Code Definition

P1251 — Fuel injection timing solenoid short to positive

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Audi

About P1251

P1251 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1251 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1251 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The fuel injection timing solenoid, commonly designated N108 on Audi and Volkswagen diesel engines, is mounted on the distributor injection pump and controls the hydraulic pressure applied to the pump timing piston. The Engine Control Module supplies the solenoid with battery voltage and switches the ground side with a variable duty cycle, advancing or retarding the start of injection to match the value it has calculated from engine speed, load and temperature. Because the module monitors the voltage on its own control output, it can recognise when that line is being held at battery voltage ra...

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