B1510 — Flash To Pass Switch Circuit Short To Ground

OBD2 code B1510 flags a problem with the body electrical system (flash to pass switch circuit short to ground). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, blown fuse or failed relay, faulty switch, motor or actuator of the affected system.

body electrical

Is it safe to drive?

Short-term driving is OK Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1510 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the body electrical system for damage, corrosion, chafing or poor contact.
Subsystem check Operate the affected function while watching its switch and motor PIDs in live data.
Subsystem check Inspect connectors and wiring at flex points (door jambs, tailgate hinges) — wires break there first.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1510 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1510 (parts and labor, USD, independent shop rates): Replace the switch or actuator: $120–$450; Repair wiring or connectors: $80–$250; BCM repair or replacement: $300–$900. Overall, fixing B1510 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with B1510?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

What does OBD2 code B1510 mean?

What is the most common cause of B1510?

The most common causes are: corroded or loose connectors, blown fuse or failed relay, faulty switch, motor or actuator of the affected system.

Will B1510 clear itself?

Sometimes B1510 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose B1510 myself?

Start with a scan: confirm B1510, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

When you activate the flash-to-pass function, you expect your headlights to flare bright for a moment. Behind the scenes, a switch sends a signal to the vehicle's body control module, which then powers up the lamps. Code B1510 means the BCM has detected something wrong with that switch circuit—specifically, an electrical path where current is being pulled to ground when it shouldn't be. The module reads this as a short, and after confirming the condition across multiple ignition cycles, it logs the fault and illuminates the check engine light.

The body control module monitors all body electrical inputs continuously, including the flash-to-pass switch. When voltage readings fall outside the expected range for a sustained period, the module recognizes a malfunction and records the diagnostic trouble code. It also saves a freeze frame—a snapshot of engine speed, load, coolant temperature, and vehicle speed at the exact moment the problem appeared. This data helps you recreate the conditions that triggered B1510 during testing.

The good news is that B1510 is classified as a body system fault, not a drivetrain problem. Your engine runs normally, but certain convenience features may stop working or behave erratically depending on which circuit is affected.

Common Symptoms of B1510

Check engine or warning light stays on in the instrument cluster
The flash-to-pass function no longer operates when you actuate the lever
Related body functions such as lighting, wipers, or door locks may operate intermittently or fail completely
In most cases, engine performance and transmission function remain unaffected
The malfunction indicator lamp may clear temporarily after a reset but returns if the underlying fault persists

What Causes B1510?

Damaged wiring or connectors in high-movement areas such as door jambs or hinges
Corrosion or moisture intrusion at electrical connectors, causing unintended ground paths
A failed or worn flash-to-pass switch that internally shorts to ground
Body control module itself malfunctioning and misinterpreting circuit inputs
Blown fuse or failed relay associated with the body electrical circuit
Chafed wiring insulation allowing bare conductors to contact metal chassis ground

How to Diagnose B1510

Connect an OBD2 scanner and retrieve all stored codes. Confirm B1510 is present, then record the freeze frame data. This information shows what the engine was doing when the fault occurred and guides your next steps.
Look for additional trouble codes in the body control module. B1510 often appears alongside related codes that point more directly to the failing component.
Check manufacturer technical service bulletins for your specific make and model. Many body electrical faults have documented fixes or software calibration updates—search by vehicle identification number on the manufacturer website or NHTSA database.
Perform a visual inspection of the wiring harness and connectors tied to the body electrical system. Focus on areas where wires flex repeatedly: door hinges, tailgate openings, and under-dash routing.
Using your scanner's live data function, monitor the switch and motor PIDs for the affected circuit while operating the component. Erratic or stuck readings confirm the problem area.
After clearing B1510, complete a full drive cycle that reproduces the conditions from your freeze frame data. If the code reappears, the fault is confirmed and active.

Repair Options and Costs

The appropriate repair depends on what inspection reveals. Here are typical costs at independent shops, including parts and labor:

Replace the flash-to-pass switch or associated actuator: $120–$450
Repair damaged wiring or connector issues: $80–$250
Body control module diagnosis, repair, or replacement: $300–$900

How Much Should You Expect to Pay?

The total cost hinges entirely on which component failed. Most B1510 faults trace back to simple wiring or switch problems, not expensive module replacement. Parts and labor typically run:

Switch or actuator replacement: $120–$450
Wiring and connector repair: $80–$250
BCM service or replacement: $300–$900

Across all scenarios, expect to spend between $80 and $900 to resolve B1510. Diagnose before you buy—replacing the body control module as a first guess is costly and rarely necessary.

Can You Drive with B1510?

Generally yes—B1510 does not impair engine operation or safety systems in most vehicles. The BCM is designed to fail gracefully, meaning critical functions stay online. However, safety implications exist if the short affects exterior lighting or wipers during poor weather. A central locking malfunction that leaves your car unsecured is also a concern. Address the underlying problem within a reasonable timeframe to restore full functionality.