Cat ECM codes

I have 4.0.2 installed on an HP laptop. The coach is a 2000 CC with 3126 Cat engine. Will VMSpc display engine failure codes when they occur? I'm having some intermittent engine issues, but the green No Errors Reported box never changes. Do I need to go to a mechanic and have him plug into the diagnostic port at the back of the coach to pull codes?

No Check Engine light either.

v4.0.2 should be updated, first.

Hello Fred

v4.0.2 had issues with capturing and saving the error messages. This was resolved in v4.0.5, currently available in the downloads section.

This new version has many bug fixes as well--and while not perfect yet, does much better. During installation, be sure to temporarily disable your antivirus. Our program may lose track of files that are being 'sniffed' first--which has left some programs working oddly.
It can be re-enabled just afterwards. A second 'gotcha' is the gauge layouts. If memory serves, the newer program will not accept the gauge layouts from v4.beta-through-v.4.0.2. With v4.0.3 and after, all are compatible moving 'upwards'.

Keep me posted on what you find.

As always, you may download the v2.5 or v3.0 version as well.

A little house keeping may be needed to add shortcuts to your Desktop for the various versions.

Be sure to check the History, using the top-line item 'Diagnostics,' when in doubt.


OK thanks. I have 4.0.5

OK thanks. I have 4.0.5 installed. We might be using the coach this weekend.

OK with 4.0.5 installed and

OK with 4.0.5 installed and configured, we still find nothing in the Diagnostics box and "No Errors Reported" in the green diagnostics box.

I have the application running with the laptop at my side at all times. And the green box never flips to red even when the engine misses.

Maybe the application is looking in the wrong folder for engine errors?

Just to be clear, the engine definitely mis-fires periodically but never throws a code in VMSpc.

re: v.4.0.5 Never displays a code....

I understand the software loading is a bit of a hassle-factor--however, lets make sure it is in fact the program. v3.0, though limited in features, has a long history of capturing diag codes. At your convenience, would you install that version (as well) as a 'bench mark?'

If it shows the code thrown--yet v4.x is not, well...we have our work cut out for us.

Keep me posted.


OK I'll try that. We'll be

OK I'll try that. We'll be running it again 9/18. Thanks Art.

OH yah. One more thing I

OH yah. One more thing I noticed in 4.0.5. The Odometer box doesn't display speed correctly. It consistently displayed a lower speed than what we were running.

Finally getting back to you

Finally getting back to you here Art. I DID load and run 3.0 build 1. Still no diagnostics. I went to a truck shop had them pull the codes from the ECM and found that it had a low coolant code and a loss of engine speed code. So I filled the overflow tank and got crank and cam sensors from Cat and installed them. The engine runs flawlessly now. Seems strange that VMSpc doesn't read and display those codes. Or was that capability not part of the plan anyway?

re: Cat codes

Hello Fred

You unit can capture any code broadcast by the engine--with very few exceptions and there's many exceptions with a 3126 engine. Not sure about this when it comes to the nature of the Coolant-Low code however. It could be that v4.0.5 wasn't able to trap it, I've seen this. However, at the point you put on v3.0 you should have been able to trap any other standard code.

I'll round-table this with the guys and see if this rings a bell.


re: Low Coolant on Cat 3126

Hello Fred
We talked about this here at the shop and found consensus in pointing the finger at Caterpillar. They've been pretty good about maintaining the SAE standard for J1708 messages. However, early on, they had some non-standard codes and one was for Coolant level. This was at a time when J1708 didn't yet support this measurement and resulting codes.** so Cat made one up. Its not clear how it differs from the current code but it does.

International did this as well. However, not to be outdone, they have a bunch of these non-compliant codes.



**it would only be another year before it was included and standardised.

Art we're preparing to make a

Art we're preparing to make a 3,500 mile journey next week and I'm still running 3.0. I've fixed my engine issues (low coolant/cam&crank sensors). Should I go back to 4.0.5 ??

Use v3.0 or v4.0.5?

Use either.

Hello Fred
You're familiar with the features of both now; it seems you should use the one which gives you the best results.

Glad to hear your engine is back up to snuff. Have you ever uploaded / emailed me any 'Gallery' pictures of your setup?