OBD-II Code B1175: The Ultimate Guide for Mechanics & DIYers

What Does B1175 Mean?

B1175 is a manufacturer-specific body control module (BCM) code, meaning it has different definitions depending on your vehicle. For Honda and Acura, it points to a problem with the fuel level sensor circuit, leading to an incorrect gas gauge. For many Ford and Lincoln vehicles, it signals a fault in a door or hood ajar switch circuit, which disables alarms, remote start, and door locking. For Chevrolet, it indicates an issue with the ignition lock cylinder sensor. For Land Rover, it indicates a door or trunk latch issue.

Technical definition: The formal SAE/OBD-II definition of code B1175 is not standardized. Common definitions include: Honda/Acura: Fuel Level Sensor (Fuel Gauge Sending Unit) Circuit Open/Malfunction. Ford: Hood Ajar Switch Circuit Fault or DIS Wakeup Line Short Circuit To Vcc. Lincoln: Door Latch Control Module Circuit Current Above Threshold (B1175:19). Land Rover: Driver Door Open Switch / Passenger Door Ajar Switch / Luggage Compartment Open Switch Circuit Fault. Chevrolet: Ignition Lock Cylinder Sensor Data Incorrect.

Can I Drive With B1175?

Yes, But With Caution. You can drive, but with significant cautions. A faulty door latch (Ford/Lincoln) prevents the door from locking, creating a security issue, or keeps interior dome lights on, draining the battery. On some Lincoln models, the electronic interior door release becomes inoperative, posing a safety risk. A faulty fuel gauge (Honda/Acura) causes unexpected fuel exhaustion, leading to a dangerous loss of power and a $100-$300 tow.

Common Causes

• Hood Misalignment or Worn Bump Stops (Ford) (Very Common) — On Ford F-150s, the hood itself is often not aligned properly. The rubber bump stops under the hood wear down or fall out of adjustment, preventing the hood from pressing the switch securely. Adjusting these stops or the latch position is a common free fix.
• Faulty Fuel Level Sending Unit (Honda/Acura) (Very Common) — The float or variable resistor inside the fuel tank wears out, gets contaminated with sulfur from fuel, or fails electrically, sending incorrect signals to the fuel gauge. This is the most frequent cause for this code on Honda and Acura vehicles.
• Faulty Hood Latch Assembly (Ford) (Very Common) — On many Ford F-150s, the hood ajar micro-switch is built into the latch assembly. It is exposed to heat and moisture and frequently fails, causing a persistent 'Hood Ajar' warning and disabling remote start.
• Door Control Module Software Glitch (Lincoln) (Common) — On Lincoln Aviator models, the door control module's software is overly sensitive to minor battery voltage drops, falsely triggering a 'Door Fault' message and a B1175:19 code. A software update is the required fix per TSBs SSM 51788 and 50967.
• Weak or Failing 12V Battery (Ford/Lincoln) (Common) — Modern Ford and Lincoln vehicles are highly sensitive to battery voltage. A weak or failing battery causes numerous false electronic codes, including B1175 on Aviators and 'Frunk Ajar' issues on F-150 Lightnings.
• Damaged Wiring or Loose Connectors (Common) — Wires break, chafe, or corrode, and connectors become loose. This happens frequently in areas that move (door hinge harnesses), are exposed to moisture (under the hood), or are subject to damage (rear axle wiring on F-150s).
• Faulty Door/Trunk Ajar Switch (Various) (Less Common) — The mechanical or magnetic switch in a door or trunk latch that detects if it is closed fails, gets stuck from dirt, or suffers water damage. On modern cars, this switch is integrated into the latch assembly.
• Poor Quality or Incompatible Aftermarket Parts (Less Common) — Using a low-quality aftermarket replacement part causes the code to persist, especially with Honda fuel level sensors. The new part often fails to meet the exact resistance specifications the vehicle's computer expects.
• Faulty Ignition Lock Cylinder (Chevrolet) (Less Common) — On Chevrolet vehicles, this code points to a problem with the sensor in the ignition lock cylinder, causing starting issues or problems with security systems.
• Frunk Latch or Software Issue (Ford F-150 Lightning) (Less Common) — On the F-150 Lightning, the B1175 code manifests as a 'Frunk Ajar' warning. This stems from a faulty latch, a software glitch in the frunk controller, or a weak 12V battery.
• Faulty Body Control Module (BCM) (Rare) — The Body Control Module is the computer that receives signals from these sensors. The BCM itself occasionally fails, misinterpreting signals from perfectly good sensors. Consider this only after exhausting all other possibilities.

Symptoms

• Inaccurate or Erratic Fuel Gauge (Honda/Acura) — The fuel gauge gets stuck on empty, full, or fluctuates randomly, making it impossible to know how much fuel is in the tank.
• 'Hood Ajar' or 'Door Ajar' Warning Light On (Ford/Lincoln/Land Rover) — A persistent warning message appears on the dashboard even when the hood and all doors are securely closed.
• Remote Start and/or Alarm System Disabled — The vehicle's computer disables remote start for safety if it thinks the hood is open. The alarm triggers unexpectedly or fails to arm.
• Interior Dome Lights Stay On — If the car thinks a door or hood is open, it keeps the interior lights on, leading to a drained battery overnight.
• Low Fuel Light Blinking (Honda/Acura) — The low fuel warning indicator blinks continuously, regardless of the actual fuel level, signaling a fault in the sensing circuit.
• 'Door Fault' Message on Instrument Cluster (Lincoln) — Specific to Lincoln Aviator models, this message appears with code B1175:19 and indicates a fault in a specific door's electronic latch system.
• 'Frunk Ajar' Warning (Ford F-150 Lightning) — On the all-electric F-150, a fault in the front trunk latch system triggers this specific warning message.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Adjust Hood Latch and Bump Stops (Ford F-150) — Parts: $0, Labor: $0, ~0.1 hr book time (Beginner)
• Replace Hood Latch Assembly (Ford F-150) — Parts: $75-$115, Labor: $120-$160, ~0.8 hr book time (DIY)
• Reprogram Door Control Module (Lincoln Aviator) — Parts: $0, Labor: $200-$400, ~1.5 hr book time (Professional)
• Replace Fuel Level Sending Unit (Honda/Acura) — Parts: $150-$400, Labor: $250-$500, ~2.5 hr book time (Professional)
• Replace Door Ajar Switch / Latch Assembly (Various) — Parts: $50-$700, Labor: $100-$250, ~1.2 hr book time (Intermediate)

Used vs. New Parts: Buying Guide

When a used part is worth it: For a Ford hood latch, a used OEM part from a low-mileage, non-accident vehicle is a cost-effective alternative to new. For a Honda fuel level sender, buying used is highly discouraged due to high labor costs and the likelihood of repeat failure.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Verify the exact part number matches; small changes in design make it incompatible.
• For mechanical parts like latches, inspect for rust, damage, or excessive wear.
• Avoid parts from vehicles in regions with heavy road salt use.

Decision logic:

• If The part is a Ford hood latch and the new OEM part is under $100 → Buy new OEM or a quality aftermarket part (e.g., TRQ, Dorman) for peace of mind and warranty.
• If The part is a Honda fuel level sending unit → Always buy a new OEM or OEM-supplier (e.g., Denso) part. The risk and high labor cost of a used part failing is not worth the initial savings.
• If The part is an electronic module like a Door Control Module → Used is an option, but ensure the seller has a good return policy as it requires dealer programming to work with your vehicle.

Warranty tradeoff: Used parts from salvage yards typically offer a 30-90 day warranty. New aftermarket parts usually come with a 1-year to limited lifetime warranty. New OEM parts have a 1-2 year warranty.

Worst-case if a used part fails: $200-$900. A failed used hood latch is a minor inconvenience requiring repeat labor ($100-$150). A failed used fuel sending unit is a major expense, requiring a second, costly installation ($350-$700).

What Happens If You Wait — Timeline

1. Immediate: For Ford/Lincoln: 'Hood/Door Ajar' warning appears, remote start is disabled, and alarm fails to arm correctly. For Honda/Acura: Fuel gauge becomes erratic or stuck, low fuel light blinks. (MPG impact: 0%% · Added cost: $0)
2. 1-4 Weeks: For Ford/Lincoln: If a door ajar switch is stuck 'open', interior lights stay on, draining the battery. Alarm triggers randomly at night. For Honda/Acura: High risk of running out of fuel, requiring a tow. (MPG impact: 0%% · Added cost: $100-$350 (Cost of a tow or a new battery if drained completely))
3. 1-6 Months: For Ford/Lincoln: A door that fails to latch properly presents a security risk and potential safety hazard. Continued electrical drain shortens battery life. For Honda/Acura: Repeatedly running the tank completely dry causes the fuel pump to ingest debris and overheat. (MPG impact: 0%% · Added cost: $150-$350 (New battery cost))
4. 6+ Months: For Honda/Acura: The fuel pump fails prematurely from overheating and debris ingestion. This is a much more expensive repair than the sending unit alone. (MPG impact: 0%% · Added cost: $600-$1,200 (Cost to replace the entire fuel pump assembly due to secondary damage))

Cost of Not Fixing It

• Immediate: On Ford/Lincoln: Remote start disabled, alarm malfunctions, and 'Hood Ajar' or 'Door Ajar' warning is a constant annoyance. On Honda/Acura: Inability to know fuel level, creating a risk of running out of gas. (Added cost: $100-$300 for a tow if you run out of fuel.)
• 1-3 Months: On Ford/Lincoln: If interior or puddle lights stay on, the battery drains, requiring a jump start or a new battery. A door that fails to latch presents a significant security and safety risk. (Added cost: $150-$350 for a new 12V battery.)
• 3+ Months: On Honda/Acura: Repeatedly running the fuel tank dry causes the fuel pump to overheat and fail prematurely, as it relies on surrounding fuel for cooling. (Added cost: $600-$1,200 for a fuel pump assembly replacement.)

Diagnosis Steps

1. Identify Your Vehicle's B1175 Definition
   Determine what B1175 means for your specific vehicle. Check your manufacturer (Honda/Acura = Fuel Gauge, Ford/Lincoln = Hood/Door Latch, Chevrolet = Ignition). This is the most important first step.
   Tools: Owner's Manual, Google Search (Beginner)
2. Check for Technical Service Bulletins (TSBs)
   Search online for TSBs related to code B1175 for your vehicle's make, model, and year. Manufacturers like Ford (TSB SSM 52468) and Lincoln (TSB SSM 51788) have issued specific bulletins that point to a software update or simple adjustment as the fix.
   Tools: Google Search (Beginner)
3. Perform Simple Mechanical Checks & Adjustments
   For door/hood issues, confirm all doors, the trunk, and hood are fully closed. For Ford F-150s, adjust the two rubber bump stops under the hood (turn them clockwise to raise them) to make it close tighter. Try loosening the two 10mm bolts on the hood latch and moving it slightly upwards before re-tightening. Spray latch mechanisms with white lithium grease.
   Tools: 10mm socket wrench, White lithium grease spray (Beginner)
4. [PRO TIP] Bypass the Switch (Ford Hood Ajar)
   To determine if the fault is in the hood latch switch or the wiring, disconnect the electrical connector from the bottom of the latch. Use a small jumper wire or paperclip to create a bridge between the two pins on the vehicle's harness-side connector. Turn the ignition on. If the 'Hood Ajar' message disappears, the latch assembly itself is faulty. If the message remains, the problem is in the wiring or BCM.
   Tools: Jumper wire or paperclip (Intermediate)
5. Inspect Connectors and Wiring
   Visually inspect the wiring and connectors going to the component in question (fuel pump assembly, hood latch, or door latch). Look for obvious signs of corrosion, water damage, or broken/chafed wires. Disconnect the connector and check for bent or corroded pins.
   Tools: Flashlight, trim removal tools (optional) (Intermediate)
6. [PRO TIP] Test the Sensor with a Multimeter
   For a Ford hood switch, disconnect it and set your multimeter to continuity (Ω). With the latch open, you should see an open circuit (OL). Manually close the latch; you should see continuity (near 0 Ω). For a Honda fuel level sensor, measure resistance across the sensor's pins. It should read approximately 105-110 Ω when the float is at Empty and 3-5 Ω when at Full.
   Tools: Multimeter (Advanced)
7. Check for Power and Ground at the Component
   Using a multimeter and a vehicle-specific wiring diagram, verify that the sensor or switch is receiving the correct reference voltage from the control module and has a solid ground connection (typically less than 10 ohms to chassis ground).
   Tools: Multimeter, vehicle-specific wiring diagram (Advanced)
8. [ADVANCED] Honda Fuel Circuit Voltage Test
   Disconnect the fuel tank unit connector. Turn the ignition to ON (II). Measure the voltage between the specified terminals on the harness-side connector (e.g., terminals 1 and 3 on a CR-V). You should read battery voltage. If there is no voltage, check the METER fuse and inspect for an open or short in the wiring. If voltage is present, the issue is the sending unit itself.
   Tools: Multimeter, vehicle-specific service manual (Advanced)
9. [ADVANCED] Ford Hood Switch Circuit Test
   If bypassing the switch did not resolve the 'Hood Ajar' message, disconnect the harness from the hood latch and at the BCM. Set a multimeter to resistance (Ω) and check for continuity on the signal wire from end to end. A reading of OL indicates a broken wire. Check for a short by measuring resistance from the signal wire pin at the latch connector to a clean chassis ground. A reading near 0 Ω indicates a short to ground.
   Tools: Multimeter, vehicle-specific wiring diagram, socket set (for BCM access) (Advanced)
10. Scan with an Advanced Scan Tool
    A professional scan tool reads live data from the Body Control Module. Watch the status of the switch (e.g., PID: 'HOOD_AJAR', Value: 'Yes/No') as you operate it manually. For a Honda, monitor the fuel level resistance PID in Ohms. This instantly confirms if the BCM is receiving the signal correctly.
    Tools: Bi-directional OBD-II Scan Tool (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• Vehicle Speed: 0-70 mph (Any. For Ford, the code sets when parked. For Honda, it sets during steady driving as the BCM cross-checks fuel level vs. consumption.)
• Battery Voltage: 11.5-14.5V (Any. On Ford/Lincoln, a low voltage event (e.g., <12.0V during cranking) triggers the code, especially on Aviator models.)
• Ignition/Key Status: ON or RUN (The Body Control Module is active and monitoring circuits. For door/hood switches, the fault is detected immediately upon key-on.)
• Time Since Code Clear: Varies (For a 'hard fault' like a broken wire or failed switch, the code reappears almost instantly after being cleared. For intermittent issues, it takes several drive cycles.)

Related Codes

• P0461, P0462, P0463 — These are generic powertrain codes for the fuel level sensor circuit. B1175 is the body module code for the same fault. A P0462 (Circuit Low) or P0463 (Circuit High) helps diagnose a short or open circuit faster than the generic B1175.
• B1176, B11C0, B11C1 — On Lincoln Aviators, these codes are identical in meaning to B1175:19 ('Circuit Current Above Threshold'). The specific code tells you WHICH door is at fault (e.g., DCME, DCMF, DCMG, DCMH), instantly pinpointing the problem location.
• P166B — On modern Ford F-150s, this powertrain code is stored along with B1175 and other B-codes when there is a door or hood ajar warning, as noted in TSB SSM 52468.
• B1323 — On older Ford vehicles, this code for 'Door Ajar Warning Lamp circuit failure' appears with other door switch-related codes. If you have B1175 and B1323, the problem is in the wiring or logic related to the dashboard warning light itself.
• U-codes (e.g., U0155) — If the issue is with a control module (like the BCM or a door module), you see U-codes, which indicate a loss of communication between modules. A U-code accompanying a B-code suggests the module itself or its communication network is the problem.

Climate & Environmental Factors

• High Ambient Temperature: On some Ford and Lincoln models, high heat causes internal components of the door latch pawl to fracture, preventing the door from latching correctly. This has been the cause of several recalls.
• High-Sulfur Fuel: On Honda/Acura vehicles, sulfur contaminants in gasoline build up on the fuel level sending unit's variable resistor contacts. This buildup creates an insulating layer, causing incorrect resistance readings and an erratic fuel gauge.
• Humidity and Moisture: Water intrusion and high humidity corrode the micro-switches and electrical connectors within hood and door latch assemblies. On Lincoln models with electronic door handles, moisture causes the exterior release button to fail.
• Cold Weather: In freezing temperatures, moisture inside a latch mechanism freezes, causing the mechanical parts to stick. This prevents a door or hood from closing securely or from opening when commanded.

How to Talk to a Mechanic About This Code

Say this: "This depends on your vehicle. For a Ford F-150: 'I have a B1175 code and a 'Hood Ajar' warning. Before quoting a latch replacement, can you please check the hood alignment and bump stops per TSB 52468?' For a Lincoln Aviator: 'I have a B1175:19 code and a 'Door Fault' message. I believe this is a software issue. Can you check TSB SSM 51788 and quote me for a door control module reprogram?' For a Honda/Acura: 'I have a B1175 code and an inaccurate fuel gauge. I need a diagnosis of the fuel level sending unit circuit. Please provide a quote using an OEM sending unit if it needs replacement.'"

Using specific, TSB-aware language signals that you are an informed customer. It directs the shop to perform the correct, and often cheapest, diagnostic steps first, preventing them from immediately replacing an expensive part when a simpler fix like an adjustment or software update is the true cause.

Avoid saying:

• 'Just fix whatever's wrong'
• 'My car is acting weird, can you look at it?'
• 'Do whatever you think is best'

Questions to ask before authorizing the repair:

• Will you provide a written estimate with a full cost breakdown for parts and labor?
• For a Ford, did you attempt the latch and bump stop adjustments first?
• For a Lincoln, can you confirm you checked for the software update TSB before recommending a new latch?
• For a Honda, what is the price difference for an OEM vs. an aftermarket fuel sender, and what is the warranty on each?
• Will you contact me for approval if any unexpected issues or additional costs arise?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Required for the Lincoln Aviator software fix. Recommended for warranty work. For most other B1175 scenarios, a trusted independent shop is more cost-effective.
  Best for: Lincoln Aviator software reprogramming, which requires manufacturer-specific tools (FDRS)., Vehicles still under warranty., Complex electrical diagnostics if other shops are stumped.
  Downsides: Significantly higher labor rates for simple, common fixes (e.g., Ford F-150 hood latch)., Less willing to attempt simple adjustments before recommending a full part replacement. (Typical cost: +50% vs. baseline)
• Independent Shop: Best fit for the most common versions of this code (Ford latch, Honda fuel sender). Find a well-reviewed shop with ASE-certified technicians.
  Best for: Most B1175 repairs, like replacing a Ford F-150 hood latch or a Honda fuel level sending unit., Out-of-warranty vehicles where cost is a major factor., Building a long-term relationship with a mechanic you trust.
  Downsides: Shop quality and expertise vary widely; vetting is crucial., Unlikely to have the proprietary software needed for the Lincoln Aviator reprogram., Less familiar with the very latest TSBs. (Typical cost: +0% vs. baseline)
• Chain Shop: Avoid for diagnosis and repair. The complexity and vehicle-specific nature of B1175 are a poor match for the chain shop business model.
  Best for: Simple, unrelated maintenance like oil changes or tires.
  Downsides: Technician skill varies dramatically., High pressure to upsell services and parts., Very unlikely to be aware of the specific TSBs and diagnostic nuances of a manufacturer-specific code like B1175, leading to misdiagnosis and unnecessary parts replacement. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost for the B1175 issue exceeds 40-50% of your car's private-party value (e.g., from Kelley Blue Book), you should pause and consider your options, especially if other expensive maintenance is also due.

• Car worth $4000, fix is $700: Fix it. A $700 fuel sender replacement on a $4,000 Honda Civic is a necessary repair to keep the vehicle safely drivable.
• Car worth $25000, fix is $275: Fix it. A $275 hood latch replacement on a $25,000 Ford F-150 is a minor and necessary repair.
• Car worth $35000, fix is $350: Fix it. A $350 software update for a Lincoln Aviator is well below the threshold and solves a major annoyance.

What Scan Tool You Need for This Code

Minimum: A scanner that can read manufacturer-specific Body (B) codes and display live data from the Body Control Module (BCM).

A basic $20 code reader only checks for engine (P) codes and will not see BCM faults like B1175. For this code, you need to see the specific BCM data, such as the 'Hood Ajar' switch status or the fuel level sensor's resistance, which requires a more capable tool.

Budget: BlueDriver Pro (~$99) — This Bluetooth scanner connects to your phone and reads BCM codes, provides manufacturer-specific definitions, and streams live data PIDs (like door/hood switch status) to help you pinpoint the fault.

Mid-range: Foxwell NT510 Elite (~$180) — A powerful handheld tool that offers full-system diagnostics, including reading BCM codes and viewing live data. It also features bi-directional controls (active tests), which help test components like door locks.

Professional: Autel MaxiCOM MK808S/MK808Z-BT (~$450-550) — Provides comprehensive, dealer-level diagnostics for all systems. It reads and clears all codes, graphs live data from any sensor, and performs active tests to command components to operate, making diagnosis much faster and more certain.

Rent vs buy: Auto parts store rental scanners are often basic models that do not read BCM codes. For a B1175, renting is a gamble. If you plan to do your own diagnostics more than once, buying a tool like the BlueDriver Pro is a worthwhile investment.

How to Clear the Code After You Fix It

1. Use an OBD-II scan tool to clear the Diagnostic Trouble Code from the Body Control Module (BCM).
2. For switch-related faults (Ford/Lincoln), cycle the ignition off and on, then operate the repaired component to confirm the warning message is gone.
3. For fuel level faults (Honda), a test drive is needed to verify the gauge reads correctly and responds to fuel level changes.

Drive cycle (~20 minutes): For a Honda fuel level sensor, start with at least 1/4 tank of fuel. Drive for 15-20 minutes with a mix of city and highway speeds. The BCM needs to see a rational change or a stable reading over time. For Ford/Lincoln latch issues, no specific drive cycle is required.

Readiness monitors affected: None

Watch out for:

• Disconnecting the battery does not always clear a B-code from the BCM's memory.
• The code returns immediately if the underlying electrical or mechanical fault is not properly repaired.
• For Honda, if the gauge doesn't respond after repair, the system requires a reset by pulling a specific fuse for 10 seconds.

Will This Fail Emissions / State Inspection?

No — by itself this code doesn't fail OBD inspection (but it can keep readiness monitors from setting, which causes a separate fail).

• California: This code is a Body (B) code and does not trigger the Check Engine Light (MIL). California's OIS smog check primarily fails vehicles for active powertrain (P) codes that turn on the MIL. B1175 alone will not cause a failure.
• New York: New York's inspection focuses on MIL illumination and emissions-related P-codes. A B-code will not cause an emissions failure unless accompanied by an illuminated MIL.
• Texas: In counties where emissions testing is required, the test is an OBD-II check for readiness monitors and MIL status. A B1175 code will not cause a failure on its own.

Most Commonly Affected Vehicles

• Ford F-150 (2015-2024) — Extremely common for B1175 as a 'Hood Ajar' warning. Caused by a faulty sensor in the hood latch assembly or simple misalignment. See TSB SSM 52468 for 2021-2024 models.
• Honda Civic, Accord, CR-V (2006-2016) — Prone to B1175 as a 'Fuel Level Sensor Circuit Malfunction' due to the sending unit in the fuel tank failing.
• Lincoln Aviator (2020-2023) — Known for setting B1175:19 due to sensitive door control module software. Requires a dealer reprogram per TSB SSM 51788, especially for models built before Oct 12, 2022.
• Acura MDX, TL, TSX (2005-2015) — Similar to Honda, B1175 indicates an open circuit or malfunction in the fuel gauge sending unit.
• Ford Explorer (2020-2024) — Shares a platform with the Lincoln Aviator and experiences similar issues with door latch sensors and related Body Control Module faults.
• Ford F-150 Lightning (2022-2024) — Presents as a 'Frunk Ajar' warning. Caused by the latch assembly, a weak 12V battery, or software glitches in the frunk control module.
• Land Rover Defender, Range Rover (2015-Present) — Uses B1175 for faults in various door and trunk ajar switches. On modern Defenders, the switch is integrated into the door latch assembly, making diagnosis more complex.
• Chevrolet Impala, Malibu (2006-2016) — On Chevrolet vehicles, B1175 is defined as 'Ignition Lock Cylinder Sensor Data Incorrect', which affects vehicle starting and security systems.

Manufacturer-Specific Notes

• Ford/Lincoln: On modern Fords and Lincolns, this code is frequently caused by a software issue, a simple latch misalignment, or a weak battery rather than a broken part. Always check for TSBs and check battery health before replacing hardware. For F-150s, see TSB SSM 52468. For Lincoln Aviators, see TSB SSM 51788.
• Honda/Acura: For these brands, B1175 is almost exclusively related to the fuel gauge sending unit or its circuit. The problem is located in or around the fuel tank. Diagnosis focuses on resistance checks of the sender.
• Land Rover: This code points to any door, the hood, or the tailgate. On newer models like the Defender, the switch is integrated into the latch. Diagnosis requires a capable scan tool to monitor the live data for each individual switch to see which one is not reporting the correct state to the BCM.
• Other Makes: For manufacturers like Toyota, Hyundai, Nissan, BMW, Subaru, and Volkswagen, B1175 is not a commonly used or consistently defined public code. Its appearance on these makes is rare, and diagnosis requires a factory-level scan tool and service manual.

Real Owner Stories

2018 Ford F-150 with 'Hood Ajar' Warning

Owner reported a persistent 'Hood Ajar' message appeared after an oil change, disabling the remote start. The alarm also began triggering randomly at night.

What they tried:

1. Slamming the hood repeatedly.
2. Cleaning and lubricating the latch mechanism with WD-40.
3. Checking for a weak battery.

Outcome: The owner found a forum post suggesting a simple mechanical adjustment. By loosening the two 10mm bolts holding the latch assembly and sliding it slightly upwards before re-tightening, the issue was permanently resolved.

Lesson: On Ford F-150s, always attempt the free mechanical adjustments (bump stops, latch position) before buying a new latch assembly. This is a very common issue where the fix is alignment, not a broken part.

2008 Honda Civic LX with 180K miles and B1175

The fuel gauge stayed on full for 120 miles, then dropped rapidly. A scan revealed code B1175, but the Check Engine Light was not on.

What they tried:

1. Replaced the fuel pump assembly with a new aftermarket (Hella) unit.
2. Made a warranty claim and installed a second new Hella pump when the problem persisted.

Outcome: The second new aftermarket pump behaved identically to the first, and the B1175 code remained. The owner was left with the same problem after replacing the part twice.

Lesson: This is a classic misdiagnosis due to a poor-quality aftermarket part. The aftermarket sending unit's resistance curve did not match OEM specifications. For Honda fuel sending units, using a genuine OEM part is critical.

2020 Lincoln Aviator with 'Door Fault' Message

The rear passenger door would not open electronically from the inside. A 'Door Fault - Service Required' message appeared on the dash, accompanied by code B1175:19.

What they tried:

1. Initially suspected the physical latch mechanism was failing.
2. Searched owner forums and discovered multiple Technical Service Bulletins (TSBs).

Outcome: The owner learned from TSBs SSM 51788 and 50967 that the issue was overly sensitive software in the door control module. A dealer reprogrammed the module with updated software, fixing the issue permanently.

Lesson: Before replacing expensive electronic parts on modern Lincolns, search for TSBs. A software update at the dealer often fixes the problem and prevents the unnecessary replacement of a $700+ latch assembly.

How to Prevent This Code From Triggering

• Lubricate All Door and Hood Latches (Once per year, or every other oil change) — Dirt and moisture cause the mechanical parts of a latch to stick, preventing the ajar switch from operating correctly. Spraying moving parts with white lithium grease ensures smooth operation and displaces moisture.
• Use Top Tier Certified Gasoline (Every fill-up) — For Honda/Acura, sulfur and contaminants in low-quality fuel build up on the fuel level sending unit's resistor contacts, creating an insulating layer that causes incorrect readings. Top Tier gas contains detergents that keep the sending unit clean.
• Perform Regular Battery Health Checks (Every oil change, especially on vehicles over 3 years old) — On modern Ford and Lincoln vehicles, a weak 12V battery causes low voltage spikes during engine cranking, triggering false electronic codes like B1175 in sensitive modules.
• Clean Door Jambs and Drain Holes (Twice per year (spring and fall)) — Water gets trapped inside doors if the drain holes at the bottom are clogged. This moisture corrodes the electrical connectors for door latch assemblies and ajar switches.

Frequently Asked Questions

Can I fix code B1175 myself?

It depends on the cause. On a Ford F-150, adjusting the hood or replacing the hood latch is a very DIY-friendly job. However, replacing a fuel sending unit inside a Honda gas tank or reprogramming a Lincoln computer module is best left to a professional.

What does the ':19' mean on a Lincoln B1175 code?

The ':19' suffix on a Lincoln code like B1175:19 stands for 'Circuit Current Above Threshold.' It means the door control module has detected an electrical anomaly, which it interprets as a fault. This is the specific signature of the software glitch addressed by TSBs.

Can I just bypass the hood ajar sensor on my F-150?

Yes, you can temporarily bypass the sensor by jumping the two wires on the harness connector. This makes the computer think the hood is always closed, re-enabling your remote start and stopping the alarm. However, this disables a safety feature and is not a recommended permanent fix.

What are common misdiagnosis pitfalls for code B1175?

A major pitfall on Ford/Lincoln vehicles is replacing hardware immediately when the real issue is a simple hood adjustment, a weak battery, or a software glitch. For Hondas, a mistake is assuming a new aftermarket part is good; many aftermarket fuel sending units do not meet correct resistance specifications.

Why is my remote start not working with code B1175?

If your vehicle is a Ford or Lincoln and the code relates to a hood ajar sensor, the remote start is automatically disabled as a safety feature. This prevents the engine from starting while someone is working under the hood.

My alarm keeps going off randomly. Could code B1175 be the cause?

Yes. If you have a Ford, Lincoln, or Land Rover, the B1175 code often means the car thinks a door or the hood is open. When you lock the car, the alarm system arms, and if it detects what it thinks is an entry point opening, it triggers the alarm.

How much does it cost to fix a B1175 code?

Costs vary widely based on the manufacturer. A Ford hood latch adjustment is free, while replacing the latch costs $195-$275. A Lincoln dealer software update runs $200-$400, and a Honda fuel sending unit replacement averages $350-$700.

Is B1175 a serious code?

It is moderately serious. While it won't stop your car from running, it creates unsafe or inconvenient situations, such as running out of fuel unexpectedly, having a car alarm that goes off randomly, a door that doesn't lock properly, or a dead battery.

Key Takeaways

• Code B1175 is a manufacturer-specific Body Control Module (BCM) fault, meaning its definition changes entirely depending on whether you drive a Honda, Ford, or Chevrolet.
• On Honda and Acura vehicles, B1175 indicates a failing fuel level sending unit, while on Ford and Lincoln models, it signals a faulty hood or door ajar switch.
• Check Technical Service Bulletins (TSBs) before buying parts, as the fix is often a $0 mechanical adjustment on Ford F-150s or a $200-$400 dealer software update on Lincoln Aviators.
• Ignoring a Ford or Lincoln B1175 code disables your remote start, triggers random car alarms, and drains your 12V battery by keeping interior lights on.
• Repair costs range from $0 for a simple hood bump stop adjustment to $700+ for a new fuel sending unit, making accurate diagnosis critical.