Which Codes Will This Page Cover?
- P0056 HO2S Heater Control Circuit – Bank 2, Sensor 2
- P0057 HO2S Heater Control Circuit Low
- P0058 HO2S Heater Control Circuit High
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What Is the P0056 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
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The P0056 diagnostic trouble code’s (DTC) title is “HO2S Heater Control Circuit Bank 2 Sensor 2.”
If this diagnostic trouble code sets in your car, there is a problem with the bank 2 sensor 2 oxygen sensor heater control circuit. This code logs when the Powertrain Control Module (PCM) detects a possible problem with the heater control circuit. The code issue signifies that the oxygen sensor is not heating up properly due to a problem in the oxygen sensor heater circuit.
This code can appear for various reasons, so it’s crucial to have a certified technician diagnose the specific cause for it triggering in your situation.
Bank 2 is the side of the engine that does not contain the #1 cylinder. The oxygen sensor 2 is located on bank 2, which is the side of the engine that doesn’t contain the #1 cylinder. The bank 2 sensor 2 oxygen sensor is also referred to as the downstream oxygen sensor due to its location after the catalytic converter.
The PCM’s function is to maintain your vehicle’s correct air-to-fuel ratio. It does this by analyzing the data of the oxygen content of the exhaust received by the vehicle’s oxygen sensors in the exhaust system before and after the catalytic converter. So, if the PCM determines that the oxygen sensor is not heating up correctly or that the heater wire is not functioning correctly, it could trigger the P0056 code.
What Are the Symptoms of a P0056 Code?
If your vehicle encounters a P0056 code issue, several symptoms may appear. One of the first things you may notice is that the Check Engine Light may appear on your vehicle’s dashboard. This is because your car may also experience a decrease in fuel efficiency. Additionally, the emissions coming from your car can increase because the oxygen sensor takes longer to reach optimal operating temperature. Therefore, the Check Engine Light typically comes on due to your vehicle’s emissions increase.
What Are Some Causes of a P0056 Code?
One common cause of the P0056 code is a faulty or broken oxygen sensor. The oxygen sensor’s primary function is to measure the oxygen content in the exhaust gasses after leaving the engine. For the oxygen sensor to measure this information correctly, the sensor must be at a specific temperature. Therefore, a heater wire within the oxygen sensor is located that brings the sensor up to the correct temperature. When the PCM detects an issue with the heater wire, it triggers the P0056 code.
Another common cause can be circuit issues such as an incorrect amount of resistance in the heater circuit that can cause the heater control circuit to malfunction due to the high operating temperature of the heater. Additionally, a malfunctioning PCM can cause a P0056 code to appear in your vehicle.
How Serious Is the P0056 Code?
With the P0056 issue, you’ll be dealing with an oxygen sensor that takes more time to reach operating temperature. While this sensor is taking more time to warm up because the heater isn’t working, the result is usually higher emissions from your vehicle. With that said, we highly recommend addressing this issue as soon as possible and getting your vehicle checked out by a qualified technician to prevent any potential further damage to your car.
Can I Still Drive with a P0056 Code?
Owners can drive most cars with the P0056 set without any severe performance and driving-related issues. In addition, most people won’t notice the increase in their car’s emissions. Therefore it’s strongly recommended not to wait any longer and get it inspected as soon as possible.
How Easy Is It to Diagnose a P0056 Code?
Correctly diagnosing the P0056 code can be tricky as it has several potential causes. Note that the diagnostic process will depend on your vehicle’s specifications and varies from manufacturer to manufacturer.
Suppose there aren’t any visible damages to the bank 2 sensors and circuits after a visual inspection. In that case, a technician will use a multimeter to measure the resistance of the heater circuit in the oxygen sensor.
If the sensor’s resistance is not in line with the manufacturer’s determined threshold, the technician will deem it faulty and replace the oxygen sensor.
If the sensor is deemed ok by the technician, then he will check the resistance of the rest of the circuit from the Powertrain Control Module to the bank 2 sensor 2 oxygen sensor. A typical reading of this wiring is less than half an ohm.
If the technician deems that the wiring is in order, the powertrain control module may be at fault.
For a more detailed list of service centers near you, visit KBB’s service center list.
How Difficult Is It to Inspect a P0056 Code?
Regardless of the vehicle’s manufacturer, the first step technicians usually take in inspecting a P0056 code is to complete a visual inspection of the bank 2 sensor 2 oxygen sensor and its wiring. Often, the wiring can get damaged or frayed due to road debris and hazards.
Correctly inspecting and diagnosing the P0056 issue can be difficult depending on the make and model of the vehicle in question. Therefore, we don’t recommend self-diagnosing the P0056 code issue and suggest that you take your car to a certified technician.
For a more detailed list of service centers near you, visit KBB’s service center list.
Need Additional Help with Your P0056 Code?
In conclusion, a P0056 code issue may cause your Check Engine Light to come on and increase your vehicle’s emissions. Therefore, if you’ve noticed your Check Engine Light turn on and a possible decrease in your vehicle’s fuel efficiency, you shouldn’t wait any longer to get it inspected by a proper technician to reduce the risk of further damage to your car.
For more information on the P0056 and other similar diagnostic codes, visit KBB’s vast library of OBD-II codes.
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