Ford Codes List

Ford-enhanced trouble code lookup
for Ford, Lincoln and Mercury.

Repair Order

655 Ford-enhanced codes on file

Code
P1663

Fuel Demand Command Signal Circuit Malfunction

Category
Powertrain - Fuel/Air Metering
Severity
Check Engine Light
Applies to
Ford diesel models with electronic fuel demand
Related
No single generic twin. See OBD Codes List

Findings, check these first

  • Open fuel demand signal wire
  • Corroded demand connector
  • Failing demand sensor
  • Controller input fault
  • Harness damage

Standard procedure

  1. Test demand signal through its range
  2. Check circuit continuity
  3. Inspect the connector
  4. Verify controller receives the demand
  5. Repair wiring per tests

Code lookup

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Sources and review

Review: checked against the recorded source material.

  • OBDII.pro: P1663 Ford definition

    live reference page (obdii.pro)

    Supports: Ford-family meaning for P1663: Fuel Demand Command Signal Circuit Malfunction

    Fetched directly. obdii.pro is a publisher independent of the engine-codes family.

  • P1663 FORD Code: Meaning, Causes, and Symptoms | OBD2 Codes

    live reference page (obd2-codes.co)

    Supports: Ford meaning for P1663: Fuel Demand Command Signal Circuit Malfunction

    Fetched directly. obd2-codes.co phrasing matches the engine-codes family, so it counts as one publisher.

Last updated 2026-09-06.

Report a correction for P1663. Include your vehicle, the issue and a source if you have one.

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