P1220 — Fuel pump control circuit malfunction

Diagnostic algorithm

1. Retrieve codes and freeze-frame data; check for other fuel or electrical codes that help locate fault.
2. Confirm symptom: verify whether pump primes with key ON and measure fuel pressure while cranking. If no prime, continue electrical checks.
3. Inspect battery, charging system, and main power distribution fuses/relays. Replace any blown fuse and retest.
4. Locate fuel pump relay and swap with a known-good identical relay (if possible) to test; retest pump operation.
5. Visually inspect connectors at fuel pump, FPDM (if fitted), and ECM for corrosion, bent pins, or water intrusion. Repair as needed.
6. Back-probe the pump connector: check for constant battery voltage at the supply pin and reliable ground or control signal on the control pin when priming/cranking.
7. Measure pump current draw while running. Excessive or no current indicates pump or short/open condition. Compare to spec.
8. If supply and ground are good but pump not running, bench-test pump (remove from tank) or apply fused 12 V to pump to confirm operation.
9. If pump works when directly powered, trace and repair wiring between pump and relay/FPDM/ECM. Repair broken wires, corroded pins, or poor grounds.
10. If wiring and pump OK, test/replace the FPDM (if equipped) or consider PCM output fault — only replace ECM after all other causes are eliminated and bench/oscilloscope tests confirm bad output.
11. After repair, clear codes, recheck for DTCs, verify fuel pressure and normal operation under road test, and re-scan to confirm no return of P1220.