Returning Knock Sensor Code 52 and Retarding Timing

On both cars the knock sensor is located in the intake valley.

the computer receive signals if engine knocking and adjust the timing till stop.Before replace the sensors make sure the engine have no other misfire ,bad gas or vacuum leak.plug scan tool and read the code.Only circuit problem will be a true knock problem. Inspect all wire connectors before start taking a part.

DTC P0326 - Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor) High Voltage ( click HERE )
Knock sensors are used to detect engine pre-detonation (engine knock or ping). The knock sensor (KS) is usually a two wire sensor. A 5 volt reference is supplied to the sensor and there is a signal return from the knock sensor to the PCM (powertrain control module). The sensor signal wire informs the PCM when a knock occurs and in what degree of severity. The PCM will ****** the spark timing to avoid pre-detonation. Most PCMs have the ability to learn spark knock trends in the engine during normal operation.

If the PCM determines that the knock is out of the ordinary or that the noise level is abnormally high, P0326 may set. If the PCM senses that the knock is severe and cannot be eliminated by retarding the spark timing, P0326 may set. Keep in mind that knock sensors cannot distinguish between a knock from pre-detonation or one from engine problems.

If an engine knock can be heard, fix the source of the mechanical problem first then retest. Make sure the proper octane of fuel was used in the engine. Using lower octane fuel than what is specified can cause a ping or pre-detonation and may cause P0326.
Unplug the knock sensor and check for water or corrosion in the connector. If the knock sensor has a seal, verify there is no coolant from the engine block fouling the sensor. Repair as necessary.
Turn ignition to run position with engine off. Ensure that 5 Volts are present at the KS connector. If there is, check for proper resistance between KS terminal and engine ground. You will need a vehicle specification for this. If resistance is out of specification, replace the knock sensor. If resistance is normal, plug KS back in and idle the engine. Using a scan tool in datastream, observe KS value. Does it indicate a knock is present at idle? If so, replace the knock sensor. If the knock sensor shows no knock at idle, then tap on the engine block while observing the knock signal. If it doesn't show a signal that corresponds with the taps, replace the knock sensor. If it does, verify the knock sensor wiring isn't routed next to ignition wires. If there was no 5 volts present at the knock sensor connector while unplugged with KOEO (Key on engine off) then go back to the PCM connector. Turn ignition off and clip the knock sensor 5 volt reference wire in a location that is easy to repair (Or remove the wire from the PCM connector). With KOEO, check for 5 volts on the PCM side of the clipped wire. If 5 volts isn't present, suspect a bad PCM. If 5 volts IS present, repair short in 5 volt reference circuit.
Since the reference circuit is a shared circuit, you will need to check all engine sensors that are fed a 5 volt reference. Unplug each sensor one at a time until the reference voltage returns. When it returns the last sensor you plugged in is the shorted sensor. If no sensors are shorted, check the wiring harness for short to voltage on reference circuit.
Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

P0326 - Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor) High Voltage
Knock sensors are used to detect engine pre-detonation (engine knock or ping). The knock sensor (KS) is usually a two wire sensor. A 5 volt reference is supplied to the sensor and there is a signal return from the knock sensor to the PCM (powertrain control module). The sensor signal wire informs the PCM when a knock occurs and in what degree of severity. The PCM will ****** the spark timing to avoid pre-detonation. Most PCMs have the ability to learn spark knock trends in the engine during normal operation.

If the PCM determines that the knock is out of the ordinary or that the noise level is abnormally high, P0326 may set. If the PCM senses that the knock is severe and cannot be eliminated by retarding the spark timing, P0326 may set. Keep in mind that knock sensors cannot distinguish between a knock from pre-detonation or one from engine problems.

Symptoms of a P0326 DTC may include:
MIL (Malfunction Indicator Lamp) illumination
Audible knocking from the engine compartment
Pinging from engine under acceleration

Potential causes of a P0326 code include:
Knock sensor connector is damaged
Knock sensor circuit is open or shorted to ground
Knock sensor circuit is shorted to voltage
Knock sensor has failed
Moisture in knock sensor connectors
Incorrect fuel octane
PCM has failed

Possible Solutions:
If an engine knock can be heard, fix the source of the mechanical problem first then retest. Make sure the proper octane of fuel was used in the engine. Using lower octane fuel than what is specified can cause a ping or pre-detonation and may cause P0326.

Unplug the knock sensor and check for water or corrosion in the connector. If the knock sensor has a seal, verify there is no coolant from the engine block fouling the sensor. Repair as necessary.

Turn ignition to run position with engine off. Ensure that 5 Volts are present at the KS connector. If there is, check for proper resistance between KS terminal and engine ground. You will need a vehicle specification for this. If resistance is out of specification, replace the knock sensor. If resistance is normal, plug KS back in and idle the engine. Using a scan tool in datastream, observe KS value. Does it indicate a knock is present at idle? If so, replace the knock sensor. If the knock sensor shows no knock at idle, then tap on the engine block while observing the knock signal. If it doesn't show a signal that corresponds with the taps, replace the knock sensor. If it does, verify the knock sensor wiring isn't routed next to ignition wires. If there was no 5 volts present at the knock sensor connector while unplugged with KOEO (Key on engine off) then go back to the PCM connector. Turn ignition off and clip the knock sensor 5 volt reference wire in a location that is easy to repair (Or remove the wire from the PCM connector). With KOEO, check for 5 volts on the PCM side of the clipped wire. If 5 volts isn't present, suspect a bad PCM. If 5 volts IS present, repair short in 5 volt reference circuit.

Since the reference circuit is a shared circuit, you will need to check all engine sensors that are fed a 5 volt reference. Unplug each sensor one at a time until the reference voltage returns. When it returns the last sensor you plugged in is the shorted sensor. If no sensors are shorted, check the wiring harness for short to voltage on reference circuit.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Hi Thomas,
We have a couple different issues here.
First, your Maxima is either NOT a 1995 model, or it is a very late 1995 model that "thinks" it's a 1996. The reason I say this is because a 1995 model Maxima is NOT OBD compatible and is not capable of outputting "P-codes" to a generic OBD scanner.
Those Nissans that were claimed to be OBD compatible in the late 1995 model year only output certain codes. To find out the rest of the story, you still need a scanner that has software capable of accessing the engine computer through the Nissan-2 connector (usually in the fuse block area).
Then you need to understand about Diagnostic Trouble Code (DTC) P0325.
This code does not necessarily mean that you need a new knock sensor. I think you will be a little less confused if you know the facts. What you need to know about ALL fault codes is that they NEVER tell you what parts to replace. Fault codes only tell you that the computer has a problem with one of the many circuits and systems that it monitors. The fault code will tell you which system is failing or which circuit is failing. They DO NOT tell you what is wrong with the circuit or system that it is reporting. The person diagnosing the vehicle is supposed to figure that one out.
Most people think that "diagnostics" means plug in the "magic box" and replace everything the computer tells you to replace. I WISH it was that easy!
Now that you know all of this, we can examine the code itself. What causes this code to set? ...I'm glad you asked. The computer controls the ignition timing in your car. The trick is to advance the timing as far as possible (for more power and efficiency) while not advancing it too far, which will cause pre-detonation (also known as "ignition ping"). Pre-detonation can cause serious engine damage, including burning holes through a piston.
Here is where the knock sensor comes in.
SCENARIO 1: The computer advances the ignition until the knock sensor "hears" an ignition ping. When this happens, the knock sensor sends a signal to the PCM to let it know that the engine is "knocking". So the computer responds by retarding the timing a little to stop the knock. When the knock stops, the knock sensor will stop sending a knock signal to the computer.
DTC P0325 sets when the computer has ******** the ignition timing as far as it possibly can and the knock sensor is STILL sending a knock signal.
SCENARIO 2: The computer also tests the knock sensor by deliberately advancing the timing too far for a few seconds to see if it gets a signal from the knock sensor.
So, P0325 can also set if there is NO signal from the knock sensor when the computer is EXPECTING a signal.
For scenario 1, the cause is usually a mechanical knock in the engine. Loose timing belts, worn/loose timing chains worn distributor shafts, bad pulley bearings, etc. The knock sensor does not know the difference between a knock caused by pre-detonation and a knock caused by a loose valve lifter (or other mechanical reason). The knock does not go away when the timing is ******** because the knock is not CAUSED by timing....code P0325 sets.
For scenario 2, the cause is usually either the knock sensor itself or a problem with the wire between the knock sensor and the computer or the knock sensor is not grounded properly. These things will cause the knock sensor to not be able to get a message through to the computer....code P0325 sets.
Now, the misfire at idle is a whole other issue. The computer will default to base ignition timing settings if there is a knock sensor fault. You may notice a little loss of performance, particularly during heavy acceleration, but there is NO WAY that your knock sensor is the CAUSE of ANY misfire - especially not at idle. However, it is VERY possible that whatever is causing the misfire could also be the cause of the knock sensor code.
Basically what I am saying here is that you need to put the knock sensor problem "on the back burner" until you find out what is causing your misfire. Unfortunately, misfires can be cause by a LOT of different things ranging from a bad spark plug to a cracked cylinder head or worn-out piston rings. The misfire simply has to be diagnosed using the proper procedures to avoid replacing a bunch of things that will not fix the problem.
With all that said, WHEW! I hope you got through all that!
The older Nissans are notorious for the distributor shaft bushing going bad and causing a loud "rattling" noise. The movement of the shaft can cause a cylinder misfire, and the rattling can cause a knock sensor code to set. I have fixed many of the Nissan V-6 engines with this same problem by replacing the distributor. This is the FIRST place I would look. If your distributor is not rattling, try revving the motor just a little and see if it rattles. If it does, replace it. If it does not, let me know and we will look elsewhere for the cause of your problem.
-Dave (dttech)

Code 12 Engine revolution signal missing
Code 52 Knock sensor fault
Code 71 EGR system malfunction

OBD Code 12 - No Distributor Reference Pulse (Diagnostic Test Active) The Engine Control Module-ECM uses the distributor reference pulse to calculate the engine speed. On newer engines, the Crank Shaft Position Sensor performs this function.

Symptoms:

• When flashing the Check Engine Light to read codes, code 12 will always display first, indicating the diagnostic system is active
  
• The engine will not run with a "hard" code 12 set
  

Common Problems:

• Chances are you will never need to diagnose a code 12. Rather, the problem would be a crank, no-start condition.
• If code 12 does not flash, that would indicate a communication problem with the ECM.
• Code 12 does not show when reading codes with a scan tool. If there is a communication problem, the scan tool will let you know.

OBD Code 46 - Pass-Key II System Error - Circuit out of Frequency Range The ECM receives a signal from the Pass-Key module. When the correct signal is received, the ECM will allow the engine to start and run. Please review the RepairPal article on the GM Pass-Key Anti-theft systems for more information.

Symptoms:

• Engine may not start

Common Problems:

• Faulty ignition lock cylinder

OBD Code 43 - Knock Sensor error The ECM receives a signal from the Knock Sensor based on the amount of engine ping detected. The ECM uses information from this sensor to help calculate fuel delivery and spark timing.

Symptoms:

• Engine ping
• Lack of power

Common Problems:

• Faulty Knock sensor
• Poor connection at Knock sensor

OBD Code 55 - End Test.


Hope ehit help (remember comment and rated this).

The 43 is the knock sensor, the wires must be broken or fused together to continue to get the same code.
Testing the sensor for the DIY Knock sensors detect detonation ( knocking ) by reacting to the ping by retarding the ignition timing so you will need a timing light for this. connect the timing light and locate the knock sensor, ( many are on the intake manifold ) now use a metal object to tap ( not too hard and not on the sensor itself ) on the intake manifold ( light tapping should suffice ), if the sensor is functioning you will see the timing ******. If the timing does not ****** you will need to check voltage across the terminals of the knock sensor connector.
Though that excerpt says your sensor is in the intake,I believe yours is in the water drain hole for the engine block.
I also found that most shops are to replace the wire to the knock sensor because of so much failure of those wires because of heat.
Enough information?Repost if this doesn't help and we can look at some other things to try.

very common for these to have a knock sensor code. it usually isnt the knock sensor that is the problem. it will set the code when the knock sensor has adjusted all it can.
By any chance has the car been a little gutless lately. Thats because the knock sensor is retarding the timing because of pinging. First thing I would do is fill the tank with chevron highest octane and add the techron cleaner to help clean your injectors. And then clear the code and drive for a couple days. If the code comes back, clear it again. Could take a couple weeks to clean up the injectors but what you really are trying to decide is if the truck seems to have more power which will be an indicator that pinging is less.
Going from summer fuels to winter fuels can create this sort of issue. The blends are not the same

P0332 - Knock Sensor 2 Circuit Low Input (Bank 2)

This sensor signals the engine-control computer when detonation is detected, momentarily retarding ignition timing until detonation ceases.

Most computer-controlled systems use knock sensors to ****** timing when the engine is experiencing pinging or knocking.


Obviously, a faulty knock sensor produces problems that appear to be ignition-system-related. If the knock sensor system does not provide an engine detonation signal to the PCM (powertrain control module), the engine detonates, especially on acceleration.

• The first step in diagnosing the knock sensor and knock sensor module is to check all the wires and connections in the system for loose connections, corroded terminals, and damage.
• With the ignition switch on, be sure that 12 volts are being supplied through the fuse to the knock sensor module.
• A quick check of a knock sensor is to watch the ignition's timing while the engine is running and the engine block is tapped with a hammer.
  • The noise should cause a change in timing.
• The knock sensor can also be checked by tapping near the sensor and watching for an AC pulse on a DMM or lab scope.

A knock sensor is simply a microphone that is screwed into the engine block. It is there to listen for pinging or engine "knock" that is caused by poor fuel or extreme load. When the computer hears the knock, it retards timing, which in turn reduces the tendency for knocking, however, it will reduce power to a certain extent as well. It is possible that a faulty knock sensor can be telling the computer to ****** ignition timing too much, it is also possible that there is a mechanical problem within the engine that is mimicking the sound of knocking and retarding timing as well.