The VSS is located in the transaxle housing at the rear section near the right driveaxle
The ODB code chart yields this; P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
2003 sunfire
The fan switch is a sensor located in right side of the head
http://autorepair.about.com/cs/troubleshooting/l/bl_obd_1.htmshows this code:P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)FriPilot
on the back of the motor wright below the crank sensor
In a 2004 Pontiac Sunfire, there are two oxygen sensors. One would be located in the exhaust before the catalytic converter. The other is located in the exhaust after the catalytic converter.
back side by coil pack
The 2001 Pontiac sun fire speed control sensor is located on the front passenger wheel. The sensor can be found on the inside of the rotor.
The upstream O2 sensor is mounted in the ehxaust manifold The downstream O2 sensor is mounted in the exhaust pipe after the catalytic converter
The vehicle speed sensor is located on the transaxle
on the 2.4 its to the left of the starter above the oil filter
On a 1998 Pontiac Sunfire, the fuel vapor sensor, also known as the fuel tank pressure sensor, is typically located on or near the fuel tank. It is often integrated into the evaporative emission control (EVAP) system, which may be found on the top of the fuel tank or along the EVAP lines. To access it, you may need to lower the fuel tank. Always consult the vehicle's service manual for specific details and diagrams.