P00D2: O2 Sensor Heater Control Circuit Range/Performance Bank 1 Sensor 2
What to do
Ask whether other faults from the same oxygen sensor are stored. The heater is what brings the sensor up to working temperature, so a heater fault makes the sensor report nonsense too — and one repair usually clears both.
Ask for the connector to be inspected for heat damage. This circuit carries real current, so a failing connection burns rather than just corroding, and the discolouration is usually visible.
Have the battery and charging system checked if that has not been done recently, since a weak supply slows the heater enough to fail the test with nothing wrong.
The car will drive normally. This is an emissions monitoring fault, so plan the repair around your MOT rather than treating it as urgent.
What this code means
The heater circuit for the downstream oxygen sensor on bank 1 is behaving oddly without being open or shorted.
An oxygen sensor's heater is a precondition rather than a convenience, and knowing that explains why a heater fault sets sensor codes. A zirconia element produces no usable signal below roughly 300°C, so until the heater has done its work the sensor is simply not reporting.
Range/performance means the module is watching how the heater behaves and finding it wrong — usually by measuring the current it draws, from which the element's resistance and therefore its temperature can be inferred. The circuit conducts; it does not conduct correctly.
Which points at three things:
- Resistance in the circuit. A heater draws real current, so a corroded terminal both drops voltage and heats itself — which oxidises it further. Look for discoloured connector plastic, not just continuity.
- A degrading heater element, whose resistance has drifted with age so the module can no longer predict its temperature.
- Supply quality. A weak battery or poor earth slows warm-up enough to fail the test with a sound heater.
Expect sensor response or closed-loop codes stored alongside, and treat the heater as the cause. A sensor that never gets hot cannot report properly, so fixing the heater usually clears several codes at once.
On the downstream sensor the practical consequence is emissions monitoring rather than driveability — the car drives normally and cannot complete its self-checks.
Likely causes
Start here
- Faulty oxygen sensor heater · moderate
- High resistance in sensor wiring · moderate
- Corroded or loose connector · easy
Less common
- Low system voltage · easy
- Blown fuse supplying the heater circuit · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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