Need 4L60E help- stuck in 1st, pressure solenoid buzzing!?

beertestr

beertestr

Club Member
Ok. Trying to get my 4L60E running in my 79 Caprice. It's a carb'd setup, running a Powertrain Control Solutions (PCS) TCM-2000 Controller.

All the analog inputs seem to be working find, but I am not getting feedback from the TFT/TFP (trans fluid temp/trans fluid pressure aka Manual valve position) sensor, and I can't see gear position through that sensor. The sensor is supposed to be able to tell what manual (PRNDL) position the shifter is in, but all I get is D1 regardless of actual shifter position. I can run the trans in first and reverse, any forward shifter positions give me the same stuck in 1st problem. If I pull the power from the TCM it defaults to D3, just as the trans should, and I can get manual second in D2. While I was thinking that maybe the TFP switch is not connected, I get fluid temp, and all 3 pressure sensors and temp sensor are on the same connector.

I checked all the wires between the TCM connector and the trans connector, and all 3 test out fine.

Here's the other odd thing, I was getting a buzzing from the trans with the engine off, TCM powered on. I drained and pulled the pan, it's the pressure control solenoid buzzing audibly. Again, all the wiring checks out correct, no shorts or damaged wiring on the trans harness. I can't see anything obvious on the internal harness, the harness looks new.

I'm about to start throwing parts at the problem. Harness, TFP/TFT sensor and pressure control solenoid.

Anybody have any ideas?
 
I should add that I pulled the schematic for the TFP sensor, and ground the individual wires to see if the TCM-2000 monitor (laptop interface) would detect it, and it did, I was able to toggle digital inputs off and on by grounding the individual leads (which is all it does).
 
That brand of stand alone controller is a pita. Once you do get the controller up and running and you go through the process of adjusting all of the tables, they still work like shit. Ive yet to see one that works perfectly (or even good) in a vehicle.
The compushift controller are more money, but they are plug and play. Adjustments can be made on the fly (literally, while your driving the car) in seconds. Installation and set up are simple. Your end result is a trans that works/shifts exactly like factory programing, and performance adjustments can be made in seconds. It the only one I recommend (and sell.) https://www.hgmelectronics.com/display/hgm/COMPUSHIFT+II?gclid=CKem3omd57ACFQYKKgodSxrY2Q
If your doing a complete LS swap, Howell offers some packages that work well, but they still will need some advanced tuning (HP Tuners type).
Back to your problem. Does your unit have a MLPS sensor mounted on the outside of the trans? Dual plug or Single Plug?
If your controller is not seeing gear changes out of manual low it not going to shift. Start with the MLPS sensor. I would not be to concerned with a buzzing epc solenoid at the moment.
Also....what year is the trans? Are all of the sensors in the trans original for the same year?
 
Detroit Gearbox said:
That brand of stand alone controller is a pita. Once you do get the controller up and running and you go through the process of adjusting all of the tables, they still work like shit. Ive yet to see one that works perfectly (or even good) in a vehicle.
The compushift controller are more money, but they are plug and play. Adjustments can be made on the fly (literally, while your driving the car) in seconds. Installation and set up are simple. Your end result is a trans that works/shifts exactly like factory programing, and performance adjustments can be made in seconds. It the only one I recommend (and sell.) https://www.hgmelectronics.com/display/hgm/COMPUSHIFT+II?gclid=CKem3omd57ACFQYKKgodSxrY2Q
If your doing a complete LS swap, Howell offers some packages that work well, but they still will need some advanced tuning (HP Tuners type).
Back to your problem. Does your unit have a MLPS sensor mounted on the outside of the trans? Dual plug or Single Plug?
If your controller is not seeing gear changes out of manual low it not going to shift. Start with the MLPS sensor. I would not be to concerned with a buzzing epc solenoid at the moment.
Also....what year is the trans? Are all of the sensors in the trans original for the same year?
Click to expand...


It's a 1994 4L60E. 1 piece case, with the non-PWM pump. I think it was only made this way for 2 years, 1993 in the trucks, then the LT1 cars got it in 1994 only. No MLPS. The TCM is supposed to determine PRNDL state based on the TFP switch internally.

All the solenoids look correct for the vintage, it has the PCS with the 2 metal tangs, not the molded connector. The TFT/TFP sensor is common for many years, if not all 4L60E's. While I had the pan off (and dumped out $20 worth of fresh fluid), I replaced the PCS anyway since I had one on the shelf, and swapped in a TFT/TPF sensor in from one of my other trannies (03 LS trans core I have). Aside from the lack of buzzing (which I am not less concerned with), the behavior is the same.

TCM off it's defaulted in 3rd, with Manual 2nd working. I think that rules out a hardware issue, the 2-4 band and servo work. Turn on the TCM, and it's stuck in first.

I am going to try and read the digital inputs on the monitor to see if it's seeing the change in TFP state. I downloaded the logic for each gear position, so I'll see if it follows. The monitor certainly does not show it on the graphic.

I did manually ground the A B and C sensor a the trans connector side of the harness, and the digital inputs did cycle from low-hi, so the TCM recognizes the digital signal.

I now remember you recommending the Compushift. WHen I started to look for a controller again last winter, I came across the TCM-2000 and thought that was the one was exchanged PM's about. A coworker who does a ton of moonlighting with cal work recommended it as well, and has some really fast cars running 60E's and 80E's on them, even with late model CAN communication.
 
So it only sees pressure at the manifold pressure switch.
Look at output rpm, tps voltage, map sensor voltage. Your on the right track to look at inputs to the controller rather than a output problem.
I could understand why a cal programer might like something thats complex to program.
I think they repackage that controller and sell it to tci, gm. They look identical.
 
I verified last night that I can see the digital inputs 1-3 change state with PRDNL position changes. The logic looked flipped to me, so I reversed it.

Still nothing. So the PCS is working, all solenoids have power, TFP sensor is working. I now have the shifter logic correct I think.

Monitor was reading LOW HI LOW in Park, should be HI LOW HI. SO I flipped it. No change, still stuck in first. Either way, it still don't frickin work.
TPS is working properly, MAP is disabled, RPM signal is correct, VSS is reading right on the monitor as well. I have not dialed VSS in perfectly but it's within 5%.

I even pulled the 1-2 shift line to 1 mph to run in 2nd gear.. nothing.

The monitor screen still shows PRNDL in 1st gear even though the TCM is seeing the TFP signal and the logic is NOT 1st gear.
 
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