Peugeot & Citroën
Stellantis OBD codes explained
The codes that show up on Peugeot, Citroën, DS, Opel, Fiat, Jeep and Alfa Romeo — fuel pressure, injectors, EGR and misfires — with causes and fixes.
Peugeot / Citroën (Stellantis) check engine light codes
Stellantis group models (Peugeot, Citroën, DS, Opel, Fiat, Jeep, Alfa Romeo) use standard OBD-II engine codes. DiagBox/Proxia unlocks the deeper layers, but most engine codes are readable with any scanner.
Here are the codes most often reported by Peugeot and Citroën drivers, especially on HDi diesel engines.
OBD-II code decoder
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Most common Peugeot / Citroën (Stellantis)
Common Stellantis faults behind these codes.
| Code | Description |
|---|---|
| P0011 | "A" Camshaft Position Timing Over-Advanced (Bank 1) |
| P0087 | Fuel Rail Pressure Too Low |
| P0171 | System Too Lean (Bank 1) |
| P0263 | Injector Circuit Contribution Balance (Cylinder 1) |
| P0300 | Random/Multiple Cylinder Misfire |
| P0401 | EGR Flow Insufficient |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1) |
| P0442 | EVAP System Small Leak Detected |
Common Peugeot / Citroën (Stellantis) faults
Common Stellantis faults behind these codes.
Fuel pressure too low (P0087) — high-pressure pump or regulator wear on HDi diesels.
Injector contribution (P0263) — clogged or failing diesel injectors.
Misfires (P0300) — coils and plugs on petrol engines.
EGR flow (P0401) — carbon buildup on the EGR, common on all Stellantis diesels.
Lean mixture (P0171) — vacuum leaks or MAF issues on petrol models.
Peugeot / Citroën (Stellantis) FAQ
What causes P0087 on a Peugeot diesel?
Is P0263 serious?
Why does my Citroën show P0401?
Can a cheap scanner read Peugeot codes?
Does the check engine light always mean a big repair?
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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