What Does B1220 Mean?
B1220 indicates the Body Control Module (BCM) has detected an open circuit condition in the fuel tank pressure sensor wiring or sensor itself. This sensor monitors vapor pressure within the evaporative emissions system to detect leaks and ensure proper fuel tank venting. An open circuit means the BCM is receiving no signal or infinite resistance from the sensor circuit, preventing proper EVAP system monitoring.
Common Causes
45%
Damaged, corroded, or disconnected wiring harness connector at fuel tank pressure sensor
30%
Failed fuel tank pressure sensor with internal open circuit
15%
Broken or chafed wiring between BCM and fuel tank pressure sensor
10%
Corroded or damaged BCM connector pins or internal BCM failure
Diagnostic Steps
1
Step 1: Perform visual inspection of fuel tank pressure sensor connector and wiring. Check for corrosion, water intrusion, damaged pins, or loose connections at the sensor mounted on or near the fuel tank. Clean and repair any obvious connector issues.
2
Step 2: Using a digital multimeter, backprobe the fuel tank pressure sensor connector and measure resistance across sensor terminals (typically 2-wire or 3-wire sensor). Compare readings to manufacturer specifications (usually 1-5 kΩ at atmospheric pressure). An infinite resistance reading confirms sensor internal failure.
3
Step 3: Disconnect the sensor and measure continuity from BCM connector pins to sensor connector on both signal and ground wires. Expected reading is less than 5 ohms on each circuit. Infinite resistance indicates open circuit in wiring harness requiring repair or replacement.
4
Step 4: Check reference voltage supply from BCM at sensor connector (typically 5V). If no voltage is present and wiring is intact, suspect BCM failure. If voltage is correct and wiring tests good, replace fuel tank pressure sensor.
5
Step 5: After repair, clear codes and perform EVAP system test procedure. Monitor live data for fuel tank pressure sensor voltage/signal to confirm proper operation and verify code does not return.
Estimated Repair Cost
$120 - $450
Parts + labor, varies by vehicle and location
B1220 indicates the Body Control Module (BCM) has detected an open circuit condition in the fuel tank pressure sensor wiring or sensor itself. This sensor monitors vapor pressure within the evaporative emissions system to detect leaks and ensure proper fuel tank venting. An open circuit means the BC...
The most common cause of B1220 (Fuel Tank Pressure Sensor Circuit Open) is: Damaged, corroded, or disconnected wiring harness connector at fuel tank pressure sensor
Typical repair costs for B1220 range from $120 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this does not affect vehicle operation or driveability. Repair should be completed within a reasonable timeframe to maintain proper emissions system function and prevent potential fuel vapor leaks.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1220 to identify the root cause.
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Quick Info
Category
Body
System
Evaporative Emissions System
Difficulty
Type
Manufacturer
Recommended Tools
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