Dodge Repair Questions? Ask a Mechanic for Answers ASAP
Diagnosing a PCI BUS Communication failure can be a nightmare without the aid of a diagnostic port tester and a DRB-III or equivalent scan tool. Without those tools, you basically have to check all the modules on the BUS for power and ground, plus check that the BUS circuit itself is not open. Can you get access to those tools?
Oh well, I could only hope. What brand model is that scan tool of yours? Perhaps we can use it.
Centech doesn't make scan tools, just code readers, so that won't help us at all.
Let's do process of elimination; turn the ignition OFF and disconnect the ABS module under the hood; turn ignition ON. Is the NO BUS message still on? If so, then repeat with the transmission control module (TCM); and so on with all the modules on that vehicle until the NO BUS message is gone.
Components that are connected to the PCI bus circuit are as follows.
Air Bag Control Module (ACM) Central Timer Module (CTM) Compass Mini Trip Computer (CMTC) Controller Anti-Lock Brake (CAB) Module Electro-Mechanical Instrument Cluster (EMIC) Heating Ventilation Air Conditioning (HVAC) Module Powertrain Control Module (PCM) Radio Sentry Key Immobilizer Module (SKIM) Transfer Case Control Module Transmission Control Module
If none of the modules are faulty, then you'll need to test integrity/continuity of the PCI BUS circuit (Violet/Yellow wire) from the data link connector to each and every one of those modules.
I understand. That's the way the Dodge boys designed this system - they don't want regular Dodge owners to be able to fix their own vehicles once the warranty period expires; they want them to go the dealers and spend more money there or buy new trucks.
Being a retired Chrysler Master Tech, the one scan tool I'm familiar with is the DRB-III. Last time I checked, those were being sold for about $6000.00; however, there was also a rental option for about $200.00 a day. Besides that, I'm not familiar with any other scan tool that has the capabilities of a DRB-III when it comes to Chrysler products.
As a suggestion to break the monotony, try checking the Violet/Yellow wire. Sometimes it is an issue with that wire what brings the BUS down.
The correct name is***** or CTM - I uploaded a list of modules for your vehicle; where are you getting BCM and EMIC from?
Your vehicle might not have a transfer control module if it was not equipped with that feature at the factory. If there is one, it will be behind the instrument panel, right of the steering column.
The Violet/Yellow wire is what the PCI BUS uses for transmitting serial data. It starts at the data link connector (where you plug your code reader) and goes to each and every module.
At this point, I don't think I can continue working on this issue. I'll opt out so others may try. Please do not reply until another expert responds or the site will cycle this back to me.
Hello and welcome! My name isCustomerand I can assist you with your question. Was the PCM replaced?
The PCM is the most common cause of this condition. You would just need to verify the powers and grounds going into the PCM with the key on before replacing it.
Pins 2 and 22 for the power (should have full battery voltage on them with the key on.. 12.6 volts or so) then pins 31 and 32 for ground on the C1 connector at the PCM.
I am glad I can help!
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YES, connector 1
YES, everything should be plugged in when running this test
Hello and sorry for the delay! The colors on the three connectors is black, gray and white. We are checking connector 1 which is the black connector. Here is the pinout chart or connector view of this black connector. You can see the color wire going into pin 2 is a light green/black wire and the wire color for pin 22 is white with red stripe. See attached diagram.
Here, this one is more accurate. It is for a 4.7 liter engine.. however, the powers are still the same.
Hello and sorry for the delay! I have never tried to disconnect the PCM in this situation and verified that the no BUS message goes away. That is a good question. And when we get to the bottom of the problem, please let me know for my own knowledge. My guess would be that it would not go away because without the PCM, there would not be any communication between modules so there would be NO BUS. However, my experience has been that the PCM goes bad ALL OF THE TIME on these vehicles causing this problem.
You didn't mention whether or not this is another test? Or is this in continuation of what Juan wanted me to do
This is a different test
I dont see any other questions above..
The voltage test (power and ground) check out good. This means the PCM is likley at fault.
So why is the "no bus" error still there when the PCM is completely disconnected?
I answered this question already.
My guess would be that it would not go away because without the PCM, there would not be any communication between modules so there would be NO BUS.
Have you checked the voltage on the BUS circuit yet?
You need to use a lab scope and check for a 7.5 volt square wave form on pin 7 of the diagnotic connector with the key on.
Pin 2. Not pin 7. Sorry.
You can try using a factory scan tool..
But again, it will most likley say no communication.. so you will be right back where you started.
Other than that, there is no other way.
The Transmission Control Module (TCM) is located in the engine compartment on the right (passenger) side and is mounted to the radiator core support.
The SKIM is located on the right side of the steering column, below the ignition lock cylinder housing and is concealed beneath the steering column shrouds.
Sorry about that. Here is a pic
IT is located under the dash on the drivers side
The dealership is always your best bet. However, you can shop around on line to save a few bucks.
Hello! It'sCustomerfrom just answer.
I am just checking in to see if you need any further assistance?
Let me know!