unicoder

Hey!

95 S14 with RS Enthalpy Tune so s13 ECU - I am getting Code 34

1. I replaced my knock sensor with a new one
2. Volt meter to the ecu side harness is measuring 2.5V (found in this thread http://zilvia.net/f/showthread.php?t=113140)
3. While idling backprobing the signal wire of the knock sensor is 1.8v (shouldn't it be 2.5v while running, and 5v while not running?)

Since replacing it didn't resolve the code. I tried the resistor bypass, which also did not resolve the code.

Im getting voltage through the harness so I don't think theres an issue there.

But is there any way to test and know for sure it is the knock sensor? I also found while searching that a different issue all together can cause this code?

**UPDATE** I was able to resolve the issue while waiting for a reply here. So hopefully someone finds this and it helps them in the future.

1. Replaced Knock Sensor with cheap replacement, did not resolve issue.
2. You cannot test a KS to be "good", and you cannot check for a 5v reference voltage (confirmed in several threads, the FSM, and through Martin at RS Enthalpy)
3. Check continuity from the ECU (pin 27 for s13, i think 56 for s14) all the way to the harness connector where the KS plugs in. (I had good continuity)
4. Checked Coolant Temp Sensor and Alternator (IDK why, but they have several threads showing them as the culprit)
5 *Solution* Just spend the dang money and buy a real KS ~$105 - This resolved the issue for me after a lot of pain staking troubleshooting.

TIP: You can OHM a knock sensor (will read 560k ohms) but it is not a test that it is good, my bad one tested 560k ohms too. The piezo element is bound to a frequency you just cant reproduce by hand.

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