P1240 on SEAT: How to Diagnose & Fix
Manufacturer-Specific Injector / Fuel System Circuit Fault
1 SEAT model · 1 documented issue · 1 critical · $300-$1,800 repair
P1240 on SEAT by model: symptoms, diagnosis and fix
The 1.6 TDI common-rail engine in Ibiza Mk4/5, Leon Mk2/3 (and across VW Group small diesels) suffers Bosch injector failure typically at 100,000-180,000 km. Symptoms: rough cold start, individual-cylinder misfire, sometimes back-leak overwhelming the rail pressure regulator. Injector copper washers often re-seal poorly after the first removal.
Common Symptoms
- rough cold start
- misfire
- limp mode
- fuel smell
How to Fix
Back-leak test (10 min) confirms diagnosis. Single injector replacement €300-€600 incl. coding. Full set (4) €1,000-€1,800. Use VW 507.00 spec oil and quality diesel from major-brand stations.
P1240 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1240 mean on a SEAT?
P1240 stands for "Manufacturer-Specific Injector / Fuel System Circuit Fault." P1240 is a manufacturer-specific powertrain code, generally associated with a fuel injector or fuel-system circuit fault, though the exact assignment differs by manufacturer. On several platforms it indicates a problem in a specific cylinder's injector circuit (often referenced as cylinder 4) or a related fuel-control/power-supply issue. A fault here can disrupt precise fuel delivery and lead to rough idle, misfire, and reduced performance. Confirm the exact meaning with make-and-model service information. On SEAT it is documented across 1 model: Ibiza.
What are the most common causes of P1240?
The most common causes of P1240 are: Faulty or open fuel injector (cylinder-specific), Wiring, connector, or harness fault in the injector circuit, Injector power-supply or ground problem, Corroded or loose electrical connections, Faulty injector driver in the PCM/ECM, Fuel-system pressure or delivery fault (some makes), Internal PCM/ECM fault. The specific cause varies by vehicle.
How much does it cost to fix P1240 on a SEAT?
Published repair estimates on SEAT range from $300 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P1240 on a different make?
View P1240 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.