on u-tube a couple guys show a much cheaper 14 dollars fix for this not easy but can be done im tj and have blogged on this before,the car may run ok but gas mileage and will not pass emissions where applicable have had this problem multiple times it is listed under engine and drive train also
2003 Cadillac Seville STS Problem Reports
Newest 2003 Cadillac Seville STS Problem Reports
An ignition coil may fail causing one of the cylinders to misfire. Each of the two banks of cylinders has its own coil assembly. If one ignition coil fails the coil assembly for the corresponding cylinder bank must be replaced.
The torque converter clutch (TTC) may stop working due to an internal transmission failure. The Check Engine Light will illuminate if this occurs. Our technicians tell us the transmission will require dis-assembly to correct this concern.
Water may be drawn into the secondary air injection (AIR) pump causing the pump to fail and the Check Engine Light to illuminate. Our technicians tell us there is a kit available from General Motors to relocate the air intake for the pump which should prevent future damage from water intrusion.
A Loose or worn gas cap may cause Check Engine Light to illuminate.
An intake manifold vacuum leak can develop from a variety of sources, often causing illumination of the Check Engine Light with codes P0171 & P0174 stored. Thorough diagnoses will be necessary to pinpoint the cause in order to make the correct repairs. A "smoke" machine is often used to isolate the cause of difficult to find vacuum leaks.
One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.
The battery may leak acid at the battery cable connections. As a result corrosion may form on the battery cable ends. Leaking batteries should be replaced and the cables need to be thoroughly cleaned or replaced if necessary.
The trunk pull down switch may fail causing the trunk lid not to close completely. Our technicians tell us that the failed switch can be replaced without changing the complete pull down motor assembly.
One or both transmission output shaft seals may leak. Our technicians tell us that worn bushings inside the transmission could be the cause of the damaged seals. Our technicians tell us that if a bushing is worn, excess play will be noted where the drive axle attaches to the transmission.
Overheating of the engine may cause the cylinder head to expand, severely straining the head bolts and damaging the threads in the engine block. This commonly results in a blown head gasket. Our technicians tell us the engine block threads must be repaired before the cylinder head is reinstalled.
The engine may develop an oil leak from the lower crankcase portion of the engine block. Our technicians tell us that the engine must be removed from the vehicle to properly repair this oil leak.
The anti-lock brake system (ABS) control module may fail causing the ABS light to illuminate. Failed modules should be replaced to restore ABS operation.