Engine-Codes - Scion - P0301 Scion

P0301 Scion Code - Cylinder 1 Misfire Detected

- Code Popularity: 23,878 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
ChatAC AutoCodes.com AI Chat

What are the Possible Causes of the DTC P0301 Scion?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Intake air leak
  • Faulty spark plug #1
  • Faulty ignition coil #1
  • Clogged or faulty fuel injector #1
  • Fuel injectors #1 harness is open or shorted
  • Fuel Injectors #1 circuit poor electrical connection
  • Ignition coils #1 harness is open or shorted
  • Ignition coils #1 circuit poor electrical connection
  • Incorrect Fuel pressure
  • Faulty Mass Air Flow (MAF) Sensor
  • Faulty Engine Control Module (ECM)
  • Faulty Engine Coolant Temperature (ECT) Sensor

Code Tech Notes

The P0301 code means that cylinder #1 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder #1. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.

⚠ Does your Scion have Safety Recalls? → Check here

How to Fix the DTC P0301 Scion?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Search for P0301 Scion Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0301 Scion code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Lack/loss of power
  • Hard start
  • Engine hesitation

What Does the P0301 Scion Code Mean?

When the engine misfires, high concentrations of Hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the Engine Control Module (ECM) monitors the misfire count. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels and could cause emission control system performance deterioration, the ECM illuminates the MIL and stores a Diagnostic Trouble Code (DTC).

P0301 Scion Code - Cylinder 1 Misfire Detected

Need more Information on the Code?

Need more information on how to fix the P0301 Scion code? Get Access to Factory Service Manuals

Information for Specific Scion Models

Need Help with the Code?

Get the P0301 Scion code diagnosed by a professional: Find a repair shop in your area