A couple of months ago I was driving my '02 MCS. I stopped for gas and pumped it with the car running. As I got back in the car I noticed the "service engine soon" light, as well as the DSC light, were lit. Also the car began to run really rough. I shut the car off then started it back up and it ran smoothly again, but the "SES" and "DSC" lights were still on. I then had a diagnostic scan performed and was given 4 fault codes:

1st- P0445 (Evap Emission Control System Purge Valve C Short), I replaced the Purge Solenoid Valve.
2nd- P0340 (Camshaft Position Sensor A Bank 1 Circuit Malfunction), I replaced the Camshaft Position Sensor.
3rd- P0031 (HO2s Bank 1 Sensor 1 Heater Circuit Low), I replaced O2 sensor A/F.
4th- P0037 (HO2s Bank 1 Sensor 2 Heater Circuit Low), not replaced.

My question is, could all of these sensors have gone bad all at once, or would a bad PCM be a more likely culprit?

Any enlightenment on the matter would be appreciated.

 

Are you sure those parts were bad?
A code does not mean a part is bad, just the reading is abnormal...can be caused a a problem upstream mechanically....
Swapping parts can get $$$.
Corrosion on a plug...a loose wire...who knows.on a 10 year old car, anything electronic is suspect...add a computer, heat, salt, cold....just have to troubleshoot.

 

Go drive around with the gas cap open and see what codes get set