I had p21w bulbs in my DRL. Replaced em because they were old. The guy in the store gave me ba15s type leds. He said its the same. Fits ok, but got the check RDL lights on the dash. They were canbus though. Can i leave em, or replace with p21w?

P21W bulbs use a BA15S base which is also known as 1156.

 

The problem is the fact they are LED's - just because they are 'CAN-bus friendly' doesn't mean the car won't notice the wrong bulbs are fitted

 

Either refit halogen bulbs, fit load resistors or use quality 'CAN-bus unfriendly' LED's and have the car re-coded to suit. The last option relies on having a BCM fitted that supports LED lighting.