Mazda OBD Codes
decoded & explained
The codes Mazda owners actually see — coolant temp, ignition coils, lean idle and catalysts — with clear causes and fixes.
Mazda check engine light codes
Mazda uses standard OBD-II engine codes, readable with any scanner. Its SKYACTIV engines are efficient but sensitive to oil, EGR and injector condition.
Here are the codes most reported on Mazda3, Mazda6, CX-5 and CX-30 models.
OBD-II code decoder
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Most common Mazda
Classic Mazda faults behind these codes.
| Code | Description |
|---|---|
| P0011 | "A" Camshaft Position Timing Over-Advanced (Bank 1) |
| P0126 | Insufficient Coolant Temperature for Stable Operation |
| P0171 | System Too Lean (Bank 1) |
| P0300 | Random/Multiple Cylinder Misfire |
| P0350 | Ignition Coil Primary/Secondary Circuit Malfunction |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1) |
| P0442 | EVAP System Small Leak Detected |
| P2187 | System Too Lean at Idle (Bank 1) |
Common Mazda faults
Classic Mazda faults behind these codes.
Coolant temp (P0126) — thermostat stuck open, very common on Mazda engines.
Ignition coil (P0350) — coil faults and misfires on SKYACTIV petrol engines.
Lean at idle (P2187) — vacuum leaks, especially around the intake and PCV.
Catalyst efficiency (P0420) — aging converter at higher mileage.
EVAP leaks (P0442) — fuel cap or purge valve.
Mazda FAQ
Why does my Mazda show P0126?
What causes P0350 on Mazda?
Is P2187 expensive to fix?
Are Mazda codes the same across models?
Can I read Mazda codes myself?
Codes vary slightly by model, year and engine. Always confirm with a proper diagnosis. Manufacturer-specific codes (P1xxx/P2xxx) may differ from generic descriptions.
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Use the free decoder below, or browse the most common Mazda codes.