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

Our certified mechanics come to you · 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 $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 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 $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0030 DIAGNOSTIC Get a fair and transparent estimate upfront

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.

Check Engine Light
P0030
trouble codes

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0030 code.

SCHEDULE P0030 DIAGNOSTIC
Get a $50 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

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...
P0030 p0015 chk eng lgt on whining noise stuck 2 gear 1 yr had car let son drive 2 NV havent chk fluid N trans hope it wasnt low
The code P0015 is a bank 1 timing over retarded warning. The P0030 code stands for the heated oxygen sensor malfunction, which also pertains to bank 1. The oxygen sensor malfunction could be due to a failed sensor, heater, or...

More related articles

P0608 OBD-II Trouble Code: Control Module VSS Output "A" Malfunction
P0608 means there is an malfunction in the vehicle speed sensor A control module often due too faulty speed sensor or shorted electrical wiring.
P0621 OBD-II Trouble Code: Generator Lamp “L” Control Circuit Malfunction
P0621 means there is an malfunction with the generator lamp "L" control circuit often due to a defective generator or corroded wires.
P0907 OBD-II Trouble Code: Gate Select Position Circuit High
P0907 code means there is an issue within the vehicle's transmission gate select position circuit often due too wiring or rarely, the PCM.

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 (855) 347-2779 · hi@yourmechanic.com