P2B8BIntake Air O2 Sensor Heater Control Circuit/Open Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B8B is about the heater of bank 1's intake oxygen sensor: the module switches the heater on but sees no current, the classic sign of a broken heater coil, an open feed or control lead, or a blown fuse in the heater supply. A wide-band sensor only measures once its ceramic is hot. Ford's patent US9309838B2 gives about 800 °C as an example set point for the intake sensor, held by closed-loop heater control, and Bosch rates the LSU 4.9 heater at 7.5 W in steady state. With the heater dead the sensor never becomes ready, and EGR loses its oxygen feedback. No manufacturer documents P2B8B publicly; CARB treats sensor heaters as monitored components that must be checked for circuit faults. P2B8D and P2B8E are the shorts, P2B8C judges whether the heater does its job.
- What you may notice
- Check engine light on
- EGR stays inactive because the intake sensor never becomes ready
- Possible companion code for the sensor signal
- Likely causes
- LikelyHeater coil inside the sensor burnt through or cracked
- PossibleBlown fuse or failed relay in the heater supply
- PossibleOpen heater feed or control wire, loose connector pin
- RareHeater driver in the engine module failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.