Secondary air injection blockage
Major $1,200–$4,0001996–1998 OBD-II cars. The 1995 cars predate the system.
Carbon and oil residue build up in the secondary air passages drilled into the cylinder heads. The system cannot pass its self-test at startup, the check engine light comes on, and the car fails emissions testing. Clearing it properly means getting at ports inside the heads, which is why a conceptually simple job turns expensive.
- Check engine light with secondary air system codes
- Failed emissions test with no driveability complaint
- Light returns within days of being cleared
Cleaning the passages is the correct repair and it is labour-intensive. Beware a seller who has simply cleared the code before your viewing — ask when the light last appeared, and drive the car from cold.