Engine/Transmission (1998.5 - 2002) Help with code

[Dsullenberger]

This may be the same problem I posted in June. ( Power then no Power ). I changed out the fuel filter again and made sure there wasn't any air in the system. Just got back from a 250 mile trip. Coming down Douglas pass in colo and the alarm went off. All gauges went dead along with check engine, airbag, brakes lights came on. Engine still ran and we made it another 100 miles home. I don't know what the code is. It says ( no bu5 ). Is that code 605 or what? I was going to change out the tps from Geno's Garage but didn't get it done. Could that be the problem. Still having problems with power then no power. If it was the tps my thought is the truck would just quit running. I have plenty of psi from the lift pump 16psi so it can't be the fuel injection pump. If someone has a list of the codes for 2002 maybe I could figure it out without taking it to a garage. Thanks

 

[JLandry]

Questions:

When the gauges went dead, was engine power reduced?

Where and when did you see the "no buS" message? Was it in the odometer window after the gauges went dead?

Have you checked for any active or stored DTC's (Diagnostic Trouble Codes)?

Based on the info you've provided so far, I'm going to go out on a limb and suggest their could be an intermittent or corroded connection in either the 50-pin ECM connector or one of the 3 PCM connectors. I'd disconnect each connector, spray with aerosol contact cleaner (available at a good auto parts store), then reconnect. You should also clean any grounding connections you find.

I may have more suggestions after you answer the above questions.

Best regards,

John L.

PS: Does your truck have an overhead display, and if so, what was it doing when the instrument cluster was misbehaving?

 

[WCPoe]

Hmmm, no buS message isn't a code but an connection error as JLandry mentioned above. I found a decent code list on the Edge Products site here: http://www.edgeproducts.com/product_images/customer_support_article-pdf-39.pdf Let us know what you discover. Anyone else have any thoughts?

 

[Dsullenberger]

JLandry, when the gauges went dead there wasn't any loss of power at all. Yes the code ( no bu5 ) was in the odometer window and no I haven't had time to check on dtc's yet. Do you think ( no bu5 ) is a code or is it #605? Thanks for the info

 

[Dsullenberger]

Thanks WC for the Codes. I can't find anything that even comes close to what was in the odometer window.

 

[Dsullenberger]

JLandry the overhead display changed to ccd.

 

[WCPoe]

Try searching Dodge Ram no bus dtc message on the web. From what I found several folks have reported this. Could be just a connector not completely plugged in or something more serious as the PCM or ECM going bad. I would first find all the connection/ plugs and try reseating them completely. Several folks reported this fixed their problem. Just a thought, but in auto repair always do the simple stuff first before throwing out a lot of dollars and effort. Good luck.

 

[JLandry]

JLandry, when the gauges went dead there wasn't any loss of power at all.

Then that loss of power incident you mentioned is very unrelated to the problem with the instrument cluster... two separate problems.

Yes the code ( no bu5 ) was in the odometer window and no I haven't had time to check on dtc's yet. Do you think ( no bu5 ) is a code or is it #605?

The message you saw is indeed "no bu5" which is short for NO BUS and means the instrument cluster lost communication with the vehicle's communication network. This is usually caused by:



1. Faulty connections at the ECM and/or PCM.

2. A faulty connection where the instrument cluster plugs into the dash (behind the instrument cluster).

3. A hardware or software failure on the instrument cluster.



If you have an overhead display and it also stopped working, that's usually an indication of faulty connections at the ECM and/or PCM.



You can check for a faulty instrument cluster connection by trying to shove the instrument cluster into the dash to possibly cause better contact.



You can verify the instrument cluster itself is working properly by executing a self-test as follows:

• With the ignition switch in the OFF position, press the odometer/trip reset button.
  
• While still holding the odometer/trip reset button, turn the ignition switch to the ON position, but do not start the engine.
  
• Keep pressing the odometer/trip reset button for about ten seconds until "CHEC" appears in the odometer display, then release the button.
  
• A series of three-digit numeric failure messages may appear in the odometer display, depending upon the failure mode. If a failure message appears, post it here and we'll help diagnose further.
  
• If no failure message appears, the instrument cluster will begin the Vacuum Fluorescent Display (VFD) walking segment test. This test will require you to watch each VFD segment as it is displayed to determine a pass or fail condition. First, all of the segments will be illuminated at once; then, each individual segment of the VFD will be illuminated in sequence.
  
• Following completion of the VFD walking segment test, the instrument cluster will perform a bulb check of each indicator that the instrument cluster circuitry controls.
  
• Following the bulb check test, the instrument cluster will perform a gauge actuator test. In this test the instrument cluster circuitry positions each of the gauge needles at three different calibration points, then returns the gauge needles to their relaxed positions.
  
• The actuator test completes and the instrument cluster will automatically exit from this self-diagnostic mode and return to normal operation.
  

Let us know what you find out and definitely use a code scanner to check for DTC's.



Regards,



John L.

 

[WCPoe]

On second thought just search "no bus code". I found a bunch of responses. Several good suggestions to try first.

 

[JLandry]

JLandry the overhead display changed to ccd.

This then points to faulty intermittent network connections at the ECM and/or PCM. Clean them and their grounding points and it'll probably clear up.



Faulty ECM and/or PCM connections could also cause a loss of engine power, but usually there would be associated DTC's stored along with it.



John L.

 

[Dsullenberger]

Wow, JLandry and WOPoe you guy's have some really good info on this stuff. I was a Mechanic for years but not very good on electrical problems. I'll start by pulling the connections off and checking them out. I hooked up my Jacobs exhaust brake on the 50 prong connector on the side of the engine block shortly after I got the truck. Where are the other PCM's located? On another note the problem happened just shortly after I turned the exhaust brake off. I checked to make sure the exhaust brake still worked and it does. Thanks again.

 

[JLandry]

Where are the other PCM's located?

The PCM (Powertrain Control Module) is located under the hood on the passenger side firewall behind the air cleaner. It's easiest to reach if you remove the air cleaner first. It has 3 multi-pin connectors.

On another note the problem happened just shortly after I turned the exhaust brake off. I checked to make sure the exhaust brake still worked and it does.

Interesting coincidence.



Check carefully for loose or chaffed wires in and around where the exhaust brake wires were installed.



John L.

 

[Sticks]

I'd check around the exhaust brake as well since it does sit rather close to the firewall where the PCM harnesses run. Might have a leak at the brake that cooked the harness.

IIRC the connection at the ECM for the brake only tells it when the cruise is on and when you are above a certain RPM. Since you also suffered a loss of power, the brake controller might have backfed voltage, or shorted out to the ECM causing a problem.

 

[Dsullenberger]

Just an update of what happened today. I disconnected batteries, pulled the 50 prong ECM off of the engine. Cleaned with contact cleaner and lubed with dialectic grease. Pulled the air cleaner box out and did the same thing to the 3 power train modules. Cleaned and lubed up. Checked and cleaned the ground cable from engine to battery. Made sure the batteries were full and terminals clean and had dialectic grease on them. Started her up and all gauges started working and no more (no bus ) in odometer hole. No more problem with the overhead console. Still had the abs and check engine lights on the dash. Ran engine for awhile and started and stopped engine. After the 3rd time of starting and shutting down the engine all lights went off. Took a short drive ( stopping and restarting ) and everything seams to be ok. Have a new APPS coming from Geno's garage just encase the power no power comes back. $170 good insurance and cheaper than a tow. Thanks everybody for giving me some good advice.

 

[JLandry]

Glad to hear the good outcome!



John L.

 

[klcammie]

Then that loss of power incident you mentioned is very unrelated to the problem with the instrument cluster... two separate problems.

The message you saw is indeed "no bu5" which is short for NO BUS and means the instrument cluster lost communication with the vehicle's communication network. This is usually caused by:

1. Faulty connections at the ECM and/or PCM.
2. A faulty connection where the instrument cluster plugs into the dash (behind the instrument cluster).
3. A hardware or software failure on the instrument cluster.

If you have an overhead display and it also stopped working, that's usually an indication of faulty connections at the ECM and/or PCM.

You can check for a faulty instrument cluster connection by trying to shove the instrument cluster into the dash to possibly cause better contact.

You can verify the instrument cluster itself is working properly by executing a self-test as follows:

• With the ignition switch in the OFF position, press the odometer/trip reset button.
• While still holding the odometer/trip reset button, turn the ignition switch to the ON position, but do not start the engine.
• Keep pressing the odometer/trip reset button for about ten seconds until "CHEC" appears in the odometer display, then release the button.
• A series of three-digit numeric failure messages may appear in the odometer display, depending upon the failure mode. If a failure message appears, post it here and we'll help diagnose further.
• If no failure message appears, the instrument cluster will begin the Vacuum Fluorescent Display (VFD) walking segment test. This test will require you to watch each VFD segment as it is displayed to determine a pass or fail condition. First, all of the segments will be illuminated at once; then, each individual segment of the VFD will be illuminated in sequence.
• Following completion of the VFD walking segment test, the instrument cluster will perform a bulb check of each indicator that the instrument cluster circuitry controls.
• Following the bulb check test, the instrument cluster will perform a gauge actuator test. In this test the instrument cluster circuitry positions each of the gauge needles at three different calibration points, then returns the gauge needles to their relaxed positions.
• The actuator test completes and the instrument cluster will automatically exit from this self-diagnostic mode and return to normal operation.

Let us know what you find out and definitely use a code scanner to check for DTC's.

Regards,

John L.

Hey great write up. Gotta love this site. LOTS of great info and helping people.

 

[jplock82]

had similar issues with my truck. posted a week or so ago. with the truck running and headlights on low beam, gauges did not work. clicked for hi-beams and instrument panel working correctly. maybe a faulty switch in column?

2001 2500 24v 2wd quad cab

 

[Dsullenberger]

I ended up taking the 50 prong connector off of the engine and cleaning all connectors and lubing up with dialectric grease. Then pulled the air box out and did the same with the connections on the computer. Made sure the batteries were good and cleaned the terminals good. I purchased a throttle position switch but haven't put it in yet. I have been pulling a snowmobile trailer this winter and made a 500 mile trip to pick up a van with a car hauler. Haven't had a problem yet ( knock on wood ). I plan on installing the throttle position switch this summer anyway.

had similar issues with my truck. posted a week or so ago. with the truck running and headlights on low beam, gauges did not work. clicked for hi-beams and instrument panel working correctly. maybe a faulty switch in column?

2001 2500 24v 2wd quad cab

 

[Dsullenberger]

I ended up taking the 50 prong connector off of the engine and cleaning all connectors and lubing up with dialectric grease. Then pulled the air box out and did the same with the connections on the computer. Made sure the batteries were good and cleaned the terminals good. I purchased a throttle position switch but haven't put it in yet. I have been pulling a snowmobile trailer this winter and made a 500 mile trip to pick up a van with a car hauler. Haven't had a problem yet ( knock on wood ). I plan on installing the throttle position switch this summer anyway.

 

[jplock82]

thanks for the info. im not real good at this stuff so i still have a question. first, where is the 50 prong connector? i will clean the battery cables and terminals, then the pcm/ecm on the firewall. dialectric grease?? guess i can get that at any auto parts store? i really appreciate all of the helpful information.

01 green/silver qc 2wd swb auto stock except for exhaust