B1220 — Fuel Tank Pressure Sensor Circuit Open #

Note: The code label may vary depending on the vehicle manufacturer.

• Fuel Tank Pressure Sensor Circuit Open (Ford)
• Fuel Tank Pressure Sensor Circuit Malfunction/Open (Toyota)
• Fuel Tank Pressure Sensor Circuit Open (Nissan)
• Fuel Tank Pressure Sensor Circuit Break (Mazda)

Code Summary for B1220 #

The B1220 diagnostic trouble code (DTC) signals an issue detected by the vehicle’s onboard computer in the fuel tank pressure sensor circuit. This sensor is a key component of the Evaporative Emission Control (EVAP) system, which prevents fuel vapors from escaping into the atmosphere. When this code appears, it means the Electronic Control Module (ECM) or Powertrain Control Module (PCM) has noticed an “open” circuit—essentially, a break or loss of electrical continuity—between itself and the sensor. This disrupts the ability to monitor fuel tank pressure, which can affect emissions and system diagnostics. The code is typically triggered by wiring problems, connector issues, or a faulty sensor itself.

Common Symptoms for Code B1220 #

A B1220 code doesn’t always produce dramatic drivability issues, but it does indicate a breach in the vehicle’s emissions monitoring system. Most drivers may not notice performance changes, but some warning signs can appear, especially during emissions testing or EVAP system checks.

• Illuminated Check Engine Light or Malfunction Indicator Lamp (MIL)
• Possible “EVAP system not ready” flag during emissions testing
• Occasional fuel odor near the vehicle
• Difficulty passing a state or local emissions inspection
• Stored pending or active trouble codes related to EVAP system

Probable Causes for Code B1220 #

The B1220 code is most often linked to electrical issues within the fuel tank pressure sensor circuit. Here are the most probable causes, listed in order of frequency:

1. Damaged or corroded wiring between the sensor and the ECM/PCM
2. Disconnected or loose sensor connector
3. Defective fuel tank pressure sensor
4. Blown fuse in the sensor circuit (if applicable)
5. Faulty ECM/PCM (rare)

Step-by-Step Diagnostic for Code B1220 #

Diagnosing a B1220 code requires systematic electrical testing and visual inspection. Here’s a practical approach to pinpoint the root cause:

• 1. Scan for additional codes: Use a scan tool to check for other EVAP or sensor-related codes that may provide more clues.
• 2. Visual inspection: Examine the fuel tank pressure sensor, its wiring harness, and connectors for obvious damage, corrosion, or loose connections.
• 3. Check sensor connector: Make sure the connector is fully seated and free of moisture, dirt, or corrosion.
• 4. Test sensor voltage and ground: Using a digital multimeter, verify the presence of reference voltage (usually 5V from the ECM/PCM) and a good ground at the sensor connector.
• 5. Continuity test: With the sensor unplugged, check continuity between the ECM/PCM and sensor wires to detect open circuits or shorts.
• 6. Test the sensor: If wiring checks out, test the sensor’s resistance per OEM specifications; replace if out of range.
• 7. Check fuses: Inspect applicable fuses related to the EVAP or sensor circuit.
• 8. Review ECM/PCM operation: In rare cases, consider ECM/PCM diagnosis if all other steps pass.

Possible Repairs for Code B1220 #

Repairing a B1220 code focuses on restoring electrical integrity to the sensor circuit. Actions taken should directly address the diagnosed cause:

• Repair or replace damaged, frayed, or corroded wires between the fuel tank pressure sensor and ECM/PCM
• Clean, repair, or replace the sensor connector if pins are bent, corroded, or loose
• Replace the fuel tank pressure sensor if found faulty after testing
• Replace any blown fuses dedicated to the sensor circuit
• In rare cases, repair or replace the ECM/PCM if confirmed defective

Is It Safe to Drive with Code B1220? #

Limited: While the B1220 code doesn’t usually cause immediate drivability problems, it does affect your vehicle’s emissions system. You may continue driving for short periods, but it’s best to address the issue promptly to avoid failed emissions testing, potential fuel vapor leaks, or further EVAP system faults. If you notice a persistent fuel odor or additional warning lights, stop driving and seek professional help.

Vehicles Frequently Affected by Code B1220 #

This code is most often seen in vehicles that use an EVAP system with a dedicated fuel tank pressure sensor, particularly models from the following manufacturers:

• Ford (Focus, Escape, F-150, Fusion)
• Toyota (Camry, Corolla, Tacoma)
• Nissan (Altima, Sentra, Frontier)
• Mazda (Mazda3, Mazda6, CX-5)
• Some Honda and GM models (less frequently)

Common Mistakes & Best Practices for Code B1220 #

Diagnosing EVAP codes like B1220 can be tricky. Here’s how to avoid common pitfalls and maximize your repair success:

• Not thoroughly inspecting wiring and connectors for hidden corrosion or breaks
• Replacing the sensor before confirming power and ground presence at the connector
• Overlooking blown fuses that can mimic open circuit conditions
• Not clearing codes and rechecking after repairs to ensure the issue is resolved
• Ignoring OEM wiring diagrams when tracing circuits

FAQ Express for Code B1220 #

When in doubt, here are quick answers to some common questions about B1220:

• Q: Can a loose gas cap trigger B1220?
  A: No, B1220 specifically refers to an electrical open in the fuel tank pressure sensor circuit, not a loose or missing gas cap. However, a loose cap can trigger other EVAP codes.
• Q: Will replacing the sensor always fix the code?
  A: Not always. If the underlying problem is damaged wiring or a faulty connector, replacing the sensor won’t solve the issue. Always diagnose the circuit before replacing components.