10890C

What code 10890C means

Code 10890C points to a fault in the crankcase ventilation heater circuit. The crankcase ventilation system routes blow-by gases into the intake tract, and the heater keeps condensate from freezing and forming emulsion in cold weather. The fault can come from a failed heating element or a wiring problem (open circuit, short, corroded contacts).

Symptoms

• Check Engine light: the check engine lamp comes on in the instrument cluster.
• Possible oil leaks: a malfunctioning crankcase ventilation system can raise crankcase pressure, pushing oil past the seals.
• Rough idle: idle can come with stumbling or a fluctuating rpm.

Diagnosis and repair

1. Inspect the crankcase ventilation heater: check the heating element for mechanical damage, signs of overheating, or corrosion.
2. Check the wiring: make sure the wires are intact, the connectors seat firmly, and there's no corrosion. Test the circuit with a multimeter for an open or a short.
3. If you find a fault, replace the heater or repair the wiring: if the heating element has failed, replace it; if the wires are damaged, repair or replace that section of the circuit.

Tools needed: multimeter, BMW diagnostic equipment (ISTA, INPA) to read codes and check system operation.

Secondary problems

Ignoring a crankcase ventilation heater fault can let condensate freeze in the system in cold weather, which raises crankcase pressure. That can push oil past seals and gaskets and lead to rough running and higher oil consumption. Fix the fault promptly to avoid more serious damage.