US-market Sonata, Optima and Sportage. Infamous for rod bearing failures (mass recalls in the US) - metallic knocking is a fire alarm here.
Click a code for the full breakdown: symptoms, causes, and whether you can keep driving.
Random/Multiple Cylinder Misfire Detected
The engine control unit detects misfires occurring randomly across multiple cylinders, meaning combustion is failing intermittently in more than one cylinder.
Cylinder 1 Misfire Detected
Combustion is repeatedly failing in cylinder 1. The ECU counts crankshaft speed fluctuations and attributes them to that specific cylinder.
Crankshaft Position Sensor Circuit Malfunction
The ECU has lost or distrusts the crankshaft position signal - without it the engine cannot time ignition or injection.
Knock Sensor Circuit Malfunction
The knock sensor signal is invalid - the ECU can no longer detect detonation and retards timing defensively.
Catalyst System Efficiency Below Threshold (Bank 1)
The downstream oxygen sensor shows the catalytic converter on bank 1 is no longer cleaning exhaust gases efficiently.
System Too Lean (Bank 1)
The engine is getting too much air or too little fuel on bank 1 - the ECU has hit the limit of its ability to compensate.
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