CEL/MIL lights is on...Help!

[na]

Hi Guys,

I just had a clucth change few days ago.

After driving it on the CEL/MIL is on. I checked it at home and the ECU is registering code 23. Knock sensor circuit malfunction according to Honda service manual.

I reset the ECU and do idle learn procedure as instructed by the service manual...and after holding the gas @ 3000 rpm for several minutes the CEL comes back on.

However, if you turn off the engine and restart and leave it idling forever...the CEL/MIL does not turn on. Only moment after I drive it then the lights comes on.

Question:
1. Is it dangerous to leave this CEL/MIL on this code? Car runs perfectly fine previously and now...vtec is on...no stuttering whatsoever?
2. Could the noisy vibration from the clutch/flywheel combo triggered the knock sensor? The vibration/buzz on the new clutch/flywheel combo is quite harsh when decelerating @ 2500-3500rpm...However the manual on the new clutch/flywheel that this vibration/buzz/noise is to be expected due to the lightweight design on the clutch/flywheel. Flywheel is 3.6KG. The noise/buzz/vibration only occurs when i lift up the throttle...and only on that RPM range. Clutch/Gearchanging operation remains normal...
3. Could this CEL/MIL results from the installation of clutch/flywheel? Accidentaly unplug something when installing maybe?

Confused...shed somelight please...

[aaronng]

No, the knock sensor won't be tricked by your cutch and flywheel. Have you checked that the sensor is plugged in properly and not disconnected during your clutch install?

[na]

no I haven't checked whether the connection is loose or not

you know where is it?

any picture??

Is it save though to drive with this problem??

[aaronng]

On mine it is just below the intake manifold (K-series). What car do you have?

[h17am]

na's car is s2000

[aaronng]

Check if it is near the intake manifold then. Otherwise, ask s2ki.

[itr224]

who replaced your clutch?
the knock sensor damage after a clutch change is a direct result of the mechanic who worked on your car.
i have had this problem with my knock sensor after the mecahnic changed my clutch and replaced the bearings in my gearbox.

check this thread and search on s2ki, alot of other owners have had the same problem after a clutch change.

http://www.s2ki.com/forums/index.php?showtopic=314157&st=0&#entry6056428

Quote from s2ki
the knock sensor is right above the starter bolt. When breaking loose the bolt if you are not careful you can hit the knock sensor and break it, which sounds like it's what happened.


here are a few more threads where other owners have had the same problem after a clutch change.

i would go back to the mechanic and make them cover it for you under warranty. a new knock sensor set me back $365 from honda.
http://www.s2ki.com/forums/index.php?showtopic=350861&st=0&#entry6807919

http://www.s2ki.com/forums/index.php?showtopic=221706&st=0&#entry4209900

[jenova]

itr224, who did the work for you?

[na]

thanks...that makes sense now...

[na]

update: brought it back to the workshop, checked it...the knock sensor is cracked...they agree to get it replaced FOC.

Problem is Honda dont have stock and have to order from Jpn and wait 3 weeks.

Just warn your mechanic abt this before your clutch change.

[aaronng]

:thumbsup: