- :
- Banned For Being A Troll
The sensor is a tuned microphone. It "Hears" Knock
Need Help identifying a sensor
- Thread starter lvevo
- Start date
I thought at first it was the oil pressure sensor, so i bought it and when I replaced it, it wasn't the one leaking the goo/glue. The oil pressure sensor is also not located above the oil filter if your looking up from underneath the car. I haven't seen the middle of the leaking sensor, so I can't see what is going on with that. Based on suggestions of what the sensor it could be, I looked up knock sensors on RockAuto and found them to be the same looking ones as my leaking sensor. The goo/glue is dark in color, almost black, and is very thick. When I hit it with brake cleaner, it didn't easily come off. I tried carb cleaner, and that worked a lot better. I know it is not oil from the filter because I can trace it back to said sensor above the oil filter.
As for my pinging, it very slight under load at low rpm only. I have also been trying to track that down along with the smoke at start up and fix any leaks this car has. I will also try and snap a picture of the sensor and it's leaking goo. When i get home today, I will look up the knock sensor in the service manual I downloaded online to try and confirm if that is the sensor. I don't know why I didn't do that in the first place. lol
As for my pinging, it very slight under load at low rpm only. I have also been trying to track that down along with the smoke at start up and fix any leaks this car has. I will also try and snap a picture of the sensor and it's leaking goo. When i get home today, I will look up the knock sensor in the service manual I downloaded online to try and confirm if that is the sensor. I don't know why I didn't do that in the first place. lol
Last edited:
- :
- Banned For Being A Troll
It sure looks like that goo is coming from the sensor itself. If the hole it threads into doesn't go anywhere then it can't be oil coming through so I'm thinking it's a sign of a bad sensor. The knock sensor MIL may not indicate a bad sensor,.. perhaps just a short or open. The ECU may may not see a lack of input from the sensor as unusual because the engine isn't supposed to 'knock' anyway. Every other sensor I can think of is giving constantly changing data to the ECU.
Here's the specs. from the manual:
KNOCK SENSOR INSPECTION [FS]
Note
• Perform the following test only when directed.
Resistance Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the knock sensor connector.
3. Measure the resistance between the knock sensor terminals A and B.
• If not as specified, replace the knock sensor.
• If the knock sensor is okay, but PCM terminals 57 and 59 voltages are out of specification, perform the “Circuit Open/Short Inspection”.
Specification 532—588 kilohms (20 C {68 F})
Here's the specs. from the manual:
KNOCK SENSOR INSPECTION [FS]
Note
• Perform the following test only when directed.
Resistance Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the knock sensor connector.
3. Measure the resistance between the knock sensor terminals A and B.
• If not as specified, replace the knock sensor.
• If the knock sensor is okay, but PCM terminals 57 and 59 voltages are out of specification, perform the “Circuit Open/Short Inspection”.
Specification 532—588 kilohms (20 C {68 F})
BRAIN_MP5T,
That looks like the one that is leaking on my car. It has a wire coming out of it offset to the edge just like that, not like the male end of the oil pressure sensor. I don't remember that sensor that is right underneath it. It sure looks like the oil pressure sensor that I replaced this weekend. Mine(Oil Pressure Sensor) was off to the left, like 6" - 8" away from the knock sensor.
That looks like the one that is leaking on my car. It has a wire coming out of it offset to the edge just like that, not like the male end of the oil pressure sensor. I don't remember that sensor that is right underneath it. It sure looks like the oil pressure sensor that I replaced this weekend. Mine(Oil Pressure Sensor) was off to the left, like 6" - 8" away from the knock sensor.
whatusername
Member
- :
- 02 protege5
smoke at startup replace ur pcv valve
I've done that and oil pressure sensor. I think it may be the valve stem seals, but the car will only smoke when it has been sitting for 5 hours or more when it is cold out. Also every once in a while the morning start up will yield no smoke. It seems the smoke starts about 15 sec. Into the warm up.
whatusername
Member
- :
- 02 protege5
just use goo gone lol
I'm worried that it might be a sign that the sensor is shot. The ECU may very well not "know" if the sensor is reporting a knock or not. It might just think everything is fine even if knock is present. I'm gonna test the resistance some time soon to see what it tells me (it's supposed to be between 532 and 588 kilohms),.... too bad there isn't some kind of test like knocking the block with a hammer to see if the sensor registers it. They are $50- $100 for a new one,... if it was less than $20 I'd just replace it. Unfortunately I've never experienced knock in any car ever. I don't think I'd recognize it if it did happen.
pcb,
the ECU , consistently runs a "Self-Diagnostic Test" every time you start the vehicle.( well, it is supposed to.)
If the ECU detects a fault, it trips a DTC. If the ECU does not detect a sensor that normally it detects, it will trip a fault code(DTC).
There are different kinds of DTC's. "One Trip" & "Two Trip"
A "one trip" fault will trip a DTC when a detected fault happens ONCE in a predetermined amount of time.(usually one drive cycle)
A "two trip" fault will trip a DTC when a fault is detected TWICE in a predetermined amount of time. (again, usually one drive cycle).
That's a simple explanation, there is more to it than that. (the newer the vehicle, the more evolved the ECU is with the car. It gets into "CAN-BUS" Communications, pre-set parameters, secondary modules, and on and on and on).
So with THAT in mind, your ECU should detect if the Knock Sensor (or any sensor for that matter) isn't doing its job. Provided that all communications wires are intact and all is working properly, etc...etc...
the ECU , consistently runs a "Self-Diagnostic Test" every time you start the vehicle.( well, it is supposed to.)
If the ECU detects a fault, it trips a DTC. If the ECU does not detect a sensor that normally it detects, it will trip a fault code(DTC).
There are different kinds of DTC's. "One Trip" & "Two Trip"
A "one trip" fault will trip a DTC when a detected fault happens ONCE in a predetermined amount of time.(usually one drive cycle)
A "two trip" fault will trip a DTC when a fault is detected TWICE in a predetermined amount of time. (again, usually one drive cycle).
That's a simple explanation, there is more to it than that. (the newer the vehicle, the more evolved the ECU is with the car. It gets into "CAN-BUS" Communications, pre-set parameters, secondary modules, and on and on and on).
So with THAT in mind, your ECU should detect if the Knock Sensor (or any sensor for that matter) isn't doing its job. Provided that all communications wires are intact and all is working properly, etc...etc...
^north42g,
The only trouble code I could find (for our FS engine) is P0325 Knock sensor circuit malfunction ON (See 01–02B–77 DTC P0325 [FS])
Then in the test procedure it says to check the resistance of the sensor at the terminals, then to check the harness for an open or a short.
Here's what a link from RockAuto says about knock sensors:
What does a Knock Sensor do?
This sensor creates a voltage signal based on the vibrations caused by detonation. The computer uses this signal to retard timing when spark knock occurs.
How to determine if these sensors are malfunctioning.
To check for proper operation, monitor the knock sensor data parameter on the scan tool. Some activity should be occurring while accelerating the engine. The diagnostic codes range between P0324 and P0333.
• Standard knock sensors are designed to respond to knock frequencies up to 1000 Hz accommodating shifts in engine knock frequency making it a more flexible sensor responding to correct engine knock over a broad range of vehicle conditions
• Manufacturing processes include an automated data acquisition system to continuously monitor the sensor output to ensure that it responds with appropriate voltage output at the specified frequency range
• All units are 100% tested using an accelerometer vibration test to ensure trouble-free operation
Our cars test procedure doesn't include any kind of "data parameter" test so we have no idea what kind of signal our sensor is supposed to send.
Here is a list of all possible knock sensor codes:
P0325 Knock Sensor 1 Circuit Malfunction (Bank I or Single Sensor)
P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
P0327 Knock Sensor 1 Circuit Low Input (Bank I or Single Sensor)
P0328 Knock Sensor 1 Circuit High Input (Bank I or Single Sensor)
P0329 Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)
P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0334 Knock Sensor 2 Circuit Intermittent (Bank 2)
I would feel a lot more comfortable if our car could throw a P0326 code because then we would know if the sensor is producing a proper signal.
My main concern (and I may very well be over thinking this) is that goo dripping off our sensors is the suspension material for the tiny accelerometer inside the sensor and may very well throw off the sensitivity so it would either over read and retard our timing too much reducing performance, or under read in which case we would need a knock like a bomb blast to register with the ECU.
I'm thinking our sensors go towards the bomb blast side of things because some people are getting knock without throwing a code.
The only trouble code I could find (for our FS engine) is P0325 Knock sensor circuit malfunction ON (See 01–02B–77 DTC P0325 [FS])
Then in the test procedure it says to check the resistance of the sensor at the terminals, then to check the harness for an open or a short.
Here's what a link from RockAuto says about knock sensors:
What does a Knock Sensor do?
This sensor creates a voltage signal based on the vibrations caused by detonation. The computer uses this signal to retard timing when spark knock occurs.
How to determine if these sensors are malfunctioning.
To check for proper operation, monitor the knock sensor data parameter on the scan tool. Some activity should be occurring while accelerating the engine. The diagnostic codes range between P0324 and P0333.
• Standard knock sensors are designed to respond to knock frequencies up to 1000 Hz accommodating shifts in engine knock frequency making it a more flexible sensor responding to correct engine knock over a broad range of vehicle conditions
• Manufacturing processes include an automated data acquisition system to continuously monitor the sensor output to ensure that it responds with appropriate voltage output at the specified frequency range
• All units are 100% tested using an accelerometer vibration test to ensure trouble-free operation
Our cars test procedure doesn't include any kind of "data parameter" test so we have no idea what kind of signal our sensor is supposed to send.
Here is a list of all possible knock sensor codes:
P0325 Knock Sensor 1 Circuit Malfunction (Bank I or Single Sensor)
P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
P0327 Knock Sensor 1 Circuit Low Input (Bank I or Single Sensor)
P0328 Knock Sensor 1 Circuit High Input (Bank I or Single Sensor)
P0329 Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)
P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0334 Knock Sensor 2 Circuit Intermittent (Bank 2)
I would feel a lot more comfortable if our car could throw a P0326 code because then we would know if the sensor is producing a proper signal.
My main concern (and I may very well be over thinking this) is that goo dripping off our sensors is the suspension material for the tiny accelerometer inside the sensor and may very well throw off the sensitivity so it would either over read and retard our timing too much reducing performance, or under read in which case we would need a knock like a bomb blast to register with the ECU.
I'm thinking our sensors go towards the bomb blast side of things because some people are getting knock without throwing a code.
DTC P0325 is set when PCM does not detect input from knock sensor(KS) for 5 seconds with engine running, engine load more than 50%,engine coolant temp more than 140 degrees F, engine speed 1500-5000 RPM.This is a continuous monitor. MIL is illuminated when PCM detects malfunction during first Drive cycle.
Possible causes are:
KS Malfunction
Open or Short Circuit between KS and PCM
PCM malfunction
Measure resistance between KS terminals; Resistance should measure at or about 560,000 ohms. If measurement is significantly different, replace KS.
Possible causes are:
KS Malfunction
Open or Short Circuit between KS and PCM
PCM malfunction
Measure resistance between KS terminals; Resistance should measure at or about 560,000 ohms. If measurement is significantly different, replace KS.
Last edited:
