Chevy_Scout

Unfortunately, all the emissions test stations are state owned/ran, so the equipment is the same. I’ve been to 2 different test sites with the same result. I’ve driving through for a test, and used the manual testing kiosk, but their scanners could not connect.

V/R,

Chevy_Scout

a55bruce

Did you try connecting the test light from pin 16 to pin 4 & pin 5 ?

hanky

A little FYI,
anytime the PCM (Computer) is replaced, the replacement must be programmed to the vehicle or the security system will not recognize the replacement and can prevent the vehicle from starting Make sure that little bit of info is not overlooked.

Gumby22

When your mechanic friend hooked up the snap on, did it connect to ALL the modules on the vehicle?

At a minimum the ECM, BCM, ABS, SIR, and DDM/DSM are on the high speed network. Depending on options it could also have a fuel pump driver module, VCIM (on star), and others.

The remaining body modules are typically on lower speed networks but should still communicate with the scan tool.

Chevy_Scout

I used the test light on both 16/4 and 16/5 without any problems or dimming.

V/R,

Chevy_Scout

Chevy_Scout

Thanks for the tip; I'll make a note of it if it comes to this.


V/R,

Chevy_Scout

Chevy_Scout

Yes it did. I was at his shop and used this as a guide. The scan tool saw the different modules.


V/R,

Chevy_Scout

Gumby22

Are you absolutely certain all the modules are communicating?

I’m not familiar with snap on specifically, but some scanners will not alert to the modules they can’t communicate with.

For example, the scanner may attempt to communicate with all the modules on the high speed network, but if it only gets a response from the ECM and ABS, it doesn’t display the remaining modules were unresponsive.

If you/your mechanic doesn’t know what modules should be present, it could appear that all modules are present when they’re actually not.

Since I don’t know what options are on your suburban, here’s a complete list of all the possibilities - you’ll have to check the RPO sticker to verify what it’s supposed to have.

(I need to correct my earlier post - in 2012 the high speed network configuration didn’t include all the modules I mentioned - that was based on what I know to be true of later models. I apologize for the misinformation.)

High speed network

ECM/TCM (or PCM if not separate)
TCCM
ABS
BCM
VCIM
FPDM
TBCM
ESC

Low Speed/LIN Bus Networks

BCM
VCIM
IPC
HVAC
SIR
Liftgate/rear hatch control
Theft deterrent
Compass
Radio
Digital Radio Receiver
Amplifier
Rear seat audio and/or heated seats
Front seat heaters
Driver and passenger door switches
Automatic running boards
Object detection sensors

Also, please post a picture of the OBD port - I may be able to tell you if the terminals are worn/loose.

Chevy_Scout

To be honest, I wasn't looking at the scanner as my buddy was nodding his head saying "yes". I'll make some time and head back out to his shop and update this post.

But the problem isn't the Snap-On scanner since the dealer also connects without a problem. The problem is with my little handheld scanner, and the scanner at the emissions testing station, which can't connect to my OBD port.

V/R,

Chevy_Scout

Gumby22

I understand that - the reason I’m asking is because I’m trying to verify all the modules are communicating.

I don’t live in an emissions regulated state and I don’t know what type of scanners they use, but I wouldn’t be surprised if one module not communicating somehow prevents the scanner from connecting at all. How or why, I don’t know.

Is your handheld scanner powering on and not communicating; or is it not powering on at all? What about the testing station?

One other thing to consider - see if there’s any software updates that need to be done. I’ve checked every resource I have for TSB’s regarding this issue and haven’t found anything, so I don’t think it’s a software problem; however it wouldn’t hurt to get any updates that are due and see if it corrects the problem. Sometimes these odd problems are resolved by updating the software.