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Error Code P0326 is defined as Knock Sensor Circuit Range Performance (Bank 1 or Single Sensor). This refers to camshaft timing, which in this case is over-retarded.
This is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II, particularly vehicles made since 1996 to present. Specifications on the definition, troubleshooting, and repairs vary from one vehicle make and/or model to another.
Knock sensors (KS) are included in the engine to detect engine pre-detonation, such as pining and knocking. It’s a two wire sensor supplied with 5V reference voltage, with a signal return linked to the PCM.
Thus, the error code P0326 means the PCM (powertrain control module, also known as ECM or engine control module) has detected a reference voltage coming from the knock sensor which has fallen outside the accepted threshold set by the vehicle’s manufacturer. The job of the knock sensor is to send a signal to the PCM indicating abnormal noises in the engine that may be occurring, like spark knock. It also tells the PCM the severity of the knocks. With this, the PCM will retard the spark timing to avoid pre-detonation.
If the PCM reads the knock is out of the ordinary, severe and can’t be eliminated, then it sets the Error Code P0326. Also, you should know that the knock sensor is not capable of distinguishing the difference between pre-detonation and other forms of engine problems.
Some of the most common symptoms of Error Code P0326 include:
- Audible knocking coming from the engine compartment
- Pinging sound coming from the engine during acceleration
- Abnormal engine sound
- Loss of power
- Hesitation upon acceleration
- Spark knock
There are multiple ways a vehicle can have this error code, and sometimes, this code is accompanied by other error codes. Thus, it is important to address those other codes first. If there are no other codes present other than the P0326, the potential causes of that would be:
- Damaged knock sensor
- Damaged or faulty connector or wiring associated with the knock sensor
- Unplugged connector
- Faulty PCM (rare)
How to Check
If this code is accompanied with other error codes, mechanics usually start their diagnosis by fixing those other codes first. If there are no other problems, then the mechanic will start their diagnosis with a visual inspection of the knock sensor and make sure it is plugged in. Technicians will also check the wiring and look for signs of damage and that they’re functioning properly.
To make sure the knock sensor is still working properly, the technician will conduct a test using a digital multimeter using the procedures recommended by the manufacturer. If there are issues found during the test, the faulty parts will be either repaired or replaced.
If there are no other issues found, then there’s a chance the PCM is at fault and should be tested next. If damaged, the PCM must be replaced.
How to Fix
Repairs for this error code are pretty straightforward, which include:
- Repair or replacing of faulty connectors or wirings associated with the knock sensor
- Replacing the knock sensor
- Plugging the knock sensor back
- Replacing the PCM
If the error code P0326 is set by itself, then the problem must be serious. Other serious codes may cause this code to pop up, and they may come with dangerous drivability issues that may expose you to safety risks and cause damage to the engine in the long run. Thus, it is crucial to fix this error code as soon as possible.
Also, a thorough diagnosis is important on fixing this code, as you don’t want to replace a fully functioning knock sensor. Thus, make sure the sensor is really the problem before replacing it.