What Does B1222 Mean?
B1222 indicates the Body Control Module (BCM) has detected an electrical fault in the fuel temperature sensor #1 circuit. This sensor monitors the temperature of the fuel to allow the engine control system to adjust fuel delivery and emissions controls based on fuel density changes with temperature. The fault could be an open circuit, short circuit, or sensor failure that prevents the BCM from receiving a valid signal.
Common Causes
45%
Damaged wiring harness or corroded connector at fuel temperature sensor causing open or short circuit
35%
Failed fuel temperature sensor due to internal component failure or contamination
15%
Poor ground connection in fuel tank sender assembly or fuel pump module
5%
Body Control Module (BCM) internal fault or software issue
Diagnostic Steps
1
Step 1: Perform visual inspection of fuel temperature sensor connector (typically located at fuel tank or fuel pump module). Check for corrosion, pushed-out pins, moisture intrusion, or damaged wiring. Clean and repair connector if issues found.
2
Step 2: Using a digital multimeter, backprobe the fuel temperature sensor signal and ground wires at the connector. Measure resistance of sensor across terminals (typical range 2000-3000 ohms at 68°F, decreasing as temperature increases). Compare readings to manufacturer specifications for your specific vehicle.
3
Step 3: With sensor disconnected, measure resistance between sensor signal wire and ground at the BCM connector. Reading should be near infinite (open circuit). Then measure continuity from sensor ground pin to chassis ground (should be less than 1 ohm). High resistance indicates poor ground; low resistance on signal wire indicates short to ground.
4
Step 4: If wiring and grounds test good, substitute a known-good fuel temperature sensor or measure voltage supply at sensor connector (typically 5V reference voltage from BCM). Clear codes and test drive to verify repair.
5
Step 5: If all tests pass but code persists, check for BCM software updates or internal BCM fault requiring module replacement or reprogramming.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
B1222 indicates the Body Control Module (BCM) has detected an electrical fault in the fuel temperature sensor #1 circuit. This sensor monitors the temperature of the fuel to allow the engine control system to adjust fuel delivery and emissions controls based on fuel density changes with temperature....
The most common cause of B1222 (Fuel Temperature Sensor #1 Circuit Failure) is: Damaged wiring harness or corroded connector at fuel temperature sensor causing open or short circuit
Typical repair costs for B1222 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This code typically affects fuel system monitoring and emissions calculations but does not prevent normal vehicle operation. Repair at earliest convenience to maintain proper fuel system management and prevent potential fuel economy degradation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1222 to identify the root cause.
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Quick Info
Category
Body
System
Body Control System / Fuel System Monitoring
Difficulty
Type
Manufacturer
Recommended Tools
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