Possible causes

– Faulty Ignition/Distributor engine speed sensor
– Ignition/Distributor engine speed sensor harness is open or shorted
– Ignition/Distributor engine speed sensor circuit poor electrical connection
– Faulty Crankshaft Position sensor
– Low battery charge
– Faulty Engine Control Module (ECM)

When is the code detected?

The P0321 code is triggered when the Engine Control Module (ECM) detects the signal is out of range.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Lack/Loss of Power
– The engine may be harder to start
– The engine may stumble or stall

P0321 AUDI Description

Ignition failure sensor is used to check whether the spark ignition is occurred correctly or not and also used to tachometer drive. The sensor monitors the voltage difference between a resistance which is on the battery circuit for ignition coil. When the ignition coil works properly, the electric current through the resistance is detected as voltage drop. This is confirmed for every ignition event with the crankshaft sensor and the camshaft sensor. If ECM detects a malfunction, no ignition is possible, so the engine would not start. If there is no ignition signal for a predetermined cycle for one or two ignition coils, an ignition coil circuit failure exists.

AUDI Technical Service Bulletins for P0321 code