Hyundai Misfire in Cylinder 1 (P0301) and a glow relay short circuit (P1326) fix

This article has a guide to the Hyundai Misfire in Cylinder 1 (P0301) and a glow relay short circuit (P1326).

If you’re a Hyundai Sonata owner dealing with error codes P1326 (Glow Relay Short Circuit) and P0301 (Cylinder 1 Misfire), you’re not alone. 

In a recent conversation between a car owner and a mechanic in one of the Hyundai forums, we explore the common issues associated with these codes and potential solutions.

 mechanics repairing a car in the workshop
mechanics repairing a car in the workshop- Image by gpointstudio on Freepik

The Problem

The car owner’s Hyundai Sonata, a 2015 model, has been experiencing a misfire in Cylinder 1 (P0301) and a glow relay short circuit (P1326).

Despite replacing spark plugs and the number 1 coil pack, the misfire persisted.

The Mechanic’s Diagnosis

The mechanic indicated that P1326 is a Hyundai-specific code related to the knock sensor, not the glow plug. 

He suggested that the misfire and P1326 code are likely due to mechanical damage to the engine, specifically, rod knock.

Possible engine damage

On these Hyundai models, engine issues leading to rod knocks were relatively common. 

The misfire indicates that there might be damage to the engine’s internal components, and simply replacing ignition parts might not be enough to resolve the underlying problem.

Why RPM Improvement After Replacing Parts

The car owner noted an improvement in RPM performance after replacing the spark plugs and the number 1 coil pack. 

The mechanic explained that the improvement likely resulted from addressing the spark blowout issue. 

However, the root cause, the engine damage, remained unresolved.

Safety Concerns

When asked about the safety of driving with the P1326 code, the Mechanic warned against continued driving. 

Ignoring the engine damage could lead to a complete engine failure, leaving the driver stranded.


  1. Contact the Dealer: As P1326 might be related to a known issue, Gilbert Rey was advised to contact the Hyundai dealer. There could be an extended warranty or recall that covers the engine replacement.
  2. Address Engine Issues: Ignoring the misfire and P1326 could result in more significant problems. Seeking professional assistance to diagnose and potentially replace the engine is crucial.


If you find yourself facing error codes P1326 and P0301 in your Hyundai Sonata, it’s essential to understand that these issues might indicate internal engine damage. 

While replacing spark plugs and coil packs might provide a temporary improvement, seeking professional help and contacting the dealer for potential warranty coverage is crucial. 

Ignoring these issues could lead to more severe engine problems, impacting the safety and reliability of your vehicle.

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