what does this symbol mean?
SAE J2012 A scan tool screen showing the code P0030

P0030: HO2S heater control circuit (bank 1, sensor 1)

An OBD-II trouble code for a fault in the circuit that controls the heater of oxygen sensor 1 on bank 1.

How to read it

P0030 is one of the standard OBD-II trouble codes stored when the check engine light comes on. SAE J2012, the standard that defines the codes, names it “HO2S Heater Control Circuit Bank 1 Sensor 1”; Volkswagen’s service information gives the same name.

Also searched as: code P0030, P0030 code.

Code names follow SAE J2012. Manufacturers add codes of their own, and the same code can have several causes: the vehicle’s service information or a qualified mechanic can say what it means for a particular car.

What the monitor checks

The federal rule requires the system to detect oxygen sensor deterioration or malfunction that raises emissions to 1.5 times the standard.

What the manual says to do

Ford’s F-150 manual says that if the indicator stays on, the vehicle should be serviced at the first available opportunity, and that continued driving with it on can mean higher emissions, lower fuel economy, rougher running and more costly repairs.

How the light goes out

Under the federal rule, the check engine light may go out once the fault has not come back during three trips in a row in which its monitor runs without finding it. The system may erase the stored code if the same code has not been registered again in at least 40 engine warm-up cycles.

More OBD-II trouble codes

Sources

Last reviewed September 28, 2026 by Rory Hansen. How we research

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