This 2003 Dodge 1500 network protocol diagram is another example of multiplex networking. This diagram will show you how to check NO COMMUNICATION problems when this message is displayed in your scanner. Most garages will charge you top dollar to fix this but you can do it in a couple of hours just using a voltmeter.
This 2003 Dodge bus wires above looks similar to Ford bus wires. However, during troubleshooting, all you care is to check the PCI bus wires at DLC terminal shown here in green lines. You can get this exact wiring diagram with correct wire colors and connections from your local parts stores or get it online from ATS.
Before using this diagram:
1.) I made this diagram myself to show how 2003 Dodge 1500 data bus circuit is wired together with the DLC. This is only an approximate diagram as I see it. I don't profess that all of these information are correct but in case you find some errors, please contact me at my ATS homepage.
2.) When your 2003 Dodge truck has NO COMMUNICATION problem during scans, it means one of the data bus wires is shorted because one of the module or it's circuit is at fault. Symptoms includes NO START, intermittent issues like stalling, occasional cutting out, etc. and no amount of scanning can help you find the problem. This diagram will show you how top mechanics are fixing it.
2003 Dodge 1500 Pick Up DLC Diagram Description:
Starting on top right of the diagram, you will see the following modules:
TIPM defined as totally integrated power module which supplies fused power signal (see RED wire coming from battery going to Pin 16) to the
entire network system. For this model year, it has the distinction of
housing the PCI BUS data bus signal which is shown as heavy green line as
shown on the right of the TIPM box.
PCM or power train module is the brain of the networking system. It is connected to the following DLC pins:
DLC terminal Pin 7 is shown as orange data bus wire described as SCI transmit signal. Next is DLC terminal Pin 12 is shown as pink wire described as SCI receive signal. Then the 3rd bus link comes from DLC terminal Pin 2 displayed as PCI bus signal shown as green data bus wire. This PCI bus common signal starts at S1 on your right of the diagram all the way to S11, S10 and S9 on the left of the diagram. This same bus data link also feeds all the other 10 modules aside from the PCM.
Note also that at the end of S1 connector is connected directly to the TIPM module on top of PCM. Finally, the BLACK dots that you see here in the diagram are test points which are needed when isolating the PCM and other modules.
TCM or transmission control module is hooked up from DLC terminal Pin 9 which is a PCI receive signal, followed by DLC terminal Pin 15 which is a PCI transmit signal. Note also that this module is connected to Pin 2 by way of S2 connection of the TCM module.
Pay no attention to all these types of data bus signal terms and the only thing that matters is what voltage will you need to see if you measure
the DLC Pin terminal Pin 2 for this type of vehicle.
Using the voltmeter, you need to measure the voltage against the battery ground or DLC terminal Pin 5 which is also a ground signal. What you will get is the PCI bus data signal voltage of around 5 volts at KOEO.
Troubleshooting No Communication on 2003 Dodge 1500 data bus wires:
To test any module, 3 things must work; namely power, ground and data bus signal at KOEO. We all know battery power is 12 volts, ground signal is zero volt
or no higher than 0.250 volt at KOEO. What about the all those type of
data bus signals? (disregard all bus signals except PCI bus signal). The normal reading is the same as in GM or Ford vehicles for 2003 models; 5 volt at KOEO.
Isolating modules in 2003 Dodge 1500 data bus protocol:
You can easily isolate any module shown in the box with a single data bus wire which uses PCI bus by disconnecting it at "S" connector shown in black dots above. Example is when you disconnect at S3, you will disable the airbag module. The same goes to S4 which will disable security module. When you do this and you hook up the voltmeter between Pin 2 and Pin 5, any time the normal voltage reading shows 5 volts at KOEO, the last module disconnected is the defective module.
This is just a demo diagram to show you how to test NO COMMUNICATION problems on 2003 Dodge vehicles by just using a voltmeter. In the actual bus data circuit diagram, the exact color of the data bus wires and "S" connector locations will be shown so you can easily troubleshoot it.
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