P3485: Cylinder 11 Exhaust Valve Control Circuit/Open

What does P3485 mean?

P3485 is triggered by an open circuit on a separate exhaust valve actuator at cylinder 11. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. Bentley's engineers say their W12 shut-off leaves both valve sets working, and they rotate the dormant bank to keep it hot; Lamborghini's Aventador V12 and Audi's group V10 likewise talk only about banks. No published system on an engine of this size switches the exhaust valve of an individual cylinder. A GM patent explains why exhaust timing is a topic of its own: its hydraulic control valves deactivate the exhaust valves first and bring them back first. Electrically, treat P3485 like any open actuator line. P3487 and P3488 report shorts, P3486 a functional fault.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine lamp on
• Engine no longer drops to half its cylinders

Common causes

• Medium Open wire to the cylinder 11 exhaust actuator
• Medium Coil of the cylinder 11 exhaust actuator open
• Medium Connector at the exhaust actuator corroded
• Low Engine control module output defective

Likelihood is a general estimate across vehicles; your make and model may differ.