The high-compression engine of Mazda3, Mazda6 and CX-5 (13:1 ratio). Direct injection favors valve deposits, and vacuum leaks trigger lean codes.
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.
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.
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.
Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)
A second camshaft sensor on bank 1 does not match the crankshaft position the ECU expects, pointing to a timing discrepancy on that cam.
MAP/Barometric Pressure Circuit Range/Performance
The manifold absolute pressure sensor reading is outside the range the ECU considers plausible for current conditions.
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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