Dodge Ram No Bus message

How to diagnose
Testing data wires was mis-stated. Black lead of meter to ground. Red lead to data wire. Should show approx 2.5 vdc

[@windvane_npk5844]

Why didn’t I found this video before??? My trucks been down for 2 years and this is the only video I actually needed. Your the man

[@chandamanmartin9242]

ABSOLUTELY THE BEST VIDEO I HAVE SEEN for auto repair/diagnosis. Camera is not shaking all over the place he speaks clearly and makes sure you see what he is telling you. . THANKS FOR MAKING THIS VIDEO ! And it's actually for a Dodge Ram 1500 5.9L ! I'll be subscribing to your channel and looking forward to seeing all you have on the RAM 1500 5.9

[@verdevalleyautoelectric4336]

Thank you

[@robertwhitfield8652]

⁵

[@montekingen8839]

What I ended up doing is plugging in and unplugging those three pcm connectors. For me I had just a loose connection and it reset it. Might be handy for anyone to try before having to fork out a multi meter if you don't got one

[@davido1588]

Same here. It was fixed after re-seating the plugs.

[@malcolmsanford180]

@@davido1588 11:49 2000 Dodge ram 1500/ 5.2 lit/. When cold the engine starts runs fine for 10 to -5 min. Then engin cuts out & drops about 1000 rpm then runs again for a few seconds several times. When engin gets to or Al operating temp the engine dies&wont start at all. All fuses & relays test good. I was told to get a pitcher of ice water & pour on ECM. If engine starts & runs again the ECM is bad. Should I try this? Sounds reasonable to me but will pouring water on ECM mistake or is this a quick test that won’t creat more problems? Thanks

[@davido1588]

@@malcolmsanford180 the ECM and the connections should be sealed by default, so it should be fine in that case. Just make sure the seals are in good condition or that the water won't go into the electrical plugs.

[@swollencityfitness]

This comment fuckin saved me !! Tried everything except that, read your comment and tried it. Started right UP 🥶🥶🥶🔥🔥

[@kgasper]

@@malcolmsanford180 I would probably try using a freeze spray first before pouring water over the ECM... it may be sealed and water resistant but not waterproof. You could also use a can of air duster turned upside down so it comes out all liquid to chill the PCM.

[@papabean1117]

God bless you sir for making this! My issue was the wire by the distributor I didn’t break everything apart to fix it but playing with the wire connector…..everything fired up! Again thanks for taking the time for us penny pinchers!!!

[@jonathanmalone7595]

The best video on helping fixed the no bus on my dodge.

[@JoeStanek-vu7rl]

The diagnostic plug broke and a couple pins were touching, I seperated them and the No bus went away. I suppose I will need to wire a new plug in the near future.

[@stevendunn5989]

Thanks this the best video straight forward no crap 😁

[@BluntEdgeChisel]

This is the most in depth video on this thank you so much well done!

[@joseluisgarcia3126]

Where are you located ? This is exactly what is Happening to my truck

[@jacobkeller1279]

Just replaced my computer and still have the no bus message. 5 volt is good. Any suggestions? But I do not have 2.5 volts on the no bus wires.

[@dafrautn]

Great video! I had the NO BUS issue on my '01 Ram 1500, and using the diagnostic techniques in this video, I was able to determine that my PCM was bad (mv at my PCM CON 3 pin). I ordered a used PCM pre-programmed, installed it, and my truck fired right-up, no CIL. Great job on making this video!

[@jdazmit2975]

where can I buy that pcm already programmed

[@JoshuaRoberts-k4c]

I don’t mean to be a smartass but it literally jsounds like this video was recorded in a windstorm along with 2 toddlers playing hot potatoe with the recording device alone with you many pauses along with what is in 1 and 31

[@lostbrokenmind8484]

I don't have a no bus on my 98 but good info and description for me to understand it. I am going out and doing checks on sensors now thank you

[@clintyoung6482]

Did you get it to test the gauges to see if they worked? I have a '98 SST with the 360. Just wondering if our old trucks can do it

[@ketchupmustard5465]

I didn't have a no bus issue until a shop said my truck needed a pcm. I've tracked my problem to the fuse box. When mine says no bus I can shake the wires to the relays and no bus goes away and truck works fine. Until I hit a bump

[@702Thermisticles]

Which fuse box? Dash or engine?

[@robert_murphy916]

I’m having a stalling problem and it says no bus it will start back up sometimes it won’t

[@chuydehorta67]

Me too

[@DocLockwood-u9l]

​@@chuydehorta67did you fix the problem?

[@donaldcefailjr4501]

Hey Guy, Great video! I'm applying these tests to my 99 Jeep Grand Cherokee with a 4.7 in it. I have tested pin number 2 and 22 in the number 1 PCM harness and am receiving 11.8 volts. Is this normal or do I have a leak somewhere? Incidentally I just ordered a remanufactured PCM that is coming programmed and will be here in three or four days. Thx for the help in advance. Don

[@duanedonaldson2262]

those voltage readings should match your battery voltage

[@salbahena1325]

Thank you so much and god bless you sir real helpful thanks 🙏

[@verdevalleyautoelectric4336]

sal bahena Glad it helped you!

[@nickyvlassis210]

Love what you are doing. Thank you. Have an 01 Cummins doing some strange things. Thanks for the advice

[@TimBesser]

I have a 2011 Ram 1500 with No Bus. Would these instructions work with that year?

[@chrispeters4405]

Would liked to have had the miltimeter settings for each test

[@peerless8967]

@chrispeters4405 you’re just checking dc voltage set ur multimeter for dc and set it to 20

[@Tyzx7ch]

To test the pins do I just put red in one and black in the other he doesn’t really say

[@beatswiththeboot67]

Could someone tell me if I could buy a used ECM/PCU/ECU whatever it's called as a replacement? Is there anything I need to look out for in doing this?

[@clintyoung6482]

It will need to be tuned for your specific truck You need to get the VIN number and buy it new from a company that can tune it to your specific truck

[@charlesharrison7705]

My 99 Cummins runs but has no bus!

[@DJJamOfThaDose]

Thanks for the great video, working on an 02 right now, No mumble Just straight to the point.💯👊🏼

[@MurkkOG]

This helped me find out I have a bad connection in pcm plug 2. When I press the tab of that plug down towards the firewall, I hear everything click and my pump prime. But idk if it's a loose pin on the pcm or a shit pin in the plug

[@dylangrierson5992]

I’ve had the same problem. Have you been able to find a solution?

[@MurkkOG]

@@dylangrierson5992 yea my pcm took a shit. Stopped sending fuel pulse signal

[@moecapitolnetwork2916]

hope you can help 01 ram im helping someone out. No CCD data bus from PCM to instrument cluster. DLC pins 3 & 11 read 118 ohms across both and 2.5v on each pin to ground. Car runs normally but gauges inoperative. Instrument cluster has termination resistor but can't read if PCM has a termination resistor on pins C28 and C30 on gray connector C3. PCM has been replaced twice with "rebuilt" PCM's.

[@jasedaniels4412]

Mine didn't give any codes. The no bus comes on sometimes while I'm driving then it goes off after a few seconds.

[@MJ-ig4hd]

Thank you for the help! The truck I was working on was a 1999 Dakota 6cyl, but everything is the same. I had battery voltage to the pcm, had the grounds, had the 2.5volts on the #3 plug and the 5 volts at the tp sensor. There was one other one that I believe was 7 volts ,I had less than .5 volt on the two pins on plug 3 of the pcm and was a bit confused what I was supposed to have there, but purchased a pcm and had it vin programed and the truck runs great. (no fuel, no spark, no injector pulse, no bus, no communication before), Thanks again, nice explanation, you made it pretty easy for me. Thanks for the info!

[@1dumpsters]

How can I donate you helped me .mucho

[@CJ-ok7pn]

Great video! I have no bus and the only thing that does no have power is pin 28 on connector closet to passenger side i think connector3 Any idea what that means

[@HergyBear78]

i have the same thing, did you figure it out?

[@GunsandOil]

Does this apply to the 5.9 Cummins as well? I have a 2002 Dodge 3500 Auto. I am having the following issues: No alternator Charging, Truck starts in 3rd gear, no overdrive, can drive truck when shifting manually 1-3, no gauges work other than RPM, Engine light, No Bus w Codes.. Been scratching my head about it and cant figure it out

[@JonBuchanan-sr8by]

THE MAN,THE MYTH,AND THE LEGEND! Thanks bud for the knowledge! I've been having this problem for months now, sometimes leaving me stranded! Within 5 min PROBLEM SOLVED

[@davido1588]

I can't make sense of this. "So the last number is 31, so you go in 1 from 31, you'll wanna see about 2 and a half volts on your meter on the 2 wires."

[@HergyBear78]

i don't understand him either

[@davido1588]

@HergyBear78 I just watched that part again, and I got it now. He said pins 28 and 30. I guess those are the two to probe. I think what it ended up being for me was the ground wire next to the passenger side battery. I removed some unnecessary connections and made a more direct connection to the battery.

[@sunburstiz7066]

Awesome info, thanks for your patience explaining it!

[@juliorosas6281]

Thanks its a great video and a lot of help for us since we had over a week trying to figure out our problem thanks again

[@ang3lbass]

Thankful af for this 🙏🏽🙏🏽🙏🏽

[@goinbacktovalley8826]

I have a no bus with start. Pin layouts and drawings would be great if you can help. I'm a retired instrumentation & controls tech. 1-5 vdc understood. Not a video fan butc to your approach was A1. 1999 ram 1500 5.9

[@willie6185]

Well, I checked the voltage at the tps with the key on and it read zero voltage. So I unplugged the cam sensor and the tps still read zero volts. So I unplugged the crank sensor and the tps read 5 volts. So I figured it was the crank sensor. Well I plugged in the cam sensor and them the crank sensor, and when I plugged in the crank sensor in I heard the pcm and the fuel pump kick in. I did replace the crank sensor and the truck still stalls with the no bus in the odometer. Do you think I should check the volts in the pcm plugs or do you have any suggestions. I appreciate your time.I do have my dodge idling at low rpms which might be because of the low voltage. It isles at about 560 rpms. I have replaced the tps sensor and cleaned out the trodel body.

[@duanedonaldson2262]

The PCM circuit board comes loose inside the PCM, you can resolder it at home, all 5 volts are shared from the PCM so if one is good and one is not, the one that is not has a broken wire or the sensor is shorted, same with the shared sensor ground wires, the transmission 5 volts is a different circuit.

[@willie6185]

Duane Donaldson thank you Duane for your response. In the odometer, what does the 999 code mean? When I unhook the ground to the battery and rehook it. Everything comes alive. When I unhook the ground does that reset the pcm?

[@alexandragonzalez7853]

So I have this problem and my fuel pump won’t kick on I was told it was my fuel pump but I think it’s this after watching this. Will it cause my fuel pump to shut off as well?

[@verdevalleyautoelectric4336]

Alexandra Gonzalez yes, if this relay is failing it will act like a bad fuel pump and shut off your fuel

[@alexandragonzalez7853]

@verde valley Auto Electric okay I got it it! Thanks it starts,runs and drives but every once in awhile my truck will do that and I just shake around that white connector and it works do you think it could just be that connector?

[@duanedonaldson2262]

@@alexandragonzalez7853 it could be the PCM circuit board inside the PCM, you can fix it at home

[@BluntEdgeChisel]

To be correct on connector 3 you are testing between pins 28 and 30 and looking for two and a half volts as in red probe on 30 black probe on 28?

[@catchkcsglide7945]

I'm scrolling thru the comments for the same question.

[@notme7770]

Black probe on a ground (I guess directly to the battery's negative is suggested as best, better than just touching the engine or frame with black probe to use as ground), then while leaving black probe on negative of battery('the ground'), one at a time, touch pin 28 and 30. They each should read 2.5v.

[@jasonvigil7336]

So, I've got a 2000 Dodge Ram. Had the No Bus message, so I purchased a pre-programmed, refurbished PCM. Replaced the PCM and it no longer shows the No Bus message. However, now the truck does not want to start! It'll crank when I turn the key, but it won't start up. I've checked all the fuel pump replays and switches and everything is fine. Any ideas!?

[@johnnygallardo76]

does this work on a 2000 dodge ram? i have a no bus too and it wont start.

[@Metaldrummerarizona]

Yes

[@Metaldrummerarizona]

I have a 2000 as well

[@youarewrong57]

You ever figure out what was wrong? Having the same issue with my 2000 Dodge Ram.

[@vintagestrings6]

I have a 99 Dodge Durango that I bought new and it still looks beautiful. Running down the road it will just die out for no reason and won't start for a while other times when it starts it won't idle. I replace the idle actuator and it did not do anything. I was thinking it's the PCM but I've seen other KZbin videos and comments where they said it could be some thing called the leak detection pump which pulls vacuum in the evaporation control line! Not sure if anyone's heard of this. I also get the no bus on my dashboard and it won't start then it will clear itself after about 5 minutes or so and it will start and run for a little bit and the shutdown again . Thinking about getting a new PCM

[@golpherboy13]

Did you end up figuring out the issue?

[@ricksmith196]

My truck did this, it was the coolant temp. Sensor, making mixture too rich.

[@stevencostello3990]

2000 Dakota 4 cylinder manual. No bus code. Long start when cold. Fires up and idles fine. Drive for 10 minutes or so and then dies. Will not restart untill I hear a single clicking sound behind the steering wheel. Then it will start up again only to run for another 1/16th of a mile, then dies again. Repeated over and over. Got it to the house. Started it again and did fine for about 5 minutes and did it all over again. Does this cold or hot.

[@widdleweddle7715]

I have a 2001 dodge Dakota with similar problem, going to try this when I get home. But I also have a solid green wire coming from my transmission relay that's not connected to anything. Would you happen to know where it should be going?

[@Slim_Sticky]

Hey great video man. Very helpful! I have a 2000 Dodge Ram 2500 which has recently had a new set of keys made for it and a new ignition put in it. But now after the new ignition was installed, the truck will not start. The only way I can get the truck to start is when I unplug the third connector (far left). The truck will run and drive that way but the alternator will not charge the battery up. I’m not sure exactly if my problem is in the ecm or if it is from the new ignition that the lock smiths put in. *side note* when I’m inside the truck, there is a red flashing light which I’m assuming is a security light. Would you happen to know what my problem my be with all that being said? Thanks

[@marchellocapellitini3902]

Happen to my van after rain, in the middle of the road while driving... arrived.home, turned it off, then wouldnt start. After the day got dry it didnt happen again. Probably wet cables grounding somewhere

[@vicmiddleton236]

U say it'll cause me much grief.... what kinda grief... I'm having the same issue on my 2001 Cummings but the truck runs great... what can I look for to start happening?

[@_vaporu_131]

I have a dodge dakota with the same issue, starts and runs for about 30 or 40 min, then shuts down, what i do is i move connection 1 andnthebtruck starts right back up, another thing is that while the truck is on i also move the connector 1 wires and the truck shuts off, any clue of whats going on.

[@dylanornelas454]

I am currently going through the same thing. I ended up finding out that it means there is a bad wire/connection somewhere getting too hot and the PCM does not read the 5V reading it needs for it to run everything. Ive been down for 6 months trying to figure out what the hell is wrong with it. Two other major things i discovered was that it usually is the Crankshaft Position Sensor going bad. it usually falls victim to grease build up since its behind the passenger side cam cover. I have submitted to forums and ive narrowed it down to replacing the crankshaft position sensor and PCM and everything usually gets resolved. Buying MOPAR parts is important for sensor replacement. After market sensors sometimes don't put out the correct amount of current for the PCM to function correctly. I have a 2000 Durango R/T 5.9 and ill be damned im going to let this stop me! Ill post updates when my new sensor and PCM get here! Hope this helps!!

[@tomnobody9294]

Do no have 2.5 volts at #30 but do at 28 ? Suggestions....

[@duanedonaldson2262]

double check wire diagram for your exact vehicle

[@HergyBear78]

same here, did you ever figure it out?

[@bkhummer]

Thank you for making this. I disconnected connector 1 and reconnected ut. It fixed the issue. What does connector 1 lead to?

[@bkhummer]

By the way it was no bus with start and run but has recently started to shut down when no bus occurs

[@candyallen2358]

Plz tell me what to do can't no mechanic figure it out I have to try and do it myself can someone plz help me

[@DocLockwood-u9l]

I'm not the original poster but I have made some progress on my "no bus" condition on my 5.9 gas 360. Have you fixed your problem?

[@jasonburks7227]

My truck will start and it still saying no bus what do you do to reset it it'll run but it bogs down they put it in neutral shut the key off turn it back on then I'll run normally what do I do

[@henryjohnson3851]

Had that on a 2002 2500 diesel.....turned out to be missing a ground wire

[@aaronchavez2645]

Wow!! Gonna try this all after work today on my 2001 ram 5.9. Mine only shuts down and gives “no bus” when it gets hots or is really hot out side???? Any immediate thoughts???

[@verdevalleyautoelectric4336]

Aaron Chavez Heat is the #1 killer of electronics. My bet is when it’s warm you have an internal connection in the ecm that is failing. But test test test before just throwing parts at it.

[@justinkeyes5107]

Verde Valley Auto Electric mine is the same way, but I can smell gas. 1500 5.2

[@duanedonaldson2262]

@@justinkeyes5107 sounds like you have more than one problem

[@emmanuelmacedo2673]

U got and update ?

[@Pneumamechanical]

@@verdevalleyautoelectric4336 I'm working on an '01 5.9 magnum doing the same thing, it runs when cold, but once warm, it stalls and does "No bus" was intermittent, but now not start. Everything you mentioned in the video checks out, except my can bus wires are only 2.46V but that seems close enough. good power and grounds on everything else, I'm thinking it's the ECM. But how do I know if the CPK is shorted? it's got good power/ground unplugged

[@dizzvideovision4606]

I have a 2009 Dodge Charger going through the same thing

[@chrisv1085]

I get no voltage at pin 31. Does that mean I have a shorted wire?

[@manuelverdugo1737]

La mia a veces da este problema. le doy una palmadita al dash o paso p[or un brinquito y se quita.

[@verdevalleyautoelectric4336]

Manuel Verdugo lo siento. Mis espanol es pobre.

[@manuelverdugo1737]

@@verdevalleyautoelectric4336 Mine sometimes gives this problem. I pat the dash or step over a little jump and it takes off. But I do not know which one; is the connector of the problem.

[@duanedonaldson2262]

@@manuelverdugo1737 the solder inside the PCM is a problem with these Chrysler PCM, it can be fixed at home

[@gusshernandezeltraileroreb5387]

You are the best sr thanks for you video that help me a lot

[@jamessumner6431]

I fixed a no bus problem on a Dodge Durango I bet it’s a common problem it was a short near the fuse box in the engine bay between the climate control power wire to fuse box and probably the ecm fuse power or something close to it I shotgun trouble shooted the sh*t out of that truck and tried a new pcm or ecm with no luck until I found this short

[@trainhorn55555]

What wire is is that exactly? I'm having issues with my climate control giving me a no bus when on and everything normal when it's off

[@juliorosas6281]

I checked all that after i Send my pcm to get repaired and still had the same problem so if i get 3.6 volts at the crack position sensor does that means is that ?

[@duanedonaldson2262]

The 5 volts is shared between a few sensors that use 5 volts, do the all have 5 or 3.6, check for corrosion, loose wires, poor grounds, 3.6 volts coming out of PCM instead of 5 volts. Also crank engine to move the flywheel or flexplate to move the window that the sensor uses in case you get zero volts as this is the job of the crank and cam sensors to make 5 and 0 volts, nothing between, if something between, you may have a weak sensor. Is your volt meter good?

[@kevinsukdolak5007]

So what was the culprit?

[@verdevalleyautoelectric4336]

Kevin Sukdolak bad PCM. 2.5vdc did not exist on the two data pins of the PCM with ignition on, the power and ground plug attached to the PCM and the data plug unplugged.

[@kevinsukdolak5007]

@@verdevalleyautoelectric4336 I just sent my ecm to a rebuilders...hope they can fix it....this ecu I'm using in the meantime won't idle at start up and gas gauge won't show

[@jameshenin6555]

Verde Valley Auto Electric ok so i made it that far and found the same thing you did. No 2.5 from Either pin on pcm. Should i go ahead and do the rest of the checks or stop and remove pcm.

[@celiniate]

@@verdevalleyautoelectric4336 how did you test for voltage on the pins? I have the exact same codes and I have 2.5vdc on the female plug

[@dizzvideovision4606]

Nice 💯 so in detail

[@Joseph5394]

Great video sir. I have an issue on my 1998 Dodge Ram 1500. My voltage gauge is reading around 12v on my cluster. I replaced the alternator the other day, charged the battery to 100% and I still can’t get 14v. All other gauges are working fine. I’ve seen a few videos with the same issue I have and the pcm voltage regular failed. I checked all my ground wires and they’re installed. I may need to clean them to see if it will help my voltage. I appreciate your feedback.

[@clintyoung6482]

I'm having an issue with my '98 it's an SST with the 5.9... thought I had the problem licked but the speedometer and tackle murder started messing up again

[@caspersmusicmotorsandmayhe7939]

I have no 12 volt on pin 2 connector one at pcm and have no bus the first test in this video. I do have the 5v at sensors and pcm. so where to?

[@ewadabrowska2193]

Have the same problem with just 4volts on pin no.2 plug1.are you solved? Can I jump wire 12v from battery to pin no.2?

[@evantharp7434]

@@ewadabrowska2193 what did you end up doing because I’m having this exact issue?

[@SgtEvarsmann]

Were you able to fix it?

[@SgtEvarsmann]

​@@ewadabrowska2193were you able to fix it?

[@tonygutierrez4627]

Trying this tomorrow ! Having same issue on my 2001 Dodge ram 2500. I'm thinking PCM issue

[@christophergilliland8181]

Have you got it fixed

[@lionsdejudah]

Bump

[@brianwv64]

where did you get the instruction papaer you refer to in the video/

[@verdevalleyautoelectric4336]

brianwv64 dodgeram.org/tech/repair/elect/inst_panel_check.htm

[@brianwv64]

@@verdevalleyautoelectric4336 what about the one that tells you what pins need to be tested on harness?

[@verdevalleyautoelectric4336]

brianwv64 Mitchell’s wiring diagrams

[@duanedonaldson2262]

@@verdevalleyautoelectric4336 THIS link is dead in December 2020

[@timothymorris6019]

Ok, so I get the "No Bus". But my 01 Ram 1500 5.2l still fires up. The PCM under hood, if I remove each relay and fuse and blow air or spray fine electronic cleaner on the terminals, (also removed the bottom part of the PCM box, washed and dried it), it will start. Also blew out 12 pin OBD connection, the fuse panel on the side of dash, front and back, and also the the wiring harness connector above and to the left of the brake pedal. I reset the instrument panel and run the truck which is running hot. Every time I do this process truck runs normal except for it running at 210 at idle after driving 20 minutes Also going to clean wiring harness connection mounted under front driver's side plastic wheel well shielding that is attached to the metal cab mount. I will repost after I do all checks this video has offered. This is the best video so far on this subject and I it will definitely lead me to a final conclusion. Thank you for posting this video Sir! It is very much appreciated!

[@pathlawncare744]

Did you ever find the gremlin on your truck? I have a 03 ram 1500 and it has the NoBus code but still fires up but only will drive in Limp mode and won't come out of 1st gear. All the gauges go zeroed out. I've cleaned the fuse box pins and all the grounds I can find. I figured it wouldn't run if the PCM was bad so I'm lost on what I should check next. This guy has a great video but that's for engines that won't start. Mine still runs just NoBus code keeps it in limp mode. You have any ideas of why? I appreciate any help you can give. Thanks for your time

[@Elite_marine715]

Same on the cummins ?

[@verdevalleyautoelectric4336]

Cloud 9 2.0 what year?

[@Elite_marine715]

2001

[@verdevalleyautoelectric4336]

Cloud 9 2.0 I’ll check

[@twest0011]

Thank you very well explained

[@tyronewalker5764]

OMG, this is what my 2K dodge Dakota,4.7/v8 is doing. Think my ECM/PCM is toast.

[@alexandramedinaruiz4595]

Podrían traducirlo en español

[@randyshipman6020]

I did ever thing in this video and everything checked out good but still have not fix the no bus any thing else

[@duanedonaldson2262]

smack the PCM while monitoring voltages

[@dumbass3770]

I need Eric O from south main auto on KZbin