what does no bus mean?
i did the "bungee cord to hold the plug tight" trick and drove the van to work...when i went out at lunch, i had the "no bus" thing again, only this time, i couldn't get rid of it by pressing on the plug. dangit. just ordered the PCM from autocomputerexchange through Ebay. $298...hoping i don't have any more problems!
Legend
Joined: Jul 2011
Posts: 8,259
Likes: 4
From: Austin, TX
It is definately a loose solder joint on an IC chip or other small component under the third socket. I don't want to rip out the moisture barrier goop so I placed a small square piece of wood over the spot where the broken connection is and replaced the metal cover which pushes down on the connection point keeping it good.
I have another issue now though, when I turn the ignition switch to RUN (w/o starting) the AUTO SHUTDOWN relay buzzes (I've switched relays--all work- all buzz) And the engine won't start.
#$@#!* those Chrysler engineers!
I have another issue now though, when I turn the ignition switch to RUN (w/o starting) the AUTO SHUTDOWN relay buzzes (I've switched relays--all work- all buzz) And the engine won't start.
#$@#!* those Chrysler engineers!
Registered User
Joined: Aug 2010
Posts: 15
Likes: 1
Loose connection in the PCM -- NO BUS
WWOW! What a revelation!!!
were you one of those amazing engineers?
Seriously---My van has been sitting in my d-way for 2 months now awaiting a (threaded?!?!?) ball joint replacement (don't get me started on this design marvel!) I'm driving my FORD F350 Diesel P/up in the meantime-more stories for a different forum (wish I had the time).
The connection needs to be made in the PCM for the engine to start --pushing down on the right spot eliminated the NO BUS problem originally. There is something else going on with the PCM (that those wonderful engineers mounted right above the hot engine!).
were you one of those amazing engineers?
Seriously---My van has been sitting in my d-way for 2 months now awaiting a (threaded?!?!?) ball joint replacement (don't get me started on this design marvel!) I'm driving my FORD F350 Diesel P/up in the meantime-more stories for a different forum (wish I had the time).
The connection needs to be made in the PCM for the engine to start --pushing down on the right spot eliminated the NO BUS problem originally. There is something else going on with the PCM (that those wonderful engineers mounted right above the hot engine!).
Last edited by BoxcarNY; Nov 2, 2011 at 01:59 AM.
Alright, I bit the bullet and ordered/installed a reman. PCM. Started right up and drove the mile home (i'd left it in my work parking lot while i waited for the part to arrive). Of course, before I changed the PCM, it started then too (but would stall and go to the no bus/no start mode until i pushed in on the PCM plug). Here's hoping!
Registered User
Joined: May 2009
Posts: 1
Likes: 0
On my 2001 5.9 it would randomly just quit and display "no bus" (the whole cluster went dead with the sensors). Turned out to be the engine inline connecter in the power dist cluster. That &^%$ screw in the middle is just stripped out in the plastic base. I've got it wedged under the cover with some stiff cloth but that isn't a good solution. If that connector is any bit loose you will get the "no bus" and/or stalls while driving.
Registered User
Joined: May 2015
Posts: 1
Likes: 0
The mechanics had alReady changed my icv, ecm, distribution cap, starter wires, pcv valve on my 99 Dodge Van 1500 with 142463 miles when the no bus code hit the odometer. The mileage has returned to the display but the motor still won't crank. the advice about unplugging ur ecm &turning the key to reset the data is just going to kill the pcm.
Registered User
Joined: Jul 2011
Posts: 2
Likes: 0
Computer
I had to swap out the PCM in my Truck that had this issue. 01 Ram 4x4, the truck would literally stall on the highway and I would only be able to start it again after I beat on the PCM for a couple of minutes...I got lucky and found another PCM at a Junk yard 60 bucks...that matched my trucks to the T. It's been cranking ever since...that was 4 years ago. Hope this helps.
Amateur
Joined: Jan 2018
Posts: 26
Likes: 0
From: Hampton Roads, VA
Apologies for the thread necromancy; adding to the pile of knowledge and experiences to troubleshoot this problem.
First happened to me three years ago (2018). Pulled the rear differential ABS sensor, only to find the sensor housing shattered and in the differential. Drained/cleaned/refilled rear diff, new sensor, and problem clear.
Problem returned 3 weeks ago. Pulled sensor again - no outward issues, so replaced with an OEM sensor. Didn't clear the issue.
Swam through the multiple threads here and on other boards and checked and rechecked every connection between the rear diff sensor and the PCM. Checked and rechecked all grounds; checked, cleaned, and rechecked all PCM and ABS-related connectors, incl PDC PCM connector. No change.
Then I noticed a pattern. The No Bus condition (as well as associated loss of instrumentation) wasn't happening nearly as frequently on my way to work in the morning, but much more frequently during the day - when the cab was warmer due to the sun/weather. Reminded me of an issue I had with my 90 Integra (don't judge) - after a while, the Main Fuel Relay contacts under the dash would fail to close when the key was turned to ignition when the interior would become too hot. Solution was to air out the car, let the interior cool down, and then try again.
So while I was at a stoplight the other day, with my instrument cluster in full No Bus (No Nothin') mode, I gave a solid press on the left side of the cluster. Instantly, I got oil pressure, alternator, and temp indications back. I pushed on the right side of it, and got fuel, speedo, and odometer back. All lights cleared.
Sometimes it's as simple as that.
That's why I hate this fault so much.
Hope this helps somebody.
First happened to me three years ago (2018). Pulled the rear differential ABS sensor, only to find the sensor housing shattered and in the differential. Drained/cleaned/refilled rear diff, new sensor, and problem clear.
Problem returned 3 weeks ago. Pulled sensor again - no outward issues, so replaced with an OEM sensor. Didn't clear the issue.
Swam through the multiple threads here and on other boards and checked and rechecked every connection between the rear diff sensor and the PCM. Checked and rechecked all grounds; checked, cleaned, and rechecked all PCM and ABS-related connectors, incl PDC PCM connector. No change.
Then I noticed a pattern. The No Bus condition (as well as associated loss of instrumentation) wasn't happening nearly as frequently on my way to work in the morning, but much more frequently during the day - when the cab was warmer due to the sun/weather. Reminded me of an issue I had with my 90 Integra (don't judge) - after a while, the Main Fuel Relay contacts under the dash would fail to close when the key was turned to ignition when the interior would become too hot. Solution was to air out the car, let the interior cool down, and then try again.
So while I was at a stoplight the other day, with my instrument cluster in full No Bus (No Nothin') mode, I gave a solid press on the left side of the cluster. Instantly, I got oil pressure, alternator, and temp indications back. I pushed on the right side of it, and got fuel, speedo, and odometer back. All lights cleared.
Sometimes it's as simple as that.
That's why I hate this fault so much.
Hope this helps somebody.
Registered User
Joined: Apr 2020
Posts: 15
Likes: 0
Apologies for the thread necromancy; adding to the pile of knowledge and experiences to troubleshoot this problem.
First happened to me three years ago (2018). Pulled the rear differential ABS sensor, only to find the sensor housing shattered and in the differential. Drained/cleaned/refilled rear diff, new sensor, and problem clear.
Problem returned 3 weeks ago. Pulled sensor again - no outward issues, so replaced with an OEM sensor. Didn't clear the issue.
Swam through the multiple threads here and on other boards and checked and rechecked every connection between the rear diff sensor and the PCM. Checked and rechecked all grounds; checked, cleaned, and rechecked all PCM and ABS-related connectors, incl PDC PCM connector. No change.
Then I noticed a pattern. The No Bus condition (as well as associated loss of instrumentation) wasn't happening nearly as frequently on my way to work in the morning, but much more frequently during the day - when the cab was warmer due to the sun/weather. Reminded me of an issue I had with my 90 Integra (don't judge) - after a while, the Main Fuel Relay contacts under the dash would fail to close when the key was turned to ignition when the interior would become too hot. Solution was to air out the car, let the interior cool down, and then try again.
So while I was at a stoplight the other day, with my instrument cluster in full No Bus (No Nothin') mode, I gave a solid press on the left side of the cluster. Instantly, I got oil pressure, alternator, and temp indications back. I pushed on the right side of it, and got fuel, speedo, and odometer back. All lights cleared.
Sometimes it's as simple as that.
That's why I hate this fault so much.
Hope this helps somebody.
First happened to me three years ago (2018). Pulled the rear differential ABS sensor, only to find the sensor housing shattered and in the differential. Drained/cleaned/refilled rear diff, new sensor, and problem clear.
Problem returned 3 weeks ago. Pulled sensor again - no outward issues, so replaced with an OEM sensor. Didn't clear the issue.
Swam through the multiple threads here and on other boards and checked and rechecked every connection between the rear diff sensor and the PCM. Checked and rechecked all grounds; checked, cleaned, and rechecked all PCM and ABS-related connectors, incl PDC PCM connector. No change.
Then I noticed a pattern. The No Bus condition (as well as associated loss of instrumentation) wasn't happening nearly as frequently on my way to work in the morning, but much more frequently during the day - when the cab was warmer due to the sun/weather. Reminded me of an issue I had with my 90 Integra (don't judge) - after a while, the Main Fuel Relay contacts under the dash would fail to close when the key was turned to ignition when the interior would become too hot. Solution was to air out the car, let the interior cool down, and then try again.
So while I was at a stoplight the other day, with my instrument cluster in full No Bus (No Nothin') mode, I gave a solid press on the left side of the cluster. Instantly, I got oil pressure, alternator, and temp indications back. I pushed on the right side of it, and got fuel, speedo, and odometer back. All lights cleared.
Sometimes it's as simple as that.
That's why I hate this fault so much.
Hope this helps somebody.
Registered User
Joined: Aug 2021
Posts: 1
Likes: 0
Put a piece of plastic in the pcm
OK here's the deal --AND THE REMEDY-- FINALLY!!!!!!
I always knew that it had to be an electrical contact problem within one of the three 32 pin plugs or jacks at the PCM. The van would stall (many times in the Holland tunnel under the Hudson River!) I would get out (ignition swich in run position), push down on the plug on the right side--hear the relay click - then restart. When the engine temp rose above the halfway mark this would occur- usually after sitting in slow traffic for a while.
Finally after many months of this BS I finally took the cover off the PCM and found that everything was covered in a clear gel so that made pinpointing the bad connection difficult. However when I pushed down on the gel at the lower corner of the jack on the right - contact was made and a relay clicked and the motor would start.
I really wanted to rip out the (heat dissipating?) gel and find the loose contact and solder it but instead I took a small piece of rubber placed it over the spot. I then replaced the cover which pushed down on the rubber piece which pushed down on the spot which would re-establish the connection and it's been fine since!
Repair= FREE - stess reduction= Priceless!
I always knew that it had to be an electrical contact problem within one of the three 32 pin plugs or jacks at the PCM. The van would stall (many times in the Holland tunnel under the Hudson River!) I would get out (ignition swich in run position), push down on the plug on the right side--hear the relay click - then restart. When the engine temp rose above the halfway mark this would occur- usually after sitting in slow traffic for a while.
Finally after many months of this BS I finally took the cover off the PCM and found that everything was covered in a clear gel so that made pinpointing the bad connection difficult. However when I pushed down on the gel at the lower corner of the jack on the right - contact was made and a relay clicked and the motor would start.
I really wanted to rip out the (heat dissipating?) gel and find the loose contact and solder it but instead I took a small piece of rubber placed it over the spot. I then replaced the cover which pushed down on the rubber piece which pushed down on the spot which would re-establish the connection and it's been fine since!
Repair= FREE - stess reduction= Priceless!
Pcm would turn on the relays when you push on the #3 or left plug (by the fender).
I tried Zip ties to hold the plug in but it was shutting off. I put the 1/4 inch thick X 1/2x2 inch long strip of plastic horizontal right under the #3 25 wire connector socket and screwed the lid back on it. It puts pressure on the circuit board.
Started right up. I ordered a new pcm.
I just wanted to say thanks for all your help posting great info.
I appreciate you guys!
