Forgive me if this is covered at some point and I somehow overlook it but I'm dealing with communication issues in my 2017 express van's transmission. T-pin testing with my volt meter and a propane test help convince me my o2 sensors where functioning properly. I've eliminated those codes temporarily if nothing else. (Zip ties on old harness ends.)
However, my harness end for my transmission is well behind some shrouding making access to it difficult at best. I hate the idea of penetrating any of the wiring harness wires despite evidence that someone has gotten into the harness before me. (Casing is unraveled a bit. Does anyone here put stock in any of those reasonably priced voltage testers on the market that don't require exposing the wires. Getting to the ECM requires lifting the front fuse block just to get to the other end of the harness. I'm not opposed to using all the techniques I've learned so far with a voltmeter I was just wondering if one of the non-contact testers might not be useful in establishing a current flow at least?
To tell you the truth, I'm a little confused as to how they work not being able to go to ground with a ground wire? Logic does indicate though that if they can detect voltage that they can detect a change in voltage as well which is pretty much what I'm looking for.
And what about the really low voltage signal circuit? Will they give any reading on those at all?
The tsb shows a history of tcm wiring harness failures however, it's an internal module on this model 2500. I'm hoping to start at the wiring harness as close to the transmission as possible, crossing my fingers hoping that it's a failed signal or current up until that point? The transmission, ironically, works flawlessly. I've also been told by one of the most reputable transmission guys in town but because of it's performance it just may be a bad code? With my luck I'm putting way more Hope down than money at this point that he's correct but I just might be chasing a red herring? 'Run 'er till she breaks' has to be as bad if not worse than being a parts thrower.
Not that I've ever figured out why people chase red herrings or why it's bad either but there's got to be a story behind that somewhere?
Thx for an experienced opinion on them...before I "throw my money down and get what I get".
catman...ttyl
I tried giving a more elaborate explanation in my situation a couple of times now but I get bumped off the page? This is the third time I've had to log in so even this message is a test
You get auto logged out of you take a long time writing a post. Copy it before you hit submit.
That tool is largely useless for automotive. It is an inductive probe for detecting the presence of AC voltage, and even then can not measure that voltage.
It will however blink if you hold it over an ignition coil.
"Ground cannot be checked with a 10mm socket"
The following user(s) said Thank You: juergen.scholl
Yes, I tend to be a little to verbose. I wondered about them. I've used them on AC to circuits before, this one says it measures DC as well? Unless I start opening the insulation mid harness I have three options. Completely dismantle the engine compartment fuse block just to access the ecm, then in that limited space try to sort out the 200k mile filthy harnesses that all come together there, then all but drop the transmission to access the harness at the other end all for a transmission code on a transmission that is functioning properly or.'run 'er till she breaks'. 'run 'er till she breaks' wins. My only regret YET in taking these courses is that I didn't take them sooner in life. My 07 Savanavan is on it's 3ed, transfer case and on blocks with its second transmission on just 500 miles with no reverse solenoid. I bought this we '19 Express van with a 'simple o2 replacement' repair needed and got home to 4 o2 codes and this transmission code.
I'll cut off both my feet and walk over broken glass on bloody stumps for the rest of my life before I spend another dime on any gm product, to be sure.
Thx for the reply though. This is the best site on the web for automobile enlightenment.
Topic Author
