This computer relies on feedback from various sensors to determine appropriate fuel delivery and throttle position adjustments. These sensors are calibrated to reflect a range of operating values, including those corresponding to post-combustion oxygen density.
While these types of sensors tend to be relatively durable, they are prone to occasional problems. When this happens, a diagnostic trouble code will usually be set and the vehicle's check engine light will come on.
One such sensor-related trouble code is P0131, which typically accompanies irregular sensor 02 feedback. Read on to learn more about the P0131 diagnostic trouble code, as well as how to correct this condition if it appears in the future.
What does P0131 mean?
Trouble code P0131 indicates a problem with the oxygen sensor 1 (bank 1), also called the air fuel ratio sensor or heated oxygen sensor. This error indicates that the engine control module (ECM) has detected too low or incorrect voltage in the oxygen sensor circuit or an incorrect air-fuel ratio.
“Bank 1” refers to the left side of the engine, and “sensor 1” means that said sensor is located in the exhaust pipe before the catalytic converter.
What can cause code P0131?
- The front O2 sensor (air-fuel ratio sensor) is faulty.
- Corrosion or poor connection in the front DC connector.
- There is a break in the wiring between the front DC and the ECU.
- Bad ground on the sensor or ECU.
- The oxygen sensor wiring is shorted to ground (for example, the wires are rubbing against the exhaust pipe or bracket.)
- The fuse in the DC reference voltage circuit has blown.
- Lean air/fuel mixture caused by: air leaks, stuck exhaust gas recirculation (EGR) valve, leaking purge valve, low fuel pressure, bad PCV (Positive Crankcase Ventilation) valve, dirty mass air flow sensor (MAF) or other reasons. When the mixture is lean, the engine may also lack power and the idle speed may fluctuate. Codes P0171 or P0174 may also be present.
- The ECU may need to be reprogrammed.
- The ECU is faulty (rare).
What are the symptoms of P0131?
When a P0131 error occurs, the Check Engine light will illuminate on your vehicle's dashboard. The vehicle's ECM will put the engine into limp mode and set the air-fuel mixture ratio according to preset parameters. The engine will run on a leaner fuel mixture to prevent damage to the catalytic converter. This may lead to increased fuel consumption.
Failure of the oxygen sensor will lead to a drop in power and unstable engine operation. In the worst case scenario, the car's engine will stall and will not start again.
Description of the operation of the Grant oxygen sensor, Kalina 2
The controller supplies the UDC circuit with a stable reference voltage of 3.3 V. When the UDC is not warmed up, the voltage of the sensor output signal is in the range of 1.3...3.6 V. As the sensor warms up, its internal resistance decreases and it begins to generate a varying voltage, outside this range. By changing the voltage, the controller determines that the UDC has warmed up, and its output signal can be used to control the fuel supply in closed loop mode. During normal operation of the fuel supply system in closed loop mode, the output voltage of the UDC varies between low and high levels. Poisoning of the UDC oxygen sensor can be poisoned as a result of the use of leaded gasoline or the use during assembly of room temperature vulcanizing sealants containing large amounts of silicone (silicon compounds) with high volatility. Silicone fumes can enter the crankcase ventilation system and be present during the combustion process. The presence of lead or silicon compounds in exhaust gases can lead to failure of the UDC. Malfunctions of the UDC circuits, a defect in the sensor, its poisoning or an unheated state can cause the signal voltage to remain in the range of 1.3…3.6 V for a long time. In this case, the corresponding fault code will be entered into the controller’s memory. Fuel supply control will be carried out in an open loop. If the controller receives a voltage signal indicating a prolonged lean state, the corresponding fault code is stored in its memory (low oxygen sensor signal). The cause of the malfunction may be a short circuit of the UDC output circuit to ground, a leak in the air intake system, or low fuel pressure. If the controller receives a signal with a voltage indicating a prolonged state of richness of the mixture, the corresponding malfunction code is entered into its memory (high signal level of the oxygen sensor). The cause of the malfunction may be a short circuit of the UDC output circuit to the voltage source or increased fuel pressure in the injector rail. When oxygen sensor fault codes occur, the controller controls the fuel supply in open loop mode.
How does a mechanic diagnose a P0131 code?
To properly diagnose the P0131 error code, you will need an advanced diagnostic scanner that can not only read stored error codes, but also view readings from various sensors in real time.
First, the mechanic reads all the stored data and error codes using an OBD-II scanner to find out when and under what circumstances the P0131 error occurred. He will then clear the error codes from the computer's memory and test drive the vehicle to see if the P0131 code appears again.
If the error code appears again, a mechanic will check the electrical wires and oxygen sensor connector for damage.
If the oxygen sensor wiring is OK, the mechanic will measure the voltage and resistance of the sensor and compare the readings to the manufacturer's specifications.
What to check
Check the oxygen sensor using a diagnostic scan tool or an ELM327 adapter with Torque software. When the engine speed increases, the signal changes to "rich", then when the speed decreases and the fuel is cut off, the sensor shows "lean". After this, the signal returns to normal.
If the P0131 code is caused by mechanical issues such as an air leak, a leaking purge valve or EGR valve, there will likely be other symptoms including a floating idle and lack of traction.
There may be other codes related to the EGR valve or purge valve. These errors should be checked first.
A visual inspection includes checking the sensor connector for corrosion or loose pins. The DC wiring harness should be inspected for possible damage from contact with the exhaust or other parts.
If the wiring is OK, you need to check the voltage and resistance of the sensor using a multimeter. The voltage should be below 1V and the resistance should be within the manufacturer's specifications.
Common mistakes when diagnosing code P0131
- The most common mistake when diagnosing a P0131 code is neglecting to clear the error code from the computer's memory and test drive the vehicle, which is necessary to confirm the problem.
- It is also a mistake to believe that misfires in the engine cylinders are caused by a malfunction of the oxygen sensor, although, on the contrary, misfires in the cylinders are the cause of improper operation of the oxygen sensor.
- Another mistake is not understanding that the problem may be a faulty coolant temperature sensor.
On which cars is this problem most common?
The problem with code P0131 can occur on different machines, but there are always statistics on which brands this error occurs more often. Here is a list of some of them:
- Audi (Audi a4)
- BMW
- Buick (Buick LeSabre, Park Avenue, Regal)
- Chery
- Chevrolet (Chevrolet Aveo, Camaro, Cruz, Lanos, Lacetti, Rezzo, Silverado, Tahoe, Express)
- Chrysler
- Citroen
- Daewoo (Daewoo Matiz, Nexia)
- Ford (Ford Mondeo, Fiesta, Focus, Fusion)
- Geely (Emgrand)
- Great Wall (Hover H3, Hover H5)
- Honda (Honda Accord, Odyssey, SRV, Fit, Civic, HR-V)
- Hyundai (Hyundai Solaris)
- Infiniti
- Kia (Kia Rio)
- Lifan (Lifan x60)
- Mazda (Mazda 3, Mazda 6, Mazda cx7, Protege)
- Mercedes
- Mitsubishi (Mitsubishi Outlander, Pajero)
- Nissan
- Opel (Opel Antara, Astra, Zafira, Corsa)
- Peugeot (Peugeot 207)
- Skoda
- Ssangyong
- Subaru (Subaru Outback, Impreza, Legacy, Forester)
- Suzuki
- Toyota
- Volkswagen (Volkswagen Polo Sedan)
- Volvo
- VAZ 2107, 2110, 2112, 2114, 2115
- Lada Granta, Kalina, Niva, Priora
With fault code P0131, you can sometimes encounter other errors. The most common ones are: P0130, P0132, P0134, P0171, P0336, P0480, P0506, P0742.
Formation conditions
In order for error P0134 to be stored in the memory of the electronic control unit, a certain scenario must be executed. That is, there are several mandatory conditions.
- Information about the signal from the lambda probe is completely absent or the signal is very weak.
- The relevant data is transmitted to the on-board computer and recorded.
- If the situation does not change within 60 seconds after receiving the information, the on-board computer already transmits the information to the electronic control unit.
- Approximately 5-10 seconds after the signal is received in the control unit, the check engine light on the instrument panel lights up. That is, the well-known and unloved Check Engine.
Description of error P0134
If these conditions are met, changes will occur in the stable operation of the engine.
What does code P0134 mean on a VAZ 2114?
When exhaust gases are released from the engine into the atmosphere, they are purified using a catalyst. This occurs when gases exit the engine and before entering the exhaust manifold. Here is a catalyst that provides cleaning. There is one oxygen sensor before gases enter it, and another after. When error P0134 appears on a VAZ 2114 during diagnostics, this indicates a malfunction of the one located before the catalyst. As a result, he begins to receive incorrect information.
Causes
The variety of reasons why this error may occur and generate fault code p0134 is not that great:
- breakage or delamination of insulation of oxygen supply contacts;
- short circuit;
- open circuit;
- air leak;
- moisture entering the sensor.
The main causes of error p0134 for the oxygen sensor
As a rule, if a malfunction of this nature is associated with an open or short circuit, the diagnostics will report not only an error in the inactivity of the oxygen sensor circuit, but will also generate a second error P0171 - lean mixture. Since the first lambda sensor is the control sensor for supplying the mixture, in the complete absence of the DC signal, the controller reduces the fuel supply to prevent catalyst failure. Therefore, if the autodiagnostics showed only one error, you do not have an open circuit in the sensor or oxidized connector contacts, but in 99% of cases, p0134 comes out through internal problems in the sensor .
OpenDiag program data when displaying errors P0131 and P0134
The following manifestation of the problem may also occur - at a temperature of 100 degrees, the sensor stops working. At the same time, if you connect a diagnostic scanner, the program will display 2 errors at once - P0131 and P0134. Engine operation up to 95 degrees will be normal, but when it reaches 100 degrees, the speed may become unstable and the engine will stall. The autoscanner will display the following parameters in the “Parameters” section and the “ADC Channel” subsection:
- Oxygen sensor ready - NO.
- Heating of the oxygen sensor is allowed - YES.
- Oxygen sensor voltage (V) - 0.000.
When a short to ground occurs in the sensor, the first thing you should do is check the contacts and possible air leaks. Moreover, the error “p0131” indicates that the sensor is most likely wet, it needs to be removed and dried. In addition to this, the “check” light on the dashboard lights up.
Trouble P0131 - Oxygen Sensor Low Voltage (Bank 1, Sensor 1)
Code P0131 - Oxygen Sensor (Bank 1, Sensor 1) Circuit Low Voltage. Front O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1).
The front oxygen sensor (Sensor 1) measures the amount of oxygen in the exhaust before the catalytic converter. The engine control unit (ECU) supplies a reference voltage to the oxygen sensor (OS). The sensor sends a signal voltage back to the ECU.
Low voltage means a lean air-fuel mixture—too much oxygen and too little fuel. High voltage means rich air/fuel mixture.
Code P0131 is set when the signal voltage from the front O2 sensor remains low. Modern cars use an air-fuel ratio sensor (A/F sensor) instead of an AC sensor, but it is also often called a front oxygen sensor. Bank 1 is the bank containing cylinder number 1. In a 4-cylinder engine, there is only bank 1.
Meaning and interpretation of error codes
To read the faults, first consider the list with a table of UEr errors that self-diagnosis produces (the author of the video is Ivan Vasilyevich).
| Number | Description |
| 1 | Problems with the functioning of the microprocessor. |
| 2 | Self-diagnosis of the VAZ 2114 detected problems with the electrical wiring of the fuel level indicator controller. The signal level coming from the sensor may be too high or low. It is necessary to test the controller and check the wiring. |
| 4 | Increased voltage in the on-board network. |
| 8 | Low voltage. What to do: in this and in the previous case, the battery and generator must be checked. |
| 12 | There is a problem with the diagnostic indicator circuit on the instrument panel. |
| 13 | The control unit cannot detect the signal coming from the oxygen controller. |
| 14 | An increased signal is received from the refrigerant temperature controller. |
| 15 | The problem is in the operation of the coolant temperature sensor (coolant temperature sensor) - the on-board computer records a reduced signal level. |
| 16 | There is increased voltage in the car wiring. |
| 17 | Reduced voltage in wiring. |
| 19 | Problems have been reported in the operation of the crankshaft position sensor (CPS). An incorrect signal is sent to the control unit. |
| 21 | Problems with the operation of the TPS controller (throttle position sensor). There may be problems with the throttle valve. Check the connection circuit and sensor. |
| 22 | A reduced signal is sent from the TPS. |
| 23 | The intake air temperature controller gives an increased signal. |
| 24 | There are problems with the speed controller. Its failure can be diagnosed by a non-working speedometer. |
| 25 | Reduced signal from the incoming air temperature controller. |
| 27,28 | Incorrect signal coming from the CO sensor. |
| 33,34 | Malfunctions of the mass air flow sensor (mass air flow sensor). Check the flow meter connection circuit and its functionality. |
| 35 | The ECU has detected a deviation in the idle speed values. The sensor may be faulty. |
| 41 | Incorrect pulse coming from the phase controller. |
| 42 | Problems with the electronic ignition wiring. |
| 43 | An incorrect pulse is supplied from the detonation controller. |
| 44,45 | Problems with the composition of the combustible mixture. It can be depleted or over-enriched. |
| 49 | Check for vacuum loss. |
| 51,52 | Problems in the functioning of the PROM or RAM. |
| 53 | There is no CO controller pulse. Open circuit or sensor failure. |
| 54 | No impulse is received from the octane corrector controller. |
| 55 | When the load on the power unit is reduced, the ECU detects depletion. |
| 61 | Problems with the oxygen controller. |
These codes can add up; if you see the number 6, this may indicate errors 2 and 4, or if the number 9 is displayed, errors 1 and 8.
In order to immediately read and decipher problems when diagnosing, it is advisable to download and always carry with you a printout with a description. When diagnosing using a computer, codes on engine 21124 may differ depending on the car model. To read the codes, you need to know how they are supposed to be deciphered. Errors must be reset after they have been deleted (the video was filmed and published by the KV Avtoservis channel).
| Number | Decoding |
| p0102, p0103 | An incorrect pulse is supplied from the mass air flow sensor controller. This means you need to check the wiring. |
| p0112, p0113 | 112 or 113 - the incoming air temperature sensor needs to be replaced. |
| p0115-p0118 | Errors from 0115 to 0118 - the antifreeze controller sends an incorrect impulse. There may be problems with the wiring or the sensor itself. |
| p0122, p0123 | TPDZ. The controller is sending an incorrect signal. If the wiring is damaged, interference may occur. |
| p0130, p0131 | The lambda probe requires diagnostics and replacement. |
| p0135-p0138 | Error 0135 and higher - the lambda probe heating regulator needs to be replaced. |
| p0030 | The ECU reports problems in the electrical circuit in the area from the lambda probe heater to the converter. If error p0030 occurs, you need to test the electrical circuit and the sensors themselves. |
| p0036 | P0036 - a break in the wiring of the heating device DK-2 was detected. |
| p0300, p0302 | When codes 300 and 302 appear, the ECU reports a misfire. |
| p0301 | Gaps were detected in the cylinders of the power unit. Compression needs to be checked. |
| p0325 | The knock sensor is not working correctly. In particular, we are talking about a break in the connection wiring. |
| p0335, p0336 | P0036 error VAZ 2114 or 10335 - the DPKV has failed or its connection circuit is damaged. If the wiring is intact, then the sensor is replaced. |
| p0340 | Phase sensor malfunction. |
| p0341 | Error VAZ 2114 0341 means a problem with the camshaft controller. |
| p0342, p0343 | Problems with the phase controller. With such an error, detonation of the car engine is possible. Most likely, only replacement will solve the problem. |
| p0346 | P0346 VAZ error - also a problem with the phase regulator. |
| p0363 | P0363 - misfire of the combustible mixture was detected. In cylinders that refuse to work, the fuel supply is cut off. |
| p0422 | Failure to operate the neutralizing device. |
| p0443, p0444, p0445 | Malfunctions 0443, p0444 and 0445 - adsorber regulator, purge is not carried out. |
| p0480 | The engine cooling fan device has failed. The power unit may overheat if it is not replaced in a timely manner. Before replacing, you need to check the connection contacts to the wiring. |
| p0501-p0504 | Error 0501 VAZ 2114 and error code 0504 - the speed controller refuses to work. The device needs to be replaced. |
| p0505, p0506, p0507 | The idle speed sensor does not work or does not work correctly. Its failure can lead to floating idle speed. Possible engine tripping. The controller itself is tested and the wiring is checked. |
| p0607 | The knock controller operates intermittently. |
| p1135 | Error 1135 VAZ 2114 - you need to test the oxygen controller. |
| p6060 | Processor failure. If the fault remains after resetting the code, then the controller must be replaced. |
| p2020 | It is necessary to test the intake flap position sensor. |
| p1617 | Error 1617 - Rough road controller, wiring damage. |
| p1513 | There is a short circuit in the wiring of the idle speed sensor. It is necessary to test the electrical circuit and check the contacts. |
| p1602 | Failures in the voltage supply to the vehicle's electrical network are detected. |
| p0560 | Incorrect voltage level in the on-board network. This parameter can be overestimated or underestimated. The car battery, as well as the generator unit, are subject to testing. |
| p1514, p0511 | The appearance of these errors indicates a problem with a break or short circuit in the IAC (idle speed regulator) wiring. First of all, diagnose the sensor contacts, and then test the circuit, if possible. The sensor itself may also be damaged. |
| p1303 | P1303 - A detected misfire of the air-fuel mixture in the third cylinder is reported. The malfunction must be corrected as quickly as possible, since it can be critical for the neutralizer. |
| p1578 | Throttle valve malfunction. Literally, the problem stands for “zero adaptation parameter is outside the permissible value.” There are several options to solve the problem. The first thing you need to do is clean the throttle valve. If this does not help, then the throttle is adapted. To do this, you need to activate the ignition, and then start the engine after 40 seconds. Alternatively, you can test and tighten the contact terminals on the throttle. |
| p1621 | Malfunction of the RAM, memory problems in the control unit. Detailed testing of the computer is required. |
| p0650 | Problems in the control circuit of the on-board computer error code indicator State. |
| p2135 | P2135 - malfunction of the throttle assembly. If replacing the sensor and cleaning the damper did not help, then the problem may have to be solved by flashing the on-board computer. |
| p2187 | Lean mixture in internal combustion engine cylinders. You need to do a detailed diagnosis of the problem. |
