code 83- auto tcc control feedback fault 95 firebird
Last edited by mrvedit; Jun 30, 2020 at 08:13 PM. Reason: Fix link
These can sometimes be a pain in the ***...
The 1992/1993 vehicles (and older) did not have any electronic control over the transmission (at least for the THM700-R4... and yes there is also a 1993 4L60E).
The THM700-R4 units only had one solenoid, and it turned on/ off from a ground connection and 12v+ (usually from a pressure switch on the valve-body)
This is really all that GMs OBD-1 system was intended for in terms of transmission control and monitoring.
The 1993, 1994, and 1995 4L60E units did receive additional OBD-1 monitoring, but it was not very good.
In most cases, when code 83 is present; the torque-converter gets stuck locked or stuck unlocked.
When stuck locked, this makes the engine stall when coming to a stop; and makes the shifting feel harsh.
If the transmission seems to operate properly... then the torque-converter is probably stuck off.
1995 4L60E transmissions were built two different ways.
Early 1995 units only have one TCC solenoid (just like 1993 and 1994).
Mid and late 1995 units have two TCC solenoids (this continued into very early 1996 units as well).
Not that it is relevant here; but GM was testing many of these updates on the S and T truck platforms...
You can even find on some 1994 S/T trucks, both TCC solenoids well before any other vehicle.
Usually code 83 only would only show-up on an early built 1995 unit.
This unfortunately is not guaranteed. Code 83 can still show-up if the PWM TCC solenoid is present and faulty.
Late 1995 units will usually have code 90 show-up for TCC faults.
The late 1995 units were the first year model transmission to have the torque-converter gradually lock and unlock by adding an additional solenoid to the transmission.
This is the TCC PWM solenoid. The link you posted is also the solenoid I am speaking of.
This solenoid allows to lock-up clutch of the torque-converter gradually apply and release.
I will need to know the "ID" information that is stamped into the case of your transmission to know how the trans was originally built.
When these vehicles get to be this old... the transmissions usually have been rebuilt by now...
Who knows if someone updated the transmission or not during a rebuild.
The "ID" information should be stamped into the case near where the tail-housing bolts on.
Just as in the image above... you should be able to view this from under the vehicle.
The transmission cross-member/ mount may make the "ID" difficult to see.
There is also a slim chance that your transmission case has the "ID" stamped on the passenger side of the case instead.
The "ID" would be just above the oil pan, on the passenger side, and towards the rear of the oil pan.
Look at the two images below.
Let me know the "ID" and I will look up the Julian-Date of the build...
We will see if the transmission ORIGINALLY used both solenoids or not.
You will have to be prepared to remove the oil pan to continue diagnosing the transmission.
Powering on the TCC solenoids manually and measuring the solenoid resistance should be the next steps.
Vorteciroc has "Top Secret" documents which will determine which it is from your ID.
Now, if the transmission is removed, you can just look for the "PWM" stamped into the pump cover.
To replace solenoids, there is NO need to remove the trans; only pan needs to be dropped.
So... There are two things that I did not expect.
I expected that you would have a 1995 transmission that was rebuilt... WRONG LOL!
Okay, so the two things that the ID tells us is:
-It is not the original transmission for your vehicle.
-It is a 1994 unit.
So, originally that transmission would not have the PWM TCC solenoid.
However if the transmission was ever updated... it may have the PWM TCC solenoid.
The transmission should have a bad TCC apply solenoid/ wiring/ PCM.
You will have to troubleshoot/ diagnose this yourself... We will guide you.
Solenoid:
If the solenoid itself is bad... they are available in two different ways.
-From GM; it will be sold as an internal transmission harness with TCC solenoid (1994 specific)
-From the aftermarket; sold as a TCC solenoid that you have to splice into the original internal harness.
So... There are two things that I did not expect.
I expected that you would have a 1995 transmission that was rebuilt... WRONG LOL!
Okay, so the two things that the ID tells us is:
-It is not the original transmission for your vehicle.
-It is a 1994 unit.
So, originally that transmission would not have the PWM TCC solenoid.
However if the transmission was ever updated... it may have the PWM TCC solenoid.
The transmission should have a bad TCC apply solenoid/ wiring/ PCM.
You will have to troubleshoot/ diagnose this yourself... We will guide you.
Solenoid:
If the solenoid itself is bad... they are available in two different ways.
-From GM; it will be sold as an internal transmission harness with TCC solenoid (1994 specific)
-From the aftermarket; sold as a TCC solenoid that you have to splice into the original internal harness.
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I would do this with the vehicle/ engine COLD.
If your transmission oil-pan has a drain plug... remove it and drain the oil.
Otherwise carefully remove the oil-pan, expecting to get splashed with ATF.
Take photos of the wiring-harness inside the transmission, and the solenoids that connect to the wiring.
Post them here, so we can see what is actually on the valve-body.
I expect to find only the TCC apply solenoid... but we will see if it was updated or not.
We will continue after I can look at the photos.
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That begs the question... was the PCM ever changed???
The 1995 PCM with a 1994 transmission is going to look for the PWM TCC solenoid and set a DTC when the solenoid is not found.
Your transmission only has the TCC apply solenoid... the one in the photo of my last post.
That begs the question... was the PCM ever changed???
The 1995 PCM with a 1994 transmission is going to look for the PWM TCC solenoid and set a DTC when the solenoid is not found.
Your transmission only has the TCC apply solenoid... the one in the photo of my last post.
A PCM and transmission mix-match will set a code and stay.
From the looks of the wiring harness in the transmission... that trans has not been rebuilt in a long time; or it has never been rebuilt.
The guy may have grabbed a junk-yard unit and swapped it in; when the original transmission died...
A PCM and transmission mix-match will set a code and stay.
From the looks of the wiring harness in the transmission... that trans has not been rebuilt in a long time; or it has never been rebuilt.
The guy may have grabbed a junk-yard unit and swapped it in; when the original transmission died...
But Hopefully some here who does, can chime in and help us.
I would try to have the PCM read to find out the part number of the PCM and the calibration number (software on the PCM) to know which year/ type of PCM you have.
Needing to know if you have a transmission - PCM mix-match is the next step.
But Hopefully some here who does, can chime in and help us.
I would try to have the PCM read to find out the part number of the PCM and the calibration number (software on the PCM) to know which year/ type of PCM you have.
Needing to know if you have a transmission - PCM mix-match is the next step.
-We first look at the last 8 digits of the VIN (digits #10 through #17).
-The 10th digit is the model year identifier for the vehicle; and is the letter "S" (the letter "S" indicates the year 1995).
-The 11th digit is the manufacturing plant for the vehicle; and is the number "2" (plant digits are country specific... we will get back to this later)
-The 12th - 17th digits are the 6 digit long serial number for the vehicle.
-Next we look at the first 8 digits of the VIN.
-The 1st digit is for the country the vehicle was produced in (You have the number "2" which is for Canada. Back to the 11th digit for the plant, which is a "2" and for Saint Therese assembly plaint in Quebec Canada).
-The 2nd digit is for the manufacturing company (the letter "G" is for General Motors).
-The 3rd digit is for the brand of that manufacturing company (the number "2" is for Pontiac).
-The 4th digit is for the vehicle platform/ body line/ series (the letter "F" is for the F-Body car-line)
-The 5th digit is for the model and sub-model (the letter "V" is for a non-base model Fire-Bird; meaning a Formula or Trans-Am and may denote a convertible in some cases).
-The 6th digit is for the actual type of body/ body-style (the number "2" is for a 2 door/ coupe).
-The 7th digit is for seat-belt and air-bag configuration (the number "2" is for driver and front passenger air-bags).
-The 8th digit is for the engine type/ model (the letter "P" is for the LT-1 Gen-II SBC V8)
I am assuming that the VIN entered into the PCM matches your actual vehicle tags/ VIN.
Now the PCM calibration number/ software ID number that you have (16209471) is for a 1995 LT1 with a 1995 4L60E and 2.73:1 gears.
For this reason; I believe that the DTC you have is due to a PCM - Transmission mix-match (sadly on top of this the 1 TCC solenoid could have been damaged as well).
I am not an expert for what I am going to say next...
I believe that you can have your PCM software changed to that of a 1994 F-Body LT1, 4l60E, 2.73:1 gears.
The PCM software ID for this is #16210031.
I do not know if this will change anything with the engine control/ monitoring (we need advice from someone who does know).
So what I would recommend; is that you find a shop that can re-tune your PCM to change it to operate with a 1994 transmission and not change anything regarding the engine.
I personally have never done any custom tuning on these pre-OBD-2 vehicles (Just only OBD-2/ newer vehicles... sorry).
Again, hopefully someone more knowledgeable than me on this can chime in and help us.
-We first look at the last 8 digits of the VIN (digits #10 through #17).
-The 10th digit is the model year identifier for the vehicle; and is the letter "S" (the letter "S" indicates the year 1995).
-The 11th digit is the manufacturing plant for the vehicle; and is the number "2" (plant digits are country specific... we will get back to this later)
-The 12th - 17th digits are the 6 digit long serial number for the vehicle.
-Next we look at the first 8 digits of the VIN.
-The 1st digit is for the country the vehicle was produced in (You have the number "2" which is for Canada. Back to the 11th digit for the plant, which is a "2" and for Saint Therese assembly plaint in Quebec Canada).
-The 2nd digit is for the manufacturing company (the letter "G" is for General Motors).
-The 3rd digit is for the brand of that manufacturing company (the number "2" is for Pontiac).
-The 4th digit is for the vehicle platform/ body line/ series (the letter "F" is for the F-Body car-line)
-The 5th digit is for the model and sub-model (the letter "V" is for a non-base model Fire-Bird; meaning a Formula or Trans-Am and may denote a convertible in some cases).
-The 6th digit is for the actual type of body/ body-style (the number "2" is for a 2 door/ coupe).
-The 7th digit is for seat-belt and air-bag configuration (the number "2" is for driver and front passenger air-bags).
-The 8th digit is for the engine type/ model (the letter "P" is for the LT-1 Gen-II SBC V8)
I am assuming that the VIN entered into the PCM matches your actual vehicle tags/ VIN.
Now the PCM calibration number/ software ID number that you have (16209471) is for a 1995 LT1 with a 1995 4L60E and 2.73:1 gears.
For this reason; I believe that the DTC you have is due to a PCM - Transmission mix-match (sadly on top of this the 1 TCC solenoid could have been damaged as well).
I am not an expert for what I am going to say next...
I believe that you can have your PCM software changed to that of a 1994 F-Body LT1, 4l60E, 2.73:1 gears.
The PCM software ID for this is #16210031.
I do not know if this will change anything with the engine control/ monitoring (we need advice from someone who does know).
So what I would recommend; is that you find a shop that can re-tune your PCM to change it to operate with a 1994 transmission and not change anything regarding the engine.
I personally have never done any custom tuning on these pre-OBD-2 vehicles (Just only OBD-2/ newer vehicles... sorry).
Again, hopefully someone more knowledgeable than me on this can chime in and help us.
The transmission would have to come out and come apart.
The 1995 unit had several parts changes from the addition of the TCC PWM solenoid.
They consist of:
-New input-shaft check-ball capsule.
-New front pump half.
-New rear pump half.
-New valve-body.
-New separator plate.
-New internal wiring harness.
-New torque-converter
All of these 1995 components would have to be retrofitted into a 1994 transmission to operate properly.
As a last ditch effort... you can try a mail order tune for the 1995 PCM/ software that eliminates the DTCs/ PIDs for TCC related issues.
I am sorry... I can not post their business information here as they are not sponsors of the forum and that is a violation of the terms and agreements here.
He is a member here, but he is relatively inactive.
member name: JeremyF
OOOO! nevermind! he is still a sponsor LOL!
Faster Proms: 813-476-7364 or fasterproms.net
Ask for jeremy... he and his father have been tuning since the 1980s (hense the name using the term "prom" from Eprom).







