This step shows how to test the low pressure sensor more extensively. You should check this sensor if you get a C6L error.

Disconnect the low pressure sensor by squeezing its circuit board connector to disengage the lock, then pull straight up.

Attach a multimeter lead to both exposed ends of the sensor wires, making sure the leads don't touch each other.

Set the meter to resistance/continuity and test for continuity, when the sensor is resting, and when it's depressed.

The meter should show low resistance/continuous when the sensor is resting, and no continuity when the sensor's depressed.