411 swap, now P0706 and P1810

[Supercharged111]

My 411 swap went pretty good until I left a tune on for more than 10 minutes. Then the TCC stopped locking. I cleared DTCs and it locked up once, then right back to the same old shit. If I reflash, it stays away longer. From what I've researched, these appear to come together and both reference the transmission range switch, the one inside the trans that detects fluid pressure and tells the PCM what gear is selected. I've already used the .cax file to set D2400 to none, even though that's not the range switch in question. What PIDs should I be logging to help track this down? Below are the 3 pins I feel are the only relevant ones:

C1-18, red wire, Trans Range Signal C
C1-17, dark blue wire, Trans Range Signal B
C2-63, pink wire, Trans Range Signal A

The trans was flawless before the swap, so though it's possible the switch took a dump it's also unlikely in my opinion. The one thing that I know changed was the PCM, so that's the general area I've been concentrating on so far. I've verified pin placement, verified that they're all fully seated, they're all clean and in good condition as are the pins on the PCM. The harness in the trans is only a year old too.

[Supercharged111]

Every time I reflash and go for a drive, lockup seems to work for a while. If I just clear DTCs, it doesn't work for long at all. I could disable the DTC fault process enabler, but if there really is a problem then that doesn't seem like the right thing to do. The P0706 shows up right away, but the P1810 takes longer to pop up. It looks like the tstate2 PID is the one that tells me what gear the PCM thinks the trans is in based on the fluid pressure. I have a new tune to flash on tonight and I'd really like to datalog this on my test drive, but I have no idea what to do with this PID other than log it. What kind of table do I build to be able to view it on the fly? Can I throw it on the dashboard? I tend to just watch my maps as I drive most of the time. I plan to ohm out the harness as well, I'd rather not drain $50/gallon trans fluid unless I really, really need to.

[joecar]

P0706 and P1810 are for the pressure switch which tells the PCM which range has been selected (i.e. the position of the manual lever)...

The pid GM.PRNDL (there are several similarly named pids, log all of them) and observe it as you move the manual lever thru each position.

The pid GM.GEAR indicates which gear the PCM is currently commanding.

The pid GM.BOXRATIO shows the gear ratio of the current gear, if you know the gear ratios for 4L80E or 4L60E you can see if the actual gear is the same as the commanded gear.

The pid GM.TSTATE02 (and some of the other TSTATE pids) shows reasons for TCC not being applied... but first figure out P0706/P1810.

Trans line pressure is indirectly viewed by the pid GM.TFMPRS... log this, and also GM.TRQENG and take note if engine torque is being calculated too low).

[joecar]

Post tune file and any log files.

What year/model/vehicle...?

Do you have a PCM/trans wiring schematic for this vehicle...?

[joecar]

Does vehicle have 4L60E or 4L80E...?

Which year OS did you flash into the 0411 PCM...? Do you have a PCM/trans wiring diagram for this year (on similar vehicle)...?

Not all years of OS and transmission are necessarily compatible.

[Supercharged111]

Shit, sorry didn't post the pre-requisite stuff! This is all on the truck in my signature so 350 Vortec with 4L80E, OS is COS5 so 12212156 based. I swapped the trans and trans diagnostic segments in from a 12212156 OS and started making it mine. I can get a schematic for the vehicle, but I just used Lextech's proven Excel spreadsheet for the pins and all 4L80Es are the same on the trans end. The 4L80E ran codeless on the blackbox for a year damn near to the day before swapping the 411 in. The trans donor OS tune is at home (I got it from gmtruckcentral's 411 swap article which I can't access at work) but I've attached the tune I'm going to flash when I get home. Only thing different on this one vs what's currently on the truck is TCC release stuff.

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When I originally got the PCM, I had Justin at Blackbear give me a 2001 Express van tune with 5.7/4L60E and then he plopped COS5 on top of it. Between then and now the 4L80E swap happened, but that initially seemed seamless until now. Thanks for the reply, hope all turns out well on your end.

[bmc1025]

Did you swap an 80 in a truck that originally had a 60? If so did you re-pin the round grey connector on the side of the transmission?

Is your tune for an 80. Preferably the 2002 express van tune?

[Supercharged111]

Yes, I swapped the transmission in one year ago and ran it off the blackbox with a trans segment swap and repinned the grey connector accordingly. It ran without codes this whole time, but the lazy TCC lockup was slowly driving me insane. The donor trans segment should be from an 01-02 Express van, but can't confirm that beyond a shadow of a doubt until I get home.

[bmc1025]

Sorry I was typing when you posted!

[Supercharged111]

That makes a lot more sense!

I just got back from a drive. I logged the PIDs you requested and the pressure switches all worked fine. I didn't get the P1810 this time. As I think back, I got the P1810 before I swapped in the 4L80E diagnostic segment. I forgot that initially I just plugged the trans segment in and hauled ass. I don't know if it's a coincidence, but the P1810 hasn't come back since I swapped the proper diagnostic segment in. There was 1 PID that caught my eye, it was GM.PNPSW. It always indicated INGEAR, never anything else. All the other PIDs read normally. This log is 411 TCC LOG.efi. I should point out here too that it still feels like adaptive shifting isn't active, I assume P0706 is the cause.

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While taking that log, I noticed the SES flashing as I did WOT pulls through 2nd gear and then, subsequently, the TCC not locking for a minute or so until it passed however many successful misfire tests. For shits and giggles, I stopped the above log and grabbed all the misfire parameters I felt were relevant. They're on the next 2 logs. It would have been just 1 log, but I got pulled over by the popo (off with a warning, almost blew a 12 year no ticket streak!) so the 2nd log I don't think has any misfires on it due to my lightened right foot. They are 411 misfire log 1 and log 2.

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With the latest, greatest TCC parameters I just can't say enough good about how the truck acts now! It locks fast and stays locked, I've been furious at times with the trailer out back because the stupid TCC won't lock because it just took too long with the old PCM. There is a poo brown lining to this cloud though, gm.cmpret hovered between -28 and -29. This is the first time I've ever checked this PID, and could be the cause of my misfires. Perhaps the blackbox was too dumb to detect these misfires? I've never had a misfire code before. My guess is the previous owner had the privilege of doing intake gaskets and reinstalled the distributor off a tooth and called it good when it never threw a check engine light. Now to guess which way it's off. I'm sure the 50/50/90 rule will come into play here.

[Supercharged111]

So there is no GM.PNPSW PID. Through process of elimination, it appears to be GM.PRNSW, but in the data column where I monitored the state of the transmission PIDs it refers to it as PID GM.PNPSW. Weird. Of course I'm at work, but if this thing is always showing in gear, which it always is, then this is definitely what's setting the P0706. But I don't understand what this is mechanically. Obviously the internal pressure sensitive range switches are working as advertised because every other PID reacted immediately to changes in the gear selector. I don't think it's a wire that needs to be grounded/faked because if it always thinks it's in park, it'll still throw the P0706.

EDIT: also forgot to mention that GM.BOXRATIO indicated 4:1 when in park, neutral, and 1st gear. All the rest was correct and my gear ratios are correct in that other table whose ID escapes me at the moment.

[joecar]

SES/MIL flashing = engine misfiring --> PCM will prevent TCC lockup during misfires.

Any PCM may not correctly detect misfires unless CASE relearn was done... if blackbox PCM was not able to do CASE relearn then it probably was not detecting misfires (properly).

[joecar]

GM.PNPSW is simply the state of the P/N switch... PCM uses this for idle airflow tables... I don't think it is used for trans control.

GM.PNRDL is the state of the internal pressure switches... PCM uses this for determining the gear range (e.g. 1->2->3 in D3).

[joecar]

Hmmm.... BOXRATIO 4.00 in 1st is strange... for 4L80E should be 2.48... (check the ratios in the tune file).

[Supercharged111]

SES/MIL flashing = engine misfiring --> PCM will prevent TCC lockup during misfires.

Any PCM may not correctly detect misfires unless CASE relearn was done... if blackbox PCM was not able to do CASE relearn then it probably was not detecting misfires (properly).


And a CASE relearn won't even be attempted until GM.CMPRET is better than -28. I'm not too worried about the misfire right now because after however many misfire tests pass, it'll allow the TCC to lock up again. In the interest of allowing the PCM to accurately detect misfires though I do plan to address it. What you say makes sense because the truck certainly doesn't act like it's misfiring when the light flashes.


GM.PNPSW is simply the state of the P/N switch... PCM uses this for idle airflow tables... I don't think it is used for trans control.

GM.PNRDL is the state of the internal pressure switches... PCM uses this for determining the gear range (e.g. 1->2->3 in D3).

Which physical switch is the P/N switch? I didn't see any mention of P/N wires on the 411 wiring spreadsheet. Since it always displays in gear, it's definitely not right and I'd like to address it.


Hmmm.... BOXRATIO 4.00 in 1st is strange... for 4L80E should be 2.48... (check the ratios in the tune file).

It was rounding them all to the nearest tenth, so I'd expect to see 2.5. That's not even right for a 4L60E. It also displays it in park. I'll have to check it when I get home, but I am currently running the tune that I attached to this thread.

[Supercharged111]

I verified the gear ratios in the tune and D1201-D1205 are all correct, so I'm lost there and completely lost as to why my P0706 remains.

[joecar]

The P/N switch is on the outside of the case, where the gear lever sticks out of the case (trucks); or on the end of the shift lever, under the console (cars).


The PRND321 (aka PRNDL) pressure switches are inside the case, integrated into the TFP switch assembly, on the bottom of the valve body, see post #8 here: 4L80E-Reference-Material (https://forum.efilive.com/showthread.php?4305-4L80E-Reference-Material)


Attached wiring diagram is from 2001/2002 F-car, shows both TFP switch assembly and P/N switch.

[Supercharged111]

From what I've posted, would you agree that the TFP is working properly and that it appears D2400 isn't working on my truck? Isn't D2400 supposed to negate the need for the P/N wires?

[Supercharged111]

I'm completely lost here. P0706 implies the TFT isn't working, but it definitely is. It sounds like the external range switch is what the PCM is butthurt over (based on PRNDSW always being in gear), but you can see in the tune I've set D2400 to none. What am I missing here?

[joecar]

I'm still looking at your files (I got swamped with various things today so I'm running behind, sorry about that)...

[joecar]

P0706 implies the TFP switches are not working... you can check that the TFP is working by logging GM.PRND431 as you move the gear lever.

I'll reread the conditions for setting P0706 in the service manual...

[Taz]

I'm completely lost here. P0706 implies the TFT isn't working, but it definitely is. It sounds like the external range switch is what the PCM is butthurt over (based on PRNDSW always being in gear), but you can see in the tune I've set D2400 to none. What am I missing here?

You used a *.cax file to change the truck default (trans mounted gear position switch) to a Camaro default (no such switch). DTCs P0705 and P0706 should be set to "Not Reported" - as they are in a Camaro tune (which you are mimicking).

As to the misfire - that could be a lot of things - but being a tooth or two off when reinstalling a Vortec style distributor is very easy to do.

[Supercharged111]

P0706 implies the TFP switches are not working... you can check that the TFP is working by logging GM.PRND431 as you move the gear lever.

I'll reread the conditions for setting P0706 in the service manual...

I did that in the datalog I posted, it worked perfectly.


You used a *.cax file to change the truck default (trans mounted gear position switch) to a Camaro default (no such switch). DTCs P0705 and P0706 should be set to "Not Reported" - as they are in a Camaro tune (which you are mimicking).

As to the misfire - that could be a lot of things - but being a tooth or two off when reinstalling a Vortec style distributor is very easy to do.

Really? So I'm not getting the SES light, but the DTC enabler should be turned off too then? If so, then that's easier than I thought!

I'm not worried about the misfire at the moment, gotta get cmpret back where it belongs and may even need a new cap/rotor before I begin scratching my head.

[joecar]

Taz always has a good simple solution :cheers:

[Supercharged111]

Taz always has a good simple solution :cheers:

I was tempted to do it before, I just wasn't certain it was the right thing to do. That P1810 hasn't come back, so it must have been because of the 4L60E trans diagnostics. If I could get just 1 free day with this thing I could get it 100%.