P1518

What P1518 Means

Code P1518 belongs to the BMW fuel injection system error group and indicates an open electrical circuit. In the source data, P1518 appears in the context of diagnosing faulty injectors, alongside codes 4501–4506 (fuel delivery deviation on cylinders 1–4), P0201–P0204 (injector circuit fault on cylinders 1–4), P0087 (fuel rail pressure), and P2147.

The injection system is controlled by the DME (engine control module). Each injector receives a control signal over its own circuit. When a circuit opens, the DME detects a missing feedback signal or a current mismatch, which sets code P1518. The cause can be the injector itself, damaged wiring, or a bad connector.

Code P1518 needs to be checked together with the other listed codes, since the fuel delivery deviation (4501–4506) and the rail pressure drop (P0087) can all stem from the same fault.

Symptoms

• Warning light: Check Engine comes on with code P1518 (open circuit).
• Engine behavior: sudden loss of power.
• Related codes: 4501–4506, P0201–P0204, P0087, P2147 may also be present.

Diagnosis and Repair

1. Read the fault codes with diagnostic equipment (ISTA, INPA) and record the full list, including 4501–4506, P0201–P0204, P1518, P0087, P2147.
2. Check the electrical circuit for the cylinder 1–4 injectors: wiring integrity, connector condition, and any open or short circuit. Code P1518 points to an open circuit.
3. Check fuel pressure at the rail (code P0087). If needed, test the fuel pump and pressure regulator.
4. Check the injectors for delivery deviation (codes 4501–4506). If an injector is confirmed faulty, replace it.
5. Repair for a broken drive cable: the source data lists a repair for a broken drive cable. Restore or replace the cable per the manufacturer's procedure.

Tools: ISTA, INPA, multimeter for circuit testing.