Eighth and ninth generation Civic. A reliability benchmark; most visits involve the thermostat, minor EVAP leaks, and the catalyst at high mileage.
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.
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.
EVAP System Leak Detected (Large Leak)
The fuel vapor recovery system has a significant leak - most often the fuel cap is loose or missing.
Coolant Temperature Below Thermostat Regulating Temperature
The engine takes too long to warm up - the ECU sees coolant temperature staying below where the thermostat should regulate it.
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