Troubleshooting a Bad TCM - CAN and Sensor Ground Circuit Problems

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.

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.

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

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. 🤟♥️

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.

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.

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!

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.

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.

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.

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 YouTube 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.

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.

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!

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.

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

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

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.

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

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

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