B1604
Low Severity (Level 2)Lamp Anti-Theft Indicator Circuit Open
B1604 usually means lamp Anti-Theft Indicator Circuit Open.
Can you still drive with B1604?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $110 – $900
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Security system working intermittently, then stopping completely
- Engine cranks but won't start — immobilizer preventing start
- Security light flashing — vehicle may not start
- Infinite resistance in the vehicle security/anti-theft circuit — broken wire or disconnected connector
Possible Causes
- Broken wire or connector pin in the vehicle security/anti-theft 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 security module — 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 ($24-110 at shop, free at auto parts store for basic scan)
- Visually inspect the vehicle security/anti-theft system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $84 diagnostic fee at shop)
- Trace the vehicle security/anti-theft system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($105-317 labor for diagnosis and repair)
- Check and reseat all connectors in the vehicle security/anti-theft system circuit — disconnect, inspect pins, clean with electrical contact cleaner, apply dielectric grease, and reconnect firmly ($10 DIY or $63 shop minimum)
- If security module has failed internally (open circuit inside), replace it — don't try to repair sealed components ($100-800)
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 B1604 mean?
B1604 stands for "Lamp Anti-Theft Indicator Circuit Open". B1604 usually means lamp Anti-Theft Indicator Circuit Open.
Can you drive with B1604?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B1604?
Repair costs for B1604 typically range from $110 to $900, 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 ($24-110 at shop, free at auto parts store for basic scan); Visually inspect the vehicle security/anti-theft system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $84 diagnostic fee at shop); Trace the vehicle security/anti-theft system wiring from connector to connector with a multimeter set to continuity/resistance mode — find and repair the break in the circuit ($105-317 labor for diagnosis and repair).
Will B1604 clear itself?
Explore Repair Costs
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