B1220 — Fuel Tank Pressure Sensor Circuit Open

What are the symptoms of B1220?

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

Will B1220 clear itself?

Sometimes B1220 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 B1220?

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 B1220 mean?

B1220 — Fuel Tank Pressure Sensor Circuit Open. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: damaged wiring in door jambs or wet areas, blown fuse or failed relay, body control module (BCM) fault.

How much does it cost to fix B1220?

Replace the switch or actuator — $120–$450; BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

When your scan tool pulls code B1220, it's telling you the vehicle's body control module has detected a problem with the fuel tank pressure sensor circuit. Specifically, the module found an open circuit — meaning the electrical path it expects to find is broken and current cannot flow through it as designed. This falls under the B-body category of diagnostic trouble codes, which covers various body and comfort system electrical faults rather than engine management issues directly.

The fuel tank pressure sensor plays a role in the evaporative emissions system, monitoring pressure changes inside the fuel tank to help detect leaks and control vapor recovery. The body control module or powertrain control module continuously watches this circuit while the vehicle operates. When sensor readings stray outside the expected parameters for a sufficient number of drive cycles, the module logs B1220 and illuminates the check engine or warning light. The freeze frame data stored alongside B1220 is particularly useful — it captures the exact operating conditions (engine speed, load, temperature, vehicle speed) when the fault first appeared, giving you a starting point for your investigation.

"Circuit open" is a straightforward electrical diagnosis: somewhere along the wiring between the sensor and control module, the path is interrupted. Common culprits include a severed wire, a connector that has come loose or suffered corrosion at its pins, a blown fuse in the feeding circuit, or a sensor that has failed internally and presents an open circuit to the module.

Common Symptoms of B1220

• Check engine light or dedicated warning indicator illuminated on the dashboard
• No noticeable effect on engine performance or drivability in most vehicles
• Intermittent or complete failure of associated body functions such as power locks, windows, interior lighting, or wipers
• Possible intermittent operation where the fault comes and goes, especially in wet weather or over rough roads
• Fuel tank pressure sensor may read abnormally in live data, often showing zero or infinite pressure

What Causes B1220?

• Physical damage to the wiring harness feeding the fuel tank pressure sensor, including cuts, abrasions, or broken strands inside the insulation
• Electrical connector at the sensor or module side is unplugged, has a backed-out pin, or shows signs of corrosion blocking current flow
• Blown fuse protecting the fuel tank pressure sensor circuit or the related control module
• Fuel tank pressure sensor has failed internally and presents an open circuit to the vehicle's electrical system
• Corroded, damaged, or loose wiring connectors at junction points, especially in areas exposed to moisture
• Failed relay or switch controlling power to the sensor circuit
• Wiring damage at flex points where wires pass through door jambs, tailgate hinges, or other moving areas
• BCM or body control module itself may be faulty, though this is less common than wiring issues

How to Diagnose B1220

1. Connect your OBD2 scanner and confirm B1220 is stored in the module's memory. Record all freeze frame data associated with the code — this snapshot shows engine and vehicle conditions when the fault occurred and guides your diagnosis.

2. Check for any other stored trouble codes. Related codes often point to the underlying cause or a secondary issue that appeared at the same time. Search for manufacturer TSBs (technical service bulletins) using your vehicle's VIN — some B1220 occurrences have documented factory fixes or software updates.

3. Perform a thorough visual inspection of the wiring harness related to the fuel tank pressure circuit. Look for damaged insulation, chafing from contact with other components, corrosion on exposed wires, and any signs of prior repairs that may have failed.

4. Test circuit continuity end-to-end using a digital multimeter. Measure resistance along the entire path from the control module to the sensor. Perform a wiggle test while monitoring readings — intermittent opens will show as fluctuating or infinite resistance when the harness is moved.

5. Access live data for the fuel tank pressure sensor if your scan tool supports it. Operate related systems (fuel filler door, evap system components) while watching the pressure readings for expected changes or lack thereof.

6. Inspect connectors and wiring at common failure points — door jambs, tailgate hinges, and areas near the fuel tank send unit. These locations experience repeated flexing and moisture exposure that breaks wires first.

7. Clear B1220 after completing your inspection and repairs. Perform a full drive cycle that recreates the conditions recorded in the freeze frame data. Re-scan after driving to confirm the code does not return.

Repair Options for B1220

Repair costs vary significantly depending on which component failed. Always address the most likely and least expensive causes before considering major component replacement.

• Wiring or connector repair: $80–$250 — Often just a matter of re-crimping a terminal, applying dielectric grease to a corroded connector, or splicing a damaged section of wire. This is the most common fix for B1220.
• Fuel tank pressure sensor replacement: $120–$300 (parts) + labor — If testing confirms the sensor itself is internally open, it must be replaced. The sensor is typically mounted on or near the fuel pump module inside the tank.
• Fuse or relay replacement: $10–$50 — A simple blown fuse or failed relay is the cheapest possible cause. Check the vehicle's fuse box diagram and replace any suspect fuses.
• BCM repair or replacement: $300–$900 — If the body control module is confirmed faulty through voltage and ground testing, repair or replacement may be necessary. This is rarely the root cause and should be diagnosed thoroughly before replacement.

The total cost to repair B1220 typically falls between $80 and $900 depending on the actual failure point. An accurate diagnosis before purchasing parts will prevent unnecessary expenses — the BCM replacement scenario is the most expensive and should be your last consideration, not your first.

Can You Drive with B1220?

Generally safe to continue driving — body electrical codes like B1220 typically do not affect engine operation, transmission function, or braking systems. However, the underlying cause matters: if the fault involves exterior lighting, wipers in adverse weather, or central locking that could leave the vehicle unsecured, address those specific safety concerns promptly. Have the code diagnosed at your earliest convenience to prevent potential emissions system complications or complete loss of the affected function.

Related OBD2 Codes

• B1200: Climate Control Pushbutton Circuit Failure
• B1201: Fuel Sender Circuit Failure
• B1202: Fuel Sender Circuit Open
• B1203: Fuel Sender Circuit Short To Battery
• B1204: Fuel Sender Circuit Short To Ground
• B1205: EIC Switch-1 Assembly Circuit Failure