Knock sensor

ryans, Sep 13, 4:14pm
On cold mornings when I drive off in my Legacy, the check engine light often comes on and I lose power for 5 or 10 seconds, then the light goes off and I get my power back.

I've checked the error code on my car and it is code 22, which is the knock sensor.

Initially I thought that meant the knock sensor is bad, but thinking about it, the check engine light goes out and the power returns, so maybe the code is telling me that the knock sensor picked up an issue and is actually working correctly.

Can anyone offer any opinions, please!
gj0502, Sep 13, 4:24pm
The check engine light will only go on if the sensor is faulty and not if it is detecting knock.
unbeatabull, Sep 13, 4:28pm
Knock sensor controls ignition timing, and is constantly picking up knock and changing the timing to suit.

If engine is dieing I'd say the sensor is picking up either a really bad knock which is causing it to cut timing & then the car going into limp home/open loop control, or the knock sensor is sending a reading out of the expected range (other words - faulty) to the computer and the computer is switching from closed loop to open loop and putting the light on the dash
zephyrheaven, Sep 13, 4:32pm
Just change the position of the knock sensor location
intrade, Sep 13, 4:34pm
and run 98 or 96 minimum octane
unbeatabull, Sep 13, 4:50pm
While Ill always agree that it is better, I doubt thats the cause of the problem. It would have to be a really bad knock for the sensor to actually cut engine power that significantly, you would certainly hear the knock anyway.
hijacka, Sep 13, 4:51pm
Just replace the farkn thing cost less than $50 ffs
ryans, Sep 13, 4:55pm
$90 or so apparently, for a genuine sensor, I know how to do it, just wondering if it was actually faulty or not.
It doesn't happen every time and only when it's cold, so I'll let the car warm up for a few minutes before setting off in the meantime.
hijacka, Sep 13, 5:10pm
What year and model is it!
ryans, Sep 13, 5:22pm
It's a 1999 Legacy b4 twin turbo.
Thanks for the picture, I took the intercooler off a few weeks ago when I replaced my coolant lines, so shouldn't have too much trouble when I do it.
hijacka, Sep 13, 5:47pm