)... It always crashes shutting down mid session...

[@Markb8608]

Danner, quick question.been watching you fir years. I wanted to use my high frequency plasma torch (yes CT 2050,) to cut off bolts on an expansion valves . Do I have to be concerned around canbuscand ecm and sensors.

[@hassandallal6314]

Danner u the best man

[@bb6075]

Is there a video/lesson I can find to understand & learn why the earth voltage is pulled up to 12v? thanks

[@amr-50]

You are a magician danner

[@ratbag359]

Some modules can be grounded by the case. Just as a alternative to using signal ground wires.

[@EilersAutoDieselLLC]

Had this exact same issue on a cobalt, it ended up melting the shift solenoid in the transmission, or vice versa. Either way I had to get the TCM to communicate, and it ended up being a bad ground also. What I ended up doing was grounding the case of the TCM, it had 2 holes at each top corner and I used an eyelid and bolt there and wire to ground, after more diagnostics I found the shift solenoid driver (ground controlled by TCM) to be showing a 12v source, unplugged the transmission plug at the transmission and the condition went away. Which led me to a faulty (melted) shift solenoid. What I believe was happening is the solenoid itself went bad and sent the 12v power straight into the TCM driver ground and in turn Burnt up the ground circuit on the board my assumption is that it burned up close to the ground pin in the TCM because after fixing the solenoid and grounding the case everything was perfect. No faults and all the data was within range. I’m gonna say that car you guys were working on probably had a bad shift solenoid also and that’s why after grounding the trans temp sensor signal wire it worked fine other than it still had shifting issues. The replacement TCM might suffer the same fate over a period of time if the solenoid wasn’t caught.

[@robertmobileman8304]

great diag and video , how do i get one of those piercing probes ? do u send to uk ? thanks to the Danner family

[@ScannerDanner]

You cand find them here www.scannerdanner.com/tools.html On my AESwave affiliate page. Thank you! And yes they can ship anywhere in the world.

[@superbestdad]

I do a lot of diag on cars from other shops. Like 2-3 shops before it gets to me. I keep old terminals from used connectors so I can drag test terminals. This one is so much like what I’m used to checking. Have to fix all their screw ups to get to the original problem that they went after.

[@robertbatista50]

ScannerDanner was looking at the Differential signal on the B.O.B. instead of Vcm.

[@ScannerDanner]

I'm sorry, was there a question here? Thanks!

[@robertbatista50]

No question, just commenting. Excellent troubleshooting BTW.👍🙌🏻

[@gieauto7175]

One of those cars you try to keep out of the shop. It could turn into one of those you replaced the wipers now seat belt won't latch. Good training video though.

[@jimmymakwega3872]

Hey scanner danner the shift-interlock circuit on most of the GM vehicles are BCM controlled after receiving brake input

[@rustypotatos]

JEEEEEEZ BRO NICEEEEE!!!!!! Awesome awesome awesome

[@davidsawyer1599]

Sometimes I wonder...... "Hey there's this guy with a KZbin channel. He seems to be honest and really knowledgeable. His Brother owns a garage. Maybe instead of taking this to the crusher. I'll take it over there and see if they will fix it." It appears as though every poj ends up at Danner's.