What Does B1510 Mean?
This diagnostic code indicates that the Body Control Module (BCM) has detected an abnormal electrical short to ground in the flash-to-pass switch circuit. The flash-to-pass feature allows the driver to momentarily activate the high beam headlights by pulling the turn signal stalk. The BCM detected excessive current flow or voltage reading below specified threshold, indicating the circuit path is completing to ground before reaching the switch.
Common Causes
40%
Damaged or pinched wiring harness between BCM and flash-to-pass switch, exposing conductor to ground
30%
Failed multifunction switch with internal short circuit to ground
20%
Corroded or damaged connector terminals at multifunction switch or BCM allowing moisture intrusion
10%
Failed or faulty Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of the multifunction switch and steering column wiring harness for visible damage, pinched wires, chafing against metal surfaces, or signs of water intrusion. Check all connectors for corrosion, bent pins, or backed-out terminals.
2
Step 2: Disconnect the multifunction switch connector and use a digital multimeter to measure resistance between the flash-to-pass switch circuit terminal (consult wiring diagram for specific pin) and chassis ground. Reading should be infinite ohms (open circuit). If reading shows continuity to ground, wiring harness has short to ground.
3
Step 3: With multifunction switch disconnected, check resistance of the switch itself between the flash-to-pass signal terminal and ground terminal with switch in both rest and activated positions. Consult manufacturer specifications, but typically should show open circuit to ground in rest position.
4
Step 4: If wiring and switch test good, inspect BCM connector for corrosion or damage. Measure voltage supply at the flash-to-pass circuit with BCM connected and ignition on (should see reference voltage, typically 5V or 12V depending on manufacturer). If voltage is present at BCM but shorts when switch is connected, replace multifunction switch.
5
Step 5: Clear codes and perform operational test of flash-to-pass function. Monitor live data on scan tool while activating switch to verify BCM sees proper signal transition. If code returns immediately with known-good switch and wiring, BCM may require replacement.
Estimated Repair Cost
$120 - $650
Parts + labor, varies by vehicle and location
This diagnostic code indicates that the Body Control Module (BCM) has detected an abnormal electrical short to ground in the flash-to-pass switch circuit. The flash-to-pass feature allows the driver to momentarily activate the high beam headlights by pulling the turn signal stalk. The BCM detected e...
The most common cause of B1510 (Flash To Pass Switch Circuit Short To Ground) is: Damaged or pinched wiring harness between BCM and flash-to-pass switch, exposing conductor to ground
Typical repair costs for B1510 range from $120 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive as this only affects the momentary high beam flash function; normal low and high beam operation should remain unaffected. Repair at convenience, though lack of flash-to-pass may reduce ability to signal other drivers in certain situations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1510 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Body Electrical and Lighting System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
