P0030 OBD-II Trouble Code: HO2S Heater Control Circuit (Bank 1 Sensor 1)

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0030 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0030 code

P0030 is a diagnostic trouble code (DTC) for "HO2S Heater Control Circuit (Bank 1 Sensor 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0030 DIAGNOSTIC Get a fair and transparent estimate upfront

check engine light logo

P0030 Trouble code definition

P0030 is the code for HO2S Heater Control Circuit (Bank 1 Sensor 1)

What the P0030 code means

P0030 indicates for the engine to operate properly, the engine exhaust should have a specific air-fuel ratio of 14.7 to 1 as determined by the heated oxygen sensors (HO2S) which detect the oxygen content of the exhaust. This information is then sent to the engine control module (ECM) to adjust the fuel delivered to the engine.

An HO2S is heated to ensure very rapid response of data to the ECM’s closed loop system which helps decrease emissions during start-up and when the engine is cold.

What causes the P0030 code?

Generally, if the code is cleared and reset, and the engine warning light comes back on along with the OBD-II code, this means that the HO2S sensor for the engine bank 1 and sensor 1 is not sending the proper signals to the ECM.

The ECM may be defective or has defective wiring. However, it is quite rare that the ECM is bad.

What are the symptoms of the P0030 code?

  • The Check Engine Light will come on.

  • With the O2 heater circuit not working the O2 sensor response time will be affected and the sensor will not respond to fuel and oxygen in the exhaust for the first 3 to 5 minutes of running or more.

  • The lack of response will affect the ECM ability to control the fuel mixture and it will go into a fixed fuel mix until the problem is fixed.

How does a mechanic diagnose the P0030 code?

P0030 is diagnosed with an OBD-II scanner. The mechanic can reset the OBD-II code and then test drive the vehicle to see if the engine warning light and code returns. If it comes back on, the mechanic should check both power and ground to the sensor, including inspecting the wiring and sensor.

Many of the problems for this code are wiring related, due to the heat of the exhaust.

Common mistakes when diagnosing the P0030 code

  • Do not assume that the HO2S is bad and replace the HO2S before checking that all of the related wiring and the connector closely.

  • The mechanic should ensure there are 12 volts to the sensor and the ground is good.

  • Both sides of the connector wiring need to be check to ensure that the connector is good and not damaged.

How serious is the P0030 code?

The P0030 code will usually be preceded by the engine warning light coming on the vehicle’s dash while it is in operation. The vehicle can still be driven but it should be properly diagnosed as soon as possible to prevent problems like the sensor loop failing, excessive fuel consumption, poor operation, or damage to other components.

Often times, if the engine warning light came on immediately at start up, the OBD-II system can be reset and the vehicle will operate normally.

What repairs can fix the P0030 code?

The most common repairs to address the P0030 code are as follows:

  • Have a certified technician from yourmechanic.com verify the code with a scanner. Reset the fault codes and perform a road test.

  • If the P0030 code returns, then follow the test procedure. It can have several problems, but wiring being damaged by excessive heat from the exhaust is most common. Make certain the wiring is in good condition and has proper voltage and ground to the sensor before replacing the sensor.

  • With key on and the engine off use a voltmeter to check for 12+ volts fused battery feed to the heater element. If there is no voltage present, repair open or short in the 12 volt feed circuit but first determine if it is necessary to replace any fuse blown from the short.

  • If the battery feed is correct, remove the ground (control) circuit from the ECM wiring connector and check for resistance on the circuit. If there is infinite resistance, repair the open in the circuit.

  • If the control circuit is good, suspect a bad O2 sensor. Replace and re-check.

The P0030 code is a relatively common situation as it is located in front of the catalytic converter and gets considerable heat generated from the converter.

In one instance, I found that after a visual and electrical test of the system that wires coming from the #1 HO2S were run above the exhaust pipe in a way that had no slack to put them on the wiring hanger. This caused all of the wires on the sensor to melt to the exhaust pipe and ground out the power and sensor wires causing the warning light to come on immediately.

During some maintenance service at another shop or dealer, someone had disconnected the sensor wires and apparently did not like the way the wires were routed, so they thought it would be better to run them above the pipe. The wires from the sensor were designed to go straight up and be held in place with a special bracket that supported the connector away from the pipe. I had to replace the sensor, reattach the wires correctly, reset code, then road test it with no issues noted. Many problems are created by the people who work on the vehicles.

Additional comments for consideration regarding the P0030 code

Many vehicles with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train. If the engine warning light comes on and the vehicle seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.

Need help with a P0030 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

P0030
Check Engine Light
trouble codes

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0030 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,484

Rating Summary
3,176
153
40
23
92
3,176
153
40
23
92

Richard

10 years of experience
415 reviews
Richard
10 years of experience
This is the second time I’ve had Richard work on my car. He always does an outstanding job and is quick, knowledgeable and professional. Highly recommended!!
2012 DODGE CHALLENGER - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Michael

13 years of experience
372 reviews
Michael
13 years of experience
Mike was an absolute professional when he arrived. He walked me thru the whole process of my repairs and also made good recommendations for preventive issues. His mechanical knowledge and good customer services was a breath of air and greatly appreciated :-)
2007 CHEVROLET AVALANCHE - CHECK ENGINE LIGHT IS ON INSPECTION - MARIETTA, GEORGIA

Rodrigo

10 years of experience
85 reviews
Rodrigo
10 years of experience
Rodrigo was exactly on time, very professional and friendly. He assessed my car, let me know the exact problem when a previous mechanic from a shop in my area was unable to. I felt he was very honest and sincere letting me know the level of urgency that I deal with the issue. Absolutely no pressure. I will absolutely use Rodrigo the next time I need anything to do with my car and will tell everyone about him. This is such a great service, I will never go to another mechanic again. It is so convenient. I couldn’t be happier. :)
2013 SMART FORTWO - CHECK ENGINE LIGHT IS ON - LAS VEGAS, NEVADA

Ricardo

8 years of experience
223 reviews
Ricardo
8 years of experience
Great service and was very helpful on what maintenance my vehicle needed and what to expect in the future. Would definitely recommend to anyone and will.
2004 MITSUBISHI LANCER - CHECK ENGINE LIGHT IS ON - LOS ANGELES, CALIFORNIA

More related articles

How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...

Related questions

Q: Q: Getting a check Engine light and codes

Both of those codes are for oxygen sensor issues. Oxygen sensors needs to heat up before it gives good readings. In pre 1996 cars, the sensor would get heated up by the cars exhaust. This took about 2 minutes. Oxygen...

Q: My car won't move when i press the gas pedal i have never had a problem before. I did notice a leak but i thought it was the oil from the transmission.

You should check for any codes that could be stored in the ECM (computer) as the check engine light is on. This will give you a starting place to check for the condition that you are having. Since the vehicle...

Q: Trouble code P0060 after changing out all of my O2 sensors

Hello. Code P0060 comes on when the computer detects excessive resistance in the heater circuit for oxygen sensor 2, of bank 2. If all of the sensors have been replaced then it may be possible that the issue is rooted...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com