B1306 — Oil Level Switch Circuit Open

Will B1306 clear itself?

Sometimes B1306 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What are the symptoms of B1306?

Drivers most often notice: warning light on the dashboard, the affected function (locks, windows, lighting, wipers) works intermittently or not at all, no impact on engine operation in most cases.

How do I diagnose B1306 myself?

Start with a scan: confirm B1306, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the oil level switch, and verify the suspect component against live data before buying parts.

What does OBD2 code B1306 mean?

Oil Level Switch Circuit Open (B1306): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, damaged wiring in door jambs or wet areas, corroded or loose connectors.

How much does it cost to fix B1306?

Repair wiring or connectors — $80–$250; Replace the switch or actuator — $120–$450; BCM repair or replacement — $300–$900. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

When your scan tool pulls code B1306, the vehicle's body control module is reporting an open circuit in the oil level switch wiring. This is a body electrical fault, not an engine or emissions issue. The "open" designation tells you the electrical pathway has been interrupted somewhere—no current can flow where the module expects to find it. That's typically a broken wire, a connector that's come loose or corroded, a blown fuse, or the switch itself has failed internally.

The oil level switch circuit falls under the body's auxiliary systems, monitoring oil level for the driver information center or warning indicators. When the control module detects no signal where it should see one, it sets B1306. That doesn't happen from a single glitch—the module must confirm the fault persists under specific operating conditions before illuminating the check engine light. The freeze frame data stored alongside B1306 shows exactly what the engine was doing (load, RPM, temperature, vehicle speed) when the fault first appeared, which points you toward the right conditions to reproduce during testing.

Getting B1306 resolved starts with understanding it's a wiring or component issue, not an engine problem. The good news is the fix is usually straightforward once you isolate the actual failure point.

Symptoms of B1306

• Check engine or warning light stays illuminated on the dashboard
• The oil level display shows incorrect information or goes blank
• Affected body electrical functions may operate intermittently or not at all
• No drivability impact—the engine runs and drives normally in most cases
• Related systems (if sharing circuits) might exhibit phantom behavior
• In some vehicles, the module may revert to a default mode for the affected function

What Causes B1306?

The most frequent culprit is simply a broken or corroded wire in the oil level switch circuit. Wires fatigue over time, especially in areas exposed to heat, moisture, or physical movement.

• Internally open oil level switch—common in high-mileage vehicles
• Broken wire in the oil level switch harness
• Connector unplugged, backed-out terminal, or heavy corrosion on pins
• Blown fuse feeding the circuit
• Failed relay that controls the circuit
• Loose or poor connections at the switch or module
• Damaged wiring at flex points like door jambs or tailgate hinges

How to Diagnose B1306

1. Connect your OBD2 scanner and confirm B1306 is stored. Save the freeze frame data—this snapshot of engine conditions (load, RPM, coolant temperature, vehicle speed) tells you when and where the fault occurred so you can replicate those exact circumstances during testing.

2. Pull any related codes. Body control codes often appear in clusters, and a secondary code might point you directly to the root cause. Check for manufacturer TSBs (technical service bulletins) for your make and model—many B0xxx faults have documented factory fixes or software calibrations.

3. Visually inspect the entire oil level switch circuit harness. Look for damaged insulation, broken strands, corrosion, and any connectors that appear dirty, bent, or loose. This takes minutes and catches most problems.

4. Perform an end-to-end continuity test on the oil level switch circuit. With the connector disconnected, check resistance from switch to module. Wiggle the harness during testing—an intermittent open will show up as flickering readings.

5. Operate the affected function while monitoring switch and motor PIDs in live data. This confirms whether the problem is upstream (the switch signal) or downstream (the motor/actuator).

6. Clear the code, then drive through the freeze frame conditions—specific RPM, load, and temperature ranges—and verify B1306 does not return. If it comes back, you've confirmed a hard failure.

Repair Options for B1306

Fix the cheapest possibilities first before replacing expensive modules:

• Wiring or connector repair: $80–$250
• Oil level switch replacement: $120–$450
• Body control module (BCM) repair or replacement: $300–$900

How Much Does Fixing B1306 Cost?

The total depends entirely on which part failed. In most cases, you're looking at a wiring issue or a faulty switch—both are manageable repairs. BCM replacement is the expensive outlier and should only be considered after wiring and switches are ruled out.

Typical independent shop rates (parts and labor, USD):

• Wiring harness or connector repair: $80–$250
• Oil level switch replacement: $120–$450
• BCM repair or replacement: $300–$900

Overall, fixing B1306 typically runs between $80 and $900. Proper diagnosis before buying parts will keep you on the lower end of that range.

Can You Drive with B1306?

Yes—B1306 is generally safe to drive short distances. Body electrical codes rarely affect engine operation, transmission function, or braking. The vehicle will start, run, and handle normally. The main concerns are functional: if the oil level display is affected, you'll lose that monitoring feature until repaired. In vehicles where the circuit shares paths with exterior lights or wipers, those systems could be affected in poor weather. Central locking faults, if present, can leave the vehicle unsecured. Use normal judgment—if something critical is acting up, get it checked promptly.

Related OBD2 Codes

• B1300: Power Door Lock Circuit Failure
• B1301: Power Door Lock Circuit Open
• B1302: Accessory Delay Relay Coil Circuit Failure
• B1303: Accessory Delay Relay Coil Circuit Open
• B1304: Accessory Delay Relay Coil Circuit Short To Battery
• B1305: Accessory Delay Relay Coil Circuit Short To Ground