B1556 on Lincoln
Ignition Run/Start Circuit Open
B1556 on Lincoln vehicles indicates ignition run/start circuit open. Au7o has documented this code across 1 Lincoln model — most commonly on Aviator. A body code most commonly documented on Ford-family vehicles. A module monitoring the ignition switch circuits detected an open in the run/start feed - it is not seeing power on the circuit that should be hot with the key in RUN and START. Symptoms range from no-crank or intermittent stalling to accessories and modules dropping offline, and the code can also store simply because a module was powered up outside normal ignition conditions. Related codes in the same family cover the run and accessory feeds separately (for example B1555 for a run/start circuit failure and B1356 for an open ignition run circuit), so read the exact code text rather than assuming. Because B1556 is in the manufacturer-specific body range, confirm the definition for your make before diagnosing.
Common Causes of B1556
- •Blown fuse on the ignition run/start circuit
- •Failed or worn ignition switch (electrical portion)
- •Damaged, chafed, or corroded wiring in the run/start circuit
- •Loose or corroded connector at the affected module or fuse box
- •Faulty ignition or starter relay
- •Poor ground at the monitoring module
B1556 on Lincoln by Model
Lincoln Aviator(1 issue)
- Power-Liftgate Faults - Apply Ford SSM Symptom Split Before Parts2020-2022
Ford documents several distinct Aviator power-liftgate conditions. On some 2020-2022 vehicles, failure only through hands-free intelligent access or the outside handle while doors are locked can result from a poor connection at rear-keyless-entry connector C4332 below the striker (SSM 50810). Some 2020-2021 inoperative liftgates can involve RGTM software (SSM 49914). Early 2020 vehicles built on or before February 17, 2020, can partially open or trigger a false anti-theft alarm with B144D, B144E, B1555, or B1556 from RGTM software (SSM 49015). These bulletins do not diagnose every liftgate fault.
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View B1556 across all makes →Frequently Asked Questions
What does B1556 mean on Lincoln?▼
B1556 stands for "Ignition Run/Start Circuit Open." A body code most commonly documented on Ford-family vehicles. A module monitoring the ignition switch circuits detected an open in the run/start feed - it is not seeing power on the circuit that should be hot with the key in RUN and START. Symptoms range from no-crank or intermittent stalling to accessories and modules dropping offline, and the code can also store simply because a module was powered up outside normal ignition conditions. Related codes in the same family cover the run and accessory feeds separately (for example B1555 for a run/start circuit failure and B1356 for an open ignition run circuit), so read the exact code text rather than assuming. Because B1556 is in the manufacturer-specific body range, confirm the definition for your make before diagnosing. On Lincoln specifically, this code is documented across 1 model.
What causes B1556 on Lincoln vehicles?▼
Common causes on Lincoln: Blown fuse on the ignition run/start circuit, Failed or worn ignition switch (electrical portion), Damaged, chafed, or corroded wiring in the run/start circuit, Loose or corroded connector at the affected module or fuse box, Faulty ignition or starter relay. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B1556 on a Lincoln?▼
Repair costs vary widely depending on the root cause and specific Lincoln model.
Which Lincoln models have B1556 documented?▼
Au7o has documented B1556 on 1 Lincoln model: Aviator.