[GrizChev]

Respectfully,
Look closer at your results for IGN pin 13 to Ground pin 18.
Address (fix) Acc pin 15 to Ground pin 18.

Then change your tactic.

First, do a conventional PARASITIC DRAIN test series. You need to get a FAST SNAPSHOT of ALL the under-hood fuse box circuits. The test sequence and fill-in forms I use are in my help files. Keep it simple. Don't get fancy. Do the basic investigation and write down observations for each.

IF YOU CANNOT IDENTIFY PARASITIC DRAIN WITH KEY OFF AND REMOVED, AND ALSO WITH KEY ON, THEN YOU ARE GUESSING AND ASSUMING AND HOPING TO STUMBLE INTO A MASSIVE FIX. NOT GONNA HAPPEN.

Get some structure pointed toward the obvious trouble that is masking: power is draining the battery right before your eyes.

Fix the probably two parasitic drains, and fix the probably one key-on power drain, and your battery will stabilize.

When battery voltage is proper and stable, the SENSOR ARRAY (12v and 5v circuits) gets adequate power to support all sensors and devices and modules. Of interest: the 5v array is converted from 12v so the lower the 12v falls below 12v the lower the converted 5v array falls below 5v. RIGHT NOW YOUR ELECTRICAL SYSTEM IS UNDER-VOLTAGE. THAT MEANS ITS OVER-AMPERAGE. THAT IS DANGEROUS AND IT CREATES PHANTOM READINGS AND CONFUSES MODULES.

Chase the power drains, both key-off parasitic and key-on.

My help files:
II
V

 

[GrizChev]

^
Ii

Keeping this separate from my post a moment ago.

Also see post #2 in my help files and look into your vehicle's current/voltage sensor to prove that the module is triggering the alternator to deliver adequate power to maintain battery. If the sensor or its plug or its wires to vehicle are compromised then fix it. This condition might be being masked by other troubles.

The process of battery failure bounces around but eventually the physical battery cannot hold deep charge and one observable symptom is a battery that jumps from 3v to 12v on trickle charge for a short time, as you reported here earlier. It is commonly the case that this sensor system is failed. The alternator tests will read normal. But no recharge power is sent to battery. This compounds the voltage-amperage consequences mentioned earlier.

 

[GrizChev]

Scroll to bottom of Post #3 and tap the desired attachments themselves. There is also a fuse box layout sheet tobuse to check-off each fuse as it's pulled for inspection.

I listed the attachments at top of post for table of contents, but that's not active link.

 

[GrizChev]

Was IGN pin 13 to Ground pin 18 done after waiting for modules to sleep?

 

[GrizChev]

Ref cool suggestion by @29 Chev

"You can also connect a jumper wire from the battery negative post (or terminal) to one terminal on your tester and connect the other terminal to your ground wire terminal 18 and use your voltmeter to determine how much voltage drop is occurring on the negative side of your circuit - just a suggestion."

Note that B- voltage drop up to 0.3v is acceptable in this sort of circuit. Anything connected thru a module needs time to sleep. Defined as all modules asleep.

I didn't see evidence in these circuits that simply metering would wake-up modules but the module circuits are black, and connections convoluted, and the 'master' module governing sleep is the last one to sleep. That can take ~20 minutes. So when possible test as B- voltage drop because that module would not likely raise beyond 0.3v after a 15~30 second momentary rise.

 

[GrizChev]

Keeping this reminder separate:

Test results are effected by battery voltage. As pressure drops, amperage rises.

Remember to occasionally run engine (alternator) or attach TRICKLE charger and allow time to reach static battery POS to NEG of 12.4v or more.

Disconnect any external charger or power source and allow time for modules to sleep before metering.

If you open a door or bump a remote button then the 'master' module will wake-up related other modules. It's a pita but it us what it is. Those related modules usually go back to sleep quickly. The 'master' takes time. The diagrams give likely hints - but much is black.

If your alarm senses a bump or contact with vehicle, then don't touch the body or door handles and put a thick blanket over fender as cushion. Or pull alarm fuse (most systems will not care).

 

[GrizChev]

I remember the days of analog meters. Infinite definition. Some guys with oscilloscopes could dig deep fast. Elegant wave forms. No choppers. When digital came out most of us were unimpressed.

Today, circuit board manufacturing is in nano scale. Transistors and even relay coils and switches don't physically look like they did. They are 4 angstroms thick and built in a diffusion or epitaxy process in a wafer lab. A 2 angstrom gateway is by nature pressure sensitive, so if electrons flow thru the gateway their simple pressure pushes thru 2 angtroms thickness of atoms, and so flows down another circuit path. Boom. A relay your eyes cannot see. And it lives in the low milliamp range. It's astounding stuff.

I was fortunate to have an opportunity to run production machines in a custom wafer lab for Motorola and ON Semiconductor. Three years of math-heavy custom diffusion. Some were new development and circuit integrations (some very smart engineers made my work look good God bless them). Most were actual production sent to market including separate processing for gov stuff. Those were exciting days. When my 3 year stint was over (2016) I had an emotional crash from realizing I would likely never again work with people that smart and dedicated. But it was time for me to get back outside, I thrived in mines and powerhouses and factories. And that wafer experience gave me tools I still use every day EVEN RETIRED! And plus I have awesome memories.

 

[GrizChev]

Re video. Touch the stud post at fuse box and then compare to video where touched terminal. This may explain voltage drop, it's a joint, possibly micro-corroded. Or possibly the threaded post or the connecting terminal-eye is unexpectedly aluminum (does not conduct as well as some other materials).

 

[GrizChev]

@Kyliecb7

I believe your post #34 (repeated in #36) is accurate and the test method is valid. Part of my belief comes from the results mirroring my own tests over time. Another part comes from the uniformity for the test set, and the wait time so all modules were asleep.

Most of the frustrating oddities you reported are actually just phantom side effects. You're getting different numbers on different days.

So re: my earlier post #19 change your focus. Do those uniform tests. I expect it will lead you to the wiring outside the transmission but before going there you need to prove voltage drop in uniform manner but most importantly you need to identify parasitic drain. Otherwise you'll just keep chasing your tail.

 

[GrizChev]

I agree.

By nature I touch:
B+ POST to B- POST,
and then B+ TERMINAL to B- TERMINAL,
and then B- TERMINAL to FB+ TERMINAL (where FB = Fuse Box).

All should read exactly the same because the distances are very small, plus I use battery post protectors, plus I've been lucky enough so far to do regular preventive maintenance.

Another neat thing is when helping family and friends and neighbors, I often used some type of basic fill-in form as a way of helping them to understand and learn how-to. Plus it makes comparison possible. Warm fuzzies.

Anyway, I only mention it here because we're talking about consistency and comparing readings toward a fix, gotta be apples-apples.

 

[GrizChev]

@29 Chev

Some of the guys use Fluid Film even on their watercraft with great success. And not just on the battery. I need to try it.

I've sorta standardized on stuff in-stock locally. I'm nearly a mile high elevation in the Sierra Nevada and lots of salt brine every winter so I know what you mean. I used certain brands in industry so always had some handy. Just sorta stayed with it. The brine means the number of under-body car washes is crazy. The moment winter temperature rises enough, zap. Gotta keep that brine at bay. So I like preventive steps.

I use NOCO Cleaner and Protector (2 part kit) for battery posts that display any level of corrosion. But its expensive so I first dip terminals into a cup of water with baking soda to bubble clean a few minutes and brush some onto the posts - and then I also pour part of a cup completely over the battery and surrounds. Then hose lightly and let dry a bit. Then NOCO Part 1 on the battery posts and loose terminals. Then hose again and let completely dry (usually while doing other things). That all takes maybe 10 minutes. Then after battery terminals are reinstalled (with pads) I coat the terminals lightly with NOCO Part 2 (*). I almost never have battery terminal corrosion the next year, meaning I consume more Part 2 than Part 1.

I also use two CRC products. One just for vehicle battery post quick-shots (*) when messing around. It gets used more on other vehicles like when someone asks for help figuring something out.

The other is a form of dielectruc grease I use for assembled but de-energized connections, home and auto, any electronics and fuse boxes and electrical devices and connectors. It's non-wicking so coats without danger of reducing circuit bandwidth.

I'm out of these two so did a screen shot.
The NOCO 2 and CRC Protector (*) get used most.

These two get used least, mostly because things stay clean longer. If I don't disassemble then I don't need them. But gotta have 'em handy!

I'm in a spot where I'm doing fewer and fewer repairs and projects. Getting older means looking for new things to do haha. I feel like I could go several years doing only the usual minor maintenance. I still hope to swap all 4 of the struts and coils this summer (but it's looking unlikely) meaning I might not put a jack under my car again until next summer. That will be weird!

 

[GrizChev]

@Kyliecb7

If you want that exact breakout box then get the type 2 that has the matching jumpers. Then, if you don't have one already, get a decent mid-to-top grade auto ranging multimeter.

Also, we all need to force ourselves to not make assumptions. The CAN buss is a unique animal.

That particular tool appears to be the type that reads circuit as a whole, but doesn't have capability to identify precisely where a trouble is along the selected CAN circuit. Also it looks to be voltage only (but I could be wrong).

I hope you'll do an after-action report for us!!

 

[GrizChev]

Mouser is great. All have high electrical life expectancy. Hard to beat.

 

[GrizChev]

I'm rooting for the fix! I hope the new battery does the trick. But I'm also worried why the battery failed. 6v is often unrecoverable and only occurs due to lack of consistent charge. Or a decade old battery (sulfation is managed for longer battery life).

I recall that you did clean all ends of both battery cables prior, and checked voltage drop, so that is all stable.

The two other suggestions (from my #17 and #18) again seem valid worries based on this development.

You performed an overall parasitic drain (#17) test - which at that moment passed - but you did not do the hard work of a full fusebox fuse-by-fuse test set, which nearly always finds a trouble if exists. I admit I lean toward your at-that-moment findings at-that-time, but zero-parasitic is not proven valid yet.

As likely right now is #18 the pesky Voltage/Current Sensor. I see tons of people ignore this. Including many here. I was one. And except me, none others have later admitted they should have gotten into it, they just do it and get on with life (very human so no worries).

That sensor and its separate plug are very inexpensive but a pita to install. IT'S WORK IS TO MONITOR BATTERY LEVEL ON THE FLY AND TO TRIGGER ON THE FLY THE ALTERNATOR (VIA MODULE) TO DELIVER A MEASURED AMOUNT OF CHARGE TO THE BATTERY.

You can do battery tests all you want, but if this system is not doing its job to the right levels at the right times then battery and alternator tests will likely not find it. You simply have to know the sensor needs to be tested, and have to actually test it (or replace it) INCLUDING it's lead wires and plug. That is the only way to prove it's SYSTEM is valid. Tests and docs are in that help file.


I hope the new battery solves everything. If not then I hope this sensor is all it is.
And I hope you look into it before . . .

Trust me I'm not being a smart arse. I'm worried that overlooking this will once again be the root of bad stuff and weird readings.

If none if these aspects solve the huge electrical troubles (which seem to morph and not really lead anyplace helpful), then it seems likely that no amount of tools are going to help, it's possible only a schooled oem electrical tech is going to dig deep enough and that is going to be bad news.


The thing is, in this case, I feel like this phantom menace is based on simple stuff. It almost always is. Heck there are pretty much no error codes in circuits that are powering many sensors, and modules having talk-back expectations, it just doesn't feel solid. It's gotta be something simple. I hope 🙂

.

 

[GrizChev]

See, we both revisit all these posts and still circle back to one trouble being someplace between the TCM following every wire to its other end. Maybe broken strands inhibiting adequate go-juice flow. Maybe TCM connector pin(s) corroded. Maybe a momentary contact break (vibration). But the other trouble really seems to be adequate battery power levels across load conditions.

 

[GrizChev]

2014 Impala LTZ 3.6 right?

And this part is your question?:

"Does anyone have a handy diagram for what the part number is for that full wiring harness between the TCM and ECM and getting the whole thing replaced instead of the connector (and all that labor charge??)"

Are you sure you don't want to start your own thread. I can do that for you. Let me know.

.

 

[GrizChev]

Keeping separate, I think the interconnect is not a single cable set direct. But go to:
Www.charm.li to see the cables.

I don't believe they are in the parts manual in my help files but when able I'll look or you can if you want.

 

[GrizChev]

Ok my bad when I looked it up all 2012~2020 Impalas using the 3.6 came with 6T70 including both body styles. The subject parts appeared to be the same. If they are not then my bad I should have dug deeper. 😊

 

[GrizChev]

@Impoor

Well, except he is after part numbers.

 

[GrizChev]

The first thing is to identify the plug for manufacturer and type, from which you can identify the terminal parts, and that will detail how pins are affixed to the wire ends and how pins capture into the plug (and same for matching half of the connector.

I don't recognize the connector shown in Post#66 from last summer. Nobody else has commented with ID either.

I realize different vehicle years and models might vary.

I'd like to see this solved.

My take, based on that recent pictured connector plug, which at-a-glance has many missing female terminal fittings (that pins plug-into) and that needs proving to know what's missing.

There's sometimes little release tools needed to match. Sometimes the new terminal snaps in. Sometimes a tool is needed.

Sometimes releasing the connector releases all the terminal ends. Other times each has its own release.

Sorry can't know what is involved until parts are udentified. There's dozens of unique bits. But most transmission shops would know and would have terminal ends.

ADDED:
THE ONLY POTENTIAL GM CONNECTOR FROM CHINA IS 88988938 HOWEVER ITS ONLY AVAILABLE AS AN 80-PIN SHELL. IT WILL NOT WORK UNLESS FITTED WITH WHAT APPEARS TO BE A SPECIAL 20-TERMINAL FEMALE PLATE AND WITH HOT FLUID SEALS. THE 20-TERMINAL FEMALE CONNECTOR ACCEPTS THE 17-PIN MALE CONNECTOR ON THE TCM VALVE BODY (3 MISSING PINS) AND THE TERMINALS (PINS AND RECEPTACLES) APPEAR TO BE MOLEX BRAND. SPECIAL TOOLS. AND A MAX 30 WATT SOLDERING "IRON" TO TIP THE (SEVENTEEN?) 18~20 GA COPPER CONDUCTORS.

THERE ARE ALSO KNOWN VARIANTS, NOTABLY IT TURNS OUT MUCH OF THE WORLD GOT IMPALAS IN AT LEAST 2011 FITTED 3.5 3.9 AND 6T70 WITH 17-PIN CONNECTOR WITH DIFFERENT SEALS AND TERMINALS. THE ONLY SOURCE FOR ALL OF THESE IS CHINA. AND THEY DON'T SEEM TO OFFER KITS WITH PARTS NEEDED FOR 17 OR 20 TERMINALS.

SEPARATE THERE IS THAT COMPUTER ADAPTER I PICTURED EARLIER ALLOWING DIRECT PLUG-IN FOR DESKTOP PROGRAMMING THE TCM. THAT IS ACTUALLY A TWO-WIRE DEVICE. IT HAS THE 20 TERMINAL SET-UP ON ONE END AND A COMPUTER PLUG ON THE OTHER. WON'T HELP. AND ITS ONLY PART OF WHAT IS NEEDED TO DESKTOP PROGRAM. THE OTHER PARTS ARE ACDELCO AND DISCONTINUED.

LOOKS LIKE THE ONLY ACTUAL SOURCE OF REPLACEMENT CONNECTOR IS SALVAGE YARDS. THEY WOULD KNOW INTERCHANGE. THE INTERCHANGE PROVIDED EARLIER HAS NOT BEEN PROVEN BY ME IT'S UP TO YOU. THAT MEANS VERIFY MOLEX TERMINALS TOO.

I DON'T SEE ANY OTHER AVENUE. HOPEFULLY OTHERS WILL HAVE INFO TUCKED AWAY.