What is P0043 & How to Solve It?

What is P0043:

P0043 is a generic diagnostic trouble code (DTC) that refers to an issue with the Oxygen Sensor Heater Control Circuit High (Bank 1, Sensor 2). This code suggests that the oxygen sensor heater on Bank 1, Sensor 2 is receiving too high a voltage, which can cause overheating of the sensor and lead to improper performance, resulting in poor engine function and increased emissions.

‍

Why This Happens

The P0043 code can be caused by:

• Faulty oxygen sensor heater sending excess voltage to the sensor.
  
• Shorted or damaged wiring in the heater circuit.
  
• Faulty Engine Control Module (ECM) providing incorrect voltage.
  
• Blown fuse for the oxygen sensor heater circuit.
  
• Corroded or loose connectors causing poor electrical connection.
  
  

How to Fix It

To resolve the P0043 code, follow these steps:

1. Inspect the wiring and connectors for any visible damage, corrosion, or loose connections.
   
2. Test the oxygen sensor heater to verify excessive voltage.
   
3. Check the fuse for the oxygen sensor heater circuit and replace it if necessary.
   
4. Test the oxygen sensor for proper functionality and replace it if needed.
   
5. Clear the fault code and restart the engine to check if the problem is resolved.
   
   

How to Avoid It Before It Happens

To prevent the P0043 fault code:

• Regularly inspect the oxygen sensor heater and related wiring.
  
• Perform routine diagnostics to monitor the heater circuit and catch issues early.
  

Keep connectors clean and corrosion-free.