Neif

Argh! I checked my ECU today and found the dreaded 03 04 code: KS failure. I had this code about 20k miles ago, and replaced the KS. It can't possibly be the KS failing again, can it?

Can anything else trigger the KS failure code, besides the KS? I'd hate to put my hand through the valley of pain again...

chilled

Thats exactly what it is too, lol.

njmodi

iTrader: (4)

Check the harness and the ground points on the intake manifold.

Was 0304 the only code stored in the ECU?

NmexMAX

iTrader: (22)

for harness.

liqidvenom

iTrader: (6)

i think that we should always replace the harnes when we replace the sensor

Neif

Yeah, the only code was 0304. I take it the harness is what connects to the wires that lead up from the knock sensor out of the valley?

Dumb question, but is the KS harness just a generic harness or a specific part? I'm thinking I could get a harness from the dealership if it's a standard replacement part.

liqidvenom

iTrader: (6)

yep, but i would say buy the harnes and sensor as one and replace them both

NmexMAX

iTrader: (22)

It's a specific part .. 15$

MDeezy

iTrader: (27)

I agree with flamethrower, try chainng the harness reset and see if it comes back. If so then change the KS again and it shouldnt come back for a while with a new harness.

Fork

iTrader: (2)

I think we should perhaps put it in the FAQ with the knock sensor that when you replace the KS, replace it's harness too...

njmodi

iTrader: (4)

I still say check the grounds first.

You can check the harness for continuity very easily. No point replacing something that isn't bad.

Also be sure to clean out all the connectors/contacts on the harnesses involved, i.e. both ends of the short KS specific harness and the connector on the engine harness that it attaches to.

Neif

Thanks for all the advice -- sounds like first I should check and clean ground points and harness connectors.. if that doesn't work replace the harness.. if that doesn't work repalce the harness and KS again.

When checking the ground points, is there anything specific I can look out for?

njmodi

iTrader: (4)

Just undo both 10mm bolts, use a wire-brush to clean up the contact areas and bolt and refasten. Don't over tighten the bolts - they are soft and will shear easily.

Once you've cleaned the mounts, check the KS resistance.

If the resistance doesn't spec out, then pull the KS and harness out of the car and bench test both (KS for resistance, harness for continuity).

Replace whatever you diagnose as bad. I would be surprised (assuming you used a brand new OEM sensor) if your KS went bad in 20k. If you overtightened it, I suppose it could have cracked - so look for cracks if you end up pulling it out of the car.