Definition- “Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 2”
P0155 is a diagnostic trouble code that occurs when the powertrain control module checks the heating element of the oxygen sensor, which is present on bank 2 and detects excessive resistance or short circuit in the heater, it mainly occurs when the heater’s circuit does not function properly.
When this code is present, it means that the heating element of the oxygen sensor is taking more time to heat up than usual.
When this problem with the heater of the oxygen sensor will occur, the power control module will set the P0155 trouble code and will alert you through engine light.
What does the heating element in an oxygen sensor do?
The heated oxygen sensor measures the oxygen content present in the exhaust stream and the heating element in the oxygen sensor helps the sensor to get to the operating conditions in less time. If the heating element of the oxygen sensor will have any malfunctioning then it will heat up the sensor to operating conditions in more time.
Causes of P0155 Code
There can be several reasons for the occurrence of this DTC code, some of them are below
- The oxygen sensor is not working properly.
- Faulty wiring and weak connections.
- The coolant temperature sensor of the engine is not working properly.
- Blown off the fuse of the sensor.
- The power control module is not working properly and detecting incorrect faults, which is a rare case.
- High resistance in the heating element of the sensor.
- The engine coolant temperature sensor is working badly.
Symptoms of P0155 code
The following things will indicate that your vehicle has this trouble
- The engine check light will start illuminating indicating the presence of error.
- A rotten egg or burning sulfur smell coming from the exhaust.
- The engine will start running rough and may also produce noise.
- Black smoke coming out of the exhaust.
- Your vehicle will consume more fuel thus becoming less fuel-efficient.
- The vehicle will also shut off sometimes.
The severity of this trouble code
P0155 is not a serious DTC code and can not cause any harm to the driver, it is a moderate serious as it can cause drivability issues and less fuel efficiency in the vehicle.
On the other hand, it can cost a decent amount if not handled on time, as replacing the parts is very expensive, so you need to fix this code as soon as possible.
Diagnosing and fixing the trouble code
The ECM sets and stores all the trouble code relating to the troubles that your vehicle has and to read those codes you have to fix the code scanner or reader into your vehicle, you will see the trouble codes on the screen of the scanner, it can show more than one trouble code, remove all the other troubles before fixing P0155 trouble code, and now to fix P0155 code have a look on the fixes mentioned below.
Fixing the trouble P0155 trouble code
To make your vehicle free from this trouble code try the following fixes
Repair all the wirings (p0155 Bank 2 Sensor 1 location)
Check for all the wirings to the oxygen sensor and inspect them visually, if you find any damage in the connections of wires then replace them otherwise head towards other fixes.
Check Voltage of the Oxygen Sensor
The fluctuating voltage of the oxygen sensor can also set this trouble code, so kindly check the voltage of the sensor using a multimeter, the voltage can fluctuate because of the faulty wiring or damaged oxygen sensor. If you find this problem then repair them and then look at the code reader to ensure that the sensor is working as it should be or not.
Replace oxygen Sensor
If the problem persists even after repairing the sensor and its wiring then replace the oxygen sensor with a new working one, but before replacing be sure that you have checked the above-given things properly.
Replace ECT sensor
The fault can be in the engine coolant temperature sensor, as it will sense the wrong temperature and make the ECM set this code while detecting troubles. So check the ECT and if it is not working properly then replace it with a new one to resolve the issue.
Replace the power control module
After trying all the above fixes, diagnose the trouble codes again and if P0155 code still exists then it might be possible that there is some problem with the PCM of your vehicle and it is detecting the trouble codes wrongly, but it is a very rare case and apply this only when you have tried every other fix. To replace the power control module of your vehicle and again scan the codes.
Frequently Asked Questions
Q1: How to check an oxygen sensor?
The oxygen sensor is an essential part of the emission system of your car, emission system reduces the emission of poisonous gases into the atmosphere thus causing less air pollution, the oxygen sensor is present in the exhaust pipe of the cars, it measures the amount of oxygen present in the exhaust gases, in some cases, the oxygen sensor stops working and to check if your oxygen sensor is bad kindly follow these steps:
- Identify the oxygen sensor on which you want to perform the test as there is more than one oxygen sensor in the exhaust of your car.
- The computer of the DTC will automatically point toward the oxygen sensor that needs checking.
- Start your car for and run it normally till it gets to the operating temperature.
- Turn the engine off after reaching operating temperature, now connect the red probe of the voltmeter to the signal wire of the oxygen sensor and the red probe to ground carefully.
- Turn on the car and measure the voltage in voltmeter, the voltage should be between 100mv-900mv.
- If your voltmeter is showing reading between the given range then the sensor is working properly but if the reading is out of this range then maybe there is a problem with your engine or the oxygen sensor is bad.
- Now check the reading in lean fuel consumption mode, remove the hose from the PVC present in the valve cover, if the voltmeter is not responding in this situation then your oxygen sensor is bad.
Q2: Is it safe to drive with a bad oxygen sensor?
Yes, you can drive with a bad oxygen sensor, but replace it as quickly as possible because your vehicle will take more fuel which will cost you a lot, also if you ignore this problem it will cost very much to replace the sensor.
Q3: How to reset the electronic control unit after changing the oxygen sensor?
- Open the fuse panel which is under the steering column by pulling it down.
- Find the fuse for the electronic control unit with the help of a fuse diagram on the fuse panel cover.
- Using fuse pullers, pull the fuse of ECU.
- Turn on the ignition and wait for 2-3 minutes, the engine check light will blink and shut off and this is the indication that ECU is reset.