Cadillac Transmission Codes P0741 TCC Off And P1258

Question
I just got back from the GM Dealer as I had my car in because the check engine light was on for 5 days. He came up with codes stored P0741, AND P1611. Also P1599. P1611 is related to SES light Code P0741 is Transmission code and there was no time to take it to transmission Department for Diagnosis for code P0741. When I picked the car up and paid for diagnose the Light was still on. 1998 Cadillac STS North Star V8 Check Engine Light on codes = P0741 TCC stuck off.

Drove back in to be told that it is possible I might need a new transmission !!! Want me to bring the car back. The car runs beautifully and it shifts as smooth as a babies bum . Can you help with this information. Do not worry about the code P1599 as supposedly air cleaner baffle leak

Answer:
Thank you for your tip/donation. Code p0741 is Torque Converter Clutch (TCC) excessive slip. There is actually a service bulletin for this code that usually fixes it. The trans would have to come out and disassembled to look for worn seals from slippage of the drive sprocket bearing inner race on the drive sprocket. With nearly 100k miles on it, then an overhaul would most likely be needed, since the trans. Would be out and apart.

For you reference, the bulletin # is 04-07-30-034.P1611 is a problem in the Continuous Variable Real Time Damping (CVRTD) serial data from the Continuously Variable Road Sensing Suspension (CVRSS) system to the PCM. This code usually points to another problem. Being that it is a communication code with no other related codes, it most likely not something to worry about. There are sometimes communication codes stored in these cars computers when there is no problem. So i would not to be concerned with it.

Question:
My 2000 Cadillac Deville Northstar V8 has 125 thousand miles on it its been babied its whole 11yr life and stored in a garage also anyway it started overheating so i repaired the thermostat that didn't fix it so I figured the next logical step would be replace the water pump so i did that and its STILL overheating every time i drive i have to put between a gallon and a gallon and a half of coolant in it I've been told i mite have a pinhole in the head gasket I'm not convinced though i love my car so PLEASE help direct me on what to do next.

Answer:
If you are losing that much coolant, and don't see it on the ground, you could definitely have a bad head gasket. Even worse, you could have a cracked cylinder head or block. This type of condition would really need to be checked out. The cooling system can be pressure tested to see if any leaks are found that way. There is also a cylinder leak down test that can be done.

Either of these would need special tools and a qualified technician. Even though you say your car has been well taken of, the Northstar engines are notoriously bad for oil leaks and cylinder head problems. If you end up needing head gaskets or more, be prepared for it to be very expensive!

Question:
Does any one know what I have to do for the following codes on a 1998 Cadillac Deville 1)P1258 - Engine Coolant Over temperature - above 268°F - Protection Mode Active 2) P0741 - TCC System Stuck Off.

Answer:
For the TCC stuck off- see above. P1258 is set because the engine is overheating, or the Powertrain control Module (PCM) thinks the engine is overheating. You need to diagnose a basic engine overheating condition.
1. Low coolant caused by a leak.
2. Head gasket problem.
3. Radiator fans don't go on etc.

Question:
When my Cadillac reaches 50 miles an hour, the car will not shift. Tried coding it to get code but it wouldn't.

Answer:
If your car will not go into 4th gear, then you have an internal transmission problem. Without being able to get the codes, i could not guess what the problem is. Could be the input speed sensor, shift solenoid, etc. Try going to your local parts store to see if they can scan it. most will do it for free.