OBD-II code · Powertrain (generic)
P0043 HO2S Heater Control Circuit Low Bank 1 Sensor 3
Heater control voltage of the bank 1, sensor 3 oxygen sensor is below the expected range — short to ground or low-resistance fault.
Is it safe to drive with P0043?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHeater wiring shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor B1s3 Heater, Heater Wiring
Related codes
- P0063HO2S Heater Control Circuit Low Bank 2 Sensor 3
- P0040O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1
- P0041O2 Sensor Signals Swapped Bank 1 Sensor 2/Bank 2 Sensor 2
- P0042HO2S Heater Control Circuit Bank 1 Sensor 3
- P0044HO2S Heater Control Circuit High Bank 1 Sensor 3
- P0045Turbocharger/Supercharger Boost Control A Circuit/Open
- P0046Turbocharger/Supercharger Boost Control A Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.