P0032: OBD-II code P0032 flags a high-voltage condition on the upstream bank 1 O2 sensor heater circuit — usually a shorted-to-battery drive wire or a failed heater driver.

Symptoms

• Check engine light is on; the O2 sensor heater may overheat or fail entirely from continuous over-current.
• Extended open-loop enrichment and poor cold-start fuel economy on some vehicles.
• The sensor may fail prematurely from sustained over-current heating of its internal element.

Common causes

• A shorted-to-battery-voltage heater drive wire holding the heater on continuously.
• A failed PCM heater driver stuck in the on state, feeding continuous voltage to the sensor.
• An internally shorted O2 sensor element pulling the sense line high.

What to do?

Disconnect the sensor and confirm no B+ voltage on the heater drive pin with the connector unplugged. Measure sensor heater resistance. Replace the sensor or repair wiring. If wiring and sensor test good, the PCM driver has failed and the module needs replacement.