sbkim

Greetings,

Could someone tell me where I would find the TCC Solenoid on a 2000 C5? I take it somewhere inside the tranny pan??? What does it look like and is there anyway of testing to ensure that it's working properly (other than autotap).

Thanks

mapman

YYou are correct that the Torque Converter Clutch (TCC) solenoid is internal to the transmission. If you are going to disassemble the transmission you should have a service manual to assist you. A scan tool would be the best way to assess operation of the TCC.

What is the problem that suggests a TCC problem?

The procedure to remove the TCC solenoid includes:

- Raise and support the vehicle.
- Remove transmission oil pan and filter.
- Disconnect the transmission harness 20-way connector.
- Remove the 1-2 accumulator assembly.
- Disconnect the internal wiring harness from:
Transmission fluid pressure switch, 1-2 shift control solenoid, 2-3 shift control solenoid, pressure control solenoid, TCC PWM solenoid (PWM is Pulse Width Modulation), 3-2 solenoid.
- Remove TCC PWM solenoid retainer.
- Remove TCC PWM solenoid in order to gain access to TCC solenoid retaining bolts.
- Remove pressure control solenoid retainer.
- Remove pressure control solenoid
- Remove TCC solenoid retaining bolts and the valve body bolts which retain the internal wiring.
- Release the pass through connector from the transmission case.
- Remove the TCC solenoid
- Inspect the TCC solenoid and wiring.

Access to a service manual is a good idea here.

WALLstAL

After taking the time to look in my manual I must reply. Yes it is located inside the transmission and you will need a scan tool for any test. Plus the rest of what he said! :yesnod: :yesnod:

sbkim

mapman,

Thanks for the info. I think I will reserve this for someone little more qualified :D

I am not sure it's TCC but my car is locking up TCC at very low speeds per Autotap.

ToplessTexan

This is one of those things where you really want to know you're programming is right. ;) There are some diagnostics related to the TCC solenoid and their absence suggest it's just a programming issue. However, it turns out that one of the diagnostics (P0742, the one related to the TCC remaining engaged following commanded release) relies on TCC slip speed being below specified limits to indicate failure (that the converter hasn't released) but that's exactly one of the values that is screwed up (dramatically inflated) by incorrectly scaled gear changes. This makes it unlikely that you ever throw this code... Ah well.

It would probably be easiest to rule out your programming being the cause rather than monkeying with the solenoid assuming you can get a copy of your flash file. I forget if you're back with your PLII or LS1-Edit tune though... If you believe you're seeing late release commanding (i.e. at excessively low speeds) it's almost certainly programming. I still owe you follow up on the second round of data you sent.

mapman

You might also want to check the throttle position sensor (foot feed). The minimum RPM for TCC engagement should be 1588 rpm with 2.73 axle, and 1714 rpm with 3.15 axle - This is at 12% of throttle. (Wide open throttle would be 100%.)

TCC application and release depends on the Throttle Sensor, if the sensor is out of specification, TCC may be applied during initial loading. The Powertrain Control Module (PCM) controls the solenoid by providing a ground path on the TCC solenoid valve control circuit. The PCM monitors the throttle position voltage, vehicle speed, and engine temperature in order to determine when to energize the TCC solenoid valve. (TCC should not engage until the engine is in closed loop operation)

Typical TCC apply speeds are 30-32 mph in THIRD gear, and 40-45 mph in FOURTH gear.

7-117,7-240

sbkim

ToplessTexan

Please call me HopelessKansan... :nonod: Local speed shop - who just got a copy of EFILive ran few runs (too bad I had to tell him some of the parameters to be looking for...) noticed that I was getting TCC mode of 3 for a sec when my car was acting weird (severe bucking) during part throttle - as he describes it almost as thought tcc locks and unlocks. He doesn't think it's stall but rather solenoid or programming (as most of you surmised).

I guess the fact that we are seeing the computer telling it to go to 3 would indicate that it's programming issue. But then I read mode 3 does not necessary mean lock up, right?

btw, I currently have PL but am planning to reflash to stock to start LS1 edit process.

ToplessTexan

HopefulKansan :) it sounds good that the local speed shop listened to you. Mode 3 just indicates that all the apply conditions are met (i.e. it's "okay" as defined by the calibration for the PCM to command application.) If you're seeing this when you *really* don't believe all the conditions are met, e.g. vehicle speed way too low, you're onto the source of the issue. It might include sensors providing faulty information that the PCM is acting on or, more likely, PCM programming issues. I am starting a packing marathon tonight and will try to sneak a look at your data when I take a break. Lord knows I'll need one.

If you get a chance, you might try to download (w/ LS1-Edit) a copy of your current tune before reflashing to stock. Your tuner should be willing to do this for you.



[Modified by ToplessTexan, 6:06 PM 8/14/2003]

sbkim

Topless,

I seriously doubt Steve Cole would be nice enough to provide that info :) He's got my PCM locked solid to prevent people from stealing his code...

I have an aptmt w/ LS1 edit expert this weekend-let's hope for the best.

AlmostHopefulKansan