P0012
"A" Camshaft Position - Timing Over-Retarded (Bank 1)
The bank 1 intake camshaft remains retarded compared to commanded position. Common causes include a stuck-closed oil control valve, blocked oil passages, or a worn cam phaser.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Power loss especially in mid-rpm range
- Possible rough idle or stalling
- Increased fuel consumption
Common causes
Ordered by how often each turns out to be the cause.
- Oil control valve stuck (retard position)Common
- Cam phaser internally wornPossible
Parts involved
- Camshaft Position Actuator
- Oil Control Valve
- Cam Phaser
P0012 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.