27C1

What the Code Means

27C1 flags a fault in the primary camshaft position sensor — typically the intake camshaft sensor on bank 1. The sensor tracks camshaft position and sends a signal to the DME, which uses it to synchronize the VANOS system and manage ignition timing. If the signal is missing, distorted, or delayed, the control unit loses its camshaft timing reference and drops the engine into limp mode.

The cause can be contamination of the sensing element, mechanical damage to the sensor, or an open circuit in the wiring.

Symptoms

• Hard starting, especially noticeable on a cold start.
• Loss of power under load.
• Rough idle.
• Check Engine light on.

Diagnosis and Repair

Step 1. Inspect the Sensor and Connector

Check the camshaft position sensor and its connector for contamination, oil residue, damaged wiring, and corroded contacts — a common cause of this fault.

Step 2. Measure Resistance

Measure the sensor winding resistance with a multimeter and compare it to the nominal value. A deviation points to degradation of the element.

Step 3. Check the Circuit to the DME

Continuity-test the wiring from the sensor connector to the DME for opens and shorts — the fault may lie in the circuit rather than the sensor itself.

Step 4. Replace the Sensor

If the sensor is faulty, replace it with an original part: 11361433770.

Secondary Damage

• Incorrect camshaft timing causes misfires.
• Misfires send unburned fuel into the exhaust and damage the catalytic converter.

Don't put off the repair: fixing the catalytic converter after driving with the fault for a long time costs far more than replacing the sensor.