What Does B1202 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the fuel tank sending unit circuit. The fuel sender is a variable resistor that changes resistance based on fuel level, signaling the fuel gauge on the instrument cluster. An open circuit means the BCM is not receiving any signal from the fuel sender, typically reading as infinite resistance or no continuity.
Common Causes
35%
Faulty fuel level sending unit with open internal winding or broken float arm
30%
Broken or corroded wiring between fuel sender and BCM, including damaged harness connector at fuel tank
20%
Corroded or loose connector terminals at fuel sender or BCM connection points
10%
Failed BCM or instrument cluster module with faulty fuel gauge input circuitry
5%
Blown fuse or open circuit in power supply to fuel sender circuit
Diagnostic Steps
1
Step 1: Visually inspect the fuel sender connector at the top of the fuel tank for corrosion, damage, or loose connections. Check connector pins for bent, corroded, or pushed-back terminals.
2
Step 2: With ignition off, disconnect the fuel sender connector and measure resistance across the sender terminals using a digital multimeter. Typical readings should range from 0-90 ohms (empty) to 250-350 ohms (full) depending on manufacturer. An infinite reading confirms sender failure.
3
Step 3: If sender resistance is normal, check circuit continuity from the fuel sender connector to the BCM connector using a multimeter in continuity mode. Wiggle wiring harness along its length to identify intermittent opens. Verify ground circuit continuity separately.
4
Step 4: If wiring is intact, backprobe the BCM fuel sender signal wire with ignition on and measure voltage. Should see approximately 5V reference voltage with sender disconnected. If no voltage present, suspect BCM fault.
5
Step 5: If reference voltage is present, reconnect sender and observe voltage change as float arm is manually moved (may require fuel tank access). Voltage should vary smoothly from approximately 0.5V to 4.5V. Erratic or no change confirms sender fault.
6
Step 6: After repair, clear codes, cycle ignition, and monitor fuel gauge response through full tank range. Verify DTC does not return and gauge reads accurately.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the fuel tank sending unit circuit. The fuel sender is a variable resistor that changes resistance based on fuel level, signaling the fuel gauge on the instrument cluster. An open circuit means the BCM is not receiving...
The most common cause of B1202 (Fuel Sender Circuit Open) is: Faulty fuel level sending unit with open internal winding or broken float arm
Typical repair costs for B1202 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving, but the fuel gauge will be inaccurate or non-functional, preventing accurate monitoring of fuel level and potentially leading to running out of fuel unexpectedly. Track mileage manually and refuel conservatively until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1202 to identify the root cause.
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Quick Info
Category
Body
System
Fuel System Monitoring / Instrument Cluster
Difficulty
Type
Manufacturer
Recommended Tools
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