P039 Code Please help.

[cobrak69]

From time to time my check engine light comes on, when I do the self diagnostic check it shows code P039. According to a code guide this translates to "Torque Coverter Clutch/Viscous Converter Clutch Engagement Problem" I don't under stand that at all because the trans is shifting smoothly and I don't feel any change in the driveablilty when the light comes on. My car is a 1994 Cadillac Seville SLS with the 4.6 North Star. I recently had the motor pulled and had the block Time Serted and new gaskets installed, I don't know that that would affect this or not. The motor and trans were never disconected from each other, or drained. Please advise what to look for or how to fix this. Thanks,

Eric

[PAUL T]

My vote would go toward an electrical instead of a mechanical problem due to the engine just being pulled and replaced. If the wiring harnesses were not put back in the correct places it will cause all kind of intermittent problems. Check the spark plug wires and see if any of them are close or touching any part of a wire harness. Also dirty plug connections can cause this problem. In my manual there is 10 pages pertaining to checking out this code. If you have access to a "real" service manual (not haynes or chiltons) you could probably narrow down the real problem. Maybe someone on the board can scan and email you the charts, I would but I do not have a scanner. Good Luck

[Poobah]

I get the P039 code from time to time.

The way I understand it, there is a clutch that locks up the torque converter during cruising conditions. When it is engaged, the torque converter can't slip and improved milage results. On high milage transmissions, wear on the TCC causes it to slip a little, especially on hard accelerations from cruising speeds. The P039 code just tells you that there has been some slippage.

I'm told that TCC repairs are costly because the transmission has to be taken out of the car and then disassembled. The best course of action is to let it go until you need to rebuild the transmission anyway. The slippage doesn't hurt anything and it won't cause you to have to walk home.

When I get the code, which isn't all that often, I just clear it and go on.

Hope this helps.

[cobrak69]

The sad part of all this is, the car only has 85K miles on it. The headbolds pulled out at 80K. Doesn't put much faith in the Northstar.

[Scotty]

The sad part of all this is, the car only has 85K miles on it. The headbolds pulled out at 80K. Doesn't put much faith in the Northstar.

You have a 94 which means that it came from the factory with green coolant. Green coolant needs to be changed every 2 years or 24,000 miles more or less so that it retains its corrosion protection. Starting in 96 they went to Dexcool which is like 5 years or 100,000 miles. If you are not the first owner of your car the question arises as to whether or not the coolant was changed on time... if not that would have been the cause of your headbolt problem... Do you know the history of you car from day one?

In terms of the 85,000 miles consider this, when we were kids when a car hit 100,000 mile you towed it to the junkyard... Try not to fault your engine unless you know its maintenance history... If you look at a survey we did here about 11% needed their head gaskets replaced, I would tend to think that a survey of that type on this board would draw a high percentage of engine that needed head gaskets.

By the way my engine is at 71,000 miles, so I am in the zone where if it is going to happen its going to happen soon, sort of a ticking timebomb.. I do know the history of my engine, so if it happens to me, we can say it was not maintenance or coolant type based..

(by the way I have been pricing engine hoists and engine stands just in case).

[Regis]

The sad part of all this is, the car only has 85K miles on it. The headbolds pulled out at 80K. Doesn't put much faith in the Northstar.

The low miles at this point probably works against you. Cars like to run.... not sit. A 94 with only 80K did a great deal of sitting. Things start rotting with that sort of stagnation. Which leads up to my question. How did you determine that the headbolts pulled? Did you diagnose it or was it a mechanic. If it was a mechanic what were the details of his/her assessment and did you see it first hand (assuming that you know what you're looking at/for)? Just curious.

[navion]

cobrak69,

If the TCC slips excessively it will cause the trans fluid to overheat. The TCC (torque converter clutch) is located in the torque converter, not in the transmission. So the transmission doesn't need to be disassembled to replace it. You will however have to remove the transmission from the engine.

To check TCC operation find a level straight section of road, with the trans in the D position (overdrive) attain a steady speed, say 60 MPH. Do not use the cruise control. While holding the speed steady with your right foot, use your left foot to LIGHTLY depress the brake while watching the tach. You should get an immediate increase in RPM. Then lift your foot off the brake and the RPM should drop back to what it was before.

If you keep driving the car, I would check the transmission fluid often to see if it is turning dark or getting a burnt smell.

Paul T may be correct in suspecting a wiring problem. You may want to check that the wiring harness plug to the transmission is assembled properly. It could be pushed together far enough to make an intermittent contact. This plug is located at the front of the engine/transmission assembly point. You may have to remove the left cooling fan to reach it.

Good Luck,

Britt

[SteveJ]

Guru said the TCC is filled with silicon fluid that over time will leak out especially if the tranny is overheated. The P039 codes then start to become more regular. Mine started leaking on a long pull up the Berkshire mountains.

The nice thing about it is that there is no panic to repair it. P039 turns off the TCC for that ignition cycle when it turns on the SES light. Then you have a standard four speed transmission just like before they put the TCC in it. You might loose a maximum of 5% mileage. It then becomes a mater of economics. Will the increased mileage make the cost of the repair worth it. In my case I will never repair it. I take comfort in the fact that more oil flows through the conveter with the tcc off so more cooling takes place.

You have a '94 so I suspect like my '95 repair isn't economic unless you have money to burn.

[MAC]

I also have the dreaded P039. It does adversely effect mileage and performance to varying degrees depending on driving habits. My gas mileage is not as good as it should be, but I still was able to get 26.3mpg driving to Washington, D.C. and back to New Jersey, which is about 370 miles.

[cardio-doc]

Read the archives from the old board - PLENTY of discussion on this. There IS a different computer chip you can plug right in that alleviates that code going off alot. I think it cost around $100. Easy install.

~Doc

[BSchlossmann]

I agree with CArdio-Doc. I seem to recall a prior post which corrected a flaw in the setting of the P039 code via a different computer chip. Mine sets every few months. This happens while on cruise under slight accerelation.

[MAC]

It is my understanding that the computer chip only changes the amount of slippage allowed before it sets the P039 code. It does not correct the problems associated with a torque converter or other parts, such as the clutch solenoid which controls the hydraulic fluid for TCC apply or release. If I remember correctly, if the difference between the engine speed and transaxle turbine speed is 46 rpm or higher the P039 code will set. The chip bumps up the tolerance to slippage by a number of rpm thereby preventing to code from setting. However, if slippage exceeds the chip’s specs. then the code will still set.

[Scotty]

I also have the dreaded P039. It does adversely effect mileage and performance to varying degrees depending on driving habits. My gas mileage is not as good as it should be, but I still was able to get 26.3mpg driving to Washington, D.C. and back to New Jersey, which is about 370 miles.

Thats interesting that your P036 negatively impacts your gas mileage..and it doesn't much for SteveJ. Do you have an ETC? The final drive ratios on the ETC and STS is different than on the Deville.. I would imagine that would have something to do with it if you have an ETC..

[Poobah]

Thats interesting that your P039 negatively impacts your gas mileage..and it doesn't much for SteveJ. Do you have an ETC? The final drive ratios on the ETC and STS is different than on the Deville.. I would imagine that would have something to do with it if you have an ETC..

I think the impact on milage depends on how badly, and how constantly, the clutch is slipping. I think mine just slips a little only under the most adverse conditions (I only get the code once in a while). It sounds like Mac's is slipping more or less continuously which would result in the decreased milage.

[Scotty]

Thats interesting that your P039 negatively impacts your gas mileage..and it doesn't much for SteveJ.  Do you have an ETC?  The final drive ratios on the ETC and STS is different than on the Deville..  I would imagine that would have something to do with it if you have an ETC..

I think the impact on milage depends on how badly, and how constantly, the clutch is slipping. I think mine just slips a little only under the most adverse conditions (I only get the code once in a while). It sounds like Mac's is slipping more or less continuously which would result in the decreased milage.

That is interesting. I would imagine that the slipping creates surplus heat sort of accelerating the TCC problem? The TCC is located in the torque convertor isn't it?

I guess the torque convertor is one of those things you would replace if you ever pulled your engine to do the head gasket along with the plastic HVAC housing, the list is growing of things to service when you pull the engine.

What is the biggest thing that creates heat in your tranny? Stop and Go, high or speed driving. When this TCC problem begins does the coolant temp rise when you go up long inclines or hills from the slipping?

[MAC]

Scotty,

I have the SLS (270hp). Mileage should be upward of 27.5-30mpg.

Poobah,

You guessed it, every time I drive the P039 sets. The slipping is obvious, though there are occasions when it’s not as bad. The shift into 4th is not crisp—it’s a lazy slow shift with obvious slipping. It’s similar to a manual with a worn clutch. When it’s real bad it slips when shifting to any gear. The smooth and effortless acceleration is lost, which is one of the things the N* is known for, and consequently gas mileage suffers. Don’t get me wrong, there’s good power, but not the power the N* is capable of putting on the pavement. Though I was able to outrun a 2000+ Grand Prix GT last year. However, if not for the P039 condition that GT would have been rolled, licked, smoked, then tossed. I shifted manually to try to control slipping, but still the shifts were not crisp and at high RPMs it only gets worse.

[navion]

I know that on a 700-R4 an inoperative TCC will generate enough heat to burn the paint off of a converter. Been there done that!

The aftermarket trans cooler people have a way to identify which transmission cooler line is the return from the radiator. (Assuming you can get you hand on it.)

With the engine & trans cold gain access to the cooler lines. Keep clear of fans, belts & other things like Ma Bell that can reach out & GRAB you!

It is best to have some one else start the car & then, with caution in mind, feel both of the cooler lines at the radiator.

You will be astounded at how fast the line to the radiator heats up! There is no doubt that the automatic transmission generates a LOT of heat! Which equals wasted energy.

I wish my SLS had a manual 5 speed. She would probably approach 30 MPG! (That is if I could keep my foot out of the throttle body!)

Britt

[Cad1]

I have had that code for maybe 40k miles that I know of. After the tranny rebuild for a thrown needle bearing in the diff. it threw the code (maybe before as well but I don't know for sure). I don't worry about it and if I tow a bunch of stuff and have the car max'd out I put her in three. When the fluid gets dark, suck it out with an electric pump and replace (20 min job).

[bigjayzway]

It's a 94 sls....P039 is a 02 sensor!

Big Jay

[bigjayzway]

Never mind....it's a 4.6, Sorry!