Possible causes
– Faulty spark plug 1
– Clogged or faulty fuel injector 1
– Faulty ignition coil 1
– Fuel injector 1 harness is open or shorted
– Fuel injector 1 circuit poor electrical connection
– Ignition coil 1 harness is open or shorted
– Ignition coil 1 circuit poor electrical connection
– Insufficient cylinder 1 compression
– Incorrect fuel pressure
– Intake air leak
– Clogged or faulty fuel injector 1
– Faulty ignition coil 1
– Fuel injector 1 harness is open or shorted
– Fuel injector 1 circuit poor electrical connection
– Ignition coil 1 harness is open or shorted
– Ignition coil 1 circuit poor electrical connection
– Insufficient cylinder 1 compression
– Incorrect fuel pressure
– Intake air leak
Tech description
The P0301 code means that the cylinder 1 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 1. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”
When is the obd code mean?
Engine Cylinder 1 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
P0301 TOYOTA OBD Code Description