B1556
Moderate Severity (Level 3)Ignition Run/Start Circuit Open
B1556 usually means ignition Run/Start Circuit Open.
Can you still drive with B1556?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $110 – $700
Severity Level 3 — Moderate
This code indicates a moderate issue that may affect vehicle performance and fuel economy. Continued driving is possible in most cases, but prompt diagnosis and repair are recommended to prevent further damage.
Common Symptoms
- Ignition not working — no response when activated
- Check Engine Light illuminated
- Ignition working intermittently, then stopping completely
- Infinite resistance in the ignition circuit — broken wire or disconnected connector
Possible Causes
- Broken wire or connector pin in the ignition system harness — common at flex points like door jambs or where wiring moves
- Disconnected or loose electrical connector — may have been bumped during other repairs
- Failed ignition module/switch — internal open circuit from age, heat cycling, or vibration
- Corrosion completely severing a wire or connector terminal — green crust on copper wiring
- Wiring harness damage from rodent chewing — look for nesting material near the engine or under dash
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($13-123 at shop, free at auto parts store for basic scan)
- Visually inspect the ignition system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $76 diagnostic fee at shop)
- Trace the ignition system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($150-334 labor for diagnosis and repair)
- Check and reseat all connectors in the ignition system circuit — disconnect, inspect pins, clean with electrical contact cleaner, apply dielectric grease, and reconnect firmly ($20 DIY or $68 shop minimum)
- If ignition module/switch has failed internally (open circuit inside), replace it — don't try to repair sealed components ($100-600)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B1556 mean?
B1556 stands for "Ignition Run/Start Circuit Open". B1556 usually means ignition Run/Start Circuit Open.
Can you drive with B1556?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B1556?
Repair costs for B1556 typically range from $110 to $700, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($13-123 at shop, free at auto parts store for basic scan); Visually inspect the ignition system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $76 diagnostic fee at shop); Trace the ignition system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($150-334 labor for diagnosis and repair).
Will B1556 clear itself?
Explore Repair Costs
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