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how to check ks

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Old 01-06-2008, 11:55 PM
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how to check ks

the knock sensor is not installed in the car, how do you check if its good or not?
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Old 01-07-2008, 01:06 AM
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Even better, from the STICKIES:
0304
Diagnostic Trouble Code 0304 points to a problem with the Knock Sensor. The KS is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is senses as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (The computer).

This malfunction is detected when an excessively high or low voltage from the KS is entered to the ECM. Possible causes include...
- the harness or connector (The KS circuit is open or shorted).
- the KS

The KS may be checked with an ohmmeter.

1) Raise the hood. View the engine from the driver's fender. Look into
the deep valley between the cylinder banks and below the intake manifold.
Identify the KS as a black item fastened to the block by a single vertical
bolt. A wire harness wrapped in black leads toward you, out of the valley.
That is the KS sub-harness.

2) Follow the KS sub-harness to it's nearest connector. This is connector F121.
It is located near the upper right-hand corner of the valve cover of the forward cylinder bank, as viewed from the front of the car.

3) Disconnect F121. You have to do a "press the latch and wiggle and
pull" to disconnect it. F121 has only two pins; if you see more than two
pins, you have the wrong connector. Use a digital ohmmeter capable of
measuring more than 10 Megohms. You want to measure the pins of F121, not
the sockets of the matching connector. Measure the resistance between a
good ground (such as the battery negative terminal) and pin #2 of connector
F121. On my car this is the highest of the two pins, the one closest to
the front of the car. The factory spec is 500 - 620 Kohms.


The manual says you have to remove the intake manifold to replace the KS. However, I think that a person with good dexterity and a 12mm ratcheting box wrench could replace the KS without disturbing the manifold.

Important note: the dealer can do a more thorough test with his CONSULT electronic tester. The resistance test described here is a useful but limited test. A Knock Sensor which fails this test is definitely bad. However, a KS which passes this test is not guaranteed to be good.

Last edited by pmohr; 01-07-2008 at 01:15 AM.
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Old 01-07-2008, 07:49 AM
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this write up is to check the one thats in the car already. i want to ckeck one that i got a hold of and want to test it before installing it. do i test it the same way as the one thats in the car already?
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Old 01-07-2008, 08:02 AM
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Ohm test.. You can do a search. Its one here somewhere.
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Old 01-07-2008, 08:48 AM
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Originally Posted by maxim82
this write up is to check the one thats in the car already. i want to ckeck one that i got a hold of and want to test it before installing it. do i test it the same way as the one thats in the car already?
Resistance is resistance. One lead on the correct terminal, the other to the bottom of the KS where it normally would touch the block.
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Old 01-07-2008, 09:01 AM
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in the past has anyone here seen a KS go bad without a CEL coming on?????
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Old 01-07-2008, 09:02 AM
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Originally Posted by crensign
in the past has anyone here seen a KS go bad without a CEL coming on?????
The KS code will never trip a CEL.
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