What Does B1224 Mean?
This code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition on the fuel temperature sensor #1 circuit, specifically a short to battery voltage (typically 12+ volts when it should read much lower). The BCM monitors this sensor to track fuel temperature for evaporative emissions control and fuel system management. The short to battery condition means the signal wire is making direct contact with a power source or has internal sensor failure causing excessive voltage.
Common Causes
45%
Damaged or chafed wiring harness causing signal wire to contact power wire or chassis-mounted power source
30%
Failed fuel temperature sensor with internal short circuit to power
15%
Corroded or damaged connector terminals causing cross-circuit contamination with adjacent power circuits
10%
BCM internal fault or water intrusion causing improper voltage reading
Diagnostic Steps
1
Step 1: Perform visual inspection of fuel temperature sensor location (typically in fuel tank or fuel line). Check for damaged wiring, melted insulation, or signs of contact with hot exhaust components or sharp edges along the harness routing path
2
Step 2: Disconnect the fuel temperature sensor connector and measure voltage at the vehicle harness side signal wire with ignition ON using a digital multimeter. Reading should be approximately 5 volts (reference voltage); if reading shows battery voltage (12+ volts), the short exists in the vehicle harness between sensor and BCM
3
Step 3: With sensor disconnected, measure resistance between sensor terminals. Compare to manufacturer specifications (typically 1500-3000 ohms at 68°F). If reading shows very low resistance (near 0 ohms) or if one terminal shows continuity to sensor body/ground, sensor has internal short and requires replacement
4
Step 4: Inspect connector pins for bent terminals, corrosion, or moisture. Check adjacent circuits in the same connector for proper pin spacing and insulation. Repair or replace connector if damage found
5
Step 5: Trace wiring harness from sensor to BCM checking for pinch points, modifications, or aftermarket accessories that may have pierced insulation. Pay special attention to areas where harness passes through metal grommets or near battery cables
6
Step 6: After repair, clear codes, cycle ignition, and verify voltage readings are within normal range (0.5-4.5 volts depending on fuel temperature). Monitor for code reoccurrence during test drive
Estimated Repair Cost
$120 - $650
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition on the fuel temperature sensor #1 circuit, specifically a short to battery voltage (typically 12+ volts when it should read much lower). The BCM monitors this sensor to track fuel temperature for evapor...
The most common cause of B1224 (Fuel Temperature Sensor #1 Circuit Short to Battery) is: Damaged or chafed wiring harness causing signal wire to contact power wire or chassis-mounted power source
Typical repair costs for B1224 range from $120 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive as this is a monitoring circuit issue that does not directly affect engine operation or safety systems. However, evaporative emissions system may not function properly, and fuel trim adaptations could be affected in extreme temperature conditions; repair within 1-2 weeks recommended.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1224 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Fuel System / Evaporative Emissions
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
