Fault code, Knock sensor
02 June 2010, 07:17 AM
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Fault code, Knock sensor
After the fun of the white smoke now stopping I had noticed the check engine light flash up for just a second.
I checked the fault with the black cables and it says it is the knock sensor.
As it was only on for a second does it mean it is on it way out, and when it breaks fully the engine light will stay on?
I checked the fault with the black cables and it says it is the knock sensor.
As it was only on for a second does it mean it is on it way out, and when it breaks fully the engine light will stay on?
02 June 2010, 08:56 AM
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No I don't think so, I believe the knock sensor is used for ignition advance and retard, this is critical. Probley best you get it checked out by someone who knows!
02 June 2010, 09:08 AM
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It is used to detect knock/detonation in the engine- allowing the engine ecu to advance retard timing to reduce the knock/detonation. Get it checked over asap!!!!!
What car is this on? classic, newage, wrx, sti??
What car is this on? classic, newage, wrx, sti??
Last edited by rookymatt; 02 June 2010 at 09:08 AM. Reason: spelling
02 June 2010, 09:59 AM
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I had knock sensor issues on my wrx bugeye (newage) Replaced it with a gen subaru item and made sure i put some good contact grease on the pins before i pluged it back in. Tigtening torque was 22nm i think. Fault never returned after that.
02 June 2010, 10:32 AM
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Now you have a 22 error code for the knock sensor try reseting the ecu first see if it removes the code.... if NOT or code comes straight back poss faulty knock sensor!!! If code removed ecu messured a prob to give the cel at that time.
Last edited by sy.; 02 June 2010 at 04:18 PM.
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02 June 2010, 01:22 PM
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Just doing a battery reset won't hurt the car at all mate. It might run a little "fruity" for the first few miles as it relearns it's adaptations. 
02 June 2010, 02:11 PM
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Mine is modded too mate! Trust me, you'll be ok. Just make sure the alarm is dissarmed when you take the battery off, and have the fob to hand when you put it back on incase it starts to cry!!!
02 June 2010, 02:43 PM
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Kingbuttmunch - what model year is your classic? While you can reset your ECU via removing the battery, this is not the best way to do it.
You'd be better advised to use the black plug/green plug/drive slowly procedure, as this will do an active check of all the car's error states and only give you the OK light flash sequence if they all pass.
The code 22 error will only activate if the knock sensor circuit goes open or short for more than a very short period of time, although on some ECUs it has a habit of coming on seemingly at random. If it has come on, the likeliest explanation is that your sensor is on its way out. If this is the case (or if there's a related error in the car's wiring), you'll probably see the error again. As r1c said earlier this sensor is critical to the knock detection and ignition learning system so if it recurs, investigate and fix it.
If you do want to reset by disconnecting the battery, as Matt has said, the alarm shouldn't go off if it's disarmed when the power is taken off.
You'd be better advised to use the black plug/green plug/drive slowly procedure, as this will do an active check of all the car's error states and only give you the OK light flash sequence if they all pass.
The code 22 error will only activate if the knock sensor circuit goes open or short for more than a very short period of time, although on some ECUs it has a habit of coming on seemingly at random. If it has come on, the likeliest explanation is that your sensor is on its way out. If this is the case (or if there's a related error in the car's wiring), you'll probably see the error again. As r1c said earlier this sensor is critical to the knock detection and ignition learning system so if it recurs, investigate and fix it.
If you do want to reset by disconnecting the battery, as Matt has said, the alarm shouldn't go off if it's disarmed when the power is taken off.
Last edited by Splitpin; 02 June 2010 at 02:45 PM.
02 June 2010, 03:24 PM
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some later classics 800 801 802 ect can flicker cel from knock error log (if high enough or malfunction circuit implorsible) ie cel light does not stay on (code is logged)also not to be confussed with apexi use of cel
Last edited by sy.; 02 June 2010 at 04:15 PM.
02 June 2010, 04:05 PM
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The sensor that gave you the error code (knock sensor)when doing so made the cel(check engine light) flicker(or come on/off for a sec)
Last edited by sy.; 02 June 2010 at 04:07 PM.
02 June 2010, 04:07 PM
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No they can't. The only way the knock sensor will illuminate the CEL is if the error state is set. These ECUs do not illuminate the light in response to real-time knock detection.
With due respect to Sy, he appears to have the wrong end of a stick somewhere. He appears to think that your ECU can light the check engine light if serious knock is detected. This belief is incorrect.
With due respect to Sy, he appears to have the wrong end of a stick somewhere. He appears to think that your ECU can light the check engine light if serious knock is detected. This belief is incorrect.
Last edited by Splitpin; 02 June 2010 at 04:10 PM.
02 June 2010, 04:13 PM
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i have edited my above posts as i seemed missleading SORRY
Last edited by sy.; 02 June 2010 at 04:23 PM.
02 June 2010, 04:36 PM
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For what it's worth the only way the code 22 error will set is if the voltage in the knock sensor circuit goes out of spec for one full second.
02 June 2010, 05:15 PM
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what i was tying to say originally is although the 22 fault code is logged and the cel light came on /off for a sec ect..it could have been a one off so to speak meaning if the ecu was reset and the code cleared and never returned!! as well as the poss of the code returning/staying leaning towards a fauty sensor..
Last edited by sy.; 02 June 2010 at 05:17 PM.
02 June 2010, 05:29 PM
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The trouble with typing stuff that comes out wrong is that you run the risk of confusing people who don't know different. Bottom line is that all the Subaru ECUs will ping the error 22 code if the knock sensor circuit goes open or short for more than the timeout value - there's nothing "special" about the three ECUs you mentioned in post #15 in this respect, they work the same way as the others.
Kingbuttmunch - do you know what you need to now, or are you even more confused?
Kingbuttmunch - do you know what you need to now, or are you even more confused?
02 June 2010, 05:49 PM
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Think I have it sorted. Just reset the ecu and it has flashed to say everything is ok. I will look out to see if the engine check light comes up again.
Really didnt take a long time at all for the car to give me the all clear only about 10 seconds but the car was already warm i guess
Really didnt take a long time at all for the car to give me the all clear only about 10 seconds but the car was already warm i guess
02 June 2010, 06:11 PM
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Really didnt take a long time at all for the car to give me the all clear only about 10 seconds but the car was already warm i guess
It takes longer when the car's stone cold as the error check sequence waits to allow the O2 and coolant temp sensors to stabilise before okaying them.
02 June 2010, 06:29 PM
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Just got the code for the knock sensor again. I called a japanese car tuner near me who cant do it till the 13th in two weeks.
Can any garage carry out this task or would they likely not have the skills to do the job?
Can any garage carry out this task or would they likely not have the skills to do the job?
Last edited by kingbuttmunch; 03 June 2010 at 11:41 AM.
03 June 2010, 11:42 AM
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Just got the code for the knock sensor again. I called a japanese car tuner near me who cant do it till the 13th in two weeks.
Can any garage carry out this task or would they likely not have the skills to do the job?
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Can any garage carry out this task or would they likely not have the skills to do the job?
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03 June 2010, 12:32 PM
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Need to remove the intercooler to gain access, but it's not a real drame. I'm sure splitpin will be on to tell you how to fit it.
03 June 2010, 01:04 PM
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Aren't you supposed to say it three times? 
KBM, as Matt says, taking the intercooler off helps and you can change it yourself in less than half an hour. Just one M8 bolt and electrical connector. The only tricky part is that it's awkward to reach beneath the inlet manifold/throttle body. A 12mm socket on the end of a 3/8 long wobble extension makes it relatively easy.
Here's a picture someone else made earlier. Your car has a slightly different shape throttle body (the throttle cable on yours is on the other side so don't get confused!) but you'll get where it's located (i.e. on the left hand block half just behind the No. 4 cylinder).
KBM, as Matt says, taking the intercooler off helps and you can change it yourself in less than half an hour. Just one M8 bolt and electrical connector. The only tricky part is that it's awkward to reach beneath the inlet manifold/throttle body. A 12mm socket on the end of a 3/8 long wobble extension makes it relatively easy.
Here's a picture someone else made earlier. Your car has a slightly different shape throttle body (the throttle cable on yours is on the other side so don't get confused!) but you'll get where it's located (i.e. on the left hand block half just behind the No. 4 cylinder).
