Acura RL P0327: Knock Sensor → Low input


P0327 is a powertrain related OBD-II trouble code. It has the same meaning for the Acura RL as it would any other vehicle. By definition, P0327 means that the vehicles ECM/PCM is getting a signal that is lower than the defined operational range. Clearing this code typically requires a new knock sensor or correcting an issue with the wiring harness.

Modern engines utilize the knock sensor to detect detonation and allow for aggressive timing. If the timing has gotten too aggressive it’ll cause the engine to knock. This sensor will let the computer know to dial back the timing.  When the knock sensor is not working it can have a strong negative impact on your RL’s performance.

P0327 Acura RL


P0327 Symptoms: Acura RL

The symptoms associated with P0327 are going to vary depending on your RL’s engine and model year. Without a proper signal from the knock sensor, many engines will curve the timing and power output to make sure that the engine is not knocking. The only other symptom that you’ll probably notice is the service engine soon light itself.


Acura RL P0327 Diagnosis


P0327 Causes: Acura RL

Most of the time, the fix for P0327 in the RL (or most any vehicle) is going to come from replacing the knock sensor or repairing the wiring harness.  It would be wise to start by taking a look at the wiring harness.


Wiring Harness

P0327 is telling you that the ECM/PCM is getting a low signal from the knock sensor.  When this happens the computer will operate as though it is getting no signal from the sensor at all.  A good place to start would be to check the wiring leading from the sensor and see if any of it has been damaged or frayed. Most of them bolt right into the block, which makes accessing them difficult. Their proximity to the engine block means that they are often susceptible to damage.


Checking Car Wiring Circuits For Continuity with a Multimeter (Youtube)
How To Find an Electrical Short On Most Any Vehicle (Backyard Mechanic)


Take a good look at where the harness plugs into the sensor as well.  If it is loose or damaged you very well could have a wiring problem.


Knock Sensor

If you find that the wiring harness is ok, and the code is still persistently registering, it is time to test and/or replace your RL’s knock sensor. There are guides out there on how to test a knock sensor, but they are very affordable. They can also take a little digging to get to, which makes replacing it the way to go.

How to Test a Knock Sensor (It Still Runs)


It is possible that a bad PCM could cause this code to pop up.  It’s not nearly as likely as a bad knock sensor or wiring issue.


Conclusion: RL P0327 Diagnosis

The most difficult part in fixing your RL’s engine to clear the P0327 code is going to be finding room to maneuver and inspect the Knock Sensor and wiring harness. This can be tedious work. If there is anything that you would like to add that could help someone with this problem, please leave a comment below.  Good luck!