Your Volvo is going to need to be diagnosed by a smog check repair station. The three trouble codes could be connected to one another. P0301 and P0351 are both related to the ignition system. According to P0351 there is a problem with your Volvo's Ignition coil, which would trigger a misfire; causing a trouble code P0301. P1238 could be an air metering problem, such as defective oxygen sensor. A fuel feedback test will show the performance of the O2 sensor, and whether the fuel control system is responsive.
posted by SmogTips Support
