Possible causes
– Faulty spark plug 12
– Clogged or faulty fuel injector 12
– Faulty ignition coil 12
– Fuel injector 12 harness is open or shorted
– Fuel injector 12 circuit poor electrical connection
– Ignition coil 12 harness is open or shorted
– Ignition coil 12 circuit poor electrical connection
– Insufficient cylinder 12 compression
– Incorrect fuel pressure
– Intake air leak
– Clogged or faulty fuel injector 12
– Faulty ignition coil 12
– Fuel injector 12 harness is open or shorted
– Fuel injector 12 circuit poor electrical connection
– Ignition coil 12 harness is open or shorted
– Ignition coil 12 circuit poor electrical connection
– Insufficient cylinder 12 compression
– Incorrect fuel pressure
– Intake air leak
Tech description
The P0312 code means that the cylinder 12 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 12. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”
When is the obd code mean?
Engine Cylinder 12 is Misfiring.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Lack/loss of power
– Hard start
– Engine hesitation
– Lack/loss of power
– Hard start
– Engine hesitation
P0312 VOLKSWAGEN OBD Code Description
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.