B1575 — Lamp Park Input Circuit Failure

OBD2 code B1575 flags a problem with the body electrical system (lamp park input circuit failure). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, faulty switch, motor or actuator of the affected system, body control module (BCM) fault.

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 B1575 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 B1575 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1575 (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 B1575 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

What does OBD2 code B1575 mean?

What is the most common cause of B1575?

The most common causes are: corroded or loose connectors, faulty switch, motor or actuator of the affected system, body control module (BCM) fault.

What are the symptoms of B1575?

Drivers most often notice: warning light on the dashboard, no impact on engine operation in most cases, the affected function (locks, windows, lighting, wipers) works intermittently or not at all.

Will B1575 clear itself?

Sometimes B1575 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.

Is it safe to drive with B1575?

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.

When your vehicle's onboard diagnostics spot something unusual in the park lamp circuit, code B1575 is the result. This trouble code falls squarely in the body electrical category, meaning it lives in the same family as problems involving lighting, power locks, windows, and windshield wipers. Unlike engine or transmission codes that can leave you stranded, B1575 typically points to a comfort or convenience feature that's acting up rather than something that kills your drivetrain.

The module responsible for watching this circuit doesn't take a passive role. It samples the park lamp input continuously as you drive, comparing real-time voltage and resistance readings against factory specifications. When those readings drift outside acceptable bounds for longer than the software allows, the module logs B1575 and illuminates the check-engine or body indicator light. Each time this happens, a snapshot gets stashed in memory — the freeze frame — capturing engine speed, load, coolant temperature, and vehicle speed at the precise instant the fault triggered. That snapshot becomes your roadmap when you start troubleshooting.

Understanding how that freeze frame data forms is critical because it tells you exactly what your car was doing when things went sideways. Was it a cold morning? Were you idling at a stoplight? Those details narrow the field dramatically and prevent chasing ghosts through your electrical system.

Common Symptoms of B1575

Dashboard warning lamp stays illuminated after the fault is detected
Engine performance remains unaffected in virtually all cases
The specific function tied to the park lamp input — whether it's lighting, wipers, locks, or windows — operates intermittently or quits entirely
In some vehicles, related body functions may behave erratically as the module enters fail-safe mode
The warning light may flicker or flash intermittently before settling to a solid state

What Causes B1575?

Chafed or broken wiring in areas exposed to movement and moisture, particularly door hinges and tailgate seams
Connectors suffering from corrosion, water intrusion, or simply loose insertion
A failing body control module unable to process inputs correctly
A blown fuse or relay that protects the affected circuit
A defective switch, motor, or actuator in whatever system the park input controls
Shorts to ground or battery caused by insulation damage over time
Poor ground connections at the module or component level

How to Diagnose B1575

Plug in your OBD2 scanner, verify that B1575 is actively stored, and record every byte of freeze frame data — this tells you driving conditions when the fault appeared.
Pull all stored codes from every module, not just the powertrain. Body codes often cluster together, and a related P-codes or C-codes may point to the actual culprit. Cross-reference any applicable TSBs for your make, model, and year via the manufacturer portal or NHTSA database.
Examine the relevant wiring harness and connectors by hand. Look for cracked insulation, green or white corrosion buildup, rubbed-through wires at flex points, and any connector that's slightly recessed or has broken locking tabs.
Activate the suspected function — lamp, wiper, lock, or window — while monitoring its switch and motor data PIDs in real time on your scan tool. Watch for stalled signals or values that jump erratically.
Pay special attention to wire bundles at door jambs and liftgate hinges. Repeated opening and closing fatigues copper and insulation alike, making these hotspots the most common failure points in body wiring.
Clear B1575 after your inspection, then drive through the exact conditions captured in the freeze frame — same speed, load, and temperature range. If the code returns, you've confirmed an active fault and can proceed with targeted repair.

Repair Options with Costs

Switch or actuator replacement — When the physical component controlling the affected function fails outright, swapping it resolves the code directly. Parts and labor typically run $120–$450 depending on location and vehicle.
Wiring or connector repair — Most persistent B1575 faults trace back to damaged harness sections or corroded terminals. Professional repair including labor generally costs $80–$250.
Body control module service or replacement — If the BCM itself is the root cause, you face either module repair (reflashing, reprogramming) or full replacement. This scenario lands between $300–$900 in most markets.

Total Repair Cost for B1575

Your final invoice hinges entirely on which link in the chain actually broke. The cheapest fix — repairing frayed wiring or cleaning a dirty connector — might set you back only $80, while a new BCM pushes toward $900. Statistically, wiring issues and bad switches account for the majority of B1575 cases, so those are the angles to explore first. Spending time with a multimeter and your freeze frame data before buying parts is the smartest money move here. Skipping the diagnosis and throwing parts at the code blindly rarely ends well for your wallet.

Can You Drive with B1575?

Yes, in most circumstances this code doesn't compromise your ability to operate the vehicle safely. Body electrical faults seldom affect engine output, transmission function, or braking systems. That said, a few scenarios warrant caution: if B1575 relates to exterior lighting, driving at night or in poor weather becomes genuinely hazardous. A central locking malfunction that prevents you from securing the doors presents a security risk. Beyond those edge cases, schedule the repair at your convenience rather than rushing to a shop.