A knock sensor helps keep your engine running efficiently. When they fail, it can cause annoying noises and may lead to further damage if left untreated.
What Does P0332 – “Knock Sensor 2 Circuit Low Input (Bank 2)” Mean?
This fault code label seems a bit complicated at first, but it’s simple when you break it down. A knock sensor is simply a small sensor that detects detonation, which is when the air and fuel in the combustion chamber ignite prematurely. Many cars have two sensors, so sensor 2 identifies an issue with the second circuit.
A low signal means that the PCM (the engine computer) doesn’t receive a good quality signal. Since the PCM relies on the knock sensor to detect knocking, the PCM can’t adjust the run conditions to prevent detonation if it isn’t working. That often causes pinging, a rhythmic ticking or popping that you will hear while the engine runs.
How Serious Is Code P0332?
A knock sensor issue may not be causing any issues. If your engine is healthy, and there is simply a weak connection to the sensor, then you may not notice any symptoms beyond your check engine light being on. While that will cause you to fail inspection, it poses little risk to your car.
However, pinging is an issue that can occur from a bad sensor. If left unfixed, it can become a bigger issue. You can read more about engine noises and the damage they can cause here. If you notice the following, though, you should stop driving immediately.
- The temperature climbs, or you smell burning coolant
- The pinging gets much louder and more erratic
- The knock sensor
- MAF or MAP sensor
- Check engine light is illuminated
- Engine runs hot
- Poor engine performance while accelerating
There are a handful of causes that will create the P0332 fault code.
- The knock sensor has failed. This is the most likely cause.
- The wires and/or connections going to the knock sensor are damaged
- The EGR valve is stuck
- A separate issue is causing the engine to run lean
- A separate issue is causing the engine to run hot
- There is a DCM issue. This issue is very rare but not unheard of.
The solution to these issues depends largely on what part has actually failed. In general, you are going to want to follow the following steps. They are listed in order of commonality of the issue.
Most of these solutions can be done by anyone with common hand tools, but don’t be afraid to take the car to a mechanic. A good mechanic can perform a knock sensor diagnostic and repair in a short amount of time, and most of the sensors involved are inexpensive.
Locate and Inspect the Sensors
Whenever a sensor fails, the first step is to use the internet or a shop manual to locate the sensor. When you find the sensor, take a moment to inspect the wires and connections. Look for corrosion, brittle or broken wires, and/or black scoring where a short may have occurred. Repair broken electrical parts if you find any.
Replace the Knock Sensor
Knock sensors are inexpensive and usually only require the removal of a single bolt to replace. Often, this will be your final step. If it’s not, you can perform the next two steps, but your time may be better spent getting professional help.
Check the Function of the EGR Valve
The EGR, or exhaust gas recirculation, sends some exhaust gas back through the engine to give it a more complete burn and lower emissions. If it fails, it can cause a variety of issues, including knocking or pinging. This article can teach you how to test the valve.
Use a Scanner to Perform Advanced Diagnostics
To narrow down any remaining underlying issues, you may need to run deeper diagnostics. Using a scanner to watch the air and fuel mixtures, logging data over time, and installing new diagnostic tools onto the computer are a few of these deeper diagnostics.