U0146 - lost communication with Gateway - SOLVED(broke wire)

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

There's an Innova 3100 for sale nearby that is relatively cheap - would that help?

geordi · **Posted:** Mon Nov 25, 2019 2:35 pm

dunl wrote:

The only codes I have showing from my generic code reader is glow plug codes (need replaced, haven't done that yet), and the 0146 Lost Connection with Gateway code.

Only real tools I have available to me are a generic code reader, the MPPS usb cable and program, and a "FasLink M2" usb bluetooth scanner.

I was just assuming the possible "limp" mode would be related to the Gateway connection error, causing issues with the transmission shifting.

It may be related, but without a scanner that can talk to the transmission... we are just guessing. An ELM327 is pretty cheap, doesn't hurt to have one around.

I don't know anything about the other scanner you mentioned, so I can't comment on whether it would help or not.

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

Does the ELM327 talk to the transmission?

I don't mind trying to hunt one down, but if it is only going to give me the same P0146 code, and nothing else, why bother?

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

Well, spent a while tonight cleaning the grounds from behind the headlight and near the brake booster. The headlight one snapped off, so I just grounded the three wires directly to the battery. Cleaning up both of these did absolutely nothing to solve any of the issues. I still have the U0146 code showing, it's still in limp mode, and I am seriously wondering why I ever bought the thing.

geordi · **Posted:** Wed Nov 27, 2019 11:19 am

The ELM327 can talk to the transmission, it depends on which app you use whether that functionality is available. There are free apps that can, so the best move is get all the free options you can find and try them all. Some allow code clearing without buying, others don't.

As far as your limp mode - you are in TRANSMISSION limp mode if it is only in 3rd gear. The ground point for the transmission is on the passenger side, on either the firewall, fender adjacent to the TCM or on / near the vacuum box. I can't remember exactly where the original location is, I moved mine a long time ago.

There should be another one behind the passenger headlight, and then there's two under the plastic by the hood latch in the driver's footwell, but those usually aren't a problem.

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

Ok, thanks for all your help so far. I've ordered in an ELM327 (none available locally), so it should be here in a few days hopefully. In the meantime, I should have some time tomorrow evening to attack those other ground points you mentioned.

I can't remember if I mentioned this or not, but the transmission shifts fine from 1st to 2nd to D manually....automatic does not shift at all.

Thanks again

geordi · **Posted:** Wed Nov 27, 2019 3:04 pm

dunl wrote:

Ok, thanks for all your help so far. I've ordered in an ELM327 (none available locally), so it should be here in a few days hopefully. In the meantime, I should have some time tomorrow evening to attack those other ground points you mentioned.

I can't remember if I mentioned this or not, but the transmission shifts fine from 1st to 2nd to D manually....automatic does not shift at all.

Thanks again

If automatic is not shifting at all, then you are not getting first gear either. It might SEEM like first gear, but it is actually just second.

First gear should be about 3000 RPM at 20mph - But this is a guess, my Jeep is hooked to a trailer I'm working on at the moment so I can't test it for you.

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

geordi wrote:

If automatic is not shifting at all, then you are not getting first gear either. It might SEEM like first gear, but it is actually just second.

You, sir, know your diesels well.

You are correct, not shifting into first, just second. And then shifts manually fine into D.....so no overdrive, no 1st.

No time to work on the other grounds until next week, ELM357 is apparently at my door now though.

geordi · **Posted:** Sat Nov 30, 2019 1:28 am

dunl wrote:

You, sir, know your diesels well.

Thanks - But that knowledge took a long time to get. I spent about 6 months banging my head against one CRD that refused to come out of transmission limp mode. For reasons I don't understand, the transmission computer just refused to work properly. Only finally replacing the computer (which had no effing codes!!!!!) fixed it.

I replaced the entire transmission, torque converter, front pump, put in a BRAND NEW solenoid pack from a dealership... It already had a new transfer case in it... Dammit that thing drove me bonkers. I STILL don't know why that computer went sideways, and it seems that there might be two more CRDs like that now on my radar. Why is this happening? There must be a reason.

Mountainman · **Posted:** Sat Nov 30, 2019 12:48 pm

dunl wrote:

Well, spent a while tonight cleaning the grounds from behind the headlight and near the brake booster. The headlight one snapped off, so I just grounded the three wires directly to the battery. Cleaning up both of these did absolutely nothing to solve any of the issues. I still have the U0146 code showing, it's still in limp mode, and I am seriously wondering why I ever bought the thing.

I'm a little late to respond to this lol, but moving a body ground to the battery may be the same thing as no ground, or a poor ground, depending on the circuit. I think the battery negative is tied to the block, and engine mounts are typically not conductive. Cleaning to bare metal elsewhere on the body with an existing bolt hole and adding some dielectric grease will give you a long life before it corrodes.
I once built an engine and it would barely turn over. I had accidentally put the body ground strap on the wrong side of the engine mount. I finally put my meter from the block to body while scratching my head. Ah ha! 10 ohms!

geordi · **Posted:** Sun Dec 01, 2019 2:46 am

There should be zero difference between grounding on the body and grounding directly to the battery - it is a completed electrical circuit, or it isn't.

The ground strap from the engine should go to the body, but there are plenty of vehicles that ground the battery directly to the frame under the battery box and have a separate line from the battery to the engine itself. VW has this. GM with their 454 (and likely others) had massive starting problems in older engines b/c the ground strap was a braided cable that could corrode between the frame and the engine.... And then the starter is drawing WAY more power than that link can handle.

A popular option when chasing power issues is to get some welding cable (VERY flexible and high grade copper) and run direct ground lines to a bolt on the starter (which gets the engine) and a fat frame bolt.

In this case, the individual circuits are looking for their own grounds, and if they can't use the factory points... Then the power will back-feed through another circuit. The computer can do this through the AC compressor circuit (and vice versa) which is why that fuse 14 pops sometimes - one of those two grounds isn't working and the power is able to go the other way, "using" the other ground through another active circuit and sometimes overloading the fuse.

WWDiesel · **Posted:** Sun Dec 01, 2019 1:30 pm

Conductivity, grounds, or lack thereof between the frame and the engine assembly can be tested very simply by using a good Multimeter like a Fluke or similar good device.
A poor ground between the engine assembly and the vehicle frame can also affect alternator voltage output.

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

Well, going to head out to it again with my new ELM327 and see what I can pull. Couldn't see any grounds on the TCM side of the engine.

When I did tune to reflash the ECM a few weeks ago, the MPPS was reading full voltage. Without the ground wires going to the battery now, it has no hazards, signals, or headlights - so hooking it up IS in fact grounding the circuit because they all work then.

dunl · **Joined:** Mon Jul 27, 2009 6:18 pm **Posts:** 53

Dammit. Apparently I need a bluetooth adapter for this ELm327 to connect.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

"ELM327" is just a chip that understands OBDII protocol. One side is the car, the other side is software that reads the output of the ELM327. In 2019, that's usually a smartphone or a tablet with an ELM327-compatible app, like Torque. You can buy ELM327-based adapters that are wired, wireless, or use Bluetooth. Lots of options! Commonly people use Bluetooth based ones as they're convenient.

For my knowledge, is this "gateway" what it sounds like? A protocol gateway for various modules to pass messages back & forth? Like ECM -> TCM, or ABS -> ECM? Since it's a U-code, that's what it sounds like... that this device is a CAN gateway. If so, a CAN analyzer might be useful:

https://www.amazon.com/seeed-studio-See ... 199&sr=8-4

CAN is pretty simple - you have signal Low and signal High, power and ground. Common failure scenarios with CAN is damage to the Low or High wires (they are low voltage, very sensitive), or a problem with the power or ground to one or more modules. A CAN analyzer can monitor messages on the bus and may give a clue about intermittent connectivity. OTOH, if it's a permanent condition you should be able to test for reliable power/ground at the gateway and integrity of the high/low wires (short to power or short to ground).

The nature of this error sounds like the ECM has lost communication with the CAN gateway, which suggests the error is between the two. I wouldn't think this is a problem at the TCM. I suspect the ECM cannot send/receive messages to the TCM because the Gateway is in the middle and it's broken. As a result, since it can't get things like throttle position and road speed, the TCM is defaulting to limp home. I would be doing integrity checks on the CAN low and CAN high wires between ECM and gateway first.

Edit: I would also echo what Mountainman said about relocating grounds. That's especially true when talking about low voltage signal wires. Often times shielding is configured in a very precise way, and moving a ground may have the unintended consequence of introducing noise that the shielding is designed to prevent. I haven't looked at wiring diagrams, I don't know what's grounded where, but on modern cars with sci-fi busses, it's wise to be sure about what's being moved.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Billybob wrote:

The 2006 CRD uses mainly a CAN bus but also some SCSI and PCI.

Help me out with this! Where is PCI and SCSI used in a Jeep? Those seem... inappropriate... for use in a car!

foxmiles · **Posted:** Mon Dec 02, 2019 4:58 pm

I'm not sure about SCSI, but the PCI bus isn't what you're thinking of~

It's a 2 wire serial bus also known as SAE J1850 VPW. For some reason Chrysler decided to call it the PCI Bus. https://www.dodgeintrepid.net/18-general-discussion-second-generation/1457441-pci-bus-documentation-reverse-engineering.html

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Ah, SAE J1850 VPW is an OBDII communication protocol. Thoughtful of ChryCo to both not use the standardized name, then use a misnomer to further confuse things. LOL

Edit: Although I begrudgingly will acknowledge that sending J1850 over a pair of wires and then calling those wires a bus works. But, man, that's really a stretch. A bus that only has two participants isn't much of a bus.

foxmiles · **Posted:** Mon Dec 02, 2019 8:33 pm

2 participants? There are a bunch of possible modules! Depending on the vehicle of course. BCM, Radio, CD-changer (controls, not audio), and EVIC are all on the PCI-bus. I think the instrument cluster is too, probably others I'm not thinking of. It's like a very slow version of CAN. I think older Chrysler vehicles were entirely PCI (no CAN). I'm not sure if the gasoline Liberties had CAN on them at all, or if it was just the Diesels (and their Bosch ECU). I think the PCI-bus was basically EOL with the KJ's.

Also, I agree it's pretty dumb to name your fancy new communications bus the same name as another well known communications bus~
(I so want to make a joke about them now using the Standardized Automotive Test Apparatus interface now (AKA: SATA Port) to avoid such confusion in the future~ :-)r

sorry, couldn't help myself~)

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Ah, it works backwards from how I expected. I thought the car was CAN but the ECM talled J1850 to the OBDII port. Didnt realize that there was also a slow bus present, although that makes perfect sense there is. Thanks!

Edit - now I wonder about your point on gas models... maybe they wre all PCI, and that gateway module is legitimately a PCI to CAN gateway, that lets the Bosch ECM talk to the ChryCo electronics. If so, that's a neat device!

U0146 - lost communication with Gateway - SOLVED(broke wire)

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