Hi everyone, looking for some help with my G35 coupe. I have no CEL but there is a pending Knock Sensor code (P0327). Car runs fine, no problems with gas mileage. No other codes. I cleared the code and in comes back almost immediately upon starting the car, again as a pending code. What is going on? Is there really a problem with the knock sensor and/or harness? Is there another problem?

 

I have the same code no C.E.L. It seems that the acceleration and fuel economy is fine as well. I was reading a thread where it said something about them replacing the sensor and it did nothing, but throw a different code: P0328 Knock sensor high signal something or other. I guess there was a wiring harness underneath that attached to another that wasn't plugged in all the way. I haven't tried clearing my codes yet to see if it comes back. Maybe I'll try that today.

 

I'm always amazed that prior to posting on this forum many seem to fail to read the FSM for their vehicle.

http://www.nicoclub.com/service-manu.../Coupe/2004/ec

Take out your multi-meter and do some troubleshooting

Start on page EC-290

DTC P0327, P0328 KS
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic Procedure
ABS003CT
1.
CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check resistance between ECM terminal 15 and ground. Refer to Wiring Diagram.
NOTE:
It is necessary to use an ohmmeter which can measure more than 10 M
Ω
.
4. Also check harness for short to ground and short to power.
OK or NG
OK
>> GO TO 4.
NG
>> GO TO 2.
2.
CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II
1. Disconnect knock sensor harness connector.
2. Check harness continuity between ECM terminal 15 and knock
sensor terminal 1.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK
>> GO TO 4.
NG
>> GO TO 3.
3.
DETECT MALFUNCTIONING PART
Check the following.


Harness connectors F37, F229


Harness for open or short between ECM and knock sensor
>> Repair open circuit or short to ground or short to power in harness or connector

If you don't have the skills to do proper troubleshooting then pay to have the dealer diagnose your problem.

Telcoman

 

 

Isn't true btw, colder air charge allows for more fuel and thus MORE timing and MORE power but I gotta say it's impressive he was able to swap the harness out like that. That's only if the problem was the actual HARNESS and not the sensor itself, it's really not hard to take the intake off though

There isn't a code that means the "harness is bad" or the "sensor is bad" only that the circuit is OPEN or that the circuit is SHORTED which can happen at either the sensor itself or the wires connecting it to the ECU. I'm suspicious about this actually fixing his issue since there was no follow up in the video saying if it fixed anything...

 

ok is this not normal?

 

No way to tell honestly unless you have it plugged into an OBD2 scanner and are data logging, you should see about +40 degrees advance on the timing under WOT.

Service Engine Soon lights are not normal, they are literally the ECU telling you there is an abnormal condition and it's taking failsafe precautions to prevent engine damage based on whatever the DTC is, sometimes the failsafe action is to stop advancing timing, sometimes it's to fully limp mode the engine, sometimes it's to not allow the engine to start at all, etc.

The knock sensor causes the ECU to retard timing -1 degree for every pulse of the sensor, these engines are prone to a knock condition due to factory ECU parameters pushing the limits of timing advance but it responds INCREDIBLY fast to pull back timing to prevent damage. If the sensor is bypassed by not being bolted properly to the top of the engine block you can literally kaboom the motor. If the ECU looses the signal due to either a short or open circuit it has precautionary values that will not allow the engine to operate at peak power, I don't know if it just halves the normal timing values or entirely stops making a correction but on most variable cam engines I've worked on it just stops making correction (zero timing advance).

A BT OBD2 scanner and the Android app Torque Pro can log data, I'm sure some handheld scanners can as well, timing advance is a parameter you can monitor.

 

Ok I've ordered an OBDII scanner. Should be here Wednesday. Then I can do she some real time sensor readings. Mine isn't shorted or open I know that much. It has low input/low voltage. I'm thinking is just like you
said has "no advance" It actually feels like it pulls more at about 3,500 RPM's and really starts to go.

 

This is a little strange, but after getting the app to connect it showed 0 DTC's not even pending ones. Also, I monitored the timing advance and it looked like all is well. It sat at ~8 degrees advance at idle and when I mash the gas it jumps way up. If I hold the RPM's at about 2,500 it says about 40 degrees advanced. So it must be working like it's supposed to.

 

Sounds like it's all working as intended then yes? Do you have a service engine soon light still because if so then it SHOULD be showing in the scanner. If the problem is intermittent (short in a wire somewhere) then it can be very frustrating to find since the code will clear itself when it's working again.

 

There isn't a light. I figured for sure it would show a code. It didn't have anything for a knock sensor reading though.

 

Ok, if the code does come back I would definitely start checking into a shorted or open circuit but NOT the actual sensor itself.

Basically you would unplug the sensor and read circuit continuity back to the corresponding pin on the ECU (it's in the factory service manual buried in the engine controls EC section, take a 10' or so length of wire and plug it into the harness and run it back into the cabin so you have a COMPLETE circuit to read) then while one person watches the meter for changes another person bends and twists the wire itself to try to find where the failing connection is. Focus on harnesses or any other termination, sometimes the crimped on pins are done poorly, sometimes engine vibration and movement only affects a certain spot where the wire is making sharp turns, sometimes it's heat damaged insulation.

Maybe you'll get lucky and the problem will never show up again !

 

Hey cleric, do you think it might be that I am using a free app? You know like not getting full features? That I am not seeing the code because the YAW sensor code didn't show either and I know that should show. The light for that is on. If I buy the iOS app for $13.99 I get "advanced diagnostics", plus other stuff. Then there is a step up from that for $31.99

EDIT: okay, it says in the help that if you are unable to connect or read DTC's that buying the basic edition for $13.99 would NOT help.

 

Sweet jesus which app are you using? Torque Pro is like $5 for android?

 

This one is called EOBD Facile for Apple. I tried iOBD2, but it kept crashing. My scanner is wifi not bluetooth so I have to have one that supports that. I believe it's an ELM327 dealy? It took me a while to figure it out, but I got it finally.

There is another for $5.99 called Engine Link OBDII - Engine Monitoring.... blah blah. I think it's a scan tool also and resets CEL. Also, clears codes whether pending, history, or current.

EDIT: Okay, went ahead and purchased the $5.99 Engine Link app. Still shows no codes. I'm guessing it only shows codes if there is a CEL on. It has a trouble code button and an "extra" codes button (ABS etc.) Both show 0 DTC's. It says fuel level is unavailable with my ECU or something like that. Which I was kind of hoping I could compare the reading to the actual gauge. Since it seems 3/4 tank = 1/2 tank. I don't have a continuity test to do any troubleshooting so yeah... But at least now I have a scanner tool and "app for that".