I recently purchased the Autel MaxiScan MS300 CAN Diagnostic Scan Tool for OBDII Vehicles. It seems to be working fine, as it reads my fault codes and successfully cleared the fault code on another vehicle. However, it will not clear the P0420 code on my 04 VDP. Has anyone else encountered this? I'm wondering if it's something about this particular scanner or something inherent with the car or the code having to do with the catalytic converter? Thanks.

 

I'd be tempted to cause a known code (such as unplugging the MAF). Then fix the fault and clear the codes. See which go/stay.