GM Low Speed Data Wires

[Robinjo]

I would start with the standard high speed wiring test. 60 ohms at the DLC?

What is the DLC, that’s a new abbreviation to me. Edit: another name for OBD-2 port.

How would one perform this? Is it ad easy as pinning both HS wire coming into the DLC? Please be plain in the description as I’m not familiar with a lot of electric terms or slang.

 

[Gtstorey]

Search on here for “aeswave”. It will lead you to link I have posted multiple times for explanation of how high speed works and a basic test.

 

[Robinjo]

I’ll try that. I do remember seeing a sequence on taking things off the HS system to find the unit with an issue.

Edit: Adding here because a lot of the search items come up with the results ‘search for aeswave’.

https://resources.aeswave.com/ATG-05_Network-Diagnostics-and-Module-Programming.pdf#:~:text=High%20speed%20GMLAN%20uses%20two%20120%20Ohm%20termination,be%20less%20stable%2C%20and%20communication%20errors%20may%20occur

.

 

[Robinjo]

Search on here for “aeswave”. It will lead you to link I have posted multiple times for explanation of how high speed works and a basic test.

Issue came back and I have time to play with it. So I checked across the 6 and 14 pins on the DLC (OBD-2 port)

I get 60 Ohms across pin 6 & 14 with the key off.
With key on I get .2 Mega ohms (or I get 0.2 set on the 2 M Ohm setting). It's 'OL" on anything except the 2 M ohm setting.

Started pulling the main three off the system, all with out power connected. Each one of these is only disconnecting the the one item.
Disconnecting the BCM gives 120 Ohms.
Disconnecting the PCM gives 120 Ohms.
Disconnecting the small Power Steering plug gives OL.

Any advice in what this all is telling me? Or, next steps to try out?

 

[Gtstorey]

I don’t think that your results mean anything after you turn the key, I don’t think I’ve ever seen any values for key on.
Disconnect tests are what you should see, once you disconnect a module past the power steering, all you will see is the resistor in the PS.

I would guess that you have an intermittent failure in a module that pulls down the high speed. The most common failure seems to be the power steering. Other than changing it out, you need a full diagnostic scanner to see what is going on. And that might have to be while it’s failing.

I should still have my extra power steering if you want to try it. Unless I’ve already given it to you.

 

[Gtstorey]

If it was mine, I would probably start hunting down the correct Saturn Vue and the EPS controller from eBay and take the EPS out of the high speed chain and get better steering control.

 

[Desert Sasqwatch]

If going the extra step of locating a Vue EPS, versus replacing with a Cobalt EPS, get the variable controller for the Vue and set the power assist to the level that feels best.

Saturn Vue Chevy Equinox Electric power steering electronic controller box EPAS | eBay

This kit allow you to install Saturn Vue electric power steering to any other vehicle. Saturn Vue - from 2002 to 2007. Saturn Vue 2002 - 2007. In these steering columns the ECU (electronic box) is mounted in the steering column.

www.ebay.com

 

[Robinjo]

I should still have my extra power steering if you want to try it. Unless I’ve already given it to you.

I don’t think I did grab that. I’ll give it a try and then look at the Vue setup after getting back to running well.
It was intermittent and now it seems to be a constant failure.

 

[Gtstorey]

Found it. I may be in Huntsville this evening or fairly early Sunday morning.

 

[Robinjo]

Let me know and I’ll meet you

I see text faster. I think you have the number?

 

[Gtstorey]

Let me know and I’ll meet you

I see text faster. I think you have the number?

Not very good at keeping numbers. Send it to me.