Our editors pick the products & services we write about. When you buy through our links, we may get a commission. Learn more.

P0030 Code: Meaning, Symptoms, Causes, And Fixes


Heated Oxygen Sensor (H02S) Heater Control Circuit Bank 1 Sensor 1


Bank 1, sensor 1 of the O2 sensor heater circuit is faulty. As such, the engine isn’t achieving closed loop and therefore the car has increased emissions.

Main Symptoms:

  • Check Engine Light comes on
  • Longer time needed to achieve closed loop
  • Decreased fuel economy
  • Engine may go into fixed fuel mix

Possible Causes:

The P0030 code might be an indication of the ECM not getting the correct signal
The P0030 trouble code can happen when the correct signal is sent to the ECM
  • H02S sensor in bank 1, circuit 1 is not sending the correct signal to ECM
  • Damaged or failed element in heater circuit
  • Open in O2 sensor heater’s circuit
  • Open/short in O2 sensor heater’s battery
  • Defective ECM (this is the least likely cause)

Diagnostic Steps:

  • Inspect wiring and power to the O2 sensor and ensure there’s no damage/open/short
  • Use code reader to pull engine codes
  • Check voltage of O2 sensor and ensure it matches manufacturer’s specs
  • Replace O2 sensor if necessary

Read More: How to Use an OBD-II Scan Tool to Diagnose Your Car

Tim MillerFounderOBD Advisor

I’m Tim Miller from Denver, Colorado. I’m the founder of obdadvisor.com, an automotive blog about "Auto Diagnostic Tools and Repair Guides". My fan page is facebook.com/autozikcom. I've been working as an automotive mechanic and blogger for over 10 years writing articles to share my experiences and expertise.

Web: https://www.obdadvisor.comEmail: [email protected]
Follow me:

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top