2009 GMC Sierra Intermittent No Crank U0100 Lost comm with ECM/PCM

In this video I demonstrate how I came to the conclusion of a bad ECM that stops commanding the power train relay. Thank you for watching. Please comment and let me know what you think.

[@michaeldegraffenried6077]

Mr. Rich hey my brother; great news finally got gmc running after a year working on truck; you want believe what it was after all the money and parts replaced: it was a relay and the fuse next each other praise God 🙏☝️!!! You given me a lot of ideas about what I should be looking for Thank you again for your help 👍🙋‍♂️🤝🇺🇸☝️🙏

[@MobileAutoDiagnostics]

Awesome! I'm glad to hear you got it running again and glad that I could be of help!

[@michaeldegraffenried6077]

@@MobileAutoDiagnostics I'll still be watching your videos always my brother 👍🙋‍♂️🤝!!!

[@MobileAutoDiagnostics]

@@michaeldegraffenried6077 I greatly appreciate that!

[@marioquan2221]

Excellent video very helpful 👍

[@oldbiker9739]

well done young man ,, subbed looking forward to more content

[@MobileAutoDiagnostics]

Thank you so much!! I really appreciate that!

[@jbh.6257]

Yes thank you!!! This is almost my same issue with a Cruze.

[@MobileAutoDiagnostics]

Awesome! I'm glad my video helped!

[@vulkn96]

Going to go thru wiring harness and connects and all grounds will let you know ,it actually started today ,ran at idle for aprx 1.5 hrs ,then died. And when I tried to start it ,it cranked over and started but acted like it was running out of fuel ,let set about 45 minutes, and it started and ran for about 5 minutes,,going to check grounds and fuel pump pressure, I do not have access to computer diagnostic equipment, nor the knowledge you have .but thank you ,and I will let you know what I do find.

[@eulondasanchez7087]

I’ve had similar problems with a few GMC going down the rd shuts off looses power. Emissions end up being the link able fuses sat on top the battery , Had a crack in the plate . 123 bucks from the dealership.

[@MobileAutoDiagnostics]

I've seen that a few times! But those fuses are so big that it makes you wonder what popped it. Had a newer body style GMC pop one of those fuses and the battery cable to the alternator was completely shorted through on the block😬

[@Katiewiseman-ez7cd]

I cant comment on the video so hope it's okay to comment on this thread... I installed an ECM myself which was pre programmed and sent to me. I installed it and did the re learn and still can not start my car... No anti theft light is on but my traction control light is on as well as my ABS light... Do you think it's a fuse or relay?

[@nbkking]

Where are you located I have similar problem

[@cbrwarrior194]

Man I have some questions about a gmc Sierra I am fixing how can someone reach out to you to get your input?

[@bobdeengineer7396]

Hi Devon, great video. I am helping friend fix a car (2018 chevy the impailer 3.6L LT) he recently bought. It was dead on arrival, lol. There was no battery and a missing spark plug. It was suspect. I placed a new batter and plug and the hazard flasher indicator (not the actual flasshers came on), high beam indicator came on(not the actual HB lights), third brake light is on all the time, no nothing is working in the car except for the radio. will not crank/start. I pulled a U0100 code and test 60 ohms (2 120 terminating parallel resistors) on the CAN BUS Hi Lo Pin6 & 14). Checked all fuses are ok. visual inspection turned up nothing. relays seems fine. No crank no start. If i swap the ecm from another impailer, even though it is not programmed for local, do you think I will get some good signs on the dash console (at least lighting up? Oh I did crank it at the starter relay, so at least the engine turned. I don't have the repair manual for thast car and limited equipment.

[@MobileAutoDiagnostics]

So if this is a mechanical key vehicle and if the ecm is bad, a used non programmed one will allow the lights to come on. I don't think it will work that easy if it's push button though. With the issue you are describing, and no knowledge of what's communicating. I would try a BCM first due to the lighting concerns

[@bobdeengineer7396]

@@MobileAutoDiagnostics thank you for your quick reply. I agree if I had a most sophisticated computer scanner I will be able to tell what's misbehaving on the CAN bus. I did take reference 5 volt from the IAT sensor (MAF) so it know the computer is chirping. I agree, I am thinking to try to unplug the BCM for inspection, cleaning and possible test with another. The car is suspect in a hail storm and possible lightening strike since there is evidence of the 300Amp being bypassed by a 12 gage wire 😂.

[@MobileAutoDiagnostics]

@Bob De Engineer I was suspicious of lightning as well when you said it was an 18 lol. If you are able to see that you have 60 ohms. I'd check voltage on CAN wires. One should be 2.7ish and the other should be 2.3 ish. If they are both ground, suspect bad module and you can unplug modules till voltages return to normal

[@bobdeengineer7396]

@@MobileAutoDiagnostics will do. Thanks. I am also going with your advice to try the BCM since it is a push button start/stop. I will definitel check for the voltages on the Hi and Lo. I will let you know the end outcome is. He bought this car from an auction and is expecting me to perform an exorcism on this car 🤣 thanks again

[@WTFBROKEGarage]

Were you giving it gas around 10:00, or was it idling up on its own? I havent had ecm communication at all for a while now, but when it was still intermittent the car would start, run for anywhere from 5 to 45 seconds, then it would idle up to around 3k, pull the timing all the way back to -15°, then it would die and all the dummy lights come on.

[@MobileAutoDiagnostics]

Hey thanks for watching! That was me giving it gas, thinking maybe it was failing when hot. But no if I left it, it would idle under 1k until it would finally die and lose the power on the circuit I was testing

[@WTFBROKEGarage]

@@MobileAutoDiagnostics I'm running out of ideas here man lol If ya don't mind me blowing you up with info in your comments, maybe you'll have a better idea of wtf is going on than I currently do lol Car is an 09 Pontiac G8 GT

[@MobileAutoDiagnostics]

Is it throwing any codes?

[@WTFBROKEGarage]

My knock off gmtechII says ecm not equipped, and the bcm is throwing now 9 codes. The steering wheel circuit code and tcm code just got added to it in the last couple days. C0277-06 B1517-03 B1517-5A B1529-03 B2615-00 B2645-07 B2652-00 B3006-5A U0198-00

[@WTFBROKEGarage]

Network resistance is 60ohm Highspeed voltage is 2.7v Lowspeed voltage is 2.3v New alternator, starter, battery, all ground and power cable replaced with 2g ofc, new hall effect sensor, every sensor on the motor is new and every plug has been probed. No blown fuses. Showing 12.5v everywhere aside from a scan tool. The bcm only sees 11.7v Interior is out, can't find any shorts in the body harness.

[@ladevinwashington1251]

Hey I have a 08 expedition with a lost communication to pcm but my truck do crank and start just idles rough,what would that be?

[@MobileAutoDiagnostics]

So if it still starts and runs, I would ignore the lost comm code and check for other issues like maybe a vacuum leak or bad o2 sensor

[@bebooth1]

Devon, I’m having a similar problem with my Yukon. I live in Birmingham, AL and don’t have the tools to diagnose myself. What type of shop had the capabilities you show in this video?

[@MobileAutoDiagnostics]

Hey thanks for watching my video! Honestly any local shop should have the tools to diagnose any issue.

[@bebooth1]

@@MobileAutoDiagnostics thanks for the response. You've been very helpful and your video was great. I think I'm going to just replace the ECM. This vehicle has 275k on it and any part replacement is valuable to me.

[@MobileAutoDiagnostics]

I appreciate that! And in case you didn't know already, the ECM will need to be programmed to your VIN and security will need to be programmed as well. I hope this fixes your issue!

[@jukorahelliott]

I hope you see this I have an 09 Saturn Aura it won’t crank or start changed out the starter, Alternator, & Battery plug it up to my car reader and received code U0100 Lost Communication ECM/PCM A what should I look to do first

[@MobileAutoDiagnostics]

I would check all your fuses and make sure you don't have any that popped. Otherwise I'd check voltages at the ECM connector and make sure you don't have any cut wires

[@Jayybirdd]

2008 Sierra. Rear camera comes up while braking. Truck won’t start on incline parked. Fog lights went out. Rear doors won’t unlock or windows won’t go down. 😢 bad BCM?

[@MobileAutoDiagnostics]

Unfortunately with the symptoms, it does sound like the bcm has gone bad. I would make sure no water has made its way into the cab

[@mateenakmal8478]

Where are you located Devon? I have an electrical issue. I need help. Thanks.

[@MobileAutoDiagnostics]

Hey! I'm in Arkansas. What kind of electrical issue are you having?

[@Edi-01]

Hi there brother I’m Havin u0100 lost communication with ecm/pcm I traced and replaced everything single part on my Cadillac Escalade “07. V8 starting from ground ending to instrumental harnesses from the fuse box and inside brand new new. My grounds are solid 120% but no start please help

[@MobileAutoDiagnostics]

@Unknown Known hey! Since you have a lost comm with ECM code, you need to check the ECM. Make sure you have all powers and grounds. And 2.3V and 2.7V on your communication lines. If you are missing any of those, that's where you need to look. If you have all of those, it's a bad ECM

[@MobileAutoDiagnostics]

@@Edi-01 also a replaced ECM has to be programmed. It won't start otherwise

[@bobbydelamar606]

We have 2 of these cases at work (4500 Expresses). Our scanner barely communicates. It pulls up U0101 but I can't pull up any live data. Only thing I see is module power 12 volt.

[@MobileAutoDiagnostics]

It sounds like you have no comm with the ECM based on that P0101. I would check all fuses and check powers and grounds to the ECM

[@bobbydelamar606]

@MobileAutoDiagnostics All powers and grounds were good. And all other modules were talking. One van ended up being a bad ECM. The other was a bad connection/open to the ECM main connector. Found by checking continuity on the CAN BUS circuit.

[@MobileAutoDiagnostics]

@@bobbydelamar606 nice! Glad you found the problems!

[@doriandiaz7269]

So what was the solution? I think the video is cut where the truck turns off again 😢😢

[@MobileAutoDiagnostics]

Hey, thanks for watching! The ECM on this particular truck was bad so it needed replaced. After replacing the problem never came back

[@toriwilliams500]

If I unplug my pcm would I need it to be reprogram to work again?

[@MobileAutoDiagnostics]

No as long as it's the original one, it will still be programmed and will work after unplugging and plugging back in like I did in this video

[@adventuresofmaryjane5342]

Hey man. I’m having a similar issue with my 2015 Sierra 2500 duramax. I took it to the Chevy dealership, and they took 2 weeks to tell me they still can’t find the problem. @ $100 an hour I just can’t afford to keep it in the shop… error codes include P2510, u0100, u0151, & u0422. They claim they checked all fuses, relays, & harnesses & couldn’t find any bad wires or grounds. The truck cranks and starts 100% of the time. It idles perfectly every time. And when it drives, it drives like normal. But it will randomly lose engine power while driving and start throwing messages on the screen like “ice possible drive with care,” “service stabilitrak,” or “check trailer brake wiring.” Each time the issue occurs, the engine power only flickers, I never lose electric power, and the truck will continue to run. Occasionally, the screen says “theft deterrent system,” and the engine will shut down completely. But it always starts back up with the turn of the key. The issue can happen after driving 50 feet or 50 miles. Smooth or bumpy roads. Driving fast or slow. Throttle or break. It doesn’t seem to have a condition that it happens. But it does tend to happen more frequently the longer I try to run it. That’s about all the info I can give you for it. Think you can point me in the right direction where to look?

[@MobileAutoDiagnostics]

So the P2510 talks about the powertrain relay and how it's lost its signal from the ECM. The U0100 is a generic "lost communication on CAN." U0151 is a lost comm with Airbag Module and U0422 Is invalid data received from BCM. Based on what is happening, I would focus on that P2510 and see if anythings going on with your PCM or under your fusebox that could be causing issues

[@MobileAutoDiagnostics]

I'm sorry I was mistaken, a U0100 is lost comm with ECM and a U1000 is the generic "something is not communicating" code. But I still recommend looking at the P2510 before checking the other codes

[@TheVmaxrider1200]

I have a 07 which I've had a few no crank no start and service 4 wheel comes up. I don't have all the stuff you have but I'm assuming it's ecm from what I've seen from this

[@MobileAutoDiagnostics]

Hey, thank you for watching and commenting! Yes it definitely could be, but it could also be something else depending on what's actually going on

[@MobileAutoDiagnostics]

Also thank you for subscribing!

[@cjthagod1959]

I have the same 2013 suburban no crank when key turns just lights and stuff check 4wd on dash gas guage and temp guage not working rear door won't unlock or open

[@MobileAutoDiagnostics]

@CJ Tha God Im guessing by rear door you mean the hatch? that may be a communication issue as well, but may be hard to pinpoint the issue. I have a video on a 2009 Malibu that could help in diagnosing that issue if that's what's going on

[@vincentaguirre3959]

​@MobileAutoDiagnostics I have same problem 07 suburban stabilize light flash on with any bump on road then stayed on moments later abs on and noticed temp and gas gage didn't work so I pulled over turned car off noticed rear door latch didn't work car wouldn't start waited and finally did start 1/2 later 😅 this time with no lights im afraid will leave me stranded

[@joshstokes5669]

I have the u1000 code on my 07 silverado newer body style. Where should I begin diagnosing a bad ecm?

[@MobileAutoDiagnostics]

Hey! Thanks for watching my video! Unfortunately a U1000 is generic and it basically says that one or more modules are not communicating on the CAN network. But if you had a U0100 that would be no communication with the ECM. If you think the ECM is bad, I would check powers, grounds, and look for 2.3V and 2.7V on the 2 CAN wires at the module before replacing

[@joshstokes5669]

⁠​⁠​⁠@@MobileAutoDiagnosticsoh sorry yes 0100 code. Will googling a wire diagram tell me how to test those wires?

[@MobileAutoDiagnostics]

@joshstokes5669 it'll at least get you close. A wiring diagram and a multimeter is all you'll need. You'll just have to make sure you get on the right wires since there are so many lol

[@Apphus144]

Were you able to fix it? I got the same damn problem.. Thanks in advance ​@@joshstokes5669

[@LuisHernandez-he53]

I'm having this same problem with my 09 yukon. Lights/windows working, however I cannot lock/unlock the doors with our without the remote I "jumped" the starter relay and it cranked, no start. ABS/traction lights are on, I can also hear the fuel pump turn on. Bad ECM??

[@MobileAutoDiagnostics]

Hey Luis! Thanks for watching my video! Given that the fuel pump runs when the key is switched on I don't think it could be a security issue but the fact that it just cranks when jumping the relay says something else is wrong. It COULD BE the ECM but without any codes to go off of its just a guess.

[@LuisHernandez-he53]

@@MobileAutoDiagnostics Thank you for replying. I finally figured out out. It was my BCM.i got one from a junkyard for $25. I replaced it (after watching av video from Spartan Autoworx) did the security relearn. Now I have the service airbag light on and my radio is locked. Any idea how I can fix that?? Thanks again!

[@MobileAutoDiagnostics]

So the BCM and the airbag share a secret code between each other and without programming the correct VIN, it's most likely setting fault codes for "mismatch VIN" which could cause the radio to be locked as well.

[@anitahendrix7573]

OMG had rabbits chewing wiring. Lights on dash but no start no crank. Had it towed to my mechanic he fixed the chewed wires but still won't start. Told me it is not his expertise and I will have to have it towed again to Chevy dealer it's a 2017 suburban. What a pain will use to. 22 on the rabbits.

[@nujay3161]

Hey man I know this is an old video but hoping you’ll see this. I have a 2009 Tahoe that has been in 3 different shops now with no fix. Fuse block has been changed, cables, bcm, grounds checked, battery, still same problem. I’ve thought about replacing the ecm but shops keep telling me they think it’s a module somewhere. The truck will run and drive perfect at times, sometimes for a whole day. But sometimes it will go crazy, multiple lights popping up on dash, gauges up and down, locks up and down, as well as shifting crazy. It also has times it won’t start but has never just shut off while running. Any ideas man, paying these shops for 2 months now to not have the problem fixed is killing me.

[@MobileAutoDiagnostics]

Hey! Thanks for watching, and I'm sorry to hear you are having this issue, especially for so long! So, with what you are explaining, it sounds like you are having a communication issue like a module is pulling down the network. Unfortunately, with it not actively failing, pinpointing that would be impossible. Considering it doesn't die when it starts acting up, I wouldn't change the ecm. I have seen some other vehicles, specifically an Avalanche, where the round transmission connector causes issues similar to this so I would check that!

[@nujay3161]

@@MobileAutoDiagnostics I’ll check and see, thanks for the response!

[@lenny_miller2357]

@@nujay3161did u get it fix? I’m having the same issues with my 2011 chevy avalanche

[@justinshields4216]

​@MobileAutoDiagnostics any luck on a definitive diagnosis?

[@shorelinearmorllc477]

​@MobileAutoDiagnostics hello. Having no start no crank out of the blue. Battery good, vehicle cranks when jumping spots where relay is, swapped relay with another in running lamp position and nothing, appears relays and fuses good. No signal to starter wire with voltmeter. Ignition switch was changed cuz it was cheap and easy fix. I hear a high pitch electrical noise like a TV is on coming from that round connector going to the transmission. Don't know if it always did that or that could be the problem it appears that module is located inside the tranny so didn't look like something I could get into. How do I go about checking that.

[@TRYtoHELPyou]

its not about the quality, its about the content. Great content. thanks for sharing this!

[@MobileAutoDiagnostics]

I appreciate that! Thank you!

[@danielwagner6517]

Hi, what kind of meter is this?

[@MobileAutoDiagnostics]

Hey! In this video I'm using a Power Probe. It hooks to the battery and gives you a live reading on any circuit and you can simulate power or ground with it. But you need to be careful as to not put power or ground on the wrong circuit as you can cause more harm than good!

[@danielwagner6517]

Danke@@MobileAutoDiagnostics

[@vulkn96]

I have a 2010 silverado 4.3 at 2wd base model truck ,gauges inop ,no Cel at all ,prndl ,indicator doesn't lite up ,NO crank ,,replaced ecm ,body control modual ,fuse box ,checked and found all engine grounds to be connected, when key is turned to crank position the headlamp relay cancels the headlights, had truck towed to a shop ,once they arrived to shop ,truck started up ,I Knew it didn't fix its self ,and when I went to get it ,I noticed no cel when the key was in the on position, truck ran for about 20 minutes in the parking lot then shut down on its own ,full power to everything but gauges and prndl indicator.

[@MobileAutoDiagnostics]

That sounds like you have some kind of communication issue. Generally on a GM, if you don't have a CEL on with Key on Engine Off, it's not communicating. Unfortunately that could anything from a bad module, to a wire temporarily shorting out.

[@aaronhaas2302]

I have this exact same problem. 08 GMC Sierra lost communication with pcm/ecu. Sometimes starts and sometimes doesn’t. Any idea on how to figure it out?

[@MobileAutoDiagnostics]

I would definitely check all powers and grounds when it's in the fail mode before changing any modules. Is there any specific way you have figured out that will make it not start?

[@aaronhaas2302]

@@MobileAutoDiagnostics yes i did and clean and checked all wiring. i have codes for u0100 and p0606. ive called several shops they said that is an internal issue with the pcm/ecm. i just do not have the full confidence that it could be the issue on a 50k miles truck. truck runs great for 2 weeks and then all the sudden shuts off, (will not turn over) but still has power.

[@aaronhaas2302]

@@MobileAutoDiagnostics also no specific way to figure out when it does. just randomly does it. the previous owner did replace the fuse box so i am thinking he was having the same issue (knowing that before he sold it to me) and they didnt figure it out.

[@MobileAutoDiagnostics]

@Aaron Haas so unfortunately, a P0606 is an Internal Processor Fault. The only fix for that is updating the programming (if it has an update) and/or replacing it. That's where I would start. I understand it only has 50k miles on it, but unfortunately, GM has many control module issues.

[@MobileAutoDiagnostics]

Now a U0100 is a communication code. Basically saying "CAN bus fault" or something similar. It doesn't mention any module specifically but it knows something is losing communication. When it has failed, have you tried unplugging the ECM and plugging it back in?

[@joseceja4832]

Okay 👌

[@age_of_reason]

I had the same issue with a Nissan Versa. I blew a fuse while probing an 02 sensor connector. Changes a 20A fuse and it fired right up. But the U0100 won't go away.

[@MobileAutoDiagnostics]

Hey, I'm sorry to hear that! Maybe you blew another fuse as well? What module is setting the U0100 and is there any symptoms that are causing you to chase this particular code?

[@age_of_reason]

The car runs fine. MPG seems normal. I don't know which module is causing the code but maybe I can find out if I look at where the fuse that blew is located. I will check for other blown fuses now that you mention it. There are no symptoms aside from CE light and TPMS lights blinking. The TPMS lights only came on after I removed a spare fuse from a blank ("-") fuse slot to replace the blown fuse. I am hoping it's the computer's memory that needs to be cleared for the CE light to go away. Is it a good idea to clear the codes at this point? When I went to clear the OBD2 codes i saw a warning saying that clearing them might make future diagnosis more difficult. I took it to a reputable shop but they are busy and can't do diagnosis until after the weekend. I told them the issue...they said they probably wouldn't be able to reprogram the computer and most independent shops don't have the tools/knowledge to either, and that I would likely have to go to the dealership to get it done.@@MobileAutoDiagnostics

[@MobileAutoDiagnostics]

So with the fact that it runs and there's no visible symptoms, I thunk you can ignore the u0100! The blinking TPMS light may be coincidence and you just have a bad sensor in one of your tires. If you take it to a place to get the codes cleared I would make sure to ask if you can get a printout of the codes just for documentation because, yes, clearing the codes can cause trouble with diagnosing a specific issue

[@age_of_reason]

@@MobileAutoDiagnostics Thank you!

[@MobileAutoDiagnostics]

@@age_of_reason you're welcome!

[@alfonsoecuevas6516]

Have you ever ran to a problem with the safety lock 🔒 on? Everything turns on fuel pump you an hear just no crank

[@MobileAutoDiagnostics]

Hello! Yes I have ran into a few with the security system active. Depending on the vehicle, it could be a bad key, Passlock sensor, TDM, PCM, BCM, cut wires, or maybe a few other things. What's wrong with it depends on the vehicle

[@alfonsoecuevas6516]

@@MobileAutoDiagnostics I got a 2007 Chevy Tahoe LTZ original key it just started doing that after my battery died and took battery to get charged

[@MobileAutoDiagnostics]

@alfonsoecuevas6516 with it being a 2007. Try leaving the key on for 10 minutes, turn key off then turn it back on for 10 minutes, then key off and back on for another 10 minutes for a total of 30 minutes. Then try and start it. If that doesn't work then either the key is bad or something else is disabling the system and it will need scanned and diagnosed further

[@vulkn96]

But what was the fault ,the ecm ?

[@MobileAutoDiagnostics]

Yes the ECM is the fault. They replaced the module, we programmed, and it never failed again

[@hamdi6068]

I have almost the same issue but the car dont stop garage is also is not able to know the problem we tryed new ecm ....nothing is working

[@MobileAutoDiagnostics]

What do you mean "won't stop" like when you turn the key off it stays running?

[@hamdi6068]

Thanks a lot for your video i finally find the problem the parking sensor module under passenger seat was full of water it was the cause of the problem

[@MobileAutoDiagnostics]

Awesome find! I'm glad I could be of help!

[@lifteddreamz830]

I had to replace a ECM connector and now it’s reading the U0100 code and won’t start. How can I fix this?

[@MobileAutoDiagnostics]

I would go through the wiring diagram and make sure I got all the terminals in the right place before checking anything else. Did you change it with the battery connected? If so, then maybe a ground and power wire touched each other and popped a fuse.

[@lifteddreamz830]

@@MobileAutoDiagnosticsI didn’t do the work. A shop did. I had battery disconnected but they might’ve connected it. I’ve tried clearing the code and nothing happened along with trying to do key relearn

[@MobileAutoDiagnostics]

@lifteddreamz830 so was this code active before you replaced the connector? Or just after? If only after, I would take it back to the shop that did it and have them recheck their work, otherwise I'd be checking powers grounds and communication to the ECM to see what voltages are missing.

[@lifteddreamz830]

@@MobileAutoDiagnosticsI don’t remember. I checked it yesterday to see if any codes popped up and that’s what it said. No check engine light is on. Only service traction control/ service stabilitrak. The shop brought it back to the house cause they said they don’t have time to fix it

[@MobileAutoDiagnostics]

@lifteddreamz830 ok so, generally with GMs when you turn the key on, if the check engine light is not lit up, that means it's not communicating. You should always have a check engine light when you have the key on with the engine not running.

[@thomasdodson3587]

Hi, I was wondering if you could help me out. I got an 07 gmc sierra that is burning up the smaller ground wire off of the battery to the front passenger core support mount. Once, I got the fire out and replaced everything that got burned up. I went to tonhook the battery back up, and it's arcing off of the positive side with the negative hooked up. I've run a test lead and mult meter to the fuse box, and I'm able to pull 12 volts between the positive and all of the fuses. Sorry for the long comment, but I'm at a loss as to what's causing this. I know it should be short, but I've checked all the wiring that I could, but I'm not seeing anything that would cause this. Thanks for any help you can give me.

[@MobileAutoDiagnostics]

Hey! So if I'm reading this correctly, you test 12V to the fuses with the key off? What is the test lead for?

[@thomasdodson3587]

@Devon Rice Sorry, test lead/ jumper wire so I could reach from the positive battery post to the multi Meter to the fuse box. I also pulled the fuse holder out to get to the connectors and I'm able to pull voltage through most of the pins in the connector

[@MobileAutoDiagnostics]

This is with the positive cable off? I'm trying to envision this scenario and I'm having trouble. So if you have 1 lead on positive and the other lead on the fuse, it would be 12 V because it doesn't have any power to it yet

[@thomasdodson3587]

@Devon Rice yes the positive cable is not attached to the battery. I first started with checking for voltage at the battery cable then went to the fuse and the starter cable. I disconnected the starter cable. Still have 12 volts. Disconnected the alternator cable. Still 12 volts. Ran the lead and multimeter over to the fuses . Had voltage. Pulled the fuse holder apart and have voltage through most of the pins in the connectors.

[@MobileAutoDiagnostics]

@@thomasdodson3587 ok when connecting negative first, you will get a slight spark when positive cable hits post, that is normal. Other than that, I'm not sure I can be of help through messaging

[@michaeldegraffenried6077]

Hey I'm having the same issues with my 2001 gmc serria I need help 😫!!!!!!

[@MobileAutoDiagnostics]

Hey! Thanks for watching! I'm sorry you're having issues with your truck. What's going on with it?

[@michaeldegraffenried6077]

@@MobileAutoDiagnostics well; this is a 2001 gmc sierra 1500 4.3 v6. sometimes it starts and sometimes it want. Runs fine! When it running, Then when I get to where I'm going; come out to start it want start?🤔 dashboard lights respond, but turn the key and it want start..?. it'll take several turns of the key and possibly several minutes and maybe hour for truck starts! Then the truck runs fine! Get up in the morning come out to start truck it want respond?🤔 once I get the truck started it runs fine Just like your video on that 2009 sierra

[@MobileAutoDiagnostics]

Ok. Something you can look for on a GM is, if it won't start but the dash lights up, look for the check engine light. If it doesn't show up, the ECM is not communicating. If it is showing up even though it won't crank. Maybe it's a bad key that is intermittently working.

[@michaeldegraffenried6077]

@@MobileAutoDiagnostics engine light is on!!! I've searched on line watched videos and haven't found a solution 😡! I bought a brand new ECM and had it reprogrammed, new battery, new starter, new throttle body,starter key ignition new fuel pump in the tank basically new everything under the hood 😡!!!!?????..... with 93,000 miles...

[@michaeldegraffenried6077]

@@MobileAutoDiagnostics but your video seems to be on track in making sense ground to power to ground 🤔... I've been all through the wiring, fuses... so got frustrated and parked truck and bought a 🚗 car! I miss driving my pickup...

[@freddyjackson4910]

Hey can a local locksmith reprogram my pcm?

[@MobileAutoDiagnostics]

In my honest opinion, I don't think so, due to the fact that they need the VIN changed, but it's possible.

[@TimothyCannon-gg1bu]

Code po 100 code 2007 Ford 500 limited

[@MobileAutoDiagnostics]

This is a lost communication with ECM code. I would check all your fuses, and check powers, grounds, and 2.3 and 2.7V on the 2 comm wires at the ECM

[@hellsgates]

Turn that god damn buzzzer off

[@MobileAutoDiagnostics]

Lol I can see why that would be obnoxious in a video but it's not that bad in person. Hopefully the rest of the video made up for it👍

[@user-cb6fz4wk2x]

Damn I'd never buy a Chevy

[@MobileAutoDiagnostics]

Hey thanks for watching my video! I'm definitely not a GM Tech, but looking back at what vehicles are in the videos I have posted... that's a smart decision😂

[@duke4274]

When you turn the camera sideways.. smh the video is now worthless

[@MobileAutoDiagnostics]

I understand what you mean and thanks for the feedback! I'll keep that in mind for future videos! Hopefully the content makes up at least a little for the mistake!

[@MobileAutoDiagnostics]

If you are watching on a phone and not on a computer, you could turn off auto rotate and that may help!