OBD 2 scanner is an essential part of all vehicles. This scanner is used to find out if any problem occurs with your car. If your vehicle faces some problem internally, you notice a code on the car screen. And there are many OBD codes used to show many types of trouble, just like that P0031, when your car faces a problem with the HO2S heater control circuit low.
What do you mean by the OBD code P0031?
The trouble code of the P0031 is related to the heater control circuit low. This code means that for the engine to run correctly, the engine exhaust must have a fixed air-fuel ratio of 14.7 to 1, signaled by the HO2S or heated oxygen sensors. These HO2s detect the oxygen content of the vehicle exhaust. The information is then sent to the ECM or engine control module to adjust the correct fuel volume delivered to the engine. The HO2s are heated to ensure very rapid signal data to the ECM closed loop system, and this helps control emission during startup when the engine is warming up or cold.
What is the reason behind the code P0031?
At first, when you notice the trouble code P0021, you see an illuminated warning light. Generally, if you reset the code and again it pops up on the screen, the problem is related to the HO2S sensor. It’s used for engine bank 1 and sensor 1 upstream of the catalytic converter. This is not sending the complete information to the ECM and may be damaged or defective. If the sensor has a lousy heater element, it could have a bad ground and a failed 12-volt battery input or connector. But the problem with ECM is a rare case.
What are the symptoms of the error code P0031?
There are some common symptoms you can find in your vehicle. This is:
- Check the illuminated engine light,
- The ECM detects the O2 sensor heater circuit is low. It will enter the failsafe mode till the ignition switch is turned off.
- You will face various drive complaints about this failsafe mood, and it depends on the vehicle and the manufacturer of the car’s ECM program.
- Until you fix the failsafe issue, you continuously face the problem.
- You can notice some common drive problems like hesitation, running rough and low power.
How to find the trouble code?
The OBD is designed to find this type of problem in the car. The technician first reset the code from memory and restarted the whole system, then performed a test drive to see if the code popped up again or not. If the code returns and the engine warning light is illuminated, check both power and ground to the sensor by inspecting the wiring sensor. Sometimes this problem occurs for faulty wiring due to the heat of the exhaust and catalytic converter.
But sometimes, you or any professional makes mistakes to find the exact issue. Like:
- Before closely checking all related wiring and connectors, don’t simply change the HO2S.
- There are 12 volts to the sensor, and the ground is good. It also needs to be assured.
- The connector’s wiring and connectors on both sides must be checked to ensure a good connection.
How to fix the P0031 code?
Some common steps to repair the trouble code P0031 are
- First, verify the code with a scanner, then reset the fault code and restart the whole system. Then perform a road test to determine whether the code returns.
- If the trouble code returns, you need to perform a test. If any wiring is damaged by excessive heat from the exhaust, this is a common reason behind this issue. So make visual inception in all wiring carefully and repair or replace any connection if it is needed before you want to change the whole sensor.
- Use a voltmeter to check if the voltage of the fused battery feed to the heater elements is 12+ volts or not when the key is on but the engine is off. If you don’t find any voltage there, then repair the open or short in the 12-volt feed circuit by first determining that it’s mandatory to replace any fuse blown from the short.
- If you find the battery feed is intact, it needs to remove the ground circuit from the ECM wiring connector and then check the resistance of the circuit.
- If you find any infinite resistance, repair the open circuit.
- Check the control circuit to suspect the faulty O2 sensor and repair or replace it.
This is the basic thing you can do to repair the trouble with your car. But sometimes, if the HO2 sensor heavily corroded, then the nut was loose where it attached to the chassis. It would help if you cleaned it up and another washer to clean the contact area thoroughly. Then recheck the system and perform a test drive. I think this will also help you to fix this issue.
How serious is the trouble code P0031 to be solved?
If you think driving a car with this problem is safe or not. At first, the P0031 code is usually preceded by the engine warning light on the dash while the OBD2 scanner catches the issue. You can continue driving with this problem, but it should be solved to prevent sensor loop failure, excessive fuel consumption, poor operation, or sometimes harm to other components. Most of the time, the engine warning light turns on immediately at startup, the OBD2 system needs to reset, and the vehicle also works properly.
Additional suggestion:
This heat sensor problem isn’t a massive problem for your vehicle. Many vehicles come with mileage over 100,000 and have monetary sensor problems on the drive train when starting up or in prolonged stressful situations. If you notice the engine light coming on and the car usually works, the OBD2 scanner system can be reset using the scanner, and the problem may not be found again. For this reason, it’s essential to verify the issue and restart the whole system before doing a replacement or repair. And if you are unable to fix the problem by yourself, then consult with an automotive technician. It costs you some money but as well it saves your time.
Kevin Nicholas is an automotive technician who is a genius at software and hardware-related issues. He manually tested more than a hundred OBD scanners and gave his honest opinion on whether the device was worth the money or not. His in-depth OBD review articles help people choose the right product, whether it is a European, American, or Asian vehicle. He completed his Automotive Specialized Training Course at Universal Technical Institute and has more than 15 years of experience in the field.
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