Faulty spark plug or wire; Faulty coil (pack); Faulty oxygen sensor(s); Faulty fuel injector; Burned exhaust valve; Faulty catalytic converter(s); Running out of fuel

Read the code and freeze-frame data with an OBD-II scanner; Check the connector and wiring of the part named in the code; Test the part with scanner live data or a multimeter, using the values in the repair manual; Fix the cause, clear the code and test-drive

P0301 on Toyota Corolla E170: Cylinder 1 Misfire Detected

Short answer: P0301 means “Cylinder 1 Misfire Detected”. The car’s computer has found a fault in the Engine system and turns on the Check engine light (MIL). First check: read the code and freeze-frame data with an OBD-II scanner.

Standard OBD-II code Same meaning on all cars (SAE J2012). Not checked against this car’s factory manual.

Code: P0301
System: Engine
Dashboard light: Check engine light (MIL)
Applies to: Generic OBD-II meaning. Not every code is used by this car.
Confidence: medium (generic OBD-II definition, not checked against the factory manual for this car)
Source: obd-codes.com

Symptoms and when it is set

Check engine light on
The engine may be harder to start
The engine may stumble / stumble, and/or hesitate

Likely causes

Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel

What to check, in order

Read the code and freeze-frame data with an OBD-II scanner
Check the connector and wiring of the part named in the code
Test the part with scanner live data or a multimeter, using the values in the repair manual
Fix the cause, clear the code and test-drive

Related on this car

Same code on other cars

← P0300 P0302 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.