Newbie - VCM Scanner Questions

[yabadaba]

Hi guys, I've only very recently bought VCM Suite and haven't yet fully explored what it can do, but one thing I want to get my head around quickly is the DTC scanning functionality. Basically because I've recently got a 2001 Z28 Camaro and want to check for any codes. I've searched for posts on this forum and have scanned the help pages, but I'm still struggling.

I've tried scanning for DTC's a few times now and always get the same result, which basically lists some communication codes and reports that the 'Continuous Tests' are complete, but that the 'Once Per Trip Tests' are all incomplete (or n/a). This has been the same with just the ignition in the on position and with the engine actually running amd me having gone for a drive (with laptop still connected). The Once Per Trip Tests would just never show as complete.

However, I tried the same thing this morning and was surprised to see most of those tests now showing as complete and a 'new' code being reported - P0420, which I think is something to do with one of the cats. But, when I tried later on, just to see if everything was still showing the same, it was back to what it was before....all incomplete again and no P0420.

What am I doing wrong guys? Why was it just the one time that the tests showed as having completed and the P0420 code showed, but then I can't replicate it.

Also, is it possible to scan for DTC's without the laptop attached? I tried using the Data Logging, which worked fine and recorded all sorts of data, but nothing showed in the DTC window when I played the file back.

By the way, this is what the DTC readout shows for me normally (I forgot to save it the one time the once Per Trip Test showed as complete)

[Brake] U1000 - Class 2 Communication Malfunction (History)
[Restraints] U1000 - Class 2 Communication Malfunction (History) (Immature)
[Restraints] U1016 - Loss of Class 2 Communication with VCM (History) (Immature)


Continuous Tests
Misfire: Complete
Fuel System: Complete
Comprehensive Component: Complete


Once Per Trip Tests
Catalyst: Incomplete
Heated Catalyst: n/a
Evaporative System: Incomplete
Secondary Air System: Incomplete
A/C System Refrigerant: n/a
Oxygen Sensor: Incomplete
Oxygen Sensor Heater: Incomplete
EGR System: n/a

[yabadaba]

Okay, I've had some partial success - I think driving from cold and for more than just a couple of times around the block was what was required!

I drove the car from cold this morning and after about 15 minutes all tests were showing as complete apart from 'Catalyst', which was the one I was particularly interested in and did complete the once before when it produced that P0420 code.

Any ideas about doing what is required to get the Catalyst test to run successfully?

[ROCNDAV]

I get these same errors too. I cant seem to Read the flash file at times either, it will say that it isnt conncted, when it really is.

Is there something I should be checking for? Bad ground or something?

[DSteck]

Go into the DTCs section in VCM Editor and set P0420 and P0430 to 3 - No Error Reported. Leave SES Enable checked. This will allow your catalyst efficiency readiness check to complete. It's not completing becuase of the fault code. To get the readiness checks to pass, you basically just have to drive for a little while.

As far as the loss of communication stuff... you might have some faulty wiring, or something could be wrong with the body control module.

[TehDago]

As far as the loss of communication stuff... you might have some faulty wiring, or something could be wrong with the body control module.

FYI: This happens when the DTC window refreshes (you can duplicate by manually refreshing DTC's). If the DTC window is open along with a scan you will get the loss of connection message.

Sorry to bump an old thread, but I thought this info might help someone in the future.

[trx2stroke4life39]

O it does now I know why it will disconnect some times.