Code Definition

P1204 — Fuel injector 4 circuit fault

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

About P1204

P1204 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 P1204 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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.

P1204 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

Battery voltage reaches the cylinder 4 fuel injector through the fuel pump relay or an injector supply fuse, and the Engine Control Module completes the circuit to ground with an internal low side driver for the calculated injection pulse width. The module checks the electrical condition of that output on every injection event, and on direct injection engines it also supervises the boosted high voltage supply that lifts the high pressure injector needle. DTC P1204 is stored when the ECM detects an electrical fault on the cylinder 4 injector circuit, covering an open circuit, a short to ground,...

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