What causes P0300 on a Hyundai Tucson?

Common causes of P0300 on Hyundai Tucson: Ignition coil failure on 2.5L Smartstream or 1.6L turbo in Tucson/Sportage/Santa Fe/Sorento; Spark plug fouling from oil consumption on 2.4L Theta II GDI engine (Santa Fe 2013-2019); Carbon buildup on intake valves from direct injection on 2.0T and 2.4L GDI engines; Fuel injector deposit buildup causing poor atomization on Smartstream 2.5L GDI; CVVT actuator wear causing variable cam timing errors at idle and low RPM.

P0300

P0300 Hyundai Tucson

Q: How much does it cost to fix P0300 on a Hyundai Tucson?

Fixes for P0300 on Hyundai Tucson include: Replace all ignition coils and spark plugs with OE Denso or NGK specifications, Verify engine recall status; if Theta II knock is present, seek warranty engine replacement, Perform intake valve cleaning service and consider oil catch can installation on GDI models, Clean fuel injectors with professional ultrasonic cleaning or replace as a set, Replace CVVT oil control valve and flush engine with fresh oil to remove sludge.

Random/Multiple Cylinder Misfire Detected · Powertrain Code · High · Repair: Moderate

What is P0300?

The ECM has detected misfires occurring in multiple or random cylinders. Common causes include worn spark plugs, faulty ignition coils, vacuum leaks, low fuel pressure, or a failing catalytic converter.

When the Hyundai Tucson triggers code P0300 (random/multiple cylinder misfire detected), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Hyundai Tucson.

This repair is rated moderate, meaning some experience and specialty tools required.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Hyundai Tucson.

Common Causes on Hyundai Tucson

Ignition coil failure on 2.5L Smartstream or 1.6L turbo in Tucson/Sportage/Santa Fe/Sorento
Spark plug fouling from oil consumption on 2.4L Theta II GDI engine (Santa Fe 2013-2019)
Carbon buildup on intake valves from direct injection on 2.0T and 2.4L GDI engines
Fuel injector deposit buildup causing poor atomization on Smartstream 2.5L GDI
CVVT actuator wear causing variable cam timing errors at idle and low RPM

Symptoms

Rough idle with noticeable engine vibration
Engine shaking or stumbling under load
Loss of power during acceleration
Check engine light flashing intermittently
Poor fuel economy
Hesitation or stumble on acceleration

Recommended Fixes

Replace all ignition coils and spark plugs with OE Denso or NGK specifications

Verify engine recall status; if Theta II knock is present, seek warranty engine replacement

Perform intake valve cleaning service and consider oil catch can installation on GDI models

Clean fuel injectors with professional ultrasonic cleaning or replace as a set

Replace CVVT oil control valve and flush engine with fresh oil to remove sludge

Notes for Hyundai Tucson

Hyundai/Kia extended warranty on Theta II engines to 150k miles for bearing and seizure issues.

P0300 Hyundai Tucson

What is P0300?

Common Causes on Hyundai Tucson

Symptoms

Notes for Hyundai Tucson

Check Hyundai Tucson Specs