Prndl going crazy
- Thread starter Spck
- Start date
Tcm not programmed, don't know the code number off hand. Prndl works fine, no speedo and abs light for inplausable data
OK... that "test" shows you that the system at least recognizes the "loss of coms" with the TCM (assuming that's the code that you are getting... hence the question). It also shows that perhaps since the system can't talk to the tcm any more, the tcm can't "talk back" and cause your problems.... maybe.
m.mcmillen
Member
It isn’t a loss of communication. The new TCM he installed doesn’t have anything written in it and that is why it won’t work. It just needs to be programmed.
m.mcmillen
Member
@Spck you might find some help here https://gmtnation.com/forums/threads/calling-all-tech-2-and-high-end-scanner-owners.13739/
Maybe someone doesn't live far from you and could help.
Maybe someone doesn't live far from you and could help.
Mooseman
Moderator
As an FYI, if the person owns a Tech 2 clone, he also probably has a copy of Tis2000, which has the required programming, so a subscription is not required unless it's a 2008+ truck. However, you got my curiosity peaked with the J2534. Apparently, it's a standard for use with emissions modules (PCM) but may not work for other modules.
https://www.boschdiagnostics.com/pro/j2534-faqs
I can confirm that J2534 is listed as an update device however I can't confirm if it will allow updating other modules since I can't get past the initial screen.
To be continued in the Scanners section...
No, I don't. I've called every gm dealership in a 30 mile radius and nobody wants to do it on a Saturday. Got a bunch of bad excuses why they can't do a 5minute job
Mooseman
Moderator
Does it shift like this? How would you get it to the dealer? Or you would take the TCM in by itself? Too bad you don't have the luxury of time to get you own J2534.
If you decide to get an MDI ... this Snap-On Forum discusses accessing the ACDelco TIS2WEB issues... perhaps they have some ideas on how to interface and download what you need with a Basic Subscription that will let your Solus work as a Pass-Thru Programming device:
http://productforum.autorepairdata.com/forum/showthread.php?t=6083
http://productforum.autorepairdata.com/forum/showthread.php?t=6083
After borrowing a vehicle last night, I couldn't get into a dealership today. I have an appointment for first thing Monday morning. I put the old tcm back in this afternoon and has been running perfectly since. Still keeping my appointment and programming the new tcm to be safe. Who knows how long it will act normal
If you think of it while you are at the Dealership on Monday coming... See if you can speak with the Tech servicing your vehicle and ask him which specific Fuses per Particular Modules he had to pull in order to ensure the smooth programming of the New TCM. In many cases... installing a variety of New Modules and programming them without this particular precaution can play havoc with OTHER Modules residing on the Databus. Knowing what he says about the matter might help others when performing this same task with their own High End Scanners. Thanks in Advance for this consideration. :>)
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m.mcmillen
Member
I’ve programmed a lot of modules on GM vehicles using Tis2Web and it always says what fuses to pull before programming. Does Tis2000 not do the same?
Not sure... I'm still in the discovery stages trying to work with and diagnose a variety of these modules in a Bench Top setting... so the opportunity to use just the Laptop TIS2000 HW & SW on other vehicles has not arisen. I was just curious what the Tech would have to say about it... sort of... Straight from The Horse's Mouth. Besides that... If @Spck is paying Good $$$ for the service that he himself will not be able to perform with his Solus Scanner and not be using the TIS2WEB update... I think he deserves to know what and how they do the job... specific to his Y-M-M TCM.
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Mooseman
Moderator
I've used Tis2000 lots (PCM, TCM, PDM, Radios, VATS) and Tis2Web just recently (BCM, Immobilizer, RKE) and neither ever told me to pull any fuses or I missed the messages. Maybe that's what happened to the ABS and SRS on my Caprice. Wound up having to relearn stuff and pull the ABS fuses to reset it.
Darn it, we're off topic again
Darn it, we're off topic again
Still good info. Planning on getting my own interface so I don't run into this again. Any extra info and links have been extremely helpfulI've used Tis2000 lots (PCM, TCM, PDM, Radios, VATS) and Tis2Web just recently (BCM, Immobilizer, RKE) and neither ever told me to pull any fuses or I missed the messages. Maybe that's what happened to the ABS and SRS on my Caprice. Wound up having to relearn stuff and pull the ABS fuses to reset it.
Darn it, we're off topic again
Mooseman
Moderator
Mooseman
Moderator
He might not have, but I do (now nearly 6 years old). Apologies for reviving this long dead one as my first post, but I'm currently experiencing a nearly identical problem. Sad that the OP never returned to update.
I'm going to assume since the last action he mentioned was replacing the TCM (well actually getting the replacement programmed so it could be used) that this resolved his problem before he disappeared never to be heard from again.
I just ordered a pre-programmed replacement TCM for mine, will update here if it resolves the issue. If not I'll create a new thread.
For reference, the symptoms I'm seeing are that while the gear selector is not in park - usually while driving in a forward direction but not always - the PRNDL indicator in the IPC will jump to P and then back to the selected gear, and the door lock(s) will cycle. Sometimes this will be coincident with hitting a bump, and sometimes it will be at completely random times. Two days ago I drove a short distance early in the morning to take my wife to the donut shop. I let it idle while parked, and while sitting idling a MIL was set. After this the ECM / TCM went into limp mode. U0101 and P0601 DTCs were set. Testing power and grounds to the TCM connector showed no issues, and since I had one on a dead soldier 4l60e in my storage unit, changing the range switch for a known good one also had no effect. After some testing and prodding I also noticed a P0700 (non-specific TCM malfunction) was set on occaison, and it would even get so bad the PRNDL indicator in the IPC would be stuck at R regardless of what gear the shifter was in.
Edit: Based on the DTCs, I'm working from the assumption that the TCM is either losing power or some other combination of unexpected input state(s) are causing it to reboot since proper operation usually resumes if a DTC isn't set after the incident.
I drove it 115 miles round-trip to work yesterday and only noticed two incidents shortly after start-up and at speeds < 50mph. Seems like after the vehicle is up to temperature the problem subsides.
I feel like this problem may be temperature dependent, which is sometimes indicative of a cracked / cold solder joint in the offending module.
Anyway, as I mentioned I'll update this post if the replacement TCM seems to solve the problem. This is a new acquisition and I've been working on it extensively over the past month to get all the gremlins solved after years of deferred maintenance from previous owners. But we've had an Atlas powered Trailblazer EXT for almost a decade, and I've had the joy of building a new transmission for it - twice. But never an issue like this (since the I6 GMTs have no separate TCM).
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This rapid change in the PRND123 Fluorescent Tube on the Dash implies a Sketchy Issue with the Park Neutral Switch possibly having one or both of the Dual Wire Connectors either coming loose or having the PNS (Park Neutral Switch) not being set and locked down on the orbit of the 4L60E Shifter Pawl Shaft. There may also be Cuts in the Wire Harness damaged in some way that are subject to these random connection-separation issues as the Harnessing gets *jounced* around while driving.
At this point, it's probably worth the effort to Jack-Stand the SUV and crawl under there with a Bright Flashlight and *jiggle* the Harnesses while someone is sitting behind the Wheel (KOEO) and shifting through the Gears with All Four Wheels Off The Ground. Being thoughtful, diligent and very suspicious of EVERY Harness might just pay dividends if the issue gets discovered in this uncomfortable manner.
At this point, it's probably worth the effort to Jack-Stand the SUV and crawl under there with a Bright Flashlight and *jiggle* the Harnesses while someone is sitting behind the Wheel (KOEO) and shifting through the Gears with All Four Wheels Off The Ground. Being thoughtful, diligent and very suspicious of EVERY Harness might just pay dividends if the issue gets discovered in this uncomfortable manner.
Keep the idea of replacing the PNS with an OEM one after using a Heat Gun to remove the Two Harness Connectors after loosening up their *Glue* ...in the back of your mind...
gmtnation.com
www.700r4transmissionhq.com
The ATSG Comprehensive OBD2 Diagnostic Guide for The 4L60E,65E,70E & 4l80E,85E Trans
This is a VERY comprehensive 185 Page PDF Service Guide covering the OBD2 Diagnostics for The GM 4L60E, 4L65E, 4L70E, 4L80E and 4L85E Transmissions. It contains a great many contributions from the Members of the GM Automatic Transmission Service Group (ATSG) imparting arcane knowledge, tips and...
gmtnation.com
Chevy Trailblazer U0101: Meaning, Causes, + Diagnosis | Drivetrain Resource
U0101 is a generic powertrain code, which means it has the same definition for the Chevy Trailblazer as it would any other vehicle. It means that your Trailblazer's TCM (Transmission Control Module) can't communicate with the rest of the vehicle, usually due to a bad wiring harness or an issue...
www.700r4transmissionhq.com
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What exactly are you referring to by "two harness connectors"? I just mentioned that I replaced the neutral safety / range switch with a known good one. It has one large connector with the plastic slide that locks it in place or releases it from the switch. There is no "glue" - I haven't seen that since 2001 model-year.
Sorry to continue to revive this old thread, but after several hundred more miles I just wanted to update some details on the problem I'm noticing as my problem seems to be quite similar to the OP's.
As mentioned previously I've yet to see the symptom (IPC indicator jumps to P and then back to D while moving, accompanied by door locks cycling) while at a steady cruise above 50 mph. That changed yesterday when I noticed a single event around 65mph on absolutely smooth, level concrete interstate.
This one is extremely odd in that I can't seem to find a distinct set of conditions that reproduce the issue. Yesterday over about 150 miles of mostly interstate driving there was one particularly bad instance that set a code and limp mode after sitting for approximately 45 minutes to have lunch. Leaving the restaurant the locks started cycling and eventually the CEL illuminated. I cleared the codes at a stoplight, got on the interstate and drove the next 60 miles back home with no further incidents.
Today I started it cold, drove 3 blocks to pick up my mother and then 52 miles to the hospital, then another 45 minute breakfast, then another 52 miles home without a single incident. Then I get in it after another 30 minutes of being off, and the locks cycle as soon as I put it in D. It sets a code before I get to the stop sign 300 feet from my front door.
Replacement TCM should be here Saturday. When it arrives I intend to open the old module and see if there's anything possibly amiss inside. Bad capacitors, cold solder joints, that sort of thing.
As mentioned previously I've yet to see the symptom (IPC indicator jumps to P and then back to D while moving, accompanied by door locks cycling) while at a steady cruise above 50 mph. That changed yesterday when I noticed a single event around 65mph on absolutely smooth, level concrete interstate.
This one is extremely odd in that I can't seem to find a distinct set of conditions that reproduce the issue. Yesterday over about 150 miles of mostly interstate driving there was one particularly bad instance that set a code and limp mode after sitting for approximately 45 minutes to have lunch. Leaving the restaurant the locks started cycling and eventually the CEL illuminated. I cleared the codes at a stoplight, got on the interstate and drove the next 60 miles back home with no further incidents.
Today I started it cold, drove 3 blocks to pick up my mother and then 52 miles to the hospital, then another 45 minute breakfast, then another 52 miles home without a single incident. Then I get in it after another 30 minutes of being off, and the locks cycle as soon as I put it in D. It sets a code before I get to the stop sign 300 feet from my front door.
Replacement TCM should be here Saturday. When it arrives I intend to open the old module and see if there's anything possibly amiss inside. Bad capacitors, cold solder joints, that sort of thing.
Three other areas worth investigating:
(1) An Errant Ignition Switch Issue...
(2) Re-Setting the Automatic Door Locks to something other than Automatic. Press the "I" Button on the panel...or examine the setup instructions for this feature from your Envoy Owner's Manual that perhaps has these options:
Automatic Door Locks
(1) An Errant Ignition Switch Issue...
(2) Re-Setting the Automatic Door Locks to something other than Automatic. Press the "I" Button on the panel...or examine the setup instructions for this feature from your Envoy Owner's Manual that perhaps has these options:
Automatic Door Locks
- Continue with the following steps in order to personalize the automatic door locks:
- Press the Select button in order to enter the menu. The first choice seen is the current setting.
- Press the Select button in order to scroll through the following options:
- LOCK DOORS: IN GEAR
- LOCK DOORS: WITH SPEED
- Press the Personalization button in order to advance to the next option.
- Press the Select button in order to enter the menu. The first choice seen is the current setting.
- Press the Select button in order to scroll through the following options:
- UNLOCK DRIVER: IN PARK
- UNLOCK DOORS: IN PARK
- UNLOCK DOORS: AT KEY OUT
- UNLOCK DOORS: MANUALLY
- Press the Personalization button in order to advance to the next option.
The schematics I have are somewhat lacking on which circuit feeds ignition voltage to the module, so the ignition switch may be an avenue worth exploring. The PDFs I have are the ones posted here for a 2006 Buick Rainier. These kind of suck, and I'm considering looking for the real GM FSM to get a more complete and searchable set of info.
The door locks cycling are a symptom and not a cause. The leds in the IPC gear indicator array are only controlled by the broadcast of a packet from the TCM on the CAN. So too does the BCM decide to lock or unlock the doors based on selected gear.
The door locks cycling are a symptom and not a cause. The leds in the IPC gear indicator array are only controlled by the broadcast of a packet from the TCM on the CAN. So too does the BCM decide to lock or unlock the doors based on selected gear.
"A Small Word To The Wise ...in Your Shell Like Ear"...
Most of the Folks who contribute the suggestions and ideas that come here often to render Help will basically "Bend Over Backwards" for anyone who likewise comes to GMT Nation for assistance. Many times, they are NOT disappointed with the outcomes from such things. Sometimes... we may fall a bit short of the Mark... and in other moments, we do occasionally manage to "Hit The Ball ...Right Out Of The Park..."
But the One Thing that might stifle any such enthusiasm is the injection of criticism that is tantamount to "Biting The Hand that FEEDS You..." So whenever you might feel even slightly *Brittle* in your assessment of the Quality of the GMT360 "Port Au Faire" among the Buffet Offerings and you feel inclined toward "Dyspepsia along with Your Critique"... tamping down such notions and keeping your own council will serve you well and truly in the long run and so.... Become a Friend ...to those who Befriend YOU.
"When the Student is Ready... The Teacher Emerges..." -- Confucius
Most of the Folks who contribute the suggestions and ideas that come here often to render Help will basically "Bend Over Backwards" for anyone who likewise comes to GMT Nation for assistance. Many times, they are NOT disappointed with the outcomes from such things. Sometimes... we may fall a bit short of the Mark... and in other moments, we do occasionally manage to "Hit The Ball ...Right Out Of The Park..."
But the One Thing that might stifle any such enthusiasm is the injection of criticism that is tantamount to "Biting The Hand that FEEDS You..." So whenever you might feel even slightly *Brittle* in your assessment of the Quality of the GMT360 "Port Au Faire" among the Buffet Offerings and you feel inclined toward "Dyspepsia along with Your Critique"... tamping down such notions and keeping your own council will serve you well and truly in the long run and so.... Become a Friend ...to those who Befriend YOU.
"When the Student is Ready... The Teacher Emerges..." -- Confucius
Yeah, I don't speak or read French so whatever that dissertation is all about, I'm not going to even bother. Not to say I don't appreciate your input because I genuinely do. I'm 52, and didn't just start working on computer controlled vehicles yesterday.
I'm not coming here begging for assistance, but hoping to offer some. If I needed help I would have posted a new thread beginning with the words "newb looking for help".
My intention wasn't to belittle your attempt at help and if that was your interpretation I sincerely apologize. I genuinely appreciate all (logical) input. Just giving intelligent data points reinforcing that I've already considered these diagnosis angles.
I'm not coming here begging for assistance, but hoping to offer some. If I needed help I would have posted a new thread beginning with the words "newb looking for help".
My intention wasn't to belittle your attempt at help and if that was your interpretation I sincerely apologize. I genuinely appreciate all (logical) input. Just giving intelligent data points reinforcing that I've already considered these diagnosis angles.
Mooseman
Moderator
If the door locks are set to unlock when in P and lock when in gear, then I would suspect a bad range/neutral safety switch or a problem with the wiring shorting. The TCM is receiving a signal that it's in Park and unlocking the doors and then goes back to D and locks them, however, because the actual mechanical gear selector remains in gear, the truck continues to move. If however you were to stop, it may shift weird or not at all if it stays in P. It possibly could also be a bad or shorting TCM. Your test with the new one should confirm it.
PS: you should READ the codes BEFORE clearing them.
For manuals, check my signature for downloadable ones. And if you check the last post of that thread, there is a link to a website that has ALL manuals up to 2013.
PS: you should READ the codes BEFORE clearing them.
For manuals, check my signature for downloadable ones. And if you check the last post of that thread, there is a link to a website that has ALL manuals up to 2013.
As I've mentioned, I've replaced the range switch with a known good one, and spent considerable time "jiggling" the involved harnesses. Additionally, the range switch isn't directly controlling the BCM, it's all a conversation of ones and zeros on the CAN.
The TCM isn't directly unlocking the doors. It's sending a broadcast message on the CAN telling all interested modules / nodes that it sees the range switch in park. This causes the ECM to do certain things, the IPC (instrument panel controller) to change the selected gear indicator LED, and the BCM to unlock the doors. This is exactly what I'm seeing. The only "BOLD" assumption I'm making here is that when freshly powered on, the TCM assumes and sends a broadcast that the gear selector / range switch is in park, as it should be.
Are you following me? I hope you are!
PS: I'm truly not trying to be an asshXle, but I did this as previously mentioned (re-read the thread?). I didn't just start working on computer controlled vehicles yesterday.
The codes I'm seeing when things are bad enough for a DTC to be set are:
U0101 - loss of communication to TCM
P0601 - checksum verification failure
P0700 - generic TCM module failure
I'm not a rocket scientist, but all of these codes seem to be consistent with the TCM rebooting due to power problems or some other trigger.
I will look closer into the last post of "that" thread.
Again, not trying to be a dick. I simply thought I'd encountered a problem similar to the OP's and wanted to hopefully follow up with a possible resolution since the OP either solved his problem and disappeared, or gave up and disappeaared in shame.
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Still no definite resolution as USPS is holding the replacement TCM hostage. It was supposed to be delivered today but still hasn't left the nearest distribution center it arrived at on Thursday evening.
Anyway, after another 52 miles on the interstate yesterday, and then start-up after a 90 minute cool-down the module went completely around the bend. Locks were cycling like crazy, and then the CEL illuminated. This time with a new PCM code: P0604 - Internal Control Module Random Access Memory Error, and it is re-set at each startup now, causing limp mode immediately. I drove it a short distance and even after getting the vehicle back up to temp it still re-set immediately upon startup. Even after disconnecting the battery. It's sitting in a hospital parking lot so I might try it out tomorrow when temps are cooler, but I feel like this is a sure sign the TCM (or hopefully not the ECM) has developed a problem in the power supply such as a degraded capacitor that's causing "dirty" power.
Anyway, after another 52 miles on the interstate yesterday, and then start-up after a 90 minute cool-down the module went completely around the bend. Locks were cycling like crazy, and then the CEL illuminated. This time with a new PCM code: P0604 - Internal Control Module Random Access Memory Error, and it is re-set at each startup now, causing limp mode immediately. I drove it a short distance and even after getting the vehicle back up to temp it still re-set immediately upon startup. Even after disconnecting the battery. It's sitting in a hospital parking lot so I might try it out tomorrow when temps are cooler, but I feel like this is a sure sign the TCM (or hopefully not the ECM) has developed a problem in the power supply such as a degraded capacitor that's causing "dirty" power.
Good information there but overall a "wandering" thread with a lot of non-specifics. The dealership shouldn't have been referring to the ECM (the v8s have a separate ECM + TCM) as a PCM (atlas powered GMTs have both functions handled by the PCM).
Another possibility that crossed my mind that would cause "dirty" power to the module is a cracked copper shunt in the fuse block. I had no idea these things are so fragile until I ran into another thread talking about the ECM shutting the engine down in a temperature-dependent manner.
gmtnation.com
Whatever the case, replacement TCM should be delivered today so I'll hopefully have good news to report. I suspect all the codes I'm getting other than U0101 are coming from the TCM because the code reader I have is extremely primitive and can't identify which module the DTC is coming from.
Another possibility that crossed my mind that would cause "dirty" power to the module is a cracked copper shunt in the fuse block. I had no idea these things are so fragile until I ran into another thread talking about the ECM shutting the engine down in a temperature-dependent manner.
2006 Envoy 5.3 Random QUIT NO RESTART WITH P1682, P0689, P0443
My usual suggestions for GM & GMC Owners are to be suspicious of "Under-Hood Vermin Chewing Wiring" if their vehicles suffer from inexplicable sudden engine stoppage and no restarts to look around for Mice setting up home under the Hood in the Engine Compartment. In many cases, SUV and Truck...
gmtnation.com
Whatever the case, replacement TCM should be delivered today so I'll hopefully have good news to report. I suspect all the codes I'm getting other than U0101 are coming from the TCM because the code reader I have is extremely primitive and can't identify which module the DTC is coming from.
...and following that possibility of having Cracked Copper Tracing is the possibility of having the Galvanized Posts atop the Fuse Box holding the Under-Plugs In Harness Connectors being left loose and thus, might also be a factor as *Sketchy Connections* subject to Asymmetric Vibrations and Thermal change involvement. This can happen in cases where Engine Swaps occur as a mere trivial peripheral installation oversight.
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I still haven't ruled that out completely but...
Replacement TCM installed this afternoon. The P0604 ram error cleared finally and everything seems to be good. No DTCs whatsoever at the moment. Will need to drive it a bit to declare it fixed but I think this is a relatively definite diagnosis.
I have a picture of the internal PCB and connections, will try to post as soon as I can but taking care of my 81 yo mother post-surgery at the moment. I don't see the PCB as being repairable, but the interconnect wires seem to be suspect. Hard to describe completely without the picture - will get that posted asap.
Replacement TCM installed this afternoon. The P0604 ram error cleared finally and everything seems to be good. No DTCs whatsoever at the moment. Will need to drive it a bit to declare it fixed but I think this is a relatively definite diagnosis.
I have a picture of the internal PCB and connections, will try to post as soon as I can but taking care of my 81 yo mother post-surgery at the moment. I don't see the PCB as being repairable, but the interconnect wires seem to be suspect. Hard to describe completely without the picture - will get that posted asap.
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