Look like we have same problem with different models make by Dodge, I have a 2002 Dodge Ram Van with a 5.2 L. engine, the engine use to run early morning times to times, which means some day start ray up and other days nothing no gauges, no fuel indicator, all the light on except engine light, slowly light's go off and in the end of the test, the "no bus" in the odometer, the check engine on and the gas indicator for empty on too.
The voltage in the connector C1 pin # 22 is 12 V, pin #2 12 V, pin #17 5.1 V, pin 31 on C2 5.1 V.
Sensor's tested, CAM sensor, Throttler position sensor, Intake Air Temperature sensor, crankshaft sensor, camshaft sensor.
The weird thing is the van some times run perfect with every gauge working normal, other times with no changes do not start and the no bus show up.
Any logical explanation where I have to look?, please help me, I can't afford the mechanic ray now.

 

No bus means there is no communication to and from between the instrument cluster and the PCM.

From what I have read here, it usually is indicative of a bad cluster.
Sometime people go to the junkyard to get a used one or they fix theirs.

It can also be the PCM, but from what I can surmise that is about 15% of the time.

 

Hi there again, thanks for the help, let see how I do.
The “no bus” message term is almost clear, let see if this is correct, the pin #C27 (SCI Transmit) and the pin #C29 (SCI receive) in the connector C3 are the ones do the communication? Are these the bus line?.
I trace the cable from #27 in the connector C3 on the PCM, to the firewall connection block left to the steering bar inside the cabin, the connector have a big bolt 7/16 holding together the two parts of the block, from there to the connector for the ODBIII and the instruments cluster. I get signal in the connector on the right side of the instruments cluster.
I trace the cable from #29 in the connector C3 on the PCM, to the firewall connection block left to the steering bar inside the cabin, from the block to the connector for the ODBIII and from there I get lost, nothing show in the instruments cluster connectors.
Is anyone have the electric diagrams?

 

see fig 06.jpg below for pinouts of the "bus" to the various modules

I thought the "bus" was the CCD pins C28 and C30 on the PCM

see 05.jpg for my handwritten notes with color codes for the various modules attached to the bus

see 389, 390, 391 for PCM pinouts...

Let me know what else you need... I am still having my no bus intermittent problem... seems to come and go with warm weather, below about 72 I have no problem, starts and runs, warm up and stalls and no bus appears. I have replaced every engine sensor and a rebuilt PCM with same results. I have traced wire connections to every control module and all were shiny bright and have good connectivity. The no bus makes the OBDII tool quit. Someone suggested that the 5V (+ and -) bus voltage comes from the inst cluster, but the 06.jpg diagram shows it coming from BCD module. I am unsure if all modules all supply voltage... I once ran the engine without the cluster installed, until it quit a few minutes later, indicating to me that the cluster is not 100% necessary.

I need to find a BCD control module and replace that.

I can supply 15 pages of Electronic Control Modules FSM reading if you would like...

Roger

 

Dodge Durango is the only other Dodge vehicle that has been reported to share any parts with the Ram van. This does not mean this particular part will work on your van. I suggest you check the part numbers on your BCM and if they match with the unit offered, you may want to take the chance.

The instrument cluster is not required for the van to run/drive, but the BCM can prevent the PCM from functioning so given where you are and what you've already replaced, I'd be looking at that next.

Personally based on my own experience, you should still be checking for bad grounds.

http://www.ebay.com/itm/2001-DODGE-D...RXcDDR&vxp=mtr

 

Be careful, the wiring and pinouts are not the same for '01 and '02.


Someone suggested that the 5V (+ and -) bus voltage comes from the inst cluster, but the 06.jpg diagram shows it coming from BCD module.

I have looked all over this picture, and I can't find a BCD or a BCM either, or anything showing where the CCD BUSS voltages originate.

 

BCM is also known as Central Timer Module (center of picture) found next to the dog house, left side near the inst cluster... see wiring diagram above 06.jpg

I mistakenly called it BCD in an earlier post... (all these dam acronyms)

see attached jpeg of FSM image of 2001 van showing voltages derived for the CCD (Csquared D) bus not the SCI bus...

I again ask if anyone knows if the CCD bus or the SCI bus controls engine functions... specifically in the 2001 model.




I thought '99 to '03 models RAM VANS, not trucks, are pretty much all the same...

 

Maybe this read will help???
look at pg 2
http://www.autonerdz.com/yabbfiles/A.../ccdandpci.PDF

 

thx funair02

interesting reading and gives me an idea on troubleshooting CCD bus better...

attached find image of DLC (data link connector) showing outputs for CCD and SCI bus on my '01

I have to re-read my FSM, but I thought somewhere it told me that the CCD bus controls the engine functions on the '01 van. I am still wondering if that is true?

When in FL, and in txt/msg communication with a Dodge tech in FL that worked on my van, he questioned me if I saw voltage fluctuations with my Fluke meter on the CCD bus through the DLC... which lead me to believe that the CCD was in control.

 

https://dodgeforum.com/forum/dodge-r...ml#post3302158 RSDATA: I posted this on your thread Monday night. See if it makes sense.