P06B3
Sensor Power Supply B Circuit/Open
Sensor power supply
Generic OBD-II
High
What it means
P06B3 means the ECM/PCM has detected an open in the "B" sensor power supply circuit. This regulated feed powers a group of sensors, so when it opens those sensors lose power, report wrong values, and the engine can run poorly or drop into limp mode. The fault usually traces to broken supply wiring, a bad connector, or the module, rather than to the engine itself.
High
Can I keep driving? It can run rough or drop into limp mode, because the sensors on this power supply lose their feed — get it diagnosed before relying on the vehicle.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp mode
- Several sensor codes stored at once (they share the same power supply)
- Rough running, hesitation, or erratic gauges
Common causes
Most likely first
- Open in the sensor power supply B circuit wiringLikely
- Corroded or disconnected connector on the supply circuitCommon
- A sensor on the circuit shorted and pulling the supply downCommon
- Faulty ECM/PCM supplying the circuitLess often
How to diagnose & fix
Work through it in order
- Scan and note every code present — the sensors sharing power supply B help pinpoint the affected circuit.
- Identify the sensors fed by supply B for this vehicle and inspect their shared wiring and connectors for an open or corrosion.
- Unplug those sensors one at a time to check whether a shorted sensor is collapsing the supply.
- Repair the open circuit or connector; if the supply stays absent with good wiring, the ECM/PCM is at fault.
FAQ
Quick answers
Is it safe to drive with P06B3?+
Not ideally — the sensors on this supply lose their feed, so the engine can run poorly or derate. Have it diagnosed promptly.
Can I just clear P06B3?+
It returns until the open in the power-supply circuit is repaired. A scan tool helps identify which sensors lost their supply.
Related codes
Often seen with P06B3
Read & clear P06B3 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX