What Does B1306 Mean?
This code indicates the body control module (BCM) or engine control module (ECM) has detected an open circuit in the oil level switch circuit. The oil level switch monitors engine oil level and sends a signal to the control module. An open circuit means there is no continuity in the wiring or the switch itself has failed, preventing the system from monitoring oil level.
Common Causes
45%
Faulty oil level sensor/switch with internal open circuit or corrosion
30%
Damaged, broken, or disconnected wiring harness between sensor and control module
15%
Corroded or loose electrical connector at oil level sensor
10%
Failed body control module or internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of oil level sensor connector and wiring for damage, corrosion, loose pins, or disconnected terminals. Check for oil contamination in connector that may cause circuit issues.
2
Step 2: Using a digital multimeter, measure resistance across the oil level sensor connector terminals with sensor disconnected. Compare readings to manufacturer specifications (typically 0-5 ohms closed, infinite ohms open depending on oil level). A constant open circuit indicates faulty sensor.
3
Step 3: Check continuity of wiring harness from sensor connector to BCM/ECM connector using multimeter. Wiggle wiring while testing to reveal intermittent opens. Repair or replace damaged wiring as needed.
4
Step 4: With ignition on and sensor connected, backprobe the sensor connector and verify reference voltage (typically 5V or 12V) is present from control module. No voltage indicates BCM/ECM issue or power supply fault.
5
Step 5: If all wiring and voltage checks pass, replace the oil level sensor and clear codes. Verify proper oil level in engine before testing. Monitor system operation through multiple drive cycles to confirm repair.
6
Step 6: If fault persists after sensor replacement and wiring verification, test BCM/ECM inputs using advanced scan tool bi-directional controls or consider control module failure requiring professional diagnosis.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
This code indicates the body control module (BCM) or engine control module (ECM) has detected an open circuit in the oil level switch circuit. The oil level switch monitors engine oil level and sends a signal to the control module. An open circuit means there is no continuity in the wiring or the sw...
The most common cause of B1306 (Oil Level Switch Circuit Open) is: Faulty oil level sensor/switch with internal open circuit or corrosion
Typical repair costs for B1306 range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive, but you will not receive warnings if engine oil level becomes critically low, which could lead to engine damage. Check oil level manually and repair promptly to restore monitoring capability.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1306 to identify the root cause.
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Quick Info
Category
Body
System
Engine Oil Monitoring System
Difficulty
Type
Manufacturer
Recommended Tools
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