Code
B1306
ALFA ROMEO
B — Body
Oil level switch open circuit
AI status
Completed
Completed
100%
Causes
- Broken or disconnected wiring in the oil level switch circuit
- Corroded, loose or contaminated connector at the oil level switch
- Failed oil level switch (open internally)
- Poor ground or power supply to the switch circuit
- Faulty instrument cluster / body control module input (less common)
Symptoms
- Oil level warning lamp or message on dash
- Incorrect oil level indication or no oil level reading
- Service or fault indicator illuminated for the body control system
- Possible stored history code without continued drivability symptoms
What to check
- Scan for stored and pending codes and note freeze frame data
- Visually inspect wiring harness and connector at the oil level switch for damage, corrosion or oil ingress
- Check connector mating faces and terminals for looseness or contamination
- Measure continuity and resistance of the switch circuit from connector to control module
- Check for proper reference voltage and ground at the switch connector
- If available, observe live data or input state for the oil level sensor on the scan tool
Signal parameters
- Typical switch state: closed (low resistance) when oil level present, open (high resistance/infinite) when low — actual resistance depends on sensor design
- Open-circuit detection: very high resistance or infinite ohms between signal and ground/reference
- Reference voltage: often switched 12V or a low voltage reference (check vehicle wiring diagram)
- Signal voltage at module: may be near 0V or near reference voltage depending on switch wiring (confirm with schematic)
Diagnostic algorithm
- Read and record DTCs and any related codes. Clear codes, then see if B1306 returns.
- Perform a visual inspection of the oil level switch connector and wiring for damage, chafing, oil contamination, or corrosion.
- Unplug the switch and check terminal condition. Clean and reseat connector; re-test for code presence.
- With ignition on, backprobe the switch connector to verify reference voltage and ground presence per wiring diagram.
- Measure resistance of the oil level switch (engine off). Compare to expected open/closed behavior. Replace switch if it is open when it should be closed or shows erratic values.
- Check continuity between switch connector and the body control/instrument cluster input. Repair any open circuits or high resistance.
- If wiring and switch test good, check the input at the control module. If the module input is faulty, follow module diagnostics per manufacturer procedures.
- After repairs, clear codes and confirm proper operation and that the code does not return after normal driving.
Likely causes
- Corroded connector at the oil level switch (most common)
- Open or damaged wiring harness near sump or underbody
- Seized or contaminated switch due to oil contamination
- Failed switch element
Fault status
Status
Oil level switch open circuit detected. The control module is not seeing the expected switch signal (open or high resistance). Inspect switch, connector and wiring; replace faulty components as required. Do not ignore oil level warnings — verify actual oil level before operating the vehicle.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email