P0036 — HO2S Heater Control Circuit Bank 1 Sensor 2

P0036: HO2S Heater Control Circuit Bank 1 Sensor 2 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

HO2S Heater Control Circuit Bank 1 Sensor 2. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • The check-engine lamp may illuminate because the heated oxygen sensor at bank 1, sensor 2 has a heater control circuit fault.
  • Driving behaviour can remain unchanged; some cars may show delayed emissions-control readiness or higher consumption.

Possible causes

  • Failure in the heater element of the oxygen sensor at bank 1, sensor 2.
  • Heat-damaged wiring, open or shorted conductors, corroded connectors or an affected heater fuse/relay.
  • Control-module output fault is a less common possibility only after other tests.

What to check

  • Record P0036 and related DTCs; confirm the precise location of bank 1, sensor 2 using the OEM layout.
  • With ignition off and the exhaust cool, inspect the correct sensor harness, connector, fuses and wiring routing.
  • Compare supply, ground and commanded heater operation with the vehicle-specific wiring diagram and diagnostic tool.
  • With the connector disconnected, measure heater resistance only using the applicable OEM test method and temperature conditions.
  • Check for circuit opens, shorts and voltage drops; do not apply direct battery power to a heater without OEM authorization.
  • Repair confirmed harness/fuse issues or replace a heater sensor only if its own tests fail; confirm DTC and monitor readiness afterward.

Also written as: P0036-00, P003600, PO036 (some scan tools add the fault-type byte, e.g. -00).