P1085 — Fuel Control Mixture Lean (Bank 2, Sensor 1)

What P1085 means

This is a manufacturer-specific code — its meaning depends on the vehicle’s make (see below).

What P1085 means on specific makes

BMW / Mini CAUTION

Same lean condition as P1083 but on Bank 2. P1083 and P1085 nearly always appear together on BMW inline-6s, which points to a shared cause (CCV or vacuum leak) rather than one bank.

1. Crankcase vent valve / oil separator + hoses ($60-200)
2. Intake boot / throttle body boot leak ($30-150)
3. DISA valve seal ($30-150)
4. Aged MAF ($150-300)

Check first: Both banks lean = central cause: smoke-test CCV system and intake boots. Replace the CCV as a known weak point on M54/N52.

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