No crank, code P180C

Yes. This can be the control module but before we get too far, we should run through the testing for these codes.

Here are a couple guides that will take us through the basics on this testing:

https://www.2carpros.com/articles/how-to-check-wiring

The U0100 is telling us that we have a communication issue which could be causing the fuel pump issue as well.

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

However, the only way we are going to know for sure is to turn through this testing and find out where we get.

I suspect you will have an ECM issue, but I would not replace that until this testing points there as well because that is costly to base that only on the info we have so far.

Please let me know what questions you have, and we can go from there. Thanks

I understand. I suspect you have an ECM issue. So, the fact that you have these codes, I would run through that testing to see if it leads you to an ECM issue.

So, if this code takes you to a replacing the ECM, then you know you have to replace it for this code and that will most likely fix the issue you are wanting to start with.

However, you also have the U0100. Take a look at the first page of that diagnosis. This is telling you that you have an issue with the ignition and B+ circuit. This fits what you are seeing as well.

So, if you look at the circuit testing this code is having you verify that you are getting power and ground at the module that is setting this code. This code is telling you that this module is not communicating.

When you add that to what you are seeing, I suspect the ECM has failed.

So basically, the best thing to do is chase the problems that you have codes for and not ignore them because it is telling you that this is an issue.

You can go through this and verify that the ECM is the issue for just the starting issue, but you are going to have to monitor the communication network with a specific scan tool.

If you look at the wiring diagram below, you will see that when you turn the key to start, it sends that voltage to the ECM, then the ECM communicates with the BCM which would keep the dash on and that the engine is starting. This is the point you are getting all these issues.

This points directly to the ECM; however, I would want a little more info, so I don't replace the ECM for no reason. Which brings me back to the other codes. If the other codes, have you replace the ECM as well, then you know it is not a waste if it doesn't fix this starting issue as well.

If it doesn't then we have a bus communication issue and those are not the easiest to diagnosis without a scan tool that can monitor bus inputs.

This is just the approach that I would take but I understand if you want to go after the starting issue so let me know what questions you have about either direction. Thanks

Couple questions on the U0100. Did you unhook the connectors from the ECM and BCM and check the resistance from end to end? If so, was the resistance 0 or was it infinite resistance (OL)?

0 ohms is different then no resistance or infinite resistance.

Also, these two modules are not directly connected through these wires. They are connected through the EBCM and TCM. So, if you have an open circuit then that would be due to the modules not communicating. It is very possible that you have an open circuit on one of the circuit boards, but this would require more investigation.

If you have continuity from battery positive to pin 86 and 87 then you do have a short. If the key was off, then 87 should not have continuity to battery positive as this is the path to ground for the switch side of the relay.

So, it sounds like you are onto the issue with the fuse block.

The reason you had no connection from the DLC to the ECM is because the DLC is connected to the BCM and then the BCM facilitates communication with all the other modules.

Unfortunately, the way we are going to have to check this system effectively is to scan the communication network and find out what modules are not communicating.

Here is a video that shows how to do this:

https://www.youtube.com/watch?v=InIlnsjOVFA

Doing the continuity check on this network will only work if you are checking the wiring from module to module. Basically, just the wiring between modules is good for this.

There is one other check that we can do without the scan tool and that is checking termination resistance. This is done by disconnecting the battery and then check the resistance at the DLC on pin 6 to 14. This network requires two modules to be what are called terminating modules and that creates the ability to communicate on this network.

If this resistance is not correct, then you will have communication issues. Let us know what this is, and we can go from there. Thanks

Wow. Great info. That will surely help others in the future. Thanks for coming back and letting us know what you found. Thanks for using 2CarPros.

We will need to get a new post started on this issue just because it is not related to this one but in short, I suspect you would be better off using an aftermarket tool that can do all that the DRB can do.

Basically, the DRB is obsolete and those that are available to buy, if they break then there is no repair process for them.

Plus, there are many aftermarket options that will do the same things.

I don't know what will be available in your country so you will need to do some research.

The best option would be to use the OEM replacement tool. Again, I don't know the availability of this in your country, but I know they offer it to the aftermarket at a fair price.

Here is a video from the OEM that will introduce you to it:

https://youtu.be/nmD5wafPUss

If you need more info, please get a new post started on this one and we will see what we can find. Thanks

This does not relate to this topic so we are getting into some detail that may help others that have the same questions. If we don't start a new post, then those that would benefit from this will never find these Chrysler specific questions under a question about a Chevrolet.

Let's get a new post started on this scan tool question and we can figure out the best option for you in your situation.

https://www.2carpros.com/questions/new

Thanks

Looks like we still have a network issue. When you checked the resistance of wires from the BCM to the ECM and had no resistance means we have an open circuit between these two connectors.

So, you need to go to the BCM X6 pin 25 and the brake module pin 13. We need to make sure we have about a half ohm of resistance. Then we need to do the same from the brake module to the power steering. Then power steering to the TCM. Finally, from the TCM to the ECM.

These modules are what are called daisy chained. Meaning if one has an issue then all others behind it will not communicate. So, if the ECM/TCM is the issue we need to make sure the wiring from the power steering to the TCM is in intact unless you are not able to communicate with the other modules as well.

Correct. You need to use a multimeter set to ohms.

Then you disconnect the connectors at both modules and connect the meter leads at both ends of the circuit. This guide talks about how to do this:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Basically, you are just testing the single wire and if you have less than a half ohm of resistance then the wire is intact. If it is OL or high resistance, then that means you have an issue with that wire between these two points.

I don't understand what you mean when you are looking for a value of a half ohm. The meter will show 0.5 ohms or less, if that is what you mean?

Good idea about the fuses. However, the best way to tell if they are okay is just go to that circuit on the ECM connector and check for power.

If you have power at the ECM then the fuse and fuse panel are fine.