DTC 2141

^ Knock sensor (ignition timing at maximum retard limit - knock still present).

This code may be caused by:

a. Faulty or loose sensor.
b. Sensor wire shielding damaged.
c. Dirt on mating surfaces between sensor and engine block.
d. Poor quality fuel.
e. Continued operation with overheated engine, insufficient engine cooling.
f. Ignition base timing (distributor position) incorrectly set. Since the hall sensor is the only reference for crankshaft position, an incorrectly set distributor will not correctly define the crank position relative to TDC of the next firing stroke. This will shift the entire ignition map toward either advance or retard, depending on which direction the distributor is out of adjustment. In other words, if the distributor base setting is off by 10~ in the advance direction, then all points on the ignition map are actually 10~ farther advanced than the control units "think" they are.

See also Audi TSB #289003