B2478
Low Severity (Level 2)ANTI THEFT INPUT SIGNAL SHORT TO GROUND
B2478 usually means aNTI THEFT INPUT SIGNAL SHORT TO GROUND.
Can you still drive with B2478?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $120 – $1000
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
- Alarm going off randomly or not arming
- Security system blowing fuses when activated
- Security light flashing — vehicle may not start
- Zero voltage on the anti-theft/security system circuit — short pulls signal to ground
Possible Causes
- Chafed or pinched wire in the anti-theft/security system circuit — wire insulation worn through, copper touching vehicle chassis/ground
- Failed security module with internal short to ground — most common when the component gets wet or overheats
- Corrosion in the electrical connector allowing current to leak to the connector shell/ground
- Damaged wiring harness where it passes through a body panel grommet or near a sharp metal edge
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 ($16-96 at shop, free at auto parts store for basic scan)
- Visually inspect the anti-theft/security system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $129 diagnostic fee at shop)
- Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($93-439 depending on accessibility)
- If security module is internally shorted, replace with a quality OEM or OEM-equivalent aftermarket unit ($100-800)
- Clean all ground points related to the anti-theft/security system — remove bolt, sand contact surface to bare metal, apply dielectric grease, and torque to spec ($36-138 at shop)
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 B2478 mean?
B2478 stands for "ANTI THEFT INPUT SIGNAL SHORT TO GROUND". B2478 usually means aNTI THEFT INPUT SIGNAL SHORT TO GROUND.
Can you drive with B2478?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B2478?
Repair costs for B2478 typically range from $120 to $1000, 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 ($16-96 at shop, free at auto parts store for basic scan); Visually inspect the anti-theft/security system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $129 diagnostic fee at shop); Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($93-439 depending on accessibility).
Will B2478 clear itself?
Explore Repair Costs
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