P0032 — Oxygen sensor heater control circuit high — bank 1, sensor 1

P0032 indicates an abnormally high electrical level in the heater control circuit for bank 1, sensor 1. This is the upstream sensor used for mixture control. “High” concerns electrical control, not a rich mixture or exhaust temperature. Supply wiring and heater control strategies differ between vehicles.

Affected system: Powertrain

Symptoms

• Engine warning lamp and a stored code.
• Delayed sensor readiness visible in diagnostic data after starting.
• Fuel consumption may increase if mixture control is affected.

Possible causes

• Short to supply or between wires near the exhaust.
• Incorrect or internally faulty heater; a control circuit fault is also possible.

What to check

• Confirm B1S1 in the engine diagram and save related codes and freeze-frame data before clearing anything.
• With the exhaust cold, inspect the B1S1 harness for melted insulation, rubbing, water in the connector and loose terminals.
• Check whether the controlled wire is accidentally connected to supply; interpret voltage or excess current using the OEM circuit information.
• Test element resistance and control response separately using suitable equipment; do not apply voltage directly to unidentified pins.
• After correcting the confirmed fault, repeat the OEM monitor conditions and check for code recurrence, beyond merely extinguishing the lamp.

Also written as: P0032-00, P003200, PO032 (some scan tools add the fault-type byte, e.g. -00).