Help with car overheating

Jeffrey Turcotte

• 8991 Answers
• Posted on Jan 03, 2011

SOURCE: 2000 caddy deville 4t80e transmission

Hi, the likely problem is that your torque converter clutch (TCC) solenoid has failed and will no longer engage the clutch. However, it may be worth a try to have your transmission fluid flushed and the filter replaced, if you haven't done that recently. There is some small chance that will fix the problem. The TCC is a device in the transmission that locks the engine to the transmission once you reach highway speeds of at least 25 mph or higher. The purpose of the clutch is to conserve fuel and reduce heat in the torque converter. The car will run fine without the TCC, but will get slightly less highway mileage. There is no harm or safety concern with driving the car as it stands now. However, if you intend to keep this car and drive a lot of highways miles, it may be worth the expense to have it repaired. (you could check your mileage to see how it's doing without the clutch) The repair should be done by a transmission expert, as there are several possible reasons it has failed--I'm only guessing it's the solenoid but would HAVE to troubleshoot to be sure. The repair can be done by any reputable transmission shop--it does not have to be done at the Cadillac/GM dealer. That said, I do recommend you shop around a bit if you want to have the car repaired, as there is considerable variation in the approach to this repair. It is possible to replace the solenoid without removing the transmission, but some shops may claim you need a complete rebuild. Make sure to tell them your trouble codes--that was very helpful to me. Please let me know if you have any questions, and thanks for using FixYa.

Trouble Code: P0741 TCC System Stuck Off - Mechanical (4L80-E)
Possible Causes:

ATF level is too low, or the fluid is burnt or contaminated Inspect transmission lines to radiator for bends or restrictions Oil pressure screen is clogged or debris in the oil pan TCC control valve is stuck "off" due to sediment or binding TCC regulator valve is stuck "off" due to sediment or binding TCC feed valve is stuck "off" due to sediment or binding TCC solenoid valve O-ring or turbine shaft seals leaking or cut

Trouble Code: P1860 TCC PWM Solenoid Circuit Malfunction (4T80-E)
Possible Causes:
TCC solenoid control circuit is open or shorted to ground TCC solenoid control circuit is shorted to system power (B+) TCC solenoid power circuit is open (check the TRANS fuse) TCC solenoid is damaged or has failed PCM has failed

SOURCE: My 2002 Audi A6 with

1. Check and replace if necessary the Camshaft Position Actuator B Bank 2. Bank 2 is the left side cylinder block bank, (driver's side for LHD vehicles). Also see if the variable camshaft mechanism movement is all right, and nothing can block it. The codes 16408 and 16684 must be eliminated definitely!
2. Then test the engine. If the code 16689 = Cylinder 5 - misfire detected, still occurs, check the spark plug, ignition coil and injector. Replace bad piece(s). The code 16689 must be eliminated definitely!
3. The codes 16805 = Warm Up Catalyst Bank-1, Efficiency Below Threshold, and 16815 = Warm Up Catalyst Bank-2, Efficiency Below Threshold, are caused by the misfires sending unburned fuel into the exhaust, and will be erased from Engine Control Module memory.

Test the car and send me back if everything is OK, or if any DTC code still remains.
Good Luck!