NP... Deleted.... However... You should know that in the latter of those 65 Images...the importance of what happens whenever the Brake Pedal is stepped upon in relation to the TCC Activity in response may be integral to other aspects of things.
Intermittent PRDNL Indicator Weirdness, P0700 and other Goodness
- Thread starter spfautsch
- Start date
I appreciate your input here, but I didn't make it past the first 10 images. At the time I had bigger fish to fry. They're fried now, read on.
That's an interesting tangent I've thought about but not in great detail. That input is a +12v signal, so if it's shorting to another power source that could be worth investigating. If it's broken / going open or shorting to ground it shouldn't make any difference. Also, it doesn't really explain why the previous TCM module eventually failed completely, setting persistent RAM verification errors. Or, why this problem seems to be directly related to temperature.
Edit: To further clarify, the previous TCM dying seems to a me a sign that whatever is happening is causing the TCM's voltage regulator / power supply filtering to be overtaxed, causing "dirty" power to the processor and memory of the TCM and subsequently causing the processor to reboot due to low voltage.
Almost ready to test. If this doesn't work it'll make good nesting material for all the birds living in my back yard.
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Well... Since I'm Batting a Thousand so far with NOT rendering any useful information to this Thread... I'll give this once last try...
Check Out @MAY03LT 's contribution shown in Post # 2 via THIS Link:
gmtnation.com
But from hereon out... it will be a "Mokusatsu" situation... 黙 殺
Check Out @MAY03LT 's contribution shown in Post # 2 via THIS Link:
The 5 Transmission p codes
I seen the video on this subject from GMTnation, I cannot find anything on it here to help me I am new to the site. I have the five P0740 p0753 p0758 p0785 p1860. I tested fuse 47 it has power both sides. I swapped an ignition switch from my 02 envoy that I had smashed up. Reset codes and...
gmtnation.com
But from hereon out... it will be a "Mokusatsu" situation... 黙 殺
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Appreciated, but already have page 164 and 166 of the 2006 Ranier 'WIRING.PDF' service manual printed in color, cut and taped together, in duplicate. It's what's in the background underneath the break-out cable and has every circuit connected to the TCM.
Edit: One thing the diagram you referenced got me thinking about - it, and most of the other references including the 2006 Ranier PDF collection - incorrectly depict the D2 switch in the manifold pressure switch (most trans guys refer to this as the "pillow switch"). It is in fact a normally closed switch, which when D2 applies breaks the circuit grounding the D4 / D3 normally open switches. I got some white-out and fixed my printed copies so as not to chase ghosts should I get to looking at this one.
Got Rusty out of storage this morning and have the break-out cable and the newest TCM module in place. Starts and runs with no issues. That's as far as I got b/c I threw my back out pulling weeds this morning and after mowing my lawn that's about as far as I'm able to get.
Have a Hantek CC65 clamp-on current sensor on the way that should make visualizing solenoid currents much easier. Just need to find my BNC extension cable so I can feed it through the firewall along with some home-made test clip leads.
Edit: One thing the diagram you referenced got me thinking about - it, and most of the other references including the 2006 Ranier PDF collection - incorrectly depict the D2 switch in the manifold pressure switch (most trans guys refer to this as the "pillow switch"). It is in fact a normally closed switch, which when D2 applies breaks the circuit grounding the D4 / D3 normally open switches. I got some white-out and fixed my printed copies so as not to chase ghosts should I get to looking at this one.
Got Rusty out of storage this morning and have the break-out cable and the newest TCM module in place. Starts and runs with no issues. That's as far as I got b/c I threw my back out pulling weeds this morning and after mowing my lawn that's about as far as I'm able to get.
Have a Hantek CC65 clamp-on current sensor on the way that should make visualizing solenoid currents much easier. Just need to find my BNC extension cable so I can feed it through the firewall along with some home-made test clip leads.
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Mooseman
Moderator
For manuals and schematics, have you tried this site?
Free Car Service Manuals from Operation CHARM — No strings attached!
Operation CHARM provides completely free repair/service/workshop manuals for over 50,000 models of cars and trucks manufactured 1982-2013. No sign-up or paywall.
charm.li
I haven't seen or heard of that, thanks! May come in handy some day.
Whatever the case, they all seem to basically be the same data packaged differently. I have to wonder how that information is licensed out, or if it's something freely available from the OEMs.
The first schematic I found on that site also incorrectly depicts the pillow switch, which I will add also has a normally closed switch for D3, according to this manual which apparently came directly from GM. (lower left corner, page 37)
Hydra-matic 4L60-E Tech Guide
You might want to add that to your manuals page as it seems slightly more comprehensive than the ATSG version.
Whatever the case, they all seem to basically be the same data packaged differently. I have to wonder how that information is licensed out, or if it's something freely available from the OEMs.
The first schematic I found on that site also incorrectly depicts the pillow switch, which I will add also has a normally closed switch for D3, according to this manual which apparently came directly from GM. (lower left corner, page 37)
Hydra-matic 4L60-E Tech Guide
You might want to add that to your manuals page as it seems slightly more comprehensive than the ATSG version.
Mooseman
Moderator
NP, happy to contribute.
Think my toolbox is finally equipped to tackle this problem.
Channel 1 is the switched IGN voltage that supplies power to the trans solenoids, and channel 2 is the 1-2 shift solenoid output. This was taken moments after starting the engine - the voltage jump at the beginning of the capture is the alternator starting to generate power. Interesting that the 1-2 shift solenoid is only energized after quite a bit of time has passed after key-on. I'll have to try quantifying that.
This isn't a lab grade DSO, but I wish I would have bought one of these years ago. There's no external trigger for the freeze / run function (that stops the sweep), but I'll get by with the big red button on the scope.
Think my toolbox is finally equipped to tackle this problem.
Channel 1 is the switched IGN voltage that supplies power to the trans solenoids, and channel 2 is the 1-2 shift solenoid output. This was taken moments after starting the engine - the voltage jump at the beginning of the capture is the alternator starting to generate power. Interesting that the 1-2 shift solenoid is only energized after quite a bit of time has passed after key-on. I'll have to try quantifying that.
This isn't a lab grade DSO, but I wish I would have bought one of these years ago. There's no external trigger for the freeze / run function (that stops the sweep), but I'll get by with the big red button on the scope.
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As I was hoping to at least be reporting I'm working through the process, it disappoints me to update that I'm nearly back to square one.
The breakout cable worked exactly as expected, and in combination with the DSO gave me the tools to capture some cool waveforms of startup and 1-2 shifts. But that's all it provided. Over the 350-odd miles I've driven with it in place, zero TCM issues were observed. Not even a hint of the PRNDL indicator moving unwarranted, doors unlocking, or the 1-2 shift solenoid losing power unexpectedly, causing the trans to go all but limp.
At this point it occurred to me that perhaps having the TCM branch of the harness out of place as it was moved some wires that were chafed to a favorable spot, or that the additional impedance of the wire and connectors of the breakout cable might be the key. So I removed the breakout cable and zip-tied the TCM to the battery tray so the harness was in roughly the same position so as to eliminate only the impedance variable.
Once again, several test drives proved uneventful. I found this to be a "good" sign, and pulled all the ECM / TCM connectors back out of the rat's nest and looked for signs of chafed wires near the red zip-tie that corresponds to the point a loom retainer clip holds the TCM branch down to the frame rail.
After going over every single wire between the TCM connector and the convergence with the ECM branches carefully with my lighted and articulated workbench magnifying glass and some mild contact cleaner on a paper towel (to clean the dirt off the wire jackets) I've come up with nothing. Absolutely nothing.
So I scoop my pride off the floor and decide to re-tape the harness and get it back in the split loom so I don't end up with something getting caught in a fan belt. Once all back to normal, for sh*ts and giggles I put the TCM back in its usual plastic carrier alongside the ECM and go for a short test drive from "cold" (current ambient temp is about 82F). Numerous incidents were observed (at least 6 in a 2 mile circuit of mixed 60mph highway and 25mph urban driving).
So for now, the "fix" to this problem seems to be zip-tying the TCM to the battery box. I'm beyond confounded.
The breakout cable worked exactly as expected, and in combination with the DSO gave me the tools to capture some cool waveforms of startup and 1-2 shifts. But that's all it provided. Over the 350-odd miles I've driven with it in place, zero TCM issues were observed. Not even a hint of the PRNDL indicator moving unwarranted, doors unlocking, or the 1-2 shift solenoid losing power unexpectedly, causing the trans to go all but limp.
At this point it occurred to me that perhaps having the TCM branch of the harness out of place as it was moved some wires that were chafed to a favorable spot, or that the additional impedance of the wire and connectors of the breakout cable might be the key. So I removed the breakout cable and zip-tied the TCM to the battery tray so the harness was in roughly the same position so as to eliminate only the impedance variable.
Once again, several test drives proved uneventful. I found this to be a "good" sign, and pulled all the ECM / TCM connectors back out of the rat's nest and looked for signs of chafed wires near the red zip-tie that corresponds to the point a loom retainer clip holds the TCM branch down to the frame rail.
After going over every single wire between the TCM connector and the convergence with the ECM branches carefully with my lighted and articulated workbench magnifying glass and some mild contact cleaner on a paper towel (to clean the dirt off the wire jackets) I've come up with nothing. Absolutely nothing.
So I scoop my pride off the floor and decide to re-tape the harness and get it back in the split loom so I don't end up with something getting caught in a fan belt. Once all back to normal, for sh*ts and giggles I put the TCM back in its usual plastic carrier alongside the ECM and go for a short test drive from "cold" (current ambient temp is about 82F). Numerous incidents were observed (at least 6 in a 2 mile circuit of mixed 60mph highway and 25mph urban driving).
So for now, the "fix" to this problem seems to be zip-tying the TCM to the battery box. I'm beyond confounded.
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I've been driving Rusty as I would any other auto-trans beater / commuter car over several days and for several hundred miles with the newest (i.e. new out of a sealed GM box) TCM module that seemed most susceptible to whatever problem has been plaguing the vehicle, only relocated from it's original plastic holder next to the ECM / radiator, to being zip-tied to the battery box.
It pains me to state this, but I'm starting to believe the problem is / was triggered by the location of the TCM. Considering I spent at least 8-10 hours "fiddling" with every wire going to the TCM to no avail after re-locating, I feel like I've covered all the faulty wiring scenarios. The only change that seems to bring definite results has been the relocation of the TCM closer to the battery tray.
As much as I'm reluctant to declare this the solution, after sleeping on it I realized that aside from the ECM, the electro-viscous fan clutch is the only other source of EMI in the vicinity of the TCM. It's control signal is also PWM controlled based on engine coolant temperature (as well as A/C pressures and trans fluid temps).
I'll report back if things change, but I'm feeling like this is a solution, albeit one I would not accept under normal circumstances.
I'll post back every few months, or if the problem recurs. But for now I'm planning on fixing all the other issues except disabling AFM (mainly a leaky rear air spring and rust-dissolved upper trailing arm mounts) and driving it 1700 miles to and from our favorite vacation spot this coming August.
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Mooseman
Moderator
Usually when the EV fan fails, it kills the throttle system and puts it in reduced power mode. However, this is on the 4.2. Haven't heard of the 5.3 being affected the same way.
I have never heard of of a PCM or TCM being affected by EMI.
Have you tried using some contact cleaner on the TCM pins and in the connector? Another possibility is a wire that's broken internally but losing contact intermittently and moving the TCM puts the wire loom in a position to keep that wire in contact.
I have never heard of of a PCM or TCM being affected by EMI.
Have you tried using some contact cleaner on the TCM pins and in the connector? Another possibility is a wire that's broken internally but losing contact intermittently and moving the TCM puts the wire loom in a position to keep that wire in contact.
Perhaps true, but the 5.3 with the E38/T42 combination was only in production in limited numbers from late 2005 to the platform's unfortunate demise.
I'm far more confounded than you could know. Yet I've thus far found no other logical explanation.
I absolutely tried contact cleaner on just about everything. I even used it to clean the vehicle harnesses' wire jackets while I was inspecting them for fraying / discoloration / etc.
Not to mention I've added a complete sub-harness between a brand-new TCM and the existing vehicle harness, complete with two used male and female ends, both of which were seriously "cobbled together". If anything this would ADD resistance / problems. But despite my best efforts no amount of manipulation of wires (even down to the 1/2" closest to the connector pins) could reproduce the problem with the sub-harness in place / TCM relocated.
Trust me, having run into that type of problem at least twice in the past several years, that is exactly what my focus was set to finding when I started into this. As such I went over every "suspect" bit of wire (discolored jacket, etc.) looking for the tell-tale feel of a jacketed wire with an internal break. I've been there and done that, and I wish it was that simple.
Edit: The scientist in me expects, and somewhat hopes to be proven wrong. I'm simply posting my current observations.
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Mooseman
Moderator
Maybe time to wrap it with a tin foil hat 
. You could try unplugging the fan and see if it resolves it. As long as it's not too hot out and not run the A/C, you should be fine and keep an eye on the temps. You will get a code for the fan.
I would have lost it too by now.
. You could try unplugging the fan and see if it resolves it. As long as it's not too hot out and not run the A/C, you should be fine and keep an eye on the temps. You will get a code for the fan.I would have lost it too by now.
Maybe time to wrap it with a tin foil hat
Right?
Ironic that you'd mention that. Though I only drove it a few hundred miles before getting the A/C working, this problem did not surface until after that. As I mentioned (possibly in the other thread) I've noticed the issue apparently coinciding with the A/C compressor clutch engaging or disengaging but not in a repeatable manner. But I've also had it happen with the climate control turned off completely.
It's due for an oil change so I might test with the fan clutch disconnected just for the hell of it.
Well I'm not at all surprised to report that disconnecting the fan clutch accomplished nothing except that I discovered someone had poorly cobbled a repair of the wiring right at the connector, likely the result of a water pump bearing failure. Whatever mental midget did this didn't feel the ground wire needed to be fixed, so the bare parts of it had frayed and broken, though not completely.
Anyway... before the post-oil change test drive, while I was clearing the fan speed sensor code I noticed an odd noise like the compressor clutch was cycling though the climate control was off. I get out and put my eyes and ears to work, and find the sound appears to be coming from the transmission. Lo and behold as I shift into neutral I witness the PRNDL indicator doing it's usual dance. So this seems to indicate it happens when in park also. (TCM was in it's intended location)
Basic reasoning would suggest that if the only thing I touched pertaining to the wiring harness was moving the TCM and it's branch a few inches higher and towards the driver side, wiggling said harness in it's new location should reproduce the problem. But it doesn't.
I've yet to work up the courage to try doing the same with the TCM loose but near it's intended location, because meeting flesh with the un-shrouded part of the spinning fan isn't all that appealing.
Edit: just for clarity, I have used a coat hanger to manipulate the TCM harness while in it's intended location to no result.
For now I'm going to drive with the knowledge that two zip-ties are just a band-aid. But the band-aid makes the boo-boo fixed, at least until it isn't. I wish I understood why, but as long as the problem appears "patched" I'm not going to let it further accelerate my achromotrichia.
Anyway... before the post-oil change test drive, while I was clearing the fan speed sensor code I noticed an odd noise like the compressor clutch was cycling though the climate control was off. I get out and put my eyes and ears to work, and find the sound appears to be coming from the transmission. Lo and behold as I shift into neutral I witness the PRNDL indicator doing it's usual dance. So this seems to indicate it happens when in park also. (TCM was in it's intended location)
Basic reasoning would suggest that if the only thing I touched pertaining to the wiring harness was moving the TCM and it's branch a few inches higher and towards the driver side, wiggling said harness in it's new location should reproduce the problem. But it doesn't.
I've yet to work up the courage to try doing the same with the TCM loose but near it's intended location, because meeting flesh with the un-shrouded part of the spinning fan isn't all that appealing.
Edit: just for clarity, I have used a coat hanger to manipulate the TCM harness while in it's intended location to no result.
For now I'm going to drive with the knowledge that two zip-ties are just a band-aid. But the band-aid makes the boo-boo fixed, at least until it isn't. I wish I understood why, but as long as the problem appears "patched" I'm not going to let it further accelerate my achromotrichia.
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