CX-5 and Mazda6 diesel with a two-stage turbocharger. A solid engine, but city driving means the DPF and EGR need regular regeneration.
Click a code for the full breakdown: symptoms, causes, and whether you can keep driving.
Turbocharger Underboost
The turbo is producing less boost pressure than the ECU requests.
EGR Flow Insufficient
The exhaust gas recirculation valve is not flowing enough exhaust back into the intake, usually due to carbon buildup.
Fuel Rail/System Pressure Too Low
Measured fuel pressure is below what the ECU commands - the engine may be starved of fuel under load.
Diesel Particulate Filter Efficiency Below Threshold
The DPF is not trapping soot as it should - it may be damaged, removed, or overloaded.
Turbocharger Overboost Condition
Boost pressure exceeded the safe limit - the wastegate or boost control is not relieving pressure.
Lost Communication With ECM/PCM
Other modules on the CAN network cannot communicate with the engine control module.
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